Integrating neuronal coding into cognitive models: predicting reaction time distributions

Neurophysiological studies have examined many aspects of neuronal activity in terms of neuronal codes and postulated roles for these codes in brain processing. There has been relatively little work, however, examining the relationship between different neuronal codes and the behavioural phenomena associated with cognitive processes. Here, predictions about reaction time distributions derived from an accumulator model incorporating known neurophysiological data in temporal lobe visual areas of the macaque are examined. Results from human experimental studies examining the effects of changing stimulus orientation, size and contrast are consistent with the model, including qualitatively different changes in reaction time distributions with different stimulus manipulations. The different changes in reaction time distributions depend on whether the image manipulation changes neuronal response latency or magnitude and can be related to parallel or serial cognitive processes respectively. The results indicate that neuronal coding can be productively incorporated into computational models to provide mechanistic accounts of behavioural results related to cognitive phenomena.