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Introduction: Chronic adolescent stress profoundly affects prefrontal cortical networks regulating top‐down behavior control. However, the neurobiological pathways contributing to stress‐induced alterations in the brain and behavior remain largely unknown. Chronic stress influences brain growth factors and immune responses, which may, in turn, disrupt the maturation and function of prefrontal cortical networks. The tumor necrosis factor alpha‐converting enzyme/a disintegrin and metalloproteinase 17 (TACE/ADAM17) is a sheddase with essential functions in brain maturation, behavior, and inflammatory responses. This study aimed to determine the impact of stress on the prefrontal cortex and whether TACE/ADAM17 plays a role in these responses. Methods: We used a Lewis rat model that incorporates critical elements of chronic psychosocial stress, such as uncontrollability, unpredictability, lack of social support, and re‐experiencing of trauma. Results: Chronic stress during adolescence reduced the acoustic startle reflex and social interactions while increasing extracellular free water content and TACE/ADAM17 mRNA levels in the medial prefrontal cortex. Chronic stress altered various ethological behavioral domains in the observation home cages (decreased ingestive behaviors and increased walking, grooming, and rearing behaviors). A group of rats was injected intracerebrally either with a novel Accell™ SMARTpool TACE/ADAM17 siRNA or a corresponding siRNA vehicle (control). The RNAscope Multiplex Fluorescent v2 Assay was used to visualize mRNA expression. Automated puncta quantification and analyses demonstrated that TACE/ADAM17 siRNA administration reduced TACE/ADAM17 mRNA levels in the medial prefrontal cortex (59% reduction relative to control). We found that the rats that received prefrontal cortical TACE/ADAM17 siRNA administration exhibited altered eating patterns (e.g., increased food intake and time in the feeding zone during the light cycle). Conclusion: This study supports that the prefrontal cortex is sensitive to adolescent chronic stress and suggests that TACE/ADAM17 may be involved in the brain responses to stress. [ABSTRACT FROM AUTHOR]

Meniere's disease (MD) is a disorder of the inner ear characterized by chronic episodes of vertigo, tinnitus, increased aural pressure, and sensorineural hearing loss. Causes of MD are unknown, but endolymphatic hydrops is a hallmark. In addition, 5%–15% of MD cases have been identified as familial. Whole‐genome sequencing studies of individuals with familial MD identified DTNA and FAM136A as candidate genes for autosomal dominant inheritance of MD. Although the exact roles of these genes in MD are unknown, FAM136A encodes a mitochondrial protein, and DTNA encodes a cytoskeletal protein involved in synapse formation and maintenance, important for maintaining the blood–brain barrier. It is also associated with a particular aquaporin. We tested vestibular and auditory function in dtna and fam136a knockout (KO) mice, using RotaRod and startle reflex‐based clicker tests, respectively. Three‐factor analysis of variance (ANOVA) results indicated that sex, age, and genotype were significantly correlated with reduced mean latencies to fall ("latencies") for male dtna KO mice, while only age was a significant factor for fam136a KO mice. Fam136a KO mice lost their hearing months before WTs (9–11 months vs. 15–20 months). In male dtna KO mice, divergence in mean latencies compared with other genotypes was first evident at 4 months of age, with older males having an even greater decrease. Our results indicate that fam136a gene mutations generate hearing problems, while dtna gene mutations produce balance deficits. Both mouse models should help to elucidate hearing loss and balance‐related symptoms associated with MD. [ABSTRACT FROM AUTHOR]

Summary: Despite the high number of studies based on subjective reports of snoring, self‐reported snoring has hardly been validated at all. As there is no "gold‐standard" for objective snoring measurements, studies must evaluate whether the presence of snoring based on parental judgement is linked to objective measurements of nasal and/or pharyngeal obstruction in children referred for obstructive sleep apnea. A total of 146 children (median age 11 years) underwent polysomnography (with snoring recording using nasal cannula signal), acoustic rhinometry and pharyngometry, while their parents filled out the Spruyt–Gozal questionnaire assessing both frequency and loudness of subjective snoring. Three categories were further differentiated (null, low and high) for both frequency and loudness. The apnea–hypopnea index was significantly different in the three groups for both frequency (p = 0.04) and loudness (p = 0.01) of subjective snoring. Children in the low or high groups (frequency or loudness), compared with those in the null group, experienced a decline in both pharyngeal (sitting and supine positions) and nasopharyngeal (supine position) volumes (frequency, pharynx sitting: p = 0.03; supine: 0.005 and nasopharynx: p = 0.002; loudness, p = 0.03; p = 0.007 and p = 0.03; three group comparisons). Objective snoring frequency during the night obtained with cannula was weakly related to loudness of subjective snoring but not to subjective snoring frequency during the week, and was biased by nasal obstruction. In conclusion, our study showed that parental assessment of snoring is related to a reduction in both pharyngeal and nasopharyngeal volumes in snorers, arguing for the adequacy of their evaluation of both snoring frequency and loudness. [ABSTRACT FROM AUTHOR]

Background: Microwave-induced thermoacoustic (TA) imaging (MTAI) is a promising alternative to biomedical imaging due to its high resolution, deep imaging depth, and minimal biohazard. To provide images of different anatomical regions and apply them to different clinical scenarios, the development of miniaturized portable TA probes is imperative. Purpose: This study is aimed to propose a highly efficient handheld nonreflective microwave-acoustic coaxial TA probe to advance the translation of MTAI for the clinical use. Methods: The TA probe integrates a hollowed microwave antenna with a forward radiating uniform microwave field and a linear ultrasonic transducer array which is placed in the hole in the middle of the antenna that has almost no effect on the microwave distribution. The integrated probe was evaluated for properties, including the excitation efficiency of the microwave and the reception efficiency of the acoustic signal. Finally, an isolated EMT6 cell tumor was embedded in a sheep mammary gland to simulate the natural breast tumor environment, and the tumor was detected with the proposed MTAI probe to evaluate its practical feasibility. Results: Compared with the previous TA imaging probe, it has improved the detection efficiency of TA signals by up to 41%, contributing to an improved signal-to-noise ratio (SNR) of the image. The proposed TA probe successfully detected tumors embedded in the breast with a contrast ratio 3.27 times higher than the surrounding tissue in phantom experiments. Conclusion: The proposed TA probe with the features of microwave illumination and ultrasonic detection of coaxial, avoiding TA signal attenuation due to reflection, enables high-efficient TA signal excitation and detection. The proposed TA probe is essential for improving the excitation and detection efficiency of TA signals, and increasing the flexibility of the probe, providing a bright future for the clinical application of MTAI technology [ABSTRACT FROM AUTHOR]

Autism spectrum disorder is a developmental disorder that can affect social interactions and sensory-motor behaviors. The present study investigates the effect of environmental enrichment (EE) on behavioral alterations and neuron responses associated with the barrel cortex of young adult female and male rats exposed prenatally to valproic acid (VPA). Pregnant female rats were pretreated with either saline or VPA (500 mg/kg, IP) on day 12.5 of gestation. Male and female pups were exposed to either EE or standard-setting (non-enrichment) conditions for 1 month (between postnatal day [PND] 30 and 63-65) and were divided into non-EE (control), EE, VPA, and VPA + EE groups. Three-chamber sociability and social novelty, acoustic startle reflex, and texture discrimination tests were conducted on PND 62. Responses of barrel cortex neurons of male pups were evaluated using the extracellular single-unit recording technique on PND 63-65. Results showed that the performance of rats of both sexes in social interactions, texture discrimination tasks, and acoustic startle reflex significantly decreased in the VPA groups compared with the control rats (P < 0.05). In this regard, EE attenuated the altered deficit performance observed in the VPA animals compared with the VPA-EE animals (P < 0.05). The performance of females was better than males in the discrimination tasks and acoustic startle reflex. In contrast, males were better than females in the three-chamber social interaction test. Additionally, the excitatory receptive field response magnitude of the barrel cortex neurons in the VPA + EE group increased compared with the VPA group (P < 0.05). The results suggest that continuous EE can attenuate cognitive function disturbances in autistic-like rats and, at least at the behavioral level, the effects depend on sex. [ABSTRACT FROM AUTHOR]

Uncertainty of threat has been linked to anxiety, but little is known about how neurophysiological responses change as uncertain threats approach and whether trait anxiety modulates these changes. The current study was designed to explore aspects of the dynamics of defensive motivation (startle reflex elicited by acoustic startle probes), attention (probe N100 component of event-related potentials elicited by acoustic startle probes), and autonomic nervous system activity (heart rate) when the approaching threat was certain or uncertain in a variant of the threat probability task. Behavioral results showed that high-trait anxious individuals reported higher levels of anxiety than low-trait anxious individuals only under the uncertain threat condition. Electromyographic data showed that high-trait anxious individuals tended to produce a more pronounced startle reflex, especially when the uncertain threat was proximal. This pattern was not observed in low-trait anxious individuals. By examining early attention engagement through probe N100, we observed a similar pattern in relation to defensive motivation. Moreover, under the uncertain threat condition, high-trait anxious individuals yielded a greater deceleration of heart rate than low-trait anxious individuals. These results indicate a distinct modulation effect of trait anxiety in the dynamics of defensive motivation, attention, and the autonomic nervous system during the anticipation of uncertain threats. [ABSTRACT FROM AUTHOR]

Optoacoustic mesoscopy (OAM) retrieves anatomical and functional contrast in vivo at depths not resolvable with optical microscopy. Recent progress on reconstruction algorithms have further advanced its imaging performance to provide high lateral resolution ultimately limited by acoustic diffraction. In this work, a new broadband model‐based OAM (MB‐OAM) framework efficiently exploiting scanning symmetries for an enhanced performance is presented. By capitalizing on the large detection bandwidth of a spherical polyvinylidene difluoride film while accurately accounting for its spatial impulse response, the new approach significantly outperforms standard OAM implementations in terms of contrast and resolution, as validated by functional in vivo experiments in mice and human volunteers. Furthermore, L1‐norm regularization enables resolving structures separated by less than the theoretical diffraction‐limited resolution. This unique label‐free angiographic performance demonstrates the general applicability of MB‐OAM as a super‐resolution deep‐tissue imaging method capable of breaking through the limits imposed by acoustic diffraction. [ABSTRACT FROM AUTHOR]

Mutations affecting DLG2 are emerging as a genetic risk factor associated with neurodevelopmental psychiatric disorders including schizophrenia, autism spectrum disorder, and bipolar disorder. Discs large homolog 2 (DLG2) is a member of the membrane‐associated guanylate kinase protein superfamily of scaffold proteins, a component of the post‐synaptic density in excitatory neurons and regulator of synaptic function and plasticity. It remains an important question whether and how haploinsuffiency of DLG2 contributes to impairments in basic behavioural and cognitive functions that may underlie symptomatic domains in patients that cross diagnostic boundaries. Using a heterozygous Dlg2 mouse model we examined the impact of reduced Dlg2 expression on functions commonly impaired in neurodevelopmental psychiatric disorders including motor co‐ordination and learning, pre‐pulse inhibition and habituation to novel stimuli. The heterozygous Dlg2 mice exhibited behavioural impairments in long‐term motor learning and long‐term habituation to a novel context, but not motor co‐ordination, initial responses to a novel context, PPI of acoustic startle or anxiety. We additionally showed evidence for the reduced regulation of the synaptic plasticity‐associated protein cFos in the motor cortex during motor learning. The sensitivity of selective behavioural and cognitive functions, particularly those dependent on synaptic plasticity, to reduced expression of DLG2 give further credence for DLG2 playing a critical role in specific brain functions but also a mechanistic understanding of symptom expression shared across psychiatric disorders. [ABSTRACT FROM AUTHOR]

Purpose: Focused ultrasound (FUS) is a promising tool to develop new modalities of therapeutic neurostimulation. The ability of FUS to stimulate the nervous system, in a noninvasive and spatiotemporally precise manner, has been demonstrated in animals and human subjects, but the underlying biomechanisms are not fully understood yet. The objective of the present study was to investigate the bioeffects involved in the generation of trains of action potentials (APs) by repetitive‐pulse FUS stimuli in a simple invertebrate neural model. Methods: The respective influences of different acoustic parameters on the neurostimulation success rate (NSR), defined as the rate of FUS stimuli capable of evoking at least one AP, were explored using the system of afferent nerves and giant fibers of Lumbricus terrestris as neural model. Each parameter was studied independently by administering random FUS sequences while keeping all but one FUS parameter constant. The NSR was evaluated as a function of (i) the spatial‐average pulse‐average intensity (Isapa); (ii) the pulse duration (PD); (iii) the pulse repetition frequency (PRF); iv) the number of cycles per pulse (Ncycles); (v) two ultrasound frequencies, f0 = 1.1 MHz and f3 = 3.3 MHz, corresponding to the fundamental and third‐harmonic resonant frequencies of the FUS transducer, respectively (spherical, radius of curvature: 50 mm); and (vi) levels of emerging stable cavitation and inertial cavitation. Results: The NSR associated to 1.1 MHz repetitive‐pulse FUS stimuli was found to increase as a function of increasing Isapa, PD, PRF, and Ncycles. When evaluating each parameter at f = 1.1 MHz, it was observed that NSRs close to 100% were achieved when sufficiently elevating their respective values. When computing the NSR as a function of the spatial‐average, temporal‐average intensity (Isata), defined as the product of PRF, PD, and Isapa, a significant elevation of the NSR from 0% to close to 100% was measured by increasing Isata from values approximate to 4 W/cm2 to values higher than 12 W/cm2. No clear and consistent trend was observed in trials aimed at exploring the effects of different levels of stable and inertial acoustic cavitation on the NSR. Finally, the feasibility of inducing neural responses with 3.3 MHz repetitive‐pulse FUS stimuli was also demonstrated with NSRs reaching up to 60%, in the range of FUS parameters studied. Conclusion: The time‐averaged value of the radiation force per unit volume of tissue is proportional to the acoustic intensity. As a result, the observations from this study suggest that the neural structure responding to the stimulus is sensitive to the mean radiation force carried by the FUS sequence, regardless of the combination of FUS parameters giving rise to such force. The results from this study further revealed the existence of a minimal activation threshold with regard to Isapa. [ABSTRACT FROM AUTHOR]

Among mesoplodonts recorded in the North Pacific, the tooth size and location in the adult male in the Baja whale most closely resembles that of the ginkgo-toothed beaked whale ( I M. ginkgodens i ) and the recently recognized Deraniyagala's beaked whale ( I M. hotaula i ; Dalebout et al., 2014). Three new species of beaked whales (Ziphiidae) have been described in the past three decades: the pygmy beaked whale ( I Mesoplodon peruvianus i ; Reyes et al. 1991), Perrin's beaked whale ( I Mesoplodon perrini i ; Dalebout et al. 2002), and Sato's beaked whale ( I Berardius minimus i ; Yamada et al. 2019). Perrin's beaked whale has never been identified alive and was discovered accidentally through genetic analysis of stranded whales in California that had been misidentified as Hector's beaked whale ( I Mesoplodon hectori i ; Dalebout et al. 2002). Previous acoustic studies characterized a unique beaked whale echolocation signal (called BW43) that, based on its limited distribution off southern California, was believed to be made by Perrin's beaked whale (Baumann-Pickering et al., 2013). [Extracted from the article]

The relative contributions of adaptation and genetic drift to morphological diversification of the skulls of echolocating mammals were investigated using two horseshoe bat species, Rhinolophus simulator and R. cf. simulator, as test cases. We used 3D geometric morphometrics to compare the shapes of skulls of the two lineages collected at various localities in southern Africa. Size and shape variation was predominantly attributed to selective forces; the between-population variance (B) was not proportional to the within-population variance (W). Modularity was evident in the crania of R. simulator but absent in the crania of R. cf. simulator and the mandibles of both species. The skulls of the two lineages thus appeared to be under different selection pressures, despite the overlap in their distributions. Difference in the crania of R. cf. simulator was centered largely on the nasal dome region of R. cf. simulator but on the cranium and mandibles of R. simulator. It is likely that the size and shape of the nasal dome, which acts as a frequency-dependent acoustic horn, is more crucial in R. cf. simulator than in R. simulator because of the higher echolocation frequencies used by R. cf. simulator. A larger nasal dome in R. cf. simulator would allow the emission of higher intensity pulses, resulting in comparable detection distances to that of R. simulator. In contrast, selection pressure is probably more pronounced on the mandibles and cranium of R. simulator to compensate for the loss in bite force because of its elongated rostrum. The predominance of selection probably reflects the stringent association between environment and the optimal functioning of phenotypic characters associated with echolocation and feeding in bats. [ABSTRACT FROM AUTHOR]

Progressive Supranuclear Palsy (PSP) is the most common atypical parkinsonism and exhibits hallmark symptomology including motor function impairment and dysexecutive dementia. In contrast to Parkinson's disease, the underlying pathology displays aggregation of the protein tau, which is also seen in disorders such as Alzheimer's disease. Currently, there are no pharmacological treatments for PSP, and drug discovery efforts are hindered by the lack of an animal model specific to PSP. Based on previous results and clinical pathology, it was hypothesized that viral deposition of tau in cholinergic neurons within the hindbrain would produce a tauopathy along neural connections to produce PSP‐like symptomology and pathology. By using a combination of ChAT‐CRE rats and CRE‐dependent AAV vectors, wildtype human tau (the PSP‐relevant 1N4R isoform; hTau) was expressed in hindbrain cholinergic neurons. Compared to control subjects (GFP), rats with tau expression displayed deficits in a variety of behavioural paradigms: acoustic startle reflex, marble burying, horizontal ladder and hindlimb motor reflex. Postmortem, the hTau rats had significantly reduced number of cholinergic pedunculopontine tegmentum and dopaminergic substantia nigra neurons, as well as abnormal tau deposits. This preclinical model has multiple points of convergence with the clinical features of PSP, some of which distinguish between PSP and Parkinson's disease. [ABSTRACT FROM AUTHOR]

Teleost fishes occupy a range of ecosystem, and habitat types subject to large seasonal fluctuations. Temperate fishes, in particular, survive large seasonal shifts in temperature, light availability, and access to certain habitats. Mobile species such as lake trout (Salvelinus namaycush) can behaviorally respond to seasonal variation by shifting their habitat deeper and further offshore in response to warmer surface water temperatures during the summer. During cooler seasons, the use of more structurally complex nearshore zones by lake trout could increase cognitive demands and potentially result in a larger relative brain size during those periods. Yet, there is limited understanding of how such behavioral responses to a seasonally shifting environment might shape, or be shaped by, the nervous system.Here, we quantified variation in relative brain size and the size of five externally visible brain regions in lake trout, across six consecutive seasons in two different lakes. Acoustic telemetry data from one of our study lakes were collected during the study period from a different subset of individuals and used to infer relationships between brain size and seasonal behaviors (habitat use and movement rate).Our results indicated that lake trout relative brain size was larger in the fall and winter compared with the spring and summer in both lakes. Larger brains coincided with increased use of nearshore habitats and increased horizontal movement rates in the fall and winter based on acoustic telemetry. The telencephalon followed the same pattern as whole brain size, while the other brain regions (cerebellum, optic tectum, olfactory bulbs, and hypothalamus) were only smaller in the spring.These findings provide evidence that flexibility in brain size could underpin shifts in behavior, which could potentially subserve functions associated with differential habitat use during cold and warm seasons and allow fish to succeed in seasonally variable environments. [ABSTRACT FROM AUTHOR]

The endocannabinoid system is an important regulator of the hormonal and behavioral stress responses, which critically involve corticotropin‐releasing factor (CRF) and its receptors. While it has been shown that CRF and the cannabinoid type 1 (CB1) receptor are co‐localized in several brain regions, the physiological relevance of this co‐expression remains unclear. Using double in situ hybridization, we confirmed co‐localization in the piriform cortex, the lateral hypothalamic area, the paraventricular nucleus, and the Barrington's nucleus, albeit at low levels. To study the behavioral and physiological implications of this co‐expression, we generated a conditional knockout mouse line that selectively lacks the expression of CB1 receptors in CRF neurons. We found no effects on fear and anxiety‐related behaviors under basal conditions nor after a traumatic experience. Additionally, plasma corticosterone levels were unaffected at baseline and after restraint stress. Only acoustic startle responses were significantly enhanced in male, but not female, knockout mice. Taken together, the consequences of depleting CB1 in CRF‐positive neurons caused a confined hyperarousal phenotype in a sex‐dependent manner. The current results suggest that the important interplay between the central endocannabinoid and CRF systems in regulating the organism's stress response is predominantly taking place at the level of CRF receptor‐expressing neurons. [ABSTRACT FROM AUTHOR]

The Gap Prepulse Inhibition of the Acoustic Startle Reflex (GPIAS) is a paradigm used to assess auditory temporal processing in both animals and humans. It consists of the presentation of a silent gap embedded in noise and presented a few milliseconds before a startle sound. The silent gap produces the inhibition of the startle reflex, a phenomenon called gap‐prepulse inhibition (GPI). This paradigm is also used to detect tinnitus in animal models. The lack of inhibition by the silent gaps is suggested to be indicative of the presence of tinnitus "filling‐in" the gaps. The current research aims at improving the GPIAS technique by comparing the GPI produced by monaural versus binaural silent gaps in 29 normal‐hearing subjects. Two gap durations (5 or 50 ms), each embedded in two different frequency backgrounds (centered around 500 or 4 kHz). Both low‐ and high‐ frequency narrowband noises had a bandwidth of half an octave. Overall, the startle magnitude was greater for the binaural versus the monaural presentation, which might reflect binaural loudness summation. In addition, the GPI was similar between the monaural and the binaural presentations for the high‐frequency background noise. However, the GPI was greater for the low‐frequency background noise for the binaural, compared to the monaural, presentation. These findings suggest that monaural GPIAS might be more suited to detect tinnitus compared to the binaural presentation. Our research unveils the unexpected importance of background noise frequency between the monaural and binaural presentation of stimuli to elicit the Gap‐prepulse inhibition of the Acoustic Startle Reflex (GPIAS). Our findings suggest that monaural presentation of stimuli might be better suited to detect the presence of tinnitus, both in animals and in humans. [ABSTRACT FROM AUTHOR]

Background and Purpose: Dysfunction of the prefrontal cortex (PFC) is involved in the cognitive deficits in neuropsychiatric diseases, such as schizophrenia, characterized by deficient neurotransmission known as NMDA receptor hypofrontality. Thus, enhancing prefrontal activity may alleviate hypofrontality‐induced cognitive deficits. To test this hypothesis, we investigated the effect of forebrain‐specific suppression or pharmacological inhibition of native Kv7/KCNQ/M‐current on glutamatergic hypofrontality induced by the NMDA receptor antagonist MK‐801. Experimental Approach The forebrain‐specific inhibition of native M‐current was generated by transgenic expression, in mice, of a dominant‐negative pore mutant G279S of Kv7.2/KCNQ2 channels that suppresses channel function. A mouse model of cognitive impairment was established by single i.p. injection of 0.1 mg·kg−1 MK‐801. Mouse models of prepulse inhibition (PPI) of acoustic startle reflex and Y‐maze spontaneous alternation test were used for evaluation of cognitive behaviour. Hippocampal brain slice recordings of LTP were used to assess synaptic plasticity. Hippocampus and cortex were dissected for detecting protein expression using western blot analysis. Key Results: Genetic suppression of Kv7 channel function in the forebrain or pharmacological inhibition of Kv7 channels by the specific blocker XE991 enhanced PPI and also alleviated MK‐801 induced cognitive decline. XE991 also attenuated MK‐801‐induced LTP deficits and increased basal synaptic transmissions. Western blot analysis revealed that inhibiting Kv7 channels resulted in elevation of pAkt1 and pGSK‐3β expressions in both hippocampus and cortex. Conclusions and Implications: Both genetic and pharmacological inhibition of Kv7 channels alleviated PPI and cognitive deficits. Mechanistically, inhibition of Kv7 channels promotes synaptic transmission and activates Akt1/GSK‐3β signalling. [ABSTRACT FROM AUTHOR]

Adolescence is a remarkable period of brain development. Prenatal stress can increase the risk of various neuropsychiatric disorders. This research investigated neurochemical and behavioural changes in the offspring rats (especially adolescences) who were treated with repeated variable prenatal stress (PNS) during the third week of gestation. The study tested the concentration of brain‐derived neurotrophic factor (BDNF), cluster of differentiation 68 (CD68), synaptotagmin‐1(Syt‐1), 5‐hydroxytryptamine (5‐HT), dopamine (DA), glucocorticoid receptors (GRs) and oestrogen receptors (ERs) in the PFC (prefrontal cortex). We also tested prepulse inhibition (PPI) of the acoustic startle reflex (ASR) (a measure of sensorimotor gating). The main results were as follows: PNS increased the BDNF and CD68 concentrations in adolescent females, and increased the Syt‐1 concentration in adolescent males. The increases in BDNF/CD68 concentration (in females) and Syt‐1/DA concentration (in males) with age were disturbed by PNS, and PNS changed the sex differences in CD68 concentration in adolescence and disturbed the sex differences in the Syt‐1 concentration (in adolescence) and DA concentration (in adults). In conclusion, we found that PNS lead to Sex‐dependent aberrant PFC development, and might accelerate the development of the adolescent PFC, and so that lessened the age difference (between adolescence and adulthood) and the sex difference. [ABSTRACT FROM AUTHOR]

Background: Functional brain imaging has been used to study brain reward function and behavioral traits in anorexia nervosa (AN). Here we tested whether eye blink relates to behavior and brain imaging response as a method that is less costly and more accessible. Method: We recruited 26 women with AN and 50 healthy matched controls. All underwent a reward‐learning prediction error task during functional magnetic resonance imaging. In addition, eye blink was measured for spontaneous blink rate, baseline blink amplitude, and startle response to an auditory stimulus. Results: Baseline blink rate, amplitude and startle response were similar between groups. In AN, there were significant positive correlations between spontaneous blink rate and bulimia symptoms, and baseline blink amplitude and prediction error response in right‐sided caudate, insula, and nucleus accumbens. Correlations between eye blink measures and body dissatisfaction or harm avoidance were no longer significant after multiple comparison adjustments. Discussion This study provides evidence that measures of eye blink response can be related to brain prediction error response and eating disorder behavior in AN. The catecholamine dopamine contributes to both eye blink and prediction error response providing indirect evidence that it could be a neurobiological correlate that contributes to behaviors relevant to AN. [ABSTRACT FROM AUTHOR]

Objective: The aim was to demonstrate that antibodies from patients with anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis alter the levels of dopamine 1 receptor (D1R) and dopamine 2 receptor (D2R) and cause psychotic-like features in mice.Methods: Cultured rat hippocampal neurons were treated with cerebrospinal fluid (CSF) from patients with anti-NMDAR encephalitis or controls, and the effects on clusters of D1R and D2R were quantified. In vivo studies included 71 C57BL/6J mice that were chronically infused with CSF from patients or controls through ventricular catheters connected to subcutaneous osmotic pumps. Prepulse inhibition of the acoustic startling reflex (PPI; a marker of psychotic-like behavior), memory, locomotor activity, and the density of cell-surface and synaptic D1R, D2R, and NMDAR clusters were examined at different time points using reported techniques.Results: In cultured neurons, CSF from patients, but not from controls, caused a significant decrease of cell-surface D1R and an increase of D2R clusters. In mice, CSF from patients caused a significant decrease of synaptic and total cell-surface D1R clusters and an increase of D2R clusters associated with a decrease of PPI. These effects were accompanied by memory impairment and a reduction of surface NMDARs, as reported in this model. The psychotic-like features, memory impairment, and changes in levels of D1R, D2R, and NMDAR progressively improved several days after the infusion of CSF from patients stopped.Interpretation: In addition to memory deficits and reduction of NMDARs, CSF antibodies from patients with anti-NMDAR encephalitis cause reversible psychotic-like features accompanied by changes (D1R decrease, D2R increase) in cell-surface dopamine receptor clusters. ANN NEUROL 2020 ANN NEUROL 2020;88:603-613. [ABSTRACT FROM AUTHOR]

Neuroplasticity - the capacity of the brain to change as a response to internal and external pressures - has been studied from a number of different perspectives. Perhaps one of the most powerful models is the study of populations that have been congenitally deprived of a sense. It has been shown that the right Auditory Cortex ( AC) of congenitally deaf humans is neuroplastically modified in order to represent visual properties of a stimulus. One unresolved question is how this visual information is routed to the AC of congenitally deaf individuals. Here, we performed volumetric analysis of subcortical auditory and visual brains regions - namely the thalamus (along with three thalamic nuclei: the pulvinar, the lateral geniculate nucleus and the medial geniculate nucleus), and the inferior and superior colliculi - in deaf and hearing participants in order to identify which structures may be responsible for relaying visual information toward the altered AC. Because there is a hemispheric asymmetry in the neuroplastic changes observed in the AC of the congenitally deaf, we reasoned that subcortical structures that also showed a similar asymmetry in their total volume could have been enlisted in the effort of relaying visual information to the neuroplastically altered right AC. We show that for deaf, but not for hearing individuals, the right thalamus, right lateral geniculate nucleus and right inferior colliculus are larger than their left counterparts. These results suggest that these subcortical structures may be responsible for rerouting visual information to the AC in congenital deafness. [ABSTRACT FROM AUTHOR]

Objective: This study examines the effectiveness of acoustic reflexes in screening for third window disorders (eg, superior semicircular canal dehiscence) prior to middle ear exploration for conductive hearing loss.Study Design: Case series with chart review.Setting: Outpatient tertiary otology center.Subjects and Methods: A review was performed of 212 ears with acoustic reflexes, performed as part of the evaluation of conductive hearing loss in patients without evidence of chronic otitis media. The etiology of hearing loss was determined from intraoperative findings and computed tomography imaging. The relationship between acoustic reflexes and conductive hearing loss etiology was assessed.Results: Eighty-eight percent of ears (166 of 189) demonstrating absence of all acoustic reflexes had an ossicular etiology of conductive hearing loss. Fifty-two percent of ears (12 of 23) with at least 1 detectable acoustic reflex had a nonossicular etiology. The positive and negative predictive values for an ossicular etiology were 89% and 57% when acoustic reflexes were used alone for screening, 89% and 39% when third window symptoms were used alone, and 94% and 71% when reflexes and symptoms were used together, respectively.Conclusion: Acoustic reflex testing is an effective means of screening for third window disorders in patients with a conductive hearing loss. Questioning for third window symptoms should complement screening. The detection of even 1 acoustic reflex or third window symptom (regardless of reflex status) should prompt further workup prior to middle ear exploration. [ABSTRACT FROM AUTHOR]

It is increasingly well established that music containing an isochronous pulse elicits motor responses at the levels of both brain and behavior. Such motor responses are often used in pedagogical and clinical practice to induce movement, particularly where motor functions are impaired. However, the complex nature of such apparently universal human responses has, arguably, not received adequate research attention to date. In particular, it should be noted that many adults, including those with disabilities, find it somewhat difficult to synchronize their movements with a beat with perfect accuracy; indeed, perfecting the skill of being musically 'in time' can take years of training during childhood. Further research is needed on the nature of both the specificity and range of motor responses that can arise from the perception of a steady auditory pulse, with different populations, musical stimuli, conditions, and required levels of accuracy in order to better understand and capture the potential value of the musical beat as a pedagogical and therapeutic tool. [ABSTRACT FROM AUTHOR]

The article investigates the somatosensory representation of the middle ear in several normal hearing subjects. The researchers found representation of tympanic membrane movements in the postcentral gyrus in Brodmann area 43 (BA 43). They concluded that at least part of this area conveys pure somatosensory information.

The aim of the present study was to simultaneously measure and compare intermodal attention effects in event-related brain potentials (ERPs) and auditory steady-state responses (ASSRs). For this purpose, 40-Hz amplitude modulated tones and a visual fixation cross were presented concurrently. By means of target detection tasks either on the sounds or on the fixation cross, participants' attention was directed to the respective modality. Attended sounds elicited a negative difference (Nd) in the ERP relative to unattended sounds. Nd was divided into an early and a late part as often observed for intramodal attention. Moreover, attention to the sounds led to a significant enhancement of the ASSR. This modulation of the ASSR by intermodal attention is demonstrated for the first time in the EEG. The present data suggest that ASSRs could provide a useful tool for the investigation of the neural dynamics of intermodal attentional processes. [ABSTRACT FROM AUTHOR]

Cortical auditory evoked potentials of instrumental musicians suggest that music expertise modifies pitch processing, yet less is known about vocal musicians. Mismatch negativity (MMN) to pitch deviances and difference limen for frequency (DLF) were examined among 61 young adult women, including 20 vocalists, 21 instrumentalists, and 20 nonmusicians. Stimuli were harmonic tone complexes from the mid-female vocal range (C4–G4). MMN was elicited by multideviant paradigm. DLF was obtained by an adaptive psychophysical paradigm. Musicians detected pitch changes earlier and DLFs were 50% smaller than nonmusicians. Both vocal and instrumental musicians possess superior sensory-memory representations for acoustic parameters. Vocal musicians with instrumental training appear to have an auditory neural advantage over instrumental or vocal only musicians. An incidental finding reveals P3a as a sensitive index of music expertise. [ABSTRACT FROM AUTHOR]

Prepulse inhibition and the suppression of reflexive saccades on the antisaccade task are thought to tap inhibitory function. Reports of a lack of association between these measures suggest that they reflect different facets of inhibition. This study aimed to reexamine this relationship in a large sample and investigate the association of prepulse inhibition with oculomotor tasks that require inhibition of a reflexive saccade with lower concurrent processing demands than antisaccades, namely the oculomotor delayed response and fixation with distractors tasks. One hundred and seven healthy volunteers took part. Prepulse inhibition was uncorrelated with oculomotor performance. The error rate was highest for antisaccades, intermediate for the delayed response task, and lowest for fixation with distractors, and was correlated across tasks. These findings provide no evidence of a relationship between prepulse inhibition and oculomotor inhibition. Failure in suppressing reflexive saccades toward a peripheral target may represent a common inhibitory component underlying these oculomotor tasks. [ABSTRACT FROM AUTHOR]

Using a push-button device, we investigated whether visual or auditory response time would increase with increasing sedation, and assessed the responsiveness score of the Observer's Assessment of Alertness/Sedation (OAA/S) scale at the point of first loss of response to visual or auditory stimulation. In experiment 1 we applied visual and auditory stimulation to 19 patients as the propofol target plasma concentration (CPT) was increased to determine whether the visual or auditory response would be lost first. Thirty patients were each then infused with propofol, starting at a CPT of 0.3 µg ml−1 and increasing by increments of 0.2 µg ml−1, during which visual (experiment 2) or auditory (experiment 3) stimulation was applied when the effect-site concentration (CE) of propofol reached CPT. Visual response time (VRT), auditory response time (ART), CE and total amounts of propofol, and OAA/S score at the first loss of visual/auditory response were measured. Visual response disappeared earlier than auditory response in 84.2% of the patients. Visual response time and ART were linearly prolonged as the CE of propofol increased. The CE and total amounts of propofol at the first loss of visual response were 1.2 ± 0.4 µg ml−1 and 57.9 ± 16.7 mg, compared with 1.4 ± 0.5 µg ml−1 and 71.6 ± 26.1 mg, respectively, at the first loss of auditory response. The median (range) OAA/S scores at the first loss of visual and auditory response were 4 (3–4) and 3 (2–4), respectively. VRT and ART were linearly prolonged with increasing sedation. Visual response may be useful in monitoring conscious sedation. [ABSTRACT FROM AUTHOR]

BACKGROUND: The high rate of comorbidity between alcoholism and anxiety disorders suggests some causal link. This study used the startle reflex to investigate whether increased reactivity to stimuli inducing fear or related affective states might be one mechanism by which a family genetic risk promotes the development of alcohol use disorders. METHODS: Thirty-one sons of alcoholics (PH+) were recruited from the participants of a longitudinal epidemiologic survey representative of the Munich area population between 18 and 25 years. Thirty male low-risk participants without parental alcoholism (PH''') were matched for age and history of psychiatric disorders. The baseline acoustic startle reflex was elicited before and after subjects drank 0.6 g/kg ethanol or placebo in a randomized, double-blind, placebo-controlled crossover design. Thereafter, the startle response was investigated while the subjects''' affective state was manipulated by announcement of aversive electric finger stimuli to induce fear potentiation and by presentation of photographic slides previously rated to be pleasant, unpleasant, or neutral in their emotional valence. RESULTS: Plain startle response was lower in PH+ than PH''' participants and was equally dampened by alcohol in PH+ and PH''' subjects. Threat of finger shocks increased the startle response to the same extent in both groups. This fear potentiation effect was significantly attenuated by alcohol given on the second experimental day but not if alcohol was administered first and placebo on the second day. Pleasant and unpleasant slides decreased and increased startle response, respectively, and this effect was influenced by neither risk group nor alcohol. CONCLUSIONS: The acoustic startle reflex seems to be reduced in sons of alcoholics. The nonsignificant results during startle modification do not support the concept of increased reactivity to anxiety-related environmental stimuli as a mechanism promoting alcohol use disorders in subjects at increased family genetic risk for alcoholism. [ABSTRACT FROM AUTHOR]

We carried out a prospective study to analyze the diagnostic potential of acoustic startle reflex (ASR), acoustic blink reflex (ABR) and electro-oculography (EOG) in early stages of atypical parkinsonian syndrome. The study was carried out in a consecutive series of 41 patients clinically diagnosed as atypical parkinsonism (mean time from first symptoms of 38 months and follow-up of 26 months). The three procedures were carried out immediately after the first clinical evaluation. ASR and ABR were elicited by auditory stimuli while the patient was attending to a simple reaction time task. Outcome measures were: ASR (absence/presence, latency), ABR (absence/presence, latency) and EOG (suggestive/not suggestive of progressive supranuclear palsy [PSP]). Final clinical diagnosis was carried out by two neurologists blind to the neurophysiological results. A study of diagnostic sensitivity and odds ratio (OR) calculation for the PSP diagnosis was carried out. Neurophysiological examination showed the following sensitivity/specificity (%) for the diagnosis of PSP: ASR: 100/89; ABR 85/89; EOG 100/72. OR values were: ASR: 0.011; ABR: 0.037; EOG: 0.038. The three tests taken simultaneously showed a sensitivity of 100% and a specificity of 95%. The three neurophysiological tests investigated provided sensitive and specific measures with predictor value in early stages of atypical parkinsonian syndrome. © 2003 Movement Disorder Society [ABSTRACT FROM AUTHOR]

The cochlear root neurons (CRNs) are thought to mediate the auditory startle reflex (ASR) in the rat, which is widely used as a behavioral model for the investigation of the sensorimotor integration. CRNs project, among other targets, to the nucleus reticularis pontis caudalis (PnC), a major component of the ASR circuit, but little is known about the organization of this projection. Thus, we injected biotinylated dextran amine (BDA) in CRNs to study their projections with light and electron microscopy. Also, we performed double-labeling experiments, injecting BDA in the CRNs and subunit B of the cholera toxin or Fluorogold in the spinal cord to verify that CRNs project onto reticulospinal neurons. Electron microscopy of the labeled CRNs axons and terminals showed that even their most central and thinnest processes are myelinated. Most of the terminals are axodendritic, with multiple asymmetric synapses, and contain round vesicles (50 nm diameter). Double-labeling experiments demonstrated that CRN terminals are apposed to retrogradely labeled reticulospinal neurons in the contralateral nucleus reticularis PnC and bilaterally in the lateral paragigantocellular nucleus. Analyses of serial sections revealed that multiple CRNs synapse on single reticulospinal neurons in PnC, suggesting a convergence of auditory information. The morphometric features of these neurons classify them as giant neurons. This study confirms that CRNs project directly onto reticulospinal neurons and presents other anatomical features of the CRNs that contribute to a better understanding of the circuitry of the ASR in the rat. J. Comp. Neurol. 460:80–93, 2003. © 2003 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

In the present study we investigated the relationship between detecting violations of structural regularities of tone sequences and detecting deviations from temporal regularities or repetitive spectral auditory stimulus features. Twelve subjects were presented with randomized sequences of two tones (differing both in frequency and intensity) delivered alternately to the left and right ears at a constant stimulus onset asynchrony (SOA). In separate blocks, occasional deviant stimuli broke one, two, or three of the following regularities: spatial alternation, the constancy of SOA, or the dominant frequency-intensity conjunctions. Unlike the mismatch negativity (MMN) elicited by alternation-plus-SOA deviants, the MMN elicited by alternation-plus-conjunction deviants was approximately equal to the sum of the two corresponding single-deviant MMNs. These results suggest that the preattentive change-detection system processes infrequent violations of the structural regularities of sound sequences together with changes in temporal regularities, but separately from changes in repetitive spectral sound features. The MMN elicited by the triple-deviant stimuli corroborated these conclusions. [ABSTRACT FROM AUTHOR]

In two experiments we investigated the effect of generalized orienting induced by changing the modality of the lead stimulus on the modulation of blink reflexes elicited by acoustic stimuli. In Experiment 1 (n = 32), participants were presented with acoustic or visual change stimuli after habituation training with tactile lead stimuli. In Experiment 2 (n = 64), modality of the lead stimulus (acoustic vs. visual) was crossed with experimental condition (change vs. no change). Lead stimulus change resulted in increased electrodermal orienting in both experiments. Blink latency shortening and blink magnitude facilitation increased from habituation to change trials regardless of whether the change stimulus was presented in the same or in a different modality as the reflex-eliciting stimulus. These results are not consistent with modality-specific accounts of attentional startle modulation. [ABSTRACT FROM AUTHOR]

In this study, we tested whether a variation in an acoustic property of the target object or in the familiarity of the partner through a variation in the duration of social contact before demonstration elicits a variation in 9-month-old infants' imitation. Results showed that infants' imitation was .facilitated by the presence of a sound but was not enhanced by an increase in the familiarity of the model. [ABSTRACT FROM AUTHOR]

The bandwidth for the recording of the orbicularis oculi blink reflex electromyogram (EMG) response is optimal when low-frequency artifacts, such as motion artifacts and cross-talk from other muscles, are maximally suppressed, whereas true EMG signal power is maximally retained. The optimal bandwidth was investigated for acoustic, electrocutaneous, and photic blink reflexes. Reflexes were recorded with varying bandwidth and interelectrode distances of 12 and 36 mm. Power spectra of the EMG signals were calculated and compared with a theoretical spectrum of the uncontaminated EMG signal. For both electrode distances, the optimal bandwidth was on the average 28–500 Hz for acoustic and electrocutaneous blink reflexes and 12–500 Hz for photic blinks. Using photic stimuli, however, a high-pass filter frequency larger than 12 Hz (probably at least 30 Hz) in combination with occlusion of the eye will be necessary to avoid influences of retinal potentials. Given the optimal bandwidth, a larger electrode spacing may be expected to moderately improve the detectability of small blinks in all stimulus conditions. [ABSTRACT FROM AUTHOR]

The eyeblink component of the startle response to acoustic probes was measured while subjects smelled pleasant odors, unpleasant odors, or no odor. Peak electromyogram (EMG) 20-90 ms after probe onset was greater during unpleasant than during no odor conditions; EMGs for pleasant odors did not differ from those for no odor. Base tension in orbicularis oculi muscles was also higher during unpleasant odors. The results for unpleasant odors parallel those found in previous studies that have used a variety of methods for producing negatively valenced experiences. The results for pleasant odors diverge from those of most previous studies, which have found startle attenuation during positively valenced experiences. However, the results may be compatible with the suggestion (Lang, Bradley, & Cuthbert, 1992) that the motivational state that modulates startle involves both valence and arousal. Pleasant odors may require appropriate contexts to produce the positive motivational state required for startle attenuation. [ABSTRACT FROM AUTHOR]

Selective attention effects on reflexes and evoked potentials are reviewed with the aim of evaluating three theories regarding sensory automaticity. (a) The peripheral-gating theory, which assumes that ignored stimuli can be filtered out soon after transduction, was tentatively rejected because neither auditory-nerve nor retinal potentials are reliably affected by attention. (b) At the other extreme, the assumption that sensory analyses are obligatory and cannot benefit from attentional resources (i.e., strong-automaticity theory) was also rejected, because longer latency components were found to be modifiable by attention. (c) An intermediate theory provides the best fit to present electrophysiological data. The earliest sensory analyses are assumed to be strongly automatic and then, at forebrain levels, there is a transition from strong to weak automaticity (i.e., analyses are obligatory but modifiable by attention). This transition can begin as early as about 15 ms for audition and about 80 ms for vision. [ABSTRACT FROM AUTHOR]

In a warned Go/No-Go reaction time experiment blink reflexes were elicited electrically immediately before, at, and shortly after the onset of a low intensity acoustic warning stimulus. This provided the opportunity to study the mutual effects of two stimuli of different modalities arriving at the facial nucleus. The warning stimulus was followed after 3 s by an acoustic response stimulus. Sixteen subjects participated in the experiment. They were informed by the response stimulus if a response (a voluntary blink of the right eye) was required. R1 magnitude was increased from 10 ms to 100 ms after warning stimulus onset, with a pronounced peak at 50 ms. The bilateral late component R2 was enhanced when the reflex eliciting stimulus preceded the warning stimulus. Between 20 ms and 30 ms after warning stimulus onset, R2 returned to control level, whereas an eliciting stimulus presented 40 ms or later after warning stimulus onset produced a pronounced inhibition. R2 latency was facilitated immediately after warning stimulus onset. It was concluded that the mutual effects of stimuli of different modalities can be interpreted only if the moment of arrival at the motor nucleus is taken into consideration. [ABSTRACT FROM AUTHOR]

Magnetic responses to frequent and infrequent auditory stimuli, all presented in the same stimulus block in randomized order, were recorded. The standard stimuli, comprising 90% of all the stimuli, were 100-ms, 1000 Hz, 90dB sinusoidal tone bursts. There were three deviant tones, each presented at a probability of 3.3%, which differed from the standard tone on one dimension only: frequency deviant (1500 Hz), intensity deviant (67dB SPL), or duration deviant (50 ms). All mismatch fields, i.e., responses elicited by different deviants, as well as N 100m to the standards and deviants, could be explained by neural activity in the supratemporal auditory cortex. The source of NI00m to standards and deviants was significantly posterior to the sources for the three different mismatch fields. The mean locations of the equivalent dipoles for the different mismatch fields did not differ significantly from each other, but some differences were found for individual subjects. [ABSTRACT FROM AUTHOR]

The rise time of an auditory prepulse was varied to determine whether the onset transient of the prepulse is of primary importance in the modification of the acoustic startle reflex. In Experiment 1, 20-ms long discrete prepulses were presented at a lead time of 150 ms, and prepulse rise time was varied from 0.1 to 20 ms. Although all prepulses resulted in decreased response amplitude (inhibition of startle), varying rise time from 0.1 to 20 ms had no effect on reflex modification. These results suggest that the startle response is not sensitive to prepulse rise time changes in the range used here. In Experiment 2, continuous prepulses (in which lead time equals duration) were presented. Several of these prepulses had a lead time of 150 ms and rise times ranging from 0.1 to 150 ms, whereas others had a rise time of 0.1 ms and lead times of 50 to 150 ms. The results showed that only the fast-rising, 50-ms lead time prepulse decreased response amplitude, with the other prepulses having no effect on amplitude, relative to control responding. Rise time changes generally had no effect on responding, but responses were larger at longer lead times than at shorter lead times. Response probability was inhibited by fast-rising prepulses at lead times of 50 to 130 ms. Together with the results of Experiment 1, these findings suggest that startle reflex inhibition is determined by the onset of a prepulse, and that this inhibition is not sensitive to small changes in prepulse rise time. Also, startle reflex facilitation is determined by the steady-state portion of the prepulse, and this effect is sensitive to prepulse duration. The inhibitory and facilitatory effects combine to determine the amount and direction of reflex modification, and these effects have different time courses, suggesting different mechanisms. It is suggested that reflex modification is due to the activation of a transient system for startle inhibition and a sustained system for startle facilitation. [ABSTRACT FROM AUTHOR]

The development and independence of short-term and long-term habituation (and short-term sensitization) of the acoustic startle response to repetitive stimuli has been repeatedly demonstrated in the experimental animal. Although short-term habituation (and sensitization) of acoustic startle has been studied in humans, neither long-term habituation nor sensitization has been demonstrated. In this study, long-term habituation (response amplitude decrement) of the blink component of the acoustic startle response occurred in normal men across five consecutive daily sessions of repetitive acoustic stimulation. Long-term sensitization (onset latency shortening) developed after the third day. Both the long-term habituation and sensitization were independent of the short-term habituation, which developed within each daily session. [ABSTRACT FROM AUTHOR]

This study investigated modulation of the acoustic cardiac reflex (ACR) in human neonates. Three groups of 16 human neonates born at term were presented an abrupt cardioacceleratory auditory stimulus during awake (AW), quiet sleep (QS), and active sleep (AS) states of wakefulness. On 3/4 of the trials this stimulus was preceded by a continuous pure tone at lead times of either 100, 250, or 4000 ms. Across state, prestimulation modified the amplitude and pattern of the neonatal ACR. Relative to trials without prestimulation, the 100-ms lead inhibited, whereas the 250-ms and the 4000-ms lead stimului enhanced the ACR. During AS, neonates exhibited a triphasic ACR that returned to baseline within 9 s in contrast to the sustained responses in AW and QS states. The results demonstrate central inhibitory and facilatatory control over the ACR early in postnatal life. The pattern of results is consistent with the adult pattern of acoustic startle modulation, as is the absence of significant state effects. Given data from 2-month-old infants suggesting an absence of inhibitory effects in acoustic modulation of cardiac startle, it appears that there are non-linear changes in this basic sensory processing mechanism during the first months after birth. [ABSTRACT FROM AUTHOR]

The effect of auditory intensity on choice reaction time (RT) and heart rate (HR) was studied in two experiments using a 2.5-sec fixed foreperiod paradigm and a mixed block intensity presentation mode. Experiment I showed a U-shaped RT/intensity function and a triphasic HR response. However, the usually obtained anticipatory HR deceleration did not appear. There was only a slight deceleration after the onset of the imperative signal. Both strong tones and faster responding were associated with a more rapid shift from less deceleration to more acceleratory recovery. A second experiment produced similar findings. In addition, differential warning with respect to signal intensity reduced its effect on RT and accelerated the HR response to the imperative signal. The triphasic HR response disappeared in reaction to a "No-Go" warning signal instructing the subject to withhold his motor response to the imperative signal. It was argued that, apart from being an input variable, auditory intensity has an additional effect upon the motor system. It was concluded that this immediate arousal effect of loud auditory signals (Sanders, 1977) could be related to Graham's (1980) notion of defense as primarily a motor facilitating system. Finally, the finding of a consistent relationship between fast reactions and less deceleration together with the absence of the anticipatory deceleration clearly does not fit either the Obrist model or the Lacey model. [ABSTRACT FROM AUTHOR]

Three experiments examined the development of the acoustic startle reflex and its modification by a preliminary stimulus in the infant rat during the 2nd and 3rd postnatal weeks. The 1st experiment employed a white noise S1 (20 msec, 70 dB), the 2nd a cutaneous S1 (.5 msec, .5 mA and 1.0 mA shock), and the 3rd identical S1-S2 pairs (20 msec, 10 kHz, 110 dB tones). The results demonstrate a similar maturation of the prepulse modification pattern over days in the 3 experiments, evidenced mainly in the growth of inhibition. The findings indicate peripheral and central mechanisms that are maturing during the period of life under observation and that contribute to the developmental patterns of modification. [ABSTRACT FROM AUTHOR]

The spectrum of diseases diagnosed and the protocol used in the investigation of 200 consecutive patients with unilateral sensorineural hearing loss (SNHL) is presented. The diagnostic tests found most useful in defining the site of the lesion were a combination of a well-masked pure tone audiogram, speech discrimination score (SDS), acoustic reflex test (ART), and a vestibular evaluation using photoelectric nystagmography (PENG) and the Torok Monothermal Differential Caloric Test. With this protocol, the site of the lesion was correctly defined in 94% of patients with unilateral progressive SNHL. Laboratory and radiological studies confirmed a variety of lesions other than acoustic tumors. It is, therefore, felt that the primary objective of investigations should be to define the site of the lesion rather than aim to diagnose a specific disease entity. [ABSTRACT FROM AUTHOR]

Sentence imitation performance was evaluated longitudinally in 26 adolescents and young adults with Down's syndrome (DS), and z6 age- and IQ-matched non-DS individuals with other causes of intellectual disability (II)). In each of three annual assessments, the OS group began sentence repetitions more slowly and imitated sentences less accurately than the ID group. DS sentence repetition accuracy was equivalent to the ID group only for two-word sentences and was poorer for every other sentence length. Comparisons of sentence imitation and auditory digit span scores suggested that only ID subjects benefitted from the additional meaning and structure provided by sentences. Correlational analyses performed between each year's sentence imitation score and a set of language, memory and hearing measures revealed that sentence imitation was related to grammatical comprehension, auditory then-term memory and IQ in both groups, and to expressive language ability, speed of spoken word processing, speech discrimination and acoustic reflexes in the DS group only. A significant relationship between sentence imitation and middle-ear functioning was further supported by a categorical analysis in which DS subjects with bilateral abnormal rympanograms tended to perform more poorly on sentence imitation casks than DS subjects with at least one normal rympanogram. It was concluded that sentence imitation is a task that is sensitive to the auditory-perceptual, cognitive and expressive difficulties evidenced by individuals with DS. [ABSTRACT FROM AUTHOR]

Patients with suspected retrocochlear disease are usually evaluated with stapedial reflex studies and BSER. Positive responses on these tests usually indicate the need for CT scans with air contrast myelogram. We have been impressed with the lack of sensitivity of these audiometric tests in separating tumor from non-tumorous causes. Although we have never found an acoustic neuroma or cerebellopontine angle tumor without stapedial reflex and BSER abnormalities, we have encountered 20 patients who have strong evidence to support a retrocochlear tumor on audiometric testing but with negative CT with air contrast scans. This report will deal with our experience with these cases and indicate the necessity for obtaining air contrast CT scans before alarming the patient about a retrocochlear disorder or possible surgery. There appear to be many non-tumorous disorders associated with stapedial reflex decay and positive BSER. [ABSTRACT FROM AUTHOR]

Hemizygous microdeletion at the chromosomal locus 22q11.2 is a copy number variation with strong genetic linkage to schizophrenia and related disorders. This association, along with its phenotypic overlap with the 22q11.2 microdeletion syndrome, has motivated the establishment of Df[h22q11]/+ mice, in which the human 22q11.2 orthologous region is deleted. Previous investigations using this model showed the presence of reduced prepulse inhibition (PPI) of the acoustic startle reflex, a form of sensorimotor gating known to be impaired in a number of psychiatric disorders. Concomitantly to reduced PPI, however, Df[h22q11]/+ mice are also characterized by a robust increase in baseline startle reactivity, which may complicate or confound the interpretation of PPI. Therefore, the present study re‐examined the relationship between acoustic startle reactivity and PPI in this mouse model. We found that while PPI is reduced in Df[h22q11]/+ mice when using its relative indexation (ie, % PPI), this deficit is no longer apparent when using the absolute quantification, that is, the direct comparison between pulse‐alone and prepulse‐plus‐pulse conditions with successively increasing prepulse intensities. We further identified marked negative correlations between % PPI and startle reactivity in Df[h22q11]/+ mice. Moreover, when stratifying Df[h22q11]/+ mice into subgroups displaying low‐ and high‐startle reactivity, only the latter subgroup displayed a significant reduction in % PPI. Collectively, our data suggest that alterations in baseline startle reactivity can confound the outcomes and interpretation of PPI in this mouse model of the human 22q11.2 microdeletion syndrome. When stratifying Df[h22q11]/+ mice into subgroups displaying low‐ and high‐startle reactivity, only the latter subgroup displayed a significant reduction in % PPI. [ABSTRACT FROM AUTHOR]

Studies the effect of acute tryptophan depletion on prepulse inhibition of the acoustic startle response (ASR) and auditory evoked potential. Mean amplitudes of the ASR; Plasma levels of the drug; Central serotonergic mechanism involved in regulating prepulse inhibition.

Presents an abstract of the paper 'Sound Pattern-Independent Activation of the Movement-Sensitive Area in Human Auditory Cortex,' presented at the Federation of European Neuroscience Societies conference in Brighton, England, from June 24-28, 2000. Absence of an effect by the type of moving sound or motion cue on the selectivity of the auditory area on the right planum temporale.

Introduction. The aim of this study was, first to determine the influence of the concentrations of volatile anaesthetics (Halothane and Isoflurane) on the intraoperative elicited electrical stapedius reflex threshold (ESRT), and second, to evaluate the relation between the obtained ESRTs and postoperative comfort (C)-levels. Material and methods. This was a prospective clinical study, performed in a single subject design. The study population comprised 13 deaf children (six boys and seven girls) undergoing cochlear implantation. The reflex thresholds were recorded at five electrodes (E22, E17, E12, E7 and E3) with four different concentrations of Halothane (0.3, 0.6, 0.9 and 1.2%) or Isoflurane (0.5, 1.0, 1.5 and 2.0%). Results. In most of the children, increasing the concentration of volatile anaesthetic agent resulted in a higher stapedius reflex threshold. After correction for this effect, a good relation was found between ESRT and C-level in all children, except one. Conclusion. The outcome of this study supports thedetermination of intraoperative electrical stapedius reflex thresholds for programming of the speech processor, post-implantation. [ABSTRACT FROM AUTHOR]