Related Experiment Video
Updated: Oct 17, 2026
In Vivo Wireless Optogenetic Control of Skilled Motor Behavior
Published on: November 22, 2021
Inactivation of the ventral premotor cortex biases the laterality of motoric choices
1Department of Neurology, University of Rochester Medical Center, NY 14642, USA. mhs@cvs.rochester.edu
Abstract:
The visual, tactile, and motor properties of neurons in the ventral premotor cortex (PMv) suggest that the PMv plays an important role in the interaction of the face and upper extremities with visual objects, a function that might be disrupted by inactivation of the PMv. The behavior of three rhesus monkeys was, therefore, examined while the PMv was reversibly inactivated by intracortical injection of muscimol. Unilateral PMv inactivation produced no overt deficit in a monkey's ability to reach out and grasp a food morsel with either hand, nor did the monkey have difficulty in extracting a food morsel from a narrow well or in performing a visually cued individuated finger movement task. Unilateral PMv inactivation did bias the laterality of the monkeys' motoric choices, however. When two equivalent food morsels were presented simultaneously to the monkey's right and left, the likelihood that the monkey would make motoric responses contralateral to the inactivated PMv was reduced. After PMv muscimol injections, a monkey was less likely to initially turn its head contralaterally to inspect food morsels, less likely to reach for the food morsel with its contralateral hand, and less likely to take the morsel on its contralateral side. Catch trials in which a food morsel was present only on one side showed that the monkey was aware of the contralateral food morsels and was able to turn its head contralaterally and to use its contralateral arm and hand promptly and accurately. These observations suggest that, when equivalent visual objects for behavioral interaction are present bilaterally, the PMv plays a role in choosing the side to which motoric responses will be directed and the body part that will be deployed as the response effector.
Insights
Inactivating the ventral premotor cortex (PMv) in monkeys did not impair basic reaching or grasping. However, it reduced the likelihood of choosing to interact with objects on the side contralateral to the inactivated PMv.
Area of Science:
- Neuroscience
- Primate Behavior
- Motor Control
Background:
- The ventral premotor cortex (PMv) contains neurons with visual, tactile, and motor properties.
- These properties suggest the PMv is involved in integrating sensory information with motor actions for object interaction.
- Understanding the PMv's role is crucial, as its disruption could affect sensorimotor functions.
Purpose of the Study:
- To investigate the behavioral consequences of reversible inactivation of the ventral premotor cortex (PMv).
- To determine if PMv inactivation affects basic motor tasks involving object interaction.
- To assess the PMv's role in directing motor responses and effector selection when faced with bilateral stimuli.
Main Methods:
- Reversible inactivation of the PMv in three rhesus monkeys using intracortical injections of muscimol.
- Behavioral assessment of motor tasks including reaching, grasping, object extraction, and visually cued finger movements.
- Evaluation of motoric choices in response to bilaterally presented food morsels, including head turning, hand selection, and side of interaction.
Main Results:
- Unilateral PMv inactivation did not cause deficits in basic reaching, grasping, or fine motor tasks.
- PMv inactivation significantly biased motoric choices, reducing the likelihood of responding to stimuli contralateral to the inactivated area.
- Monkeys showed reduced contralateral head turning, hand use, and interaction with food morsels on the affected side, despite retaining awareness and accurate motor control when prompted.
Conclusions:
- The ventral premotor cortex (PMv) is not essential for the execution of basic sensorimotor tasks.
- The PMv plays a critical role in the selection of motor responses and effectors when presented with bilateral choices.
- PMv inactivation biases decision-making, influencing which side of the body is preferentially used for interaction with visual objects.
More Related Videos
07:06Block Building Task Identifies Distinct Groups of Left/Right-hand Choice Patterns After Unilateral Peripheral Nerve Injury
Published on: March 21, 2025
07:03Evaluation of Hemisphere Lateralization with Bilateral Local Field Potential Recording in Secondary Motor Cortex of Mice
Published on: July 31, 2019
Related Concept Videos
01:28Lateralization
01:14Motor and Sensory Areas of the Cortex
Motor Areas
The motor areas located in the frontal lobe are central to controlling voluntary movements. This region is further subdivided into the primary motor cortex and the premotor cortex.
01:11Direct Motor Pathways
The corticospinal tract is responsible for the voluntary movement of the limbs and trunk. It originates in the cerebral cortex of the brain and descends through the cerebrum's internal capsule and the...
01:23Somatosensory, Motor, and Association Cortex
01:22Indirect Motor Pathways
The vestibulospinal tract originates in the vestibular nuclei of the brainstem. The vestibular system detects changes in...
01:33Somatosensation