- Originates in a region of the brainstem known as the "reticular formation" 
- Extends to the spinal cord to regulate movement 

Reticulospinal Tract 

- Originates in region of brainstem known as "red nucleus" (midbrain)
- Extends to spinal cord

Rubrospinal Tract

- Involved in coordinating the initiation, direction, and amplitude of a movement
- Works with motor cortex to start/stop movements 
- Made up of forebrain nuclei (nuclei: collection of neurons), including caudate nucleus and putamen (known as striatum), and globus pallidus 
- The substantia nigra and subthalamic nucleus are also closely associated with this region


Basal Ganglia 

- Works with the supplementary motor area (SMA) to regulate ongoing movements and create uniform movement.
- The size of the cerebellum is positively related to the complexity of an organism's movement capabilities.
- The outer layer, or "cerebellar cortex," contains Purkinje cells involved in guiding movement.
- Receives and sends information to the sensory organs of the proprioceptive and kinesthetic systems to help process body position and movement.

Cerebellum and Movement

- A motor system that goes from the forebrain to the spinal cord and brainstem
- Includes the basal ganglia and cerebellum (structures of the brain)
- These structures send messages to the spinal cord through the reticulospinal tract and the rubrospinal tract

Smith College

- Behavioral view of reflexes
- Control systems for accuracy vs speed
- Spinal cord's role in controling body movement
- Motor cortexes
- Extrapyramidal systems role in motor commands
- Brain disorders and motor impairments

Motor Control 

Breedlove, S. & Watson, N. (2017). Behavioral neuroscience, eighth edition. Oxford University Press.

Behavioral Neuroscience 8th Edition

- Our motor cortices help to facilitate the movements of our body in different ways
- There are two motor cortices: 
- Primary Motor Cortex (referred to as M1) 
- Nonprimary motor cortex (which contains the premotor cortex and the supplementary motor area), is anterior to M1 

Motor Cortices

Extrapyramidal System 

Alzheimer's disease is a specific type of dementia characterized as an irreversible, progressive brain disorder, which is understood to have a genetic basis. It gradually destroys memory and cognitive skills, eventually impairing the ability to perform simple tasks like walking, talking, and eating. This severe cognitive decline is associated with the formation of plaques in the brain resulting from cell death.

Alzheimer's Disease

- When thinking about how a behavior is initiated, researchers have questioned whether it is reflexive (meaning it is caused by a chain of events without intentionality) or planned (which is defined by a motor plan)

Sequence of Initiating Behavior 

- Similarly to engineering, in order to control movement, the body must take into account two needs: accuracy and speed 
- Two types of control mechanisms (closed and open loop) are able to prioritize one of these needs when controlling movement 

Control Systems for Movement 

- Motor neurons control the beginning, end, and organization of muscle movement  
- The spinal cord is involved in motor neuron input
- Therefore, in order to understand how movement is coordinated, the spinal cord's organization (as well as ways in which its disrupted/ how it interacts with the brain) must be understood

Spinal Cord in Controlling Body Movement

- Movement disorders can be caused by disorders of the brain, including the cerebellum, basal ganglia, and cortex

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