control of movement

• Motor System In order to understand how movement is controlled, we have to know about the functional unit of the
• Neural Control of Movement

  starts at the alpha motor neurons located at the spinal cord and the brain stem

  neuromuscular junction, motor neurons secrete acetylcholine

  neurotransmitter that signals the generation of an action potential in the muscle fiber

  As this occurs, the muscle structure becomes more permeable to calcium. As more calcium goes inside, the myosin myofilaments get connected to the actin myofilaments via cross bridges. 
• Brain is the “center of action”. It send signals to different parts of the body.
• Motor neurons are found in column groups called “colonies". When a single motor neuron in a colony is activated, the other neurons get excited as well, causing the movement of muscles. Each colony has a specific movement under its control.
• Movement is controlled by the brain via the primary motor cortex situated at the frontal lobe
• The information needed before a movement is elicited comes from the three cortical areas other than the primary motor cortex. These are the primary somatosensory cortex (receiver and processor of sensory input about the amount of force required for a movement), the posterior parietal cortex (integrator of visual, auditory and somatosensory data) and the secondary motor cortex (planner and sequencer of voluntary movement/s).
• Motor Cortex Region Controlled voluntary movements, located at cerebral cortex that is involved in the planning, controlling and execution of voluntary movement.
• Anterior Medial Pathway Controls axial muscles responsible for posture balance and coarse control of axial and proximal muscles.
• Construction of the Commands

  Intention

  Planning

  Programming

  Execution
• Intention Origin of all voluntary movements
• Intention to Act: is controlled by network of the thalamus and limbic system, that is connected to other networks by the association cortices
• Command: is constructed by a series of operations controlled by neural networks.
• Planning

  Select a stored action plan

  Deciding what we will do
• Programming

  Specifies the execution parameters of an action

  Lateral Cerebellar: adjust the action plan to the execution part.
• Execution

  Implements the planned and programmed command

  Electrical Activity of the extensors (coordinates the activation) and flexors