Interhemispheric functional differences in prefrontal cortex of monkeys

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Primate Research

Background:

• The prefrontal cortex is crucial for mnemonic processes, while the precentral cortex is involved in motor control.
• Understanding how training procedures affect hemispheric specialization is key to deciphering brain function.

Purpose of the Study:

• To investigate the effects of unilateral and bilateral hand training on cortical steady potential (SP) shifts during a spatial delayed-response (DR) task in monkeys.
• To explore interhemispheric functional dissociation between prefrontal and precentral cortical areas.

Main Methods:

• Nonpolarizable electrodes were implanted in prefrontal, precentral, and occipital cortex of monkeys.
• Monkeys were trained on a spatial delayed-response task using unilateral or alternating hand use.
• Cortical potentials, specifically steady potential (SP) shifts, were recorded during task performance and intermanual transfer tests.

Main Results:

• Unilateral hand training led to larger contralateral SP shifts in prefrontal and precentral areas.
• Intermanual transfer tests significantly affected precentral SP shifts but had minimal impact on prefrontal SP shifts.
• Subsequent unilateral training in alternating-hand trained monkeys enhanced contralateral prefrontal SP shifts and decreased ipsilateral ones.

Conclusions:

• A dissociation exists in interhemispheric functions: precentral cortex for motor control and prefrontal cortex for mnemonic processes.
• Hand-training procedures modulate this hemispheric specialization.
• Hemispheric specialization is influenced by training, but other factors may also play a role.