Functional heterogeneity of the frontal lobe: evidence from intracranial memory ERPs

Intracranial event-related potentials (ERPs) elicited during a recognition memory task were recorded in 17 epileptic patients by using depth electrodes sampling different regions within the frontal lobe. The task was a continuous recognition memory task in which repeated items were presented after six or 19 intervening items following their first presentation. Such a paradigm is one of the experimental tasks requiring both short-term memory and interference control processes which are thought to be subserved by the frontal lobe. The results provide electrophysiological support for the classical view that the frontal lobe is heterogeneous region encompassing a number of functional systems subserving different aspects of memory processing. The anterior dorsolateral and cingulate cortices were found to contribute to short-term memory and recency judgment. The orbital region is more likely to be involved in interference control. The posterior part of the frontal cortex plays a role in some processes related to the control of the motor response.