Parallel distributed processing and executive functioning: Tower of Hanoi neural networkmodel in healthy controls and...

Previous clinical studies have demonstrated that executive functioning has a significant association with the frontal lobes. In this study we examined executive functioning with parallel distributed processing (PDP) methodology by attempting to replicate Tower of Hanoi (TOH) neuropsychological test performance differences in normal healthy controls vs. left frontal lobe patients. Initial theoretical experiments were carried out to solve computer subprocessing constraints of the TOH partially by determining the programming prerequisites for a specific number of rings, efficient sequencing, and a general learning rule. These preliminary studies were then modified using a back-propagation neurocomputational approach. Computer program output showed a resemblance to normal controls' TOH moves. Degrading of the left frontal lobe patients' network resulted in characteristic impairments of executive functioning, i.e., perseveration and rule-braking.