cerebrum Flashcards
praxic
how
fcn of cerebral cortex
intentional programs
when
fcn of basal ganglia and cerebellum
elements of voluntary movement
- locate and identify target
- movement programming
- execution of the movement
external cues
PMC, PMA
sensorimotor transformations
internal cues
SMA
M-1
primary motor cortex
Brodmann’s area 4
precentral gyrus
motor homonculus - feet medial
neurons of Layer 5 become corticospinal tract with varying levels of divergence
fcn - fine, well-defined distal movements around a single joint
low electrical threshold
kept informed through thalamocortical connects and inputs from S-1 about position of limb and speed of movement
PMC
premotor cortex
Brodmann’s area 6
superior and middle frontal gyri, lateral aspect
6* larger than M-1
imprecise motor homunculus
connections w/ M-1, SMA, *PMA
outputs to brainstem RF
small contribution to CST, proximal and axial m.
- elicits complex motor responses
*prepares motor system, less during - planning
*triggered by external stimuli incl. visual stimuli
*planning and executions reliant on sensorimotor transformations done here and PMA
*coordinated movements of a limb - multiple joints ex: reaching, grasping
SMA
supplementary motor area brodmann's area 6 medial and superior frontal gyrus imprecise motor humunculs small contribution to CST - proximal m. extensive connections w/ M-1 & PMC high threshold for movement coordinates complex movements on both sides of the body directly and indirectly - postures, dancing internally generated movement selects motor programs via presupplementary cortex that learns them and stores them
PMA
posterior parietal motor area
brodmann’s 5&7
parietal lobe
inputs from s-1, PMA
area 5 - vestibular system (proprioception of head) and PMC motor plans and limbic system - motivational state
area 7 - visual and auditory inputs
fcn - correlates information about external world, proprioception, and motivation
- modulated by state of attention
- initiation of movement via frame of reference
-sensorimotor transformations
FEF
frontal eye field
posterior portion of middle frontal gyrus
Brodmann’s area 8
initiates rapid eye movements - horizontal or oblique conjugate eye movements to the contralateral side (saccades)
lesion to FEF
unilateral- gaze preference to the side of the lesion at rest and an inability to voluntarily look to contralateral side, no inhibition of vertical eye movement
bilateral - no saccades at all
S-1
primary somatosensory cortex
projects of M-1 and PMA directly
contributes fibers to CST that terminate in the dorsal horn of the spinal cord that modulate incoming sensory information before conscious awareness
lesions can cause apparent motor deficits really cause by the lack of sensory info
prefrontal cortex
part of frontal lobes anterior to PMC, SMA, FEF
helps regulate complex motor activities through connections with PMC, SMA and PMA
receives info about all senses and motivational /emotional state
ability to weigh consequences of actions and plan acordinly
prefrontal cortex lesions
alterations in attention, motivation, and ability to change a response when a stimulus changes
M-1 lesions
UMN signs
paresis
inability to make fine distal movements
pronator drift test
