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This study explores how the human brain solves the challenge of flicker noise in motion processing. Despite providing no useful directional motion information, flicker is common in the visual environment and exhibits omnidirectional motion energy which is processed by low-level motion detectors. Models of motion processing propose a mechanism called motion opponency that reduces flicker processing. Motion opponency involves the pooling of local motion signals to calculate an overall motion direction. A neural correlate of motion opponency has been observed in human area MT+/V5, whereby stimuli with perfectly balanced motion energy constructed from dots moving in counter-phase elicit a weaker response than nonbalanced (in-phase) motion stimuli. Building on this previous work, we used multivariate pattern analysis to examine whether the activation patterns elicited by motion opponent stimuli resemble that elicited by flicker noise across the human visual cortex. Robust multivariate signatures of opponency were observed in V5 and in V3A. Our results support the notion that V5 is centrally involved in motion opponency and in the reduction of flicker. Furthermore, these results demonstrate the utility of multivariate analysis methods in revealing the role of additional visual areas, such as V3A, in opponency and in motion processing more generally.

Existing studies show that CNS oxytocin (OT) signaling is important in the control of energy balance, but it is unclear which neurons may contribute to these effects. Our goals were to examine (1) the dose-response effects of acute OT administration into the third (3V; forebrain) and fourth (4V; hindbrain) ventricles to assess sensitivity to OT in forebrain and hindbrain sites, (2) the extent to which chronic 4V administration of OT reduces weight gain associated with the progression of diet-induced obesity, and (3) whether nucleus tractus solitarius (NTS) catecholamine neurons are downstream targets of 4V OT. Initially, we examined the dose-response effects of 3V and 4V OT (0.04, 0.2, 1, or 5 μg). 3V and 4V OT (5 μg) suppressed 0.5-h food intake by 71.7 ± 6.0% and 60 ± 12.9%, respectively. 4V OT (0.04, 0.2, 1 μg) reduced food intake by 30.9 ± 12.9, 42.1 ± 9.4, and 56.4 ± 9.0%, respectively, whereas 3V administration of OT (1 μg) was only effective at reducing 0.5-h food intake by 38.3 ± 10.9%. We subsequently found that chronic 4V OT infusion, as with chronic 3V infusion, reduced body weight gain (specific to fat mass) and tended to reduce plasma leptin in high-fat diet (HFD)-fed rats, in part, through a reduction in energy intake. Lastly, we determined that 4V OT increased the number of hindbrain caudal NTS Fos (+) neurons (156 ± 25) relative to vehicle (12 ± 3). The 4V OT also induced Fos in tyrosine hydroxylase (TH; marker of catecholamine neurons) (+) neurons (25 ± 7%) relative to vehicle (0.8 ± 0.3%). Collectively, these findings support the hypothesis that OT within the hindbrain is effective at reducing food intake, weight gain, and adiposity and that NTS catecholamine neurons in addition to non-catecholaminergic neurons are downstream targets of CNS OT.

This letter addresses the controversial issue of the use of oral corticosteroids during wheezing exacerbations in preschool-aged children by demonstrating findings of a prematurely terminated multi-center clinical trial, discussing lessons learned, and suggesting future directions.

Introduction: Empathy is a fundamental element of high-quality healthcare, though it has been shown to be in decline among medical students and residents. Appeals have therefore been made for the development of evidence-based empathy-enhancing experiential learning and training models. Bringing Art to Life (BATL) is a service-learning program designed within experiential learning pedagogy for psychology and pre-healthcare students. Intergenerational relationships are fostered with people with dementia through art therapy and life story/narrative at a community-based adult day services center. Methods: In this sequential mixed methods study, quantitative data were collected via electronic surveys of students in this course compared with students in didactic introductory psychology or psychology and aging courses. Survey measures included empathy, mindfulness, positive and negative affect, future time perspective, and attitudes toward older adults and working with people with dementia. Weekly BATL student journals submitted as part of their course requirements were analyzed using qualitative content analysis. Results: Within-subjects analyses of variance revealed increases in empathy and positive affect, broadened time perspective, and improved attitudes toward older adults and people with dementia among students in the BATL course compared with other undergraduate students. Analysis of BATL student journals supported and deepened understanding of these findings, with themes including attitude change, relationship building fostering existential awareness and self-development, art fostering social interactions, and perceived program effectiveness. Discussion: The findings suggest that BATL strongly supports increased empathetic attitudes and decreased stigma of aging in psychology and pre-healthcare students. Intergenerational expressive arts-based programs like BATL should be implemented in healthcare education to enhance empathy and improve attitudes toward aging and dementia care. [ABSTRACT FROM AUTHOR]

Purpose Methods Results Conclusions To assess the ability of the Dolphin air‐pulse aesthesiometer to present multiple stimuli, which are separated temporally (in sequence) or spatially (simultaneously).Two studies were performed to explore the cooling effects induced by double air‐puff stimuli generated by a novel aesthesiometer composed of two micro‐blower integrated units. The stimuli were delivered sequentially or simultaneously at the same or different spatial locations to an in vitro eye model monitored using thermography. The model eye was based on a 2‐cm LED dome light mounted on a circuit board with an 8‐V supply producing a baseline 32°C temperature. Single and repeated air‐pulse stimuli varying in intensity, duration, inter‐stimulus delay and stimulus location were presented to the model. The cooling effect produced was observed using a thermal camera and quantified using image analysis software.The instrument can deliver single stimuli, repeated single stimuli with a variable time delay or multiple stimuli either simultaneously or with a time delay between them. The thermal effects of stimuli were evaluated by measuring (relative to pre‐stimulus baseline) the local temperature change and the diameter of the model eye surface region with ≥1°C reduction. Repeated stimuli at the same location produced a significantly greater effect than a single stimulus of the same intensity (larger area of cooling after the second stimulus compared to the first [|M|{SE} = 1.48 mm {0.06}, p < 0.001]). Spatially separated stimuli produced separate cooling zones, with the amount of cooling relative to stimulus intensity (rm‐ANOVA, F2,8 = 276.01, p < 0.001, ω$$ \omega $$2 = 0.96).The combined use of two micro‐blower units allows increased options for modification of stimulus intensity and timing of delivery that enables the production of alternative stimulus presentations and intensity compared to a single stimulus. This adaptability may enable future in vivo study of corneal sensory nerve summation. [ABSTRACT FROM AUTHOR]

At rest, the menstrual cycle phase impacts ventilation and chemosensitivity. However, during exercise there is inconclusive evidence that the menstrual cycle phase affects ventilation or chemosensitivity. We sought to examine the influence of menstrual phase and hormonal birth control (BC) on chemosensitivity. We tested 12 males and 20 females (10 BC; 10 normally menstruating, NBC) on three occasions. Day 1 was a maximal exercise test and days 2 (follicular phase) and 3 (luteal phase) consisted of three bouts of chemosensitivity testing during cycle exercise at 30% of peak work rate. Females‐BC and males completed day 3 approximately 2 weeks after day 2, with females‐BC tested during the active phase of their birth control. There were no differences between the two experimental days for any groups for any (hypercapnia, hypoxia, and hyperoxia) chemosensitivity tests, p > 0.05. Females‐BC had a significantly lower average response to transient hypercapnia than both females‐NBC and males (38% and 42% lower, respectively, p < 0.05). Females‐NBC had a significantly smaller change in ventilation to hyperoxia compared to males, −11.7 ± 5.9 versus −17.9 ± 5.4%, respectively (p < 0.05). We conclude that the day‐to‐day variability in chemosensitivity is not different between males, females‐BC and NBC. [ABSTRACT FROM AUTHOR]

Acute mountain sickness (AMS) occurs due to rapid altitude ascents and/or insufficient acclimatization. Acetazolamide (AZ) is commonly prescribed for AMS prophylaxis but inhibits exercise performance. Methazolamide (MZ), an analogous drug, has similar prophylactic benefits but does not impair isolated muscle mass exercise performance in normoxia. We sought to compare whole body exercise performance in acute hypoxia (fraction of inspired oxygen, F I O 2 = 0.15) between AZ, MZ, and placebo (PLA). Fifteen healthy participants completed five testing visits: day 1 for maximal exercise test, day 2 for familiarization, and days 3–5 were the experimental visits. Each experimental visit involved a 5-km hypoxic cycling time trial (TT) performed after a 2-day dosing protocol of either AZ (250 mg three times a day), MZ (100 mg twice a day), or PLA (three times a day); the order was randomized and double-blinded. Before exercise, capillary blood samples were taken, and maximal voluntary contractions of quadriceps were performed. AZ and MZ resulted in a partially compensated metabolic acidosis at rest compared with PLA [capillary hydrogen ions (H+) 47 ± 3, 43 ± 2, and 39 ± 2 nmol for AZ, MZ, and PLA respectively, P < 0.01]. Time to complete 5 km with PLA (562 ± 32 s, P < 0.01) was significantly faster than AZ and MZ (577 ± 38 vs. 581 ± 37 s, respectively), with no differences between AZ and MZ (P = 0.96). There were no differences in average ventilation (124 ± 27, 127 ± 24, 127 ± 19 L/min) and oxyhemoglobin saturation (87 ± 2, 88 ± 2, 88 ± 3%) between AZ, MZ, and PLA, respectively (P > 0.05). Overall, both AZ and MZ impair whole body exercise performance in acute normobaric hypoxia. NEW & NOTEWORTHY: Administration of acetazolamide (AZ) and methazolamide (MZ) both resulted in a significantly slower 5-km time trial in acute normobaric hypoxia compared with a placebo. Both drugs lead to a partially compensated metabolic acidosis, but ventilation and oxyhemoglobin saturation were not different across the conditions. Overall, acetazolamide and methazolamide both impaired whole body exercise performance in acute normobaric hypoxia but potentially have different mechanisms of action. [ABSTRACT FROM AUTHOR]

Purpose: To describe an automatic system for objective measurement of visual acuity (VA) using optokinetic nystagmus (OKN). This pilot study tested the system's sensitivity and specificity for detecting reduced VA in healthy adults by comparing VA‐OKN to VA with an Early Treatment of Diabetic Retinopathy Study (ETDRS) chart (VA‐ETDRS). Methods: Adult participants (age 30 ± 12 years) with either reduced VA (n = 11, VA‐ETDRS > 0.20 logMAR) or normal VA (n = 12, VA‐ETDRS ≤ 0.20 logMAR) completed monocular VA‐OKN measurements in each eye. The VA‐OKN stimulus was an array of drifting (5°/s) vanishing discs presented in descending/ascending size order (0.00–1.00 logMAR in 0.10 steps). The stimulus was stepped every 2 s, and 10 sweeps were shown per eye (five ascending and five descending). Eye‐tracking data determined when OKN activity ceased (descending sweep) or began (ascending sweep), which was used to determine VA‐OKN for each sweep. The estimates were averaged across sweeps to produce an automated VA‐OKN. The automated sweeps were then provided in randomised order to a reviewer blinded to the VA‐ETDRS findings who determined a final VA‐OKN for an eye. Results: A single randomly selected eye from each observer was used for analysis. The sensitivity and specificity of VA‐OKN using the same 0.20 logMAR threshold as VA‐ETDRS was 100%. Comparisons between the VA‐OKN and VA‐ETDRS measures were made for participants in the reduced VA group. There was no significant difference between VA‐OKN and VA‐ETDRS (p = 0.55) and the two measures produced comparable values (r2 = 0.84, 95% limits of agreement = 0.19 logMAR, intra‐class correlation coefficient = 0.90 [95% CI:0.68–0.97]). Conclusions: Visual acuity using optokinetic nystagmus correctly identified a VA deficit in adults and for those with a VA deficit, VA‐OKN was strongly correlated with the gold‐standard clinical measure of VA. OKN is a promising method which has the potential for use in cognitively impaired adults and pre‐verbal children. [ABSTRACT FROM AUTHOR]