The development and neural basis of referential gaze perception

Infants are sensitive to the referential information conveyed by others’ eye gaze, which could be one of the developmental foundations of theory of mind. To investigate the neural correlates of gaze–object relations, we recorded ERPs from adults and 9-month-old infants while they watched scenes containing gaze shifts either towards or away from the location of a preceding object. In adults, object-incongruent gaze shifts elicited enhanced ERP amplitudes over the occipito-temporal area (N330). In infants, a similar posterior ERP component (N290) was greater for object-incongruent gaze shifts, which suggests that by the age of 9 months infants encode referential information of gaze in a similar way to adults. In addition, in infants we observed an early frontal ERP component (anterior N200), which showed higher amplitude in response to the perception of object-congruent gaze shifts. This component may reflect fast-track processing of socially relevant information, such as the detection of communicative or informative situations, and could form a developmental foundation for attention sharing, social learning and theory of mind

Singers and Sound: An Introduction to Tomatis-Based Listening Training for Singers

abstract: ABSTRACT This document introduces singers and voice teachers to Dr. Alfred A. Tomatis's listening training method with a particular emphasis on its relevance to singers. After presenting an overview of Tomatis's work in the field of audio-psycho-phonology (circa 1947 through the 1990s) and specific ways that aspects of his theory are relevant to singers' performance skills, this project investigates the impact of listening training on singers by examining published research. The studies described in this document have investigated the impact of listening training on elements of the singer's skill set, including but not limited to measures of vocal quality such as intonation, vocal control, intensity, and sonority, as well as language pronunciation and general musicianship. Anecdotal evidence, presented by performers and their observers, is also considered. The evidence generated by research studies and anecdotal reports strongly favors Tomatis-based listening training as a valid way to improve singers' performance abilities.Dissertation/ThesisD.M.A. Music 201

Genetic influences in emotional dysfunction and alcoholism-related brain damage

Alcoholism is a complex, multifactorial disorder involving problematic ethanol ingestion; it results from the interplay between genetic and environmental factors. Personality, likewise, is formed from a combination of inherited and acquired influences. Because selected dimensions of emotional temperament are associated with distinct neurochemical substrates contributing to specific personality phenotypes, certain aspects of abnormal emotional traits in alcoholics may be inherited. Emotions involve complex subjective experiences engaging multiple brain regions, most notably the cortex, limbic system, and cerebellum. Results of in vivo magnetic resonance imaging and post-mortem neuropathological studies of alcoholics indicate that the greatest cortical loss occurs in the frontal lobes, with concurrent thinning of the corpus callosum. Additional damage has been documented for the amygdala and hippocampus, as well as in the white matter of the cerebellum. All of the critical areas of alcoholism-related brain damage are important for normal emotional functioning. When changes occur in these brain regions, either as a consequence of chronic ethanol abuse or from a genetic anomaly affecting temperament and/or a vulnerability to alcoholism, corresponding changes in emotional functions are to be expected. In alcoholics, such changes have been observed in their perception and evaluation of emotional facial expressions, interpretation of emotional intonations in vocal utterances, and appreciation of the meaning of emotional materials

The fearful face and beyond: fMRI studies of the human amygdala

The amygdala has been labeled as a detector of threat , evidenced by its heightened response to fearful faces in human neuroimaging studies. A critical element of the fearful face is an increase in eye white area, hypothesized to be crucial for the rapid detection of fear in another\u27s face. Yet other facial expressions can also increase eye white area in a manner that is similar (a lateral shift in gaze) or identical (surprise) to fear. It is unknown if the amygdala can differentiate between these types of increases in eye white area and those that are specifically associated with fear when using only the eye region of the face. Furthermore, whether the fearful mouth can elicit an amygdala response when shown in isolation is unknown. Using functional magnetic resonance imaging, we found that the amygdala responded robustly to fearful eyes as well as eye stimuli that were ambiguous in nature. The fearful mouth, on the other hand, was unable to generate a significant response from the amygdala, however the happy condition elicited a slight response from the right amygdala, most likely due to the visual salience of the smile. We also observed a functional laterality between the two amygdalae in that the left amygdala responded only to fearful eyes while the right amygdala activated to any change in the eyes; the same laterality was also evident when eye stimuli were ambiguous in nature indicating that the left amygdala is more tuned to detect fear in the eyes while the right amygdala acts as a general detector of eye changes. This lends more evidence to the existence of parallel mechanisms for processing visual threat. Together, our results indicate that while the amygdala is primarily a detector of fearful faces, it has evolved to respond to other facial expressions that are also behaviorally relevant or potentially threatening to the viewer

Visual speech perception in foveal and extrafoveal vision: Further implications for divisions in hemispheric projections

When observing a talking face, it has often been argued that visual speech to the left and right of fixation may produce differences in performance due to divided projections to the two cerebral hemispheres. However, while it seems likely that such a division in hemispheric projections exists for areas away from fixation, the nature and existence of a functional division in visual speech perception at the foveal midline remains to be determined. We investigated this issue by presenting visual speech in matched hemiface displays to the left and right of a central fixation point, either exactly abutting the foveal midline or else located away from the midline in extrafoveal vision. The location of displays relative to the foveal midline was controlled precisely using an automated, gaze-contingent eye-tracking procedure. Visual speech perception showed a clear right hemifield advantage when presented in extrafoveal locations but no hemifield advantage (left or right) when presented abutting the foveal midline. Thus, while visual speech observed in extrafoveal vision appears to benefit from unilateral projections to left-hemisphere processes, no evidence was obtained to indicate that a functional division exists when visual speech is observed around the point of fixation. Implications of these findings for understanding visual speech perception and the nature of functional divisions in hemispheric projection are discussed. © 2014 Jordan et al

Evaluating Effects of Divided Hemispheric Processing on Word Recognition in Foveal and Extrafoveal Displays: The Evidence from Arabic

Background: Previous studies have claimed that a precise split at the vertical midline of each fovea causes all words to the left and right of fixation to project to the opposite, contralateral hemisphere, and this division in hemispheric processing has considerable consequences for foveal word recognition. However, research in this area is dominated by the use of stimuli from Latinate languages, which may induce specific effects on performance. Consequently, we report two experiments using stimuli from a fundamentally different, non-Latinate language (Arabic) that offers an alternative way of revealing effects of split-foveal processing, if they exist. Methods and Findings: Words (and pseudowords) were presented to the left or right of fixation, either close to fixation and entirely within foveal vision, or further from fixation and entirely within extrafoveal vision. Fixation location and stimulus presentations were carefully controlled using an eye-tracker linked to a fixation-contingent display. To assess word recognition, Experiment 1 used the Reicher-Wheeler task and Experiment 2 used the lexical decision task. Results: Performance in both experiments indicated a functional division in hemispheric processing for words in extrafoveal locations (in recognition accuracy in Experiment 1 and in reaction times and error rates in Experiment 2) but no such division for words in foveal locations. Conclusions: These findings from a non-Latinate language provide new evidence that although a functional division i

Early lateral preferences and mental processing trends in black preschoolers.

A Thesis submitted to the Faculty of Arts, University of the Witwatersrand in fulfilment of the requirements for the Degree of Doctor of PhilosophyThe current study adopts a developmental neuropsychological perspective, an approach which does not imply brain dysfunction but rather the principle of understanding the general relationship hetween brain growth and behavioural changes and the effect of environmental factors in children. A neuropsychology of normal development would seem to be an appropriate initial prerequisite if we are to understand the effects of brain insult or disease in the developing child. A modest aim was to acquire a fundamental understanding of emerging skills in black preschool children, starting with the most basic, the development of lateral preferences. This area was selected (a) as a departure point because of its location within the broad area of cerebrallateralization and (b) the opportunity it provided to explore the children's mental processing skills within the same theoretical perspective. The purpose of the present study was the longitudinal investigation of lateral preferences in a sample of Soweto children at three and five years.and information processing skills in the same sample at five years. Three hundred and thirty-five children, 170 girls and 165 boys, were sampled with the assistance of the Birth to Ten project.a longitudinal study of growth, health and development of children living in the Johannesburg Metropolitan area over a ten year period, 1990 to 2000. The children were assessed prior to starting school in January, 1996. A descriptive approach was adopted in explaining the patterns of handedness, footedness and eyeness. The findings showed that the patterns for handedness reflected the expected rightward direction at both ages although the degree to which preference has oeen established was weaker at five years than that reported in other studies with children of similar ages. Thirty-nine percent of the sample were mixed-handed at five years,only 3% were mixed-footed and 5% showed mixed-eyeness, At five years Simultaneous and Sequential information processing skills were assessed with the Kaufman Assessment Battery for Children (K-ABC). Factor analysis revealed a two factor solution broadly supporting the presence of the two processing styles. However the two coding processes were differentially distributed throughout the sample showing significant differences. More specifically.it was found that 34% of the children presented profiles of both processing styles that were below the group mean;31 % showed profiles where one or other coding style was below the group mean;23 % of the children portrayed processing profiles above the group mean. Thirty-nine children (12 %) presented patterns of processing that were above the group mean but were highly developed in one or other processing style. Each of the profiles that emerged were grouped and considered separately. Cognitive tasks involving verbal fluency, naming skills,draw-a person,basic perceptual knowledge,basic literacy.plus lateral preference information such as handedness direction, handedness consistency and handedness skills were appended to all the groups. Low scores in processing styles were found to be associated with poor verbal skills, low mental age,poor perceptual and basic literacy knowledge,poor hand skill performance,and greater (but nonsignificant) numbers of mixed-handers. The lowest scoring group also contained the majority of male left-handers. One of the highest scoring groups showed the strongest lateralizing patterns although the numbers were small (n= 11). Girls with above average sequential skills also scored highly on verbal fluency (p < .05) and hand skills (p < .05). Boys in this group showed the strongest degree of right-handedness (p < .05). In the four lower performance groups,background variables such as type of preschool experience (p <.001),the presence of books in the home (p < .05) and mothers level of education (p <.001) were found to be significant. A regression model which incorporated environmental, epigenetic, cognitive and motoric factors was found to be the most viable in predicting processing skills.Andrew Chakane 201