Some hypotheses concerning the functional organization of prefrontal cortex

Area of Science:

• Neuroscience
• Behavioral Psychology
• Cognitive Science

Background:

• Partial prefrontal lesions are associated with various behavioral deficits.
• Understanding the specific nature and localization of these deficits is crucial for effective treatment and research.

Purpose of the Study:

• To systematize behavioral disorders following partial prefrontal lesions.
• To differentiate between impairment of drive inhibition and motor-act inhibition based on lesion localization.
• To elucidate the neural systems underlying these distinct inhibitory deficits.

Main Methods:

• Systematic review and theoretical analysis of existing literature on prefrontal lesions and behavioral disorders.
• Categorization of behavioral deficits based on observed response impairments (e.g., Pavlovian differentiation, response switching).
• Postulation of distinct neural circuits (limbic-prefrontal, premotor-prefrontal, caudate-prefrontal) associated with specific inhibitory functions.

Main Results:

• Two primary behavioral disorders identified: impairment of drive inhibition and motor-act inhibition.
• Impaired drive inhibition results in disinhibition of no-go responses in Pavlovian differentiation.
• Motor-act inhibition deficits lead to difficulties in response switching (R1-R2 differentiation).

Conclusions:

• Different prefrontal cortex regions are implicated in directional and non-directional response differentiation.
• Drive inhibition is primarily dependent on the limbic-prefrontal system.
• Motor-act inhibition relies on the premotor-prefrontal system for manipulatory tasks and the caudate-prefrontal system for locomotor tasks.