Cortical activation patterns during subitizing and counting.

The exact amount of small number of items (1-4) can be detected fast and accurately (subitizing) while the enumeration of large number of items (over 4) is slower and error-prone (counting). Several counting-related cortical areas have been identified mainly in frontal and parietal regions, but cortical events associated with subitizing have remained unclear. Similarly, little is known about the temporal sequence of cortical activation during enumeration.