Lateral parietal cortex in the generation of behavior: Implications for apathy

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psychiatry

Background:

• Apathy is a common symptom in neurological and psychiatric disorders, characterized by reduced goal-directed behavior.
• Neural substrates of apathy are unclear, though prefrontal and subcortical circuits are implicated.
• Existing models do not fully explain the observed link between apathy and the lateral parietal cortex.

Purpose of the Study:

• To review the association between lateral parietal cortex dysfunction and apathy across various disorders.
• To analyze cognitive functions linking the lateral parietal cortex to goal-directed behavior.
• To propose a revised neurocognitive model of apathy incorporating the role of the lateral parietal cortex.

Main Methods:

• Literature review of studies associating lateral parietal cortex dysfunction with apathy.
• Analysis of cognitive functions potentially linking the lateral parietal cortex to goal-directed behavior.
• Synthesis of evidence to propose a revised neurocognitive model of apathy.

Main Results:

• The lateral parietal cortex, specifically the angular and supramarginal gyri, may interface internal goals with external actions.
• This region is proposed to be involved in the intentional initiation of action and sensorimotor transformation.
• Dysfunction in embedding intended actions within a 'body schema' may underlie the apathy-lateral parietal cortex link.

Conclusions:

• Impaired internal initiation of behavior by the inferior parietal lobule may cause apathy.
• This mechanism could represent a distinct volitional subtype of apathy.
• A revised neurocognitive model highlights the role of the inferior parietal lobule in the volitional aspect of goal-directed behavior.