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Neuroscience Brown Bag Series

Thursday, November 09, 2017,
  • Location: Wilson Hall • 111 21St Ave S • Nashville, TN 37240
  • Room: 316

Jon H. Kaas

Department of Psychology

Vanderbilt University

 

The evolution of the dorsal stream of sensory-motor cortical processing in primates

Dorsal stream projections from higher order visual, auditory and somatosensory areas of cortex converge in the anterior portion of posterior parietal cortex (PPC) of primates in a series of modules (domains) where electrical stimulation evokes complex motor behaviours. These ethologically relevant movements include reaching, grasping, hand-to-mouth, and body defense behaviours that are not only evoked from PPC, but also from functionally matched domains in motor and premotor cortex. Our studies on prosimian galagos and New World monkeys, together with more limited results from macaques and humans, suggest that similar domains were present in early primates, but likely new domains were added for language production and tool use in humans. Comparative studies in tree shrews, rodents, and other mammals suggest that the domains in motor cortex emerged early in the evolution of placental mammals, while domains in posterior parietal cortex emerged later with the first primates. The evolution of a dorsal stream of visual processing based on a relay of superior colliculus inputs to temporal cortex via the pulvinar goes back to early mammals or even earlier