in lesion of Area-4 of the brain why Recovery occurs on gross movement but not on fine movement

Answer 1

Lesion of Area-4 of the brain, also known as the primary motor cortex or M1, can result in motor deficits. Recovery following such a lesion is often seen in gross movements but can be limited or absent in fine movements.

The primary motor cortex is responsible for generating and executing voluntary movements. It projects its output primarily to the spinal cord and brainstem, which then translate these signals into muscle contractions. Fine movements require precise control and coordination of small muscle groups, whereas gross movements involve larger muscle groups and are less reliant on precise control.

When Area-4 is lesioned, the ability to initiate or execute movements can be affected, resulting in muscle weakness, paralysis, or difficulty with coordination. However, the brain has the ability to reorganize and compensate for such damage through a process known as neuroplasticity.

During recovery, other regions of the brain, particularly adjacent cortical areas and subcortical structures, can adapt and take over some of the functions previously performed by Area-4. This process can allow for the restoration of gross movements as these movements involve multiple muscle groups and alternative neural pathways. The brain can recruit different areas to compensate for the loss in the primary motor cortex.

On the other hand, fine movements require highly specific control, timing, and precision, which may rely more heavily on the intact neural connections in Area-4. The reorganization of neural circuits and recruitment of other brain regions may not be as effective in restoring the intricate control necessary for fine movements.

Additionally, the reorganization of neural circuits may result in a shift in the functional organization within the motor cortex. This reorganization may lead to a lack of precision or coordination, further contributing to the limited recovery of fine movements.

It is important to note that the extent and type of recovery can vary depending on the severity and location of the lesion, as well as individual differences in neuroplasticity and rehabilitation efforts.