PHYSIOL [B] motor Flashcards
role of cerebellum in voluntary movements:
compares planned action to actual action and helps correct disparity
- think touching your nose diagram!!
- drunk symptoms when it screws up
describe descending projection pathway:
primary motor cortex receives input from premotor areas
projects info to spinal cord through corticospinal tract
info goes to motor neurons and interneurons
what is the hierarchy of motor control?
premotor and non-motor cortical area basal ganglia cerebellum motor cortex brainstem spinal cord - execution
describe the path sensory info takes from skin to muscle:
receptors in the skin pick up sensory info -> dorsal ganglion(cell bodies) -> interneuron in spinal cord -> afferent pathway -> thalamus -> primary somatic sensory cortex -> primary motor cortex -> efferent pathway -> spinal cord -> muscle!
what info does the somatosensory cortex provide?
sensory info required for specific planning, initiation and ongoing movement
explain the concept of “plasticity” of the brain
brain can remodel itself in response to varying demands
eg. phantom limb, cortex normally dedicated to hand was dedicated instead to face
expansion due to training
2 main areas of sensory cortex?
primary somatosensory cortex
posterior parietal cortex
function of posterior parietal cortex(more towards back of brain):
encodes complex sensory info to ensure planned movement is matched to the external environment
guides movements of eyes, head, arms and hands
what areas does the posterior parietal cortex receive input from?
visual, auditory, somatosensory
3 mains areas of the motor cortex:
premotor cortex
supplementary motor area
primary motor cortex
function of premotor cortex:
involved with planning and coordination of movements in response to SENSORY MOVEMENTS
function of supplementary motor area:
active during planning and coordinating INTERNALLY-GUIDED movements
function of primary motor cortex:
controls simple features of movement
what does EMG stand for?
ElectroMyoGraphic
where do afferent fibres enter spinal cord?
through dorsal root
where do efferent fibres exit spinal cord?
ventral root
how are motor nuclei are interconnected across segments of the spinal cord?
by propriospinal neurons (interneurons?)
how are the motor nuclei of the spinal cord arranged?
along medial-lateral axis according to function
ie.
most medial nuclei => innervate proximal muscles
most lateral nuclei => innervate distal muscles
function of spinal cord?
integration of many basic reflexes, such as the withdrawl reflex
pathway of pain reflex:
pain receptor -> afferent pathway -> interneuron -> efferent pathway -> flexor/extensor muscles -> withdrawal response
where are voluntary movements organised?
cortex - primary motor cortex controls simple features of movement
what neurotransmitter is deficient in Parkinson’s disease?
dopamine
define voluntary movement:
continuous spectrum of movements ranging from most automatic to least automatic
what is muscle excitation-contraction coupling?
series of events linking muscle excitation to muscle contraction