Related Experiment Video
Updated: Oct 1, 2025
07:52
In Vivo Wireless Optogenetic Control of Skilled Motor Behavior
Published on: November 22, 2021
3.5K
Motor cortical output for skilled forelimb movement is selectively distributed across projection neuron classes
Junchol Park1, James W Phillips1,2, Jian-Zhong Guo1
1Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA.
Science Advances
|March 9, 2022
Summary
Motor cortex projection neuron classes carry distinct movement commands. Intratelencephalic (IT) neurons signal movement amplitude, while pyramidal tract (PT) neurons encode movement direction, revealing specialized roles in motor control.
Area of Science:
- Neuroscience
- Motor Control
- Computational Neuroscience
Background:
- Skilled motor behaviors depend on neocortical and subcortical circuit interactions.
- Two primary motor cortical projection neuron classes, pyramidal tract (PT) and intratelencephalic (IT) neurons, differ in their projection targets.
- The distinct functional roles of PT and IT neurons in motor control remain unclear.
Purpose of the Study:
- To investigate whether distinct motor cortical projection neuron classes (PT and IT) carry separate components of descending motor control signals.
- To elucidate the functional roles of IT and PT neurons in shaping motor cortical commands for skilled movements.
Main Methods:
- Combined large-scale neural recordings across motor cortex layers with cell type-specific perturbations in mice.
- Studied cortically dependent motor behaviors, including joystick manipulation and reach-to-grasp tasks.
Main Results:
- Striatum-projecting IT neuron activity preferentially represents movement amplitude.
- Pons-projecting PT neuron activity preferentially represents the variable direction of forelimb movements.
- Demonstrated separable components of descending motor cortical commands distributed across projection cell classes.
Conclusions:
- Motor cortical projection neuron classes have specialized roles in motor control.
- IT and PT neurons contribute distinctly to the neural code for movement, with IT neurons encoding amplitude and PT neurons encoding direction.
- Findings advance understanding of how motor cortical circuits generate complex skilled movements.
Related Concept Videos
01:14Motor and Sensory Areas of the Cortex
5.0K
The cerebral cortex, the brain's outermost layer, is pivotal in processing complex cognitive tasks, emotions, and various sensory inputs and executing voluntary motor activities. This intricate structure is divided into three primary functional areas: the motor areas, sensory areas, and association areas.
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....
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....
5.0K
01:11Direct Motor Pathways
2.6K
The direct motor pathways, also known as the pyramidal tracts, are a group of neural pathways that originate in the brain and descend through the spinal cord. They control the voluntary movement of the body. There are two major direct motor pathways: the corticospinal and the corticobulbar tracts.
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 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...
2.6K
01:18Hierarchy of Motor Control
3.8K
The hierarchy of motor control refers to the different levels of organization and processing involved in controlling movement in the body. These levels range from higher cortical areas involved in planning and decision-making to lower spinal cord reflexes that respond automatically to external stimuli.
3.8K
01:24Somatosensory, Motor, and Association Cortex
1.1K
The somatosensory cortex in the parietal lobes is crucial for interpreting sensory data such as touch, temperature, and proprioception. The somatosensory cortex, situated in the parietal lobes, plays a vital role in interpreting sensory information like touch, temperature, and proprioception—awareness of body position. This specialized brain region features an organized structure wherein neurons at the top primarily process sensations originating from the lower body. In contrast, those at...
1.1K
01:13Motor Units
5.4K
The motor unit is a fundamental component of the neuromuscular system and plays a crucial role in coordinating muscle contractions. It consists of a somatic motor neuron, which connects and controls multiple skeletal muscle fibers, forming a single functional segment. The axon of the motor neuron branches out and establishes synaptic connections known as neuromuscular junctions with individual muscle fibers within the motor unit.
Motor units come in different sizes, with smaller units...
Motor units come in different sizes, with smaller units...
5.4K
01:33Somatosensation
39.2K
The somatosensory system relays sensory information from the skin, mucous membranes, limbs, and joints. Somatosensation is more familiarly known as the sense of touch. A typical somatosensory pathway includes three types of long neurons: primary, secondary, and tertiary. Primary neurons have cell bodies located near the spinal cord in groups of neurons called dorsal root ganglia. The sensory neurons of ganglia innervate designated areas of skin called dermatomes.
39.2K