The Primate Temporal Lobe Structures: Maturation, Early Dysfunction, and Relationships to Human Developmental Disorders
Session 2: Cognitive and Social Phenotypes in Autism
Jocelyne Bachevalier
Beginning with the first reports of Klüver and Bucy on the dramatic effects of medial temporal lesions on monkeys' emotional reactions and the well-studied human case, H.M., who d-eveloped severe memory loss following surgical removal of his temporal lobe, tremendous progress has been made in our understanding of the functional organization of the structures within the medial temporal lobe. The focus of research during the last 50 years was placed towards identifying the specific neural processes of the hippocampus and adjacent cortical areas on a specific type of memory (e.g. declarative memory), and characterizing the role of the amygdala in the detection of emotional and social signals provided by faces and, more generally, in the regulation of socio-emotional cognition. Concurrently, a plethora of research already exists on the development of memory processes and on the emergence of social skills in human infants, due in large measure to the development of methods amenable to the study of the infant's and child's cognitive skills. However, the juxtaposition of these two fields of research, the biological bases of early cognitive functions, has received relatively little attention. The field of developmental cognitive neuroscience has emerged only recently by studying infant non-human primates using invasive methods (e.g. lesion methods, electrophysiological recordings, as well as metabolic, neuroanatomical, and neurochemical techniques) used with adults of these same species. The data from the neuropsychological studies of cognitive development are notable and promising not only because they superimpose the time course of cognitive development onto that of the brain, but also because they help explain the neural bases of human developmental disorders. Thus, the main objective of my presentation will be to review the most relevant findings on the developmental time course of the medial temporal lobe structures and its relationship to the maturation of cognitive functions, emphasize the numerous gaps in our knowledge of this field, and suggest important areas for future investigation.
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