Unity and diversity of frontal lobe functions

Area of Science:

• Neuroscience
• Primate Cognition
• Comparative Neurology

Background:

• The granular prefrontal cortex (PFC) plays a crucial role in higher cognitive functions across species.
• Understanding PFC function is complex, involving localization, temporal dynamics, and neural mechanisms.
• Previous research has established symptom localization and temporal factors in PFC studies.

Purpose of the Study:

• To review recent advancements in understanding the functions of the granular prefrontal cortex in primates.
• To identify key unresolved questions regarding the 'what' and 'how' of PFC function.
• To explore potential theoretical frameworks, such as corollary discharges, for future research.

Main Methods:

• Review of recent scientific literature on granular prefrontal cortex functions.
• Analysis of studies addressing localization ('where') and temporal aspects ('when') of PFC lesions and activity.
• Examination of hypotheses concerning the physiological roles of the PFC.

Main Results:

• Significant progress has been made in mapping PFC symptom localization ('where') with distinct gradients in monkeys and lateralization in humans.
• Temporal analyses ('when') differentiate effects of early vs. late lesions and single vs. serial removals.
• The specific functional significance ('what') of PFC symptoms and the operational mechanisms ('how') of individual neurons remain largely undetermined.

Conclusions:

• While localization and timing of PFC functions are better understood, the precise 'what' and 'how' require further investigation.
• Hypotheses suggesting the PFC as a source of 'corollary discharges' offer a promising avenue for future research.
• Understanding PFC's role in pre-setting sensory systems for action consequences may elucidate its complex functions.