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Cosmetic tattooing (permanent makeup of eyebrows, eyeliner, or lipliner) procedures are flourishing among women worldwide. Recurrent themes provide knowledge and understanding so dermatology nurses can aid in their procedural decision making. [ABSTRACT FROM AUTHOR]

Native mass spectrometry is a potent method for characterizing biomacromolecular assemblies. A critical aspect to extracting accurate mass information is the correct inference of the ion ensemble charge states. While a variety of experimental strategies and algorithms have been developed to facilitate this, virtually all approaches rely on the implicit assumption that any peaks in a native mass spectrum can be directly attributed to an underlying charge state distribution. Here, we demonstrate that this paradigm breaks down for several types of macromolecular protein complexes due to the intrinsic heterogeneity induced by the stochastic nature of their assembly. Utilizing several protein assemblies of adeno-associated virus capsids and ferritin, we demonstrate that these particles can produce a variety of unexpected spectral appearances, some of which appear superficially similar to a resolved charge state distribution. When interpreted using conventional charge inference strategies, these distorted spectra can lead to substantial errors in the calculated mass (up to ∼5%). We provide a novel analytical framework to interpret and extract mass information from these spectra by combining high-resolution native mass spectrometry, single particle Orbitrap-based charge detection mass spectrometry, and sophisticated spectral simulations based on a stochastic assembly model. We uncover that these mass spectra are extremely sensitive to not only mass heterogeneity within the subunits, but also to the magnitude and width of their charge state distributions. As we postulate that many protein complexes assemble stochastically, this framework provides a generalizable solution, further extending the usability of native mass spectrometry in the characterization of biomacromolecular assemblies., Competing Interests: PWAD, JCS, FC, AR, AH, SS, MD, CLD and NJB are employees of AstraZeneca, a company with an interest in developing adeno-associated viruses for gene-delivery., (This journal is © The Royal Society of Chemistry.)

The past 15-20 years has seen a remarkable shift in our understanding of astrocyte contributions to central nervous system (CNS) function. Astrocytes have emerged from the shadows of neuroscience and are now recognized as key elements in a broad array of CNS functions. Astrocytes comprise a substantial fraction of cells in the human CNS. Nevertheless, fundamental questions surrounding their basic biology remain poorly understood. While recent studies have revealed a diversity of essential roles in CNS function, from synapse formation and function to blood brain barrier maintenance, fundamental mechanisms of astrocyte development, including their expansion, migration, and maturation, remain to be elucidated. The coincident development of astrocytes and synapses highlights the need to better understand astrocyte development and will facilitate novel strategies for addressing neurodevelopmental and neurological dysfunction. In this review, we provide an overview of the current understanding of astrocyte development, focusing primarily on mammalian astrocytes and highlight outstanding questions that remain to be addressed. We also include an overview of Drosophila glial development, emphasizing astrocyte-like glia given their close anatomical and functional association with synapses. Drosophila offer an array of sophisticated molecular genetic tools and they remain a powerful model for elucidating fundamental cellular and molecular mechanisms governing astrocyte development. Understanding the parallels and distinctions between astrocyte development in Drosophila and vertebrates will enable investigators to leverage the strengths of each model system to gain new insights into astrocyte function., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Markey, Saunders, Smuts, von Reyn and Garcia.)

Although neurotechnology careers are on the rise, and neuroscience curriculums have significantly grown at the undergraduate and graduate levels, increasing neuroscience and neurotechnology exposure in high school curricula has been an ongoing challenge. This is due, in part, to difficulties in converting cutting-edge neuroscience research into hands-on activities that are accessible for high school students and affordable for high school educators. Here, we describe and characterize a low-cost, easy-to-construct device to enable students to record rapid Drosophila melanogaster (fruit fly) behaviors during optogenetics experiments. The device is generated from inexpensive Arduino kits and utilizes a smartphone for video capture, making it easy to adopt in a standard biology laboratory. We validate this device is capable of replicating optogenetics experiments performed with more sophisticated setups at leading universities and institutes. We incorporate the device into a high school neuroengineering summer workshop. We find student participation in the workshop significantly enhances their understanding of key neuroscience and neurotechnology concepts, demonstrating how this device can be utilized in high school settings and undergraduate research laboratories seeking low-cost alternatives., Competing Interests: The authors have declared that no competing interests exist.

Protein biopharmaceuticals are highly successful, but their utility is compromised by their propensity to aggregate during manufacture and storage. As aggregation can be triggered by non-native states, whose population is not necessarily related to thermodynamic stability, prediction of poorly-behaving biologics is difficult, and searching for sequences with desired properties is labour-intensive and time-consuming. Here we show that an assay in the periplasm of E. coli linking aggregation directly to antibiotic resistance acts as a sensor for the innate (un-accelerated) aggregation of antibody fragments. Using this assay as a directed evolution screen, we demonstrate the generation of aggregation resistant scFv sequences when reformatted as IgGs. This powerful tool can thus screen and evolve 'manufacturable' biopharmaceuticals early in industrial development. By comparing the mutational profiles of three different immunoglobulin scaffolds, we show the applicability of this method to investigate protein aggregation mechanisms important to both industrial manufacture and amyloid disease.

Electrospray ionisation-ion mobility spectrometry-mass spectrometry (ESI-IMS-MS) is a powerful method for the study of conformational changes in protein complexes, including oligomeric species populated during protein self-aggregation into amyloid fibrils. Information on the mass, stability, cross-sectional area and ligand binding capability of each transiently populated intermediate, present in the heterogeneous mixture of assembling species, can be determined individually in a single experiment in real-time. Determining the structural characterisation of oligomeric species and alterations in self-assembly pathways observed in the presence of small molecule inhibitors is of great importance, given the urgent demand for effective therapeutics. Recent studies have demonstrated the capability of ESI-IMS-MS to identify small molecule modulators of amyloid assembly and to determine the mechanism by which they interact (positive, negative, non-specific binding, or colloidal) in a high-throughput format. Here, we demonstrate these advances using self-assembly of Aβ40 as an example, and reveal two new inhibitors of Aβ40 fibrillation., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

Protein aggregation underlies an array of human diseases, yet only one small-molecule therapeutic targeting this process has been successfully developed to date. Here, we introduce an in vivo system, based on a β-lactamase tripartite fusion construct, that is capable of identifying aggregation-prone sequences in the periplasm of Escherichia coli and inhibitors that prevent their aberrant self-assembly. We demonstrate the power of the system using a range of proteins, from small unstructured peptides (islet amyloid polypeptide and amyloid β) to larger, folded immunoglobulin domains. Configured in a 48-well format, the split β-lactamase sensor readily differentiates between aggregation-prone and soluble sequences. Performing the assay in the presence of 109 compounds enabled a rank ordering of inhibition and revealed a new inhibitor of islet amyloid polypeptide aggregation. This platform can be applied to both amyloidogenic and other aggregation-prone systems, independent of sequence or size, and can identify small molecules or other factors able to ameliorate or inhibit protein aggregation.

The precise molecular mechanisms by which different peptides and proteins assemble into highly ordered amyloid deposits remain elusive. The fibrillation of human amylin (also known as islet amyloid polypeptide, hIAPP) and the amyloid-beta peptide (Aβ-40) are thought to be pathogenic factors in Type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD), respectively. Amyloid diseases may involve co-aggregation of different protein species, in addition to the self-assembly of single precursor sequences. Here we investigate the formation of heterogeneous pre-fibrillar, oligomeric species produced by the co-incubation of hIAPP and Aβ-40 using electrospray ionisation-ion mobility spectrometry-mass spectrometry (ESI-IMS-MS)-based methods. Conformational properties and gas-phase stabilities of amyloid oligomers formed from hIAPP or Aβ40 alone, and from a 1 : 1 mixture of hIAPP and Aβ40 monomers, were determined and compared. We show that co-assembly of the two sequences results in hetero-oligomers with distinct properties and aggregation kinetics properties compared with the homo-oligomers present in solution. The observations may be of key significance to unravelling the mechanisms of amyloid formation in vivo and elucidating how different sequences and/or assembly conditions can result in different fibril structures and/or pathogenic outcomes.

The search for therapeutic agents that bind specifically to precursor protein conformations and inhibit amyloid assembly is an important challenge. Identifying such inhibitors is difficult because many protein precursors of aggregation are partially folded or intrinsically disordered, which rules out structure-based design. Furthermore, inhibitors can act by a variety of mechanisms, including specific or nonspecific binding, as well as colloidal inhibition. Here we report a high-throughput method based on ion mobility spectrometry-mass spectrometry (IMS-MS) that is capable of rapidly detecting small molecules that bind to amyloid precursors, identifying the interacting protein species and defining the mode of inhibition. Using this method we have classified a variety of small molecules that are potential inhibitors of human islet amyloid polypeptide (hIAPP) aggregation or amyloid-beta 1-40 aggregation as specific, nonspecific, colloidal or non-interacting. We also demonstrate the ability of IMS-MS to screen for inhibitory small molecules in a 96-well plate format and use this to discover a new inhibitor of hIAPP amyloid assembly.

A universal property of spiking neurons is refractoriness, a transient decrease in discharge probability immediately following an action potential (spike). The refractory period lasts only one to a few milliseconds, but has the potential to affect temporal coding of acoustic stimuli by auditory neurons, which are capable of submillisecond spike-time precision. Here this possibility was investigated systematically by recording spike times from chicken auditory nerve fibers in vivo while stimulating with repeated pure tones at characteristic frequency. Refractory periods were tightly distributed, with a mean of 1.58 ms. A statistical model was developed to recapitulate each fiber's responses and then used to predict the effect of removing the refractory period on a cell-by-cell basis for two largely independent facets of temporal coding: faithful entrainment of interspike intervals to the stimulus frequency and precise synchronization of spike times to the stimulus phase. The ratio of the refractory period to the stimulus period predicted the impact of refractoriness on entrainment and synchronization. For ratios less than ∼0.9, refractoriness enhanced entrainment and this enhancement was often accompanied by an increase in spike-time precision. At higher ratios, little or no change in entrainment or synchronization was observed. Given the tight distribution of refractory periods, the ability of refractoriness to improve temporal coding is restricted to neurons responding to low-frequency stimuli. Enhanced encoding of low frequencies likely affects sound localization and pitch perception in the auditory system, as well as perception in nonauditory sensory modalities, because all spiking neurons exhibit refractoriness.

Objective: To assess vascular changes induced by hyperadrenocorticism of hyperplastic adrenal glands in dogs via contrast-enhanced ultrasonography., Animals: 12 dogs with pituitary-dependent hyperadrenocorticism (PDH) and 7 healthy control dogs ≥ 7 years old., Procedures: Dogs were assigned to the PDH and control groups and to small-breed (n = 6), medium-breed (4), and large-breed (9) subgroups. Contrast-enhanced ultrasonography of both adrenal glands in each dog was performed with IV injections of contrast agent. Time-intensity curves for the adrenal cortex, adrenal medulla, and ipsilateral renal artery of both adrenal glands were generated. Perfusion variables (time to peak [TTP], upslope of wash-in phase, and downslope of washout phase) were calculated., Results: Contrast-enhanced ultrasonography revealed no qualitative difference between PDH and control groups. Quantitatively, TTPs were longer in the adrenal cortex and adrenal medulla of the PDH group, compared with values for the control group, particularly in the adrenal cortex and adrenal medulla of the small-breed subgroup. Washout downslopes were lower for the renal artery, adrenal cortex, and adrenal medulla of the small-breed subgroup between the PDH and control groups. No other perfusion variables differed between groups., Conclusions and Clinical Relevance: Contrast-enhanced ultrasonography of the adrenal glands in dogs with PDH revealed a delayed TTP in the adrenal cortex and adrenal medulla, compared with values for control dogs. Contrast-enhanced ultrasonography was able to detect vascular changes induced by hyperadrenocorticism. Further studies are needed to evaluate whether reference ranges for clinically normal dogs and dogs with PDH can be determined and applied in clinical settings.

Background: Reporter genes are widely used in biology and only a limited number are available. We present a new reporter gene for the localization of mammalian cells and transgenic tissues based on detection of the bglA (SYNbglA) gene of Caldocellum saccharolyticum that encodes a thermophilic beta-glucosidase., Results: SYNbglA was generated by introducing codon substitutions to remove CpG motifs as these are associated with gene silencing in mammalian cells. SYNbglA expression can be localized in situ or detected quantitatively in colorimetric assays and can be co-localized with E. coli beta-galactosidase. Further, we have generated a Cre-reporter mouse in which SYNbglA is expressed following recombination to demonstrate the general utility of SYNbglA for in vivo analyses. SYNbglA can be detected in tissue wholemounts and in frozen and wax embedded sections., Conclusions: SYNbglA will have general applicability to developmental and molecular studies in vitro and in vivo.

The auditory system of young chicks (Gallus domesticus)is an important model for studying the structure and function of the inner ear. For over 20 years this model has gained interest because of the discovery that birds, and perhaps lower vertebrates in general, are capable of generating new hair cells to replace those lost to ototrauma, a capacity that is absent along the mammalian organ of Corti. Accompanying this remarkable capacity is the nearly complete restoration of auditory function to the chick peripheral ear. This article presents a review of findings on the toxic effect of exposure to extremely loud sound on the young chick ear, and the subsequent recovery from inner ear structural damage and accompanying recovery of auditory function. The evidence, surprisingly, suggests that the role of the regenerated hair cells in the latter may be minimal and that multiple other factors play more important roles. There is also a section on the unique problems encountered in using chicks as laboratory animal subjects in experiments designed to understand the consequences of acoustic trauma. The conclusion summarizes some of the issues that need to be addressed in future research.

Aging for the older women in the 21st century is more than medical issues. In this study, 62 women (ages 51-81+) obtained a total of 97 permanent makeup procedures. Procurement cues included self-improvement and friend's appearance, consistent with internal, external, and appearance perspectives of body image. Poor eyesight was also of concern (14/23%). Actual benefits included saving makeup time and money (external), while achieving personal goals (internal). This study seems to confirm that for these older women, body image remains important, especially qualities of the face. They did not shed their internal, external, nor appearance concerns associated with body image, as they aged.

Relocation and transition to an assisted living facility (ALF) is considered a critical period for the prospective new resident both in the anticipatory time prior to admission and the early weeks post admission.(1) Administrators and health care providers at a large life care, aging-in-place facility in the southwest identified a need for improving supportive nursing interventions for easing the transition of newly admitted residents into the assisted living apartments. In response, a qualitative study exploring the expectations and experiences of five newly admitted residents was conducted over a six month period. Thirty-five interviews were tape-recorded, transcribed, and interpreted using content analysis. Four themes emerged: deciding to move, becoming dependent, remembering what was and yearning for the past, and creating a new community. Understanding the perspective of residents experiencing this transition may lead to innovative changes in ALF orientation programs, caring interventions, delivery of consumer directed care, and health provider educational strategies.

Do related, differently sized species differ in size-related structural or functional traits merely because they mature at different points of a uniform allometric ontogenetic growth curve, or do they evolutionarily diverge? We tested ears of gekkotan lizards through experiments distinguishing the two. Auditory sensitivity was assessed by compound action potential (CAP) thresholds in eight species. The best thresholds characterizing species ranged 22-72 dB sound pressure level at 0.5-1.0 kHz. Direct acoustic stimulation of the columella footplate elevated thresholds by 25-50 dB. Intraspecific CAP sensitivity was primarily affected by body length in Eublepharis macularius, but by tympanic-membrane velocity in Oedura marmorata. The chief factor determining middle-ear function (difference in CAP sensitivity before and after middle-ear ablation) was body length in both species. A secondary factor was the middle-ear hydraulic lever ratio in E. macularius, but the mechanical lever in O. marmorata. When intra- and interspecific data were compared, the relation of CAP thresholds to body size in E. macularius resembled the interspecific regression. The intraspecific regression of auditory sensitivity over tympanic membrane velocity in O. marmorata differed from that calculated interspecifically. Hence, the evolutionary contribution to size effects on CAP sensitivity exceeds the ontogenetic contribution. Putatively, body length affects CAP sensitivity through absolute sizes of tympanic membrane and columella footplate. These newly discovered effects join those of the hydraulic lever and (interspecifically) hair-cell number to improve the hearing of larger species that vocally communicate across wider spaces, apparently throughout the Tetrapoda.

A laboratory model was developed to study human avoidance learning. Participants could avoid an electric shock signalled by a 5-s conditioned stimulus (CS) by pressing one of a set of response buttons. Self-reported shock expectancy and skin conductance were recorded during a subsequent 10-s interval before shock. Shock expectancy declined when the correct avoidance response was learned and returned when the response was unavailable. Learning transferred to another shock CS. Parallel effects were observed on skin conductance once performance anxiety was controlled by requiring responding on all trials. Learning was faster when the Pavlovian contingencies were trained before introduction of the instrumental response. The results support a cognitive model of anxiety in which performance of an avoidance response reduces expectancy of an aversive outcome and thereby reduces anxiety.

Objective: To compare the results of a 1996 study of tattoo possession and motivation for tattoo removal with those of a 2006 study, in light of today's current strong mainstream tattoo procurement and societal support within the young adult population., Design: Descriptive, exploratory study., Setting: Four dermatology clinics in Arizona, Colorado, Massachusetts, and Texas., Participants: The 2006 study included 196 tattooed patients (66 men and 130 women)., Main Outcome Measures: Incidence of purchase and possession risk, as measured by a 127-item survey and factor analysis., Results: In contrast to the 1996 study, more women (69%) than men (31%) presented for tattoo removal in 2006. Women in the 2006 study were white, single, college educated, and between the ages of 24 and 39 years; they reported being risk takers, having stable family relationships, and moderate to strong religious beliefs (prayer and closeness to God). Commonly, tattoos were obtained at approximately 20 years of age, providing internal expectations of uniqueness and self-identity. Tattoo possession risks were significant, cited when the quest for uniqueness turned into stigmata (P < .001), negative comments (P < .003), and clothes problems (P < .004)., Conclusions: In both the 1996 and the 2006 studies, a shift in identity occurred, and removal centered around dissociating from the past. However, in the 2006 study, more women than men were notably affected by possession risks. Societal support for women with tattoos may not be as strong as for men. Rather than having visible tattoos, women may still want to choose self-controlled body site placement, even in our contemporary society.

Many non-mammalian ears lack physiological features considered integral to the generation of otoacoustic emissions in mammals, including basilar-membrane traveling waves and hair-cell somatic motility. To help elucidate the mechanisms of emission generation, this study systematically measured and compared evoked emissions in all four classes of tetrapod vertebrates using identical stimulus paradigms. Overall emission levels are largest in the lizard and frog species studied and smallest in the chicken. Emission levels in humans, the only examined species with somatic hair cell motility, were intermediate. Both geckos and frogs exhibit substantially higher levels of high-order intermodulation distortion. Stimulus frequency emission phase-gradient delays are longest in humans but are at least 1 ms in all species. Comparisons between stimulus-frequency emission and distortion-product emission phase gradients for low stimulus levels indicate that representatives from all classes except frog show evidence for two distinct generation mechanisms analogous to the reflection- and distortion-source (i.e., place- and wave-fixed) mechanisms evident in mammals. Despite morphological differences, the results suggest the role of a scaling-symmetric traveling wave in chicken emission generation, similar to that in mammals, and perhaps some analog in the gecko.

More than 4 million (2%) people in the United States have been infected with the hepatitis C virus, of whom 2.7 million are chronically infected. The current treatment for chronic hepatitis C patients is Interferon and ribavirin combination therapy, which is associated with numerous neuropsychiatric side effects. The most common are fatigue, depression, cognitive dysfunction, and anxiety. Early identification and treatment of these symptoms may not only improve the patient's mental health, but also may increase the patient's functional ability and overall quality of life. Psychiatric nurses can play a pivotal role in the successful management of the neuropsychiatric symptoms.

Otitis media with effusion (OME) is characterized by the occurrence of fluid in the middle-ear cavity in the absence of any signs of acute ear infection and occurs most frequently in children with auditory or eustachian tube dysfunction. Its chronic form is an important clinical issue for pediatricians and otologists alike. The study by Depreux et al. in this issue of the JCI shows that absence of the transcriptional activator Eya4 in knockout mice results in abnormal structuring of the eustachian tube, thus predisposing these animals to OME (see the related article beginning on page 651). The development of this genetics-based animal model is an important advance for understanding OME and for exploring new avenues of treatment.

This paper examines the contribution of the outer and middle ears to the hearing loss associated with presbycusis in Brown Norway rats. Animals were formed into two groups; young adults (2-3 months old) and aged animals (approximately 34 months old). Auditory brainstem response (ABR) thresholds were obtained with the outer ear intact or surgically removed. Tympanic membrane (TM) velocity transfer functions were measured from the umbo with the outer ear removed. The length of the auditory meatus, TM surface area, and TM thickness were quantified. The ABR thresholds were 17-26 dB less sensitive in the aged animals between 8.0 and 40.0 kHz when the outer ear was intact. A significant and reliable reduction in the aged rat velocity transfer function of 5-8 dB occurred between 10.0 and 32.0 kHz, while the low frequency velocity response was only a few decibels greater in the younger animals. The ABR threshold differences between young adult and aged ears were compensated by removing the outer/middle ear effects of aging to reveal a purely sensorineural component of presbycusis. The outer and middle ear effects were calculated directly when the ABR and TM velocity data were obtained with the outer ear removed. The outer ear intact condition was modeled in order to compare the ABR data obtained with the outer ear intact with the TM velocity data obtained with the outer removed. With either procedure, removal of the age-related contributions of the outer and middle ear to the ABR threshold resulted in similar age-related ABR threshold shifts between the two age groups. The pure sensorineural threshold shift component of the ABR response was restricted to frequencies between 5.0 and 20.0 kHz and reached a maximum of approximately 15 dB. These results support the conclusion that there is an outer- and middle-ear contribution to the threshold loss defining presbycusis., ((c) 2008 S. Karger AG, Basel.)

Unlabelled: Tinnitus is a vexing disorder of hearing characterized by sound sensations originating in the head without any external stimulation. The specific etiology of these sensations is uncertain but frequently associated with hearing loss. The "neurophysiogical" model of tinnitus has enhanced appreciation of central nervous system (CNS) contributions. The model assumes that plastic changes in the primary and non-primary auditory pathways contribute to tinnitus with the former perhaps sustaining them, and the latter contributing to perceived severity and emotionality. These plastic changes are triggered by peripheral injury, which results in new patterns of brain activity due to anatomic alterations in the connectivity of CNS neurons. These alterations may change the balance between excitatory and inhibitory brain processes, perhaps producing cascades of new neural activity flowing between brainstem and cortex in a self-sustaining manner that produces persistent perceptions of tinnitus. The bases of this model are explored with an attempt to distinguish phenomenological from mechanistic explanations., Learning Outcomes: (1) Readers will learn that the variables associated with the behavioral experience of tinnitus are as complex as the biological variables. (2) Readers will understand what the concept of neuroplastic brain change means, and how it is associated with tinnitus. (3) Readers will learn that there may be no one brain location associated with tinnitus, and it may result from interactions between multiple brain areas. (4) Readers will learn how disinhibition, spontaneous activity, neural synchronization, and tonotopic reorganization may contribute to tinnitus.

Can it be said that body piercing is ubiquitous, found across all socioeconomic groups? The major concentration is among adolescents and young adults 15 to 30 years old, in some studies, 50% of the population. Commonly identified physical risks are bleeding, tissue trauma, and bacterial infections; psychosocial risks are unhappiness, low self-esteem, and disappointment. The Health Belief Model is used to explain decision making; purposes for body piercing consistently center on personal expression (self-identity) and uniqueness. The international and US body piercing regulations are discussed, leading to the need for tracking complications globally and standardization of regulations. Proactive health education for clients and health providers remains a priority.

Sensory systems use adaptive coding mechanisms to filter redundant information from the environment to efficiently represent the external world. One such mechanism found in most sensory neurons is rate adaptation, defined as a reduction in firing rate in response to a constant stimulus. In auditory nerve, this form of adaptation is likely mediated by exhaustion of release-ready synaptic vesicles in the cochlear hair cell. To better understand how specific synaptic mechanisms limit neural coding strategies, we examined the trial-to-trial variability of auditory nerve responses during short-term rate-adaptation by measuring spike-timing precision and spike-count reliability. After adaptation, precision remained unchanged, whereas for all but the lowest-frequency fibers, reliability decreased. Modeling statistical properties of the hair cell-afferent fiber synapse suggested that the ability of one or a few vesicles to elicit an action potential reduces the inherent response variability expected from quantal neurotransmitter release, and thereby confers the observed count reliability at sound onset. However, with adaptation, depletion of the readily releasable pool of vesicles diminishes quantal content and antagonizes the postsynaptic enhancement of reliability. These findings imply that during the course of short-term adaptation, coding strategies that employ a rate code are constrained by increased neural noise because of vesicle depletion, whereas those that employ a temporal code are not.

Although body piercing procurement continues to increase, 13% to 18% of them are removed. Reasons for piercing removal in college students were examined with three groups: (a) those who kept all their piercings, (b) those who removed some, or (c) those who removed all of their body piercings. Of the sample, 41% were still pierced; 50% in their lifetime. Their major purpose for the body piercing was "helped them feel unique." Females obtained more (in high school) and then removed more, usually as upperclassmen. Males and females reported themselves as risk takers at procedure time and currently; however, only 10% cited deviancy as a reason for the body piercing(s). Only removal elements of "I just got tired of it" and "I just decided to remove it" were present, especially with the Some Removed Group. Further examination of body piercing building personal distinctiveness and self-identity to promote their need of uniqueness is suggested.

Cochlear nerve adaptation is thought to result, at least partially, from the depletion of neurotransmitter stores in hair cells. Recently, neurotransmitter vesicle pools have been identified in chick tall hair cells that might play a role in adaptation. In order to understand better the relationship between adaptation and neurotransmitter release dynamics, short-term adaptation was characterized by using peristimulus time histograms of single-unit activity in the chick cochlear nerve. The adaptation function resulting from 100-ms pure tone stimuli presented at the characteristic frequency, +20 dB relative to threshold, was well described as a single exponential decay process with an average time constant of 18.6+/-0.8 ms (mean+/-SEM). The number of spikes contributed by the adapting part of the response increased tonotopically for characteristic frequencies up to approximately 0.8 kHz. Comparison of the adaptation data with known physiological and anatomical hair cell properties suggests that depletion of the readily releasable pool is the basis of short-term adaptation in the chick. With this idea in mind, short-term adaptation was used as a proxy for assessing tall hair cell synaptic function following intense acoustic stimulation. After 48 h of exposure to an intense pure tone, the time constant of short-term adaptation was unaltered, whereas the number of spikes in the adapting component was increased at characteristic frequencies at and above the exposure frequency. These data suggest that the rate of readily releasable pool emptying is unaltered, but the neurotransmitter content of the pool is increased, by exposure to intense sound. The results imply that an increase in readily releasable pool size might be a compensatory mechanism ensuring the strength of the hair cell afferent synapse in the face of ongoing acoustic stress.

Little is known about changes that occur to phase locking in the auditory nerve following exposure to intense and damaging levels of sound. The present study evaluated synchronization in the discharge patterns of cochlear nerve units collected from two groups of young chicks (Gallus domesticus), one shortly after removal from an exposure to a 120-dB, 900-Hz pure tone for 48 h and the other from a group of non-exposed control animals. Spontaneous activity, the characteristic frequency (CF), CF threshold and a phase-locked peri-stimulus time histogram were obtained for every unit in each group. Vector strength and temporal dispersion were calculated from these peri-stimulus time histograms, and plotted against the unit's CF. All parameters of unit responses were then compared between control and exposed units. The results in exposed units revealed that CF thresholds were elevated by 30-35 dB whereas spontaneous activity declined by 24%. In both control and exposed units a high degree of synchronization was observed in the low frequencies. The level of synchronization above approximately 0.5 kHz then systematically declined. The vector strengths in units recorded shortly after removal from the exposure were identical to those seen in control chicks. The deterioration in discharge activity of exposed units, seen in CF threshold and spontaneous activity, contrasted with the total absence of any overstimulation effect on synchronization. This suggested that synchronization arises from mechanisms unscathed by the acoustic trauma induced by the exposure.

The authors used affective modulation of the eyeblink startle response to examine the impact of traumatic brain injury (TBI) on emotional reactions to pictures. Participants were 13 individuals with severe TBI and 24 controls. Participants were presented with pictures that differed in affective valence (e.g., mutilated bodies, erotic couples, and household objects) while the eyeblink startle response to an acoustic probe was measured. Startle amplitude was used to assess valence of emotional response, and startle latency was used to index interest in the pictures. Subjective ratings of the affect and arousal elicited by the various pictures were also obtained. TBI impaired startle potentiation to unpleasant pictures but not startle attenuation to pleasant pictures. Further, subjective ratings indicated that TBI participants found unpleasant pictures less arousing than did controls. The results are consistent with recent evidence of differential impairment in negative versus positive emotions after TBI and are discussed in relation to 2 competing explanations of startle modulation.

Short-term adaptation in acoustically stimulated chick cochlear nerve fibers has recently been shown to have similar kinetics as the readily-releasable vesicle pool in patch-clamped chick hair cells, suggesting that short-term adaptation depends on the dynamics of hair cell exocytosis. Our understanding of the relationship between these two phenomena has been hampered by differences in the temperatures at which the two types of data have been collected. In this report, the effect of temperature on short-term adaptation was studied in single-units of the chick cochlear nerve. Compared to units recorded at 38-41 degrees C, spontaneous and evoked firing rates were markedly decreased when the temperature was lowered to 28-32 degrees C, but the rate of short-term adaptation during 100 ms tone bursts was relatively unchanged, with a temperature Q(10), of approximately 1.2. The continued similarity of the adaptation time-constant of cooled units to vesicle depletion kinetics in chick hair cells measured at room temperature suggests that comparison of in vitro hair cell exocytosis and in vivo cochlear nerve firing properties may not be confounded by temperature differences between the two approaches., (Copyright 2005 Wiley-Liss, Inc.)

Young and adult chickens exhibit substantial inner-ear damage and post-exposure deterioration in cochlear nerve activity following exposure to intense sound. Both the structural and functional losses largely recover in both age groups within 2-4 weeks after exposure. However, some aspects of acoustic trauma differ between the young and adult chicken ear. Overstimulation in the young chick causes considerable post-exposure loss and then recovery of the steady-state endocochlear potential, while in the adult animal there is little post-exposure effect on this potential. Moreover, in adults there is post-exposure loss but little recovery in the distortion product otoacoustic emission (DPOAE). The present study explores the possibility of an age difference in the effects of overstimulation on the DPOAE by examining these emissions in young chicks following exposure to an intense pure tone. Chicks exposed to intense sound were formed into groups at 0 and 12 days of recovery, and these were complemented by two additional groups of age-matched controls. The cubic difference tone emission (the 2f(1)-f(2) DPOAE component) was measured at 9 levels for 13 frequencies in all groups. Shortly after the exposure, the DPOAE reliably declined with the maximum loss at or above the exposure tone frequency. The exposed chicks examined 12 days after exposure showed complete recovery of the DPOAE. It would appear that 12 days of recovery sufficiently repaired inner ear damage to completely restore DPOAE production. This result is different from that in adult chicken and may be related to the greater severity of acoustic damage in the adult ear, a reduced susceptibility of the young ear to acoustic trauma, or the ability of the young animal to more successfully repair the inner ear.

Recent evidence suggests that there may be dissociable systems for recognizing emotional expressions from different media including audio and visual channels, and still versus moving displays. In this study, 34 adults with severe traumatic brain injuries (TBI) and 28 adults without brain injuries were assessed for their capacity to recognize emotional expressions from dynamic audiovisual displays, conversational tone alone, moving facial displays, and still photographs. The TBI group were significantly impaired in their interpretation of both audio and audiovisual displays. In addition, eight of the 34 were significantly impaired in their capacity to recognize still facial expressions. In contrast, only one individual was impaired in the recognition of moving visual displays. Information processing speed was not found to play a significant role in producing problems with dynamic emotional expression. Instead the results suggest that visual moving displays may enlist different brain systems to those engaged with still displays, for example, the parietal cortices. Problems with the processing of affective prosody, while present, were not clearly related to other emotion processing problems. While this may attest to the independence of the auditory affective system, it may also reflect problems with the dual demands of listening to conversational meaning and affective tone.