Functional MRI of macaque monkeys performing a cognitive set-shifting task

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Comparative Psychology

Background:

• Understanding the neural basis of cognitive flexibility is crucial for deciphering primate brain evolution.
• Previous research has identified prefrontal cortex involvement in executive functions, but direct cross-species comparisons are limited.

Purpose of the Study:

• To directly compare the functional brain organization of humans and macaque monkeys during a cognitive set shifting task.
• To identify homologous brain regions involved in behavioral flexibility across species.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed to measure brain activity in both humans and macaques.
• A modified Wisconsin Card Sorting Test was administered to assess cognitive set shifting ability.
• Equivalent visual stimuli and task sequences were utilized for both species to ensure comparability.

Main Results:

• Transient activation associated with cognitive set shifting was observed in focal regions of the prefrontal cortex in both species.
• These activated regions were identified as functional homologs located in cytoarchitectonically equivalent areas of the posterior ventrolateral prefrontal cortex.
• The findings demonstrate a shared neural substrate for cognitive flexibility in primates.

Conclusions:

• Direct comparative fMRI reveals conserved functional brain organization for cognitive set shifting in humans and macaques.
• The posterior ventrolateral prefrontal cortex plays a critical role in behavioral flexibility across primate species.
• This study provides valuable insights into the evolutionary trajectory of cognitive functions in primates.