Cortex

“Cortex”

20″ x 30″

Graphite on Paper

What determines cognitive abilities is not the number of neurons in the entire brain but in the cerebral cortex. Birds, particularly Songbirds & Parrots, have as much ‘cortex’ and neuron density as we do relatively. But it’s not organized the same. We both have 75% of our forebrain as cortex. Nerve cells in mammal’s neocortex are stacked in 6 distinct layers like plywood but in a bird’s it’s structured like cloves in a garlic bulb. But the cells are basically the same. The cell’s are capable of rapid firing, are equally sophisticated, flexible and inventive. Chickadees in particular have double the brain size of birds in the same body-weight range and can replace old brain cells with new ones when needed though many birds have hyperinflated brains like us.