The cortex is the largest part of the brain and serves as the major structure of cognitive functioning. The cortex is important for general cognitive processes and interacts with other parts of the brain to construct representations of sensory inputs. The basic structure of the cortex is modular, with local computations in neighboring cells and distal computations that send activity between brain areas. The evolution of the cortex has been studied across species and revealed the cortex of each varies in size and number of areas. For example, birds do not have a cortex, reptiles have a thin cortex, and humans have a large cortex with approximately eighty areas.
Connectionist models are mathematical tools that are useful for mapping neuronal activity.
Three connectionist models used for understanding cortical behavior were discussed. The Feed Forward Network models the basic functioning of cells. It transforms an input into an output, such as raw spatial structure into a diagonal pattern. The Hopfield Network models areas larger than a few cells. Every unit is connected to every other unit so input is transmitted to all connected units and eventually settles into a steady state.