- Common motor impairments caused by damage to the cerebral cortex include paralysis (plegia) or weakness (paresis) of voluntary movements, which typically happen one side of the body 
- This also includes increased rigidity caused by forced movement of limbs (known as spasticity), since the cortex no longer inhibit this response
- Damage to nonmotor zones of the cortex can cause apraxia (which can be further specified by ideomotor or ideational apraxia), which creates an inability to begin/ perform complex movements even while not being in a state of paralysis/weakness

Cerebral Cortex and Motor Impairments 

- Two of the most well known diseases associated with damage to the basal ganglia include Parkinson's disease and Huntington's disease 

Basal Ganglia and Motor Impairments 

- The cerebellum's three major subdivisions are responsible for specific functions, which can cause specific motor and (subsequent) behavioral impairments when damaged 
- These subdivisions include the spinocerebellum, cerebrocerebellum, and vestibulocerebellum

Cerebellum and Motor/ Behavioral Impairment 

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

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

- 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

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

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