Section 3 - Brain Areas, Function, and Damage Flashcards
Primary Motor Cortex (M1)
location - precentral gyrus
organization - somatotopic
functions - target location, speed, force, and direction. initiate movements
receives input from - M2, PFC, S1
damage - contralateral deficits, astereognosis, response weakness, difficulty moving body parts independently
Secondary Motor Areas (M2)
location - premotor cortex & SMA
organization - reciprocally connected to each other and the M1
function - premotor cortex: movement preparation (guided by visual signals); SMA: preparation for rapid sequences of movement. BOTH: electrical stimulation elicits complex movement and neurons fire during and prior to voluntary movements.
Damage - complex movement disorders, difficulty in developing and planning movement strategies
Sensorimotor Association Areas
location - prefrontal cortex and posterior parietal
organization - highest in sensorimotor hierarchy
function - PFC: controlling, adapting, and being flexible with behavior, working memory; Posterior Parietal: multimodal integration, action intention, body and object position references
Damage - Posterior parietal: Apraxia, contralateral neglect
Motor “Homunculus” explains that
the somatotopic organization of the M1 is representative of the fact that larger brain areas are devoted to body parts that are used more and the body parts that are next to each other are near each other in the brain
Which cortical motor area receives input from the PFC, M2, and S1?
the primary motor cortex (M1)
Astereognosis, the inability to recognize objects by touch, is a frequent result of damage to which area of the brain?
the primary motor cortex (M1)
Does damage to the M1 cause long term paralysis?
No.
A monkey who is unable to reach behind a glass walk to reach and object is demonstrating damage to which brain area
Secondary motor areas (specifically Premotor cortex)
Lack of coordination between two hands preventing a monkey from being able to remove an object from a container is a result of
Damage to the SMA - coordination of two hands is a sequence of movements
A test done where patients are asked to demonstrate how they will use a certain object is a test to examine the function of
the posterior parietal cortex (testing for action potential)
The inability to do what is asked, also known as apraxia, is usually caused by
damage to the posterior parietal
Contralateral neglect typically occurs with damage to the ____
right parietal
Descending motor pathways
function - M1 sends signal to motor neurons in the spinal cord through these two tracts
dorsolateral: fingers, toes, wrist
ventromedial: shoulders, trunk, hips, legs
Subcortical Motor Areas
inputs - cortical motor areas, brainstem, sensory system
outputs - different levels of cortical motor circuits
Cerebellum
anatomy - two hemispheres with three pairs of deep nuclei; topographic organization; highly regular organization
function - coordinating timing, smooth movements, motor learning and classical conditioning
damage - ataxia; learning problems
