Place Cell-Like Activity in the Primary Sensorimotor and Premotor Cortex During Monkey Whole-Body Navigation.

Area of Science:

• Neuroscience
• Primate Cognition
• Spatial Navigation

Background:

• Primary motor (M1), primary somatosensory (S1), and dorsal premotor (PMd) cortical areas are traditionally linked to sensorimotor control of limb movements.
• The classical hierarchical model of cortical processing assigns specialized spatial processing functions primarily to the hippocampal formation.

Purpose of the Study:

• To investigate whether M1, S1, and PMd neurons represent body position and orientation during whole-body navigation.
• To challenge the established understanding of functional specialization in primate cortical areas.

Main Methods:

• Two rhesus monkeys navigated a room using a wheelchair controlled by a brain-machine interface (BMI).
• Neuronal discharge rates in M1, S1, and PMd were recorded and correlated with the monkeys' 2D room position and head direction during navigation.

Main Results:

• A significant percentage of neurons in M1, S1, and PMd exhibited place cell-like activity, correlating with 2D room position (44.6% and 33.3% in monkeys K and M, respectively).
• Overlapping neuronal populations also encoded head direction (41.0% and 16.0% in monkeys K and M, respectively).

Conclusions:

• Primate primary sensorimotor and premotor cortical areas are involved in allocentric spatial representation of body position during whole-body navigation.
• These findings expand the known functional roles of M1, S1, and PMd beyond sensorimotor control, suggesting a broader involvement in spatial cognition.