8/23/2024 Jon Kaas: NEOCORTEX or ISOCORTEX: WHAT IS THE ISSUE?
Neuroscience Brown Bag
Jon Kaas, PhD
Distinguished Centennial Professor of Psychology
Associate Professor of Cell and Developmental Biology
Professor of Radiology and Radiological Sciences
Date: Friday, August 23, 2024
Time: 1:25PM-2:15PM
Location: 316 Wilson Hall
NEOCORTEX or ISOCORTEX: WHAT IS THE ISSUE?
Neocortex is a part of the forebrain that is exceptionally large in humans and other primates. It was called neocortex because it appears to be new with the emergence of mammals. Others have argued that laminar elements of neocortical layers are present as nuclei in birds, or that portions of lateral piriform cortex and medial hippocampus cortex merged to form neocortex. Thus, neocortex was better called isocortex. More recently, the older idea of the medial and lateral contributions to the origin of neocortex, have been expanded to a theory of neocortical advancement in 7 steps of rings and islands of cortex. The surprising conclusion of this effort is that primary sensory and motor areas (V1, S1, A1, and M1) exist only in primates, and those that believed otherwise were all wrong. Here, we attempt to reconstruct the organization of neocortex of the first mammals across members of clades that appear to have changed the least. We propose that neocortex emerged from a much simpler dorsal cortex that was much like the simple dorsal cortex of present-day reptiles. The multilayered cortex is new with mammals and can reasonably be called neocortex.
Questions? Contact Jon Kaas