Conditioned Sounds Enhance Visual Processing

This psychophysics study investigated whether prior auditory conditioning influences how a sound interacts with visual perception. In the conditioning phase, subjects were presented with three pure tones ( =  conditioned stimuli, CS) that were paired with positive, negative or neutral unconditioned stimuli. As unconditioned reinforcers we employed pictures (highly pleasant, unpleasant and neutral) or monetary outcomes (+50 euro cents, −50 cents, 0 cents). In the subsequent visual selective attention paradigm, subjects were presented with near-threshold Gabors displayed in their left or right hemifield. Critically, the Gabors were presented in synchrony with one of the conditioned sounds. Subjects discriminated whether the Gabors were presented in their left or right hemifields. Participants determined the location more accurately when the Gabors were presented in synchrony with positive relative to neutral sounds irrespective of reinforcer type. Thus, previously rewarded relative to neutral sounds increased the bottom-up salience of the visual Gabors. Our results are the first demonstration that prior auditory conditioning is a potent mechanism to modulate the effect of sounds on visual perception.     

Central Processing of Communication Sounds in the Anuran Auditory System

SYNOPSIS. The social behavior of anurans (frogs and toads) ismediated by a number of acoustic signals, or calls, that showboth inter- and intraspecific differences in temporal patternand spectral content. These differences provide cues usefulfor call recognition. Neural mechanisms responsible for detectingand analyzing the temporal and spectral cues of the speciesvocalizations have been the subject of investigation for almostthree decades. Here, I summarize the results of studies conductedin the northern leopard frog, Rana pipiens. These results demonstratethat (1) sound analysis is performed in the central auditorysystem of anurans by an array of neural niters operating inthe time and frequency domain, (2) behaviorally relevant soundsare represented by stimulus-dependent spatio-temporal patternsof excitation among differentially tuned filter neurons, and(3) the time and frequency selectivity of these neurons is determined,in part, by GABA-mediated inhibitory interactions that shapetheir excitatory input     

A Bayesian Model of Category-Specific Emotional Brain Responses

Understanding emotion is critical for a science of healthy and disordered brain function, but the neurophysiological basis of emotional experience is still poorly understood. We analyzed human brain activity patterns from 148 studies of emotion categories (2159 total participants) using a novel hierarchical Bayesian model. The model allowed us to classify which of five categories—fear, anger, disgust, sadness, or happiness—is engaged by a study with 66% accuracy (43-86% across categories). Analyses of the activity patterns encoded in the model revealed that each emotion category is associated with unique, prototypical patterns of activity across multiple brain systems including the cortex, thalamus, amygdala, and other structures. The results indicate that emotion categories are not contained within any one region or system, but are represented as configurations across multiple brain networks. The model provides a precise summary of the prototypical patterns for each emotion category, and demonstrates that a sufficient characterization of emotion categories relies on (a) differential patterns of involvement in neocortical systems that differ between humans and other species, and (b) distinctive patterns of cortical-subcortical interactions. Thus, these findings are incompatible with several contemporary theories of emotion, including those that emphasize emotion-dedicated brain systems and those that propose emotion is localized primarily in subcortical activity. They are consistent with componential and constructionist views, which propose that emotions are differentiated by a combination of perceptual, mnemonic, prospective, and motivational elements. Such brain-based models of emotion provide a foundation for new translational and clinical approaches.     

The Modulation by Intensity of the Processing of Interaural Timing Cues for Localizing Sounds

Features of sounds such as time and intensity are important binaural cues for localizing their sources. Interaural time differences (ITDs) and interaural level differences are extracted and processed in parallel by separate pathways in the brainstem auditory nuclei. ITD cues are small, particularly in small-headed animals, and processing of these cues is optimized by both morphological and physiological specializations. Moreover, recent observations in mammals and in some birds indicate that interaural time and level cues are not processed independently but cooperatively to improve the detection of interaural differences. This review will specifically summarize what is known about how inhibitory circuits improve the measurements of ITD in a sound-level-dependent manner.     

A Study of Normal Heart Sounds,Heart Size,Arterial Pressure and Electrocardiograms From Infancy to Early Adulthood in One Male and One Female

This study forms part of a project to define the range of normal for heart sounds and murmurs. Using the method of writing quantitative symbol phonocardiograms, data were collected on one female and one male subject from earliest infancy to adulthood (aged 27 and 25). Serial measurements of heart size, arterial pressure and records of electrocardiograms and electrophonocardiograms were made. The heart sounds are shorter and somewhat less loud under the age of two years than later. Physiologic splitting of the first and second sounds, a physiologic systolic murmur, the appearance and disappearance of a third sound are shown in the illustrations which epitomize this study. These longitudinal studies of age period changes in the electrocardiogram reveal what has been learned from the horizontal studies. The shape of the cardiac silhouette as recorded between the ages of 5 and 8 years seems to predict the adult shape. The adult type of arterial pressure became established in the early teens.