Differential Influence of Ventromedial Prefrontal Cortex Lesions on Neural Representations of Schema and Semantic Category Knowledge.

Prior knowledge, such as schemas or semantic categories, influences our interpretation of stimulus information. For this to transpire, prior knowledge must first be reinstated and then instantiated by being applied to incoming stimuli. Previous neuropsychological models implicate the ventromedial prefrontal cortex (vmPFC) in mediating these functions for schemas and the anterior/lateral temporal lobes and related structures for categories.

Schema representation in patients with ventromedial PFC lesions.

Human neuroimaging and animal studies have recently implicated the ventromedial prefrontal cortex (vmPFC) in memory schema, particularly in facilitating new encoding by existing schemas. In humans, the most conspicuous memory disorder following vmPFC damage is confabulation; strategic retrieval models suggest that aberrant schema activation or reinstatement plays a role in confabulation. This raises the possibility that beyond its role in schema-supported memory encoding, the vmPFC is also implicated in schema reinstatement itself.

What is a memory schema? A historical perspective on current neuroscience literature.

The term "schema" has been used to describe vastly different knowledge structures within the memory neuroscience literature. Ambiguous terminology hinders cross-study comparisons and confounds interpretation of the suggested role of the ventromedial prefrontal cortex (vmPFC) in schema functions. Based on an extensive review of the psychological literature, we propose a framework for distinguishing memory schemas from other knowledge structures.