Recurrent corticocortical interactions in neural disease

The cerebral cortex consists of many areas, each subserving a more or less distinct function. This view has its roots in the early work of Penfield and today is reflected in functional magnetic resonance imaging literature describing the regions of the brain that are activated during particular tasks, percepts, actions, or thoughts. Moreover, the currently held view is that these areas, and their associated functions, are organized in a hierarchical fashion. Some areas are low level, performing basic operations on the sensory input. Via feed-forward corticocortical connections, this information is transferred to intermediate and high-level areas (Figure 1A) where more sophisticated processes occur, such as object recognition, multi-sensory integration, decision making, attention, or reasoning.