Your Cortex is Flat
he cortex is a flat sheet, shown beautifully here by Van Essen et al (see the Van Essen Lab at the University of St. Louis). This is the six-layered sheet of cells and fibers that makes up our cortex, the “neo-cortex” (because it really expands for mammals like ourselves). It is helpful to think of it as a sheet about the size of a linen dinner napkin. ALL OF OUR CONSCIOUS CONTENTS, to the best of our knowledge, involves massive interactions among about 1,000 specialized areas in this sheet. Cortex also talks constantly with thalamic nuclei for input, basal ganglia and spinal tracts for output, and cerebellum.
It’s the cortex plus its giant input hub, the thalamus, that enables conscious contents.
The biggest volume in the cranium consists of CONNECTIONS among the cells of the flat sheet of the cortex. Those connections might be the most expensive pieces of tissue in our bodies, indicating that something is very important about getting the connections to work. Otherwise biology is expending huge metabolic and reproductive/survival costs on a useless chunk of tissue — not likely.
To remember the shape of the flattened hemisphere (half of cortex) I like to think of Dumbo the Flying Elephant. (Anything to remember all that stuff…) OK, OK, so it’s not EXACTLY Dumbo the Flying Hemisphere…