Sensorimotor System Overview

The sensorimotor system is organized like a large company, with higher levels focused on complex functions and lower levels handling details. For example, the brain's association cortex acts like a president, giving directions to lower levels like motor neurons and muscles which handle specific actions.

The sensorimotor system constantly monitors the environment using sensory feedback, allowing for adjustments in movements. This feedback helps with tasks like picking up objects, adjusting to unexpected forces, and maintaining steady force output.

Motor output, or movement, is influenced and guided by sensory input from the environment. This means that your body's movements are constantly adjusted based on what your senses are detecting. For example, when you pick up a cup, sensory information about the cup's weight, shape, and position is used to guide your hand movements.

Movements that are pre-programmed and completed without sensory feedback during their execution. For example, quickly swatting a fly or hitting a baseball.

The process of practicing and improving motor skills, which often involves changes in brain activity and muscle control. For example, learning to ride a bike changes the areas of the brain responsible for balance and coordination.

The association cortex, located in the higher levels of the sensorimotor system, is responsible for complex planning, decision-making, and goal-oriented behavior. It acts like the "president", assigning tasks to lower levels.

The primary motor cortex, located in the frontal lobe, is responsible for sending signals to muscles for voluntary movement, initiating actions based on instructions from the association cortex.

The spinal cord, a pathway connecting the brain to the body, receives commands from the brain and relays them to muscles, allowing for coordinated movements and reflexes.

The posterior parietal cortex (PPC) plays a crucial role in integrating sensory information from different modalities like vision, touch, and proprioception. It then guides our movements and spatial awareness.

Damage to the PPC can lead to a variety of deficits including apraxia (difficulty performing skilled movements), optic ataxia (difficulty reaching for objects seen in space), and contralateral neglect (ignoring one side of the body and space).

The Dorsolateral Prefrontal Cortex (DLPFC) executes higher-order cognitive functions and controls movement sequences and planning. It is also involved in working memory, decision-making, and goal-directed behavior.

The DLPFC receives input from the PPC and sends output to the premotor cortex before movement initiation. It is important for complex sequential tasks and guiding behavior according to internal goals.

Electrical stimulation of the PPC can elicit movements, especially when stimulating the area responsible for planning and executing specific actions.

This part of the brain helps us understand where our body parts are in relation to the world around us.

Damage to this area can lead to problems with movement, specifically the inability to perform movements on command.

This condition makes people only pay attention to one side of their body or the environment, ignoring the other side.

This prefrontal area of the brain helps us assess and understand what we see and hear in the environment

This cortex helps us make decisions about starting a movement.

This system receives information from our senses and helps us control our movements.

This part of the brain plans and initiates movements after receiving information from other brain areas.

Neurons that fire both when an individual makes a goal-directed movement and when they observe another individual making the same movement. These neurons are believed to play a role in understanding and imitating the actions of others.

A general model of the sensorimotor system describing a hierarchical organization of brain structures involved in planning, controlling, and executing movement. It starts from higher areas like the association cortex handling complex tasks and ends with lower areas like muscles executing specific movements.