motor learning physiology Flashcards
week 2 lecture 3 - part of exam 1
what is NOT an overlapping factor in evidence based clinical practice?
- clinical expertise
- personal preferences
- research
- client characteristics
personal perferences
CNS –> Brain –> forebrain –> telencephalon, diencephalon –>
telecephalon –> cerebral cortex, basal ganglia, hippocampus, amygdala
diencephalon –> thalamus, hypothalamus
Neurons have excitatory postsynaptic potential created by action potential and dies away after 3-4ms exept with summation
what are the types of summation
- spatial summation (simultatneous stimulation by several presynaptic neurons)
- temporal summation (high freq. stimulation by one presynaptic neuron)
what are the processing level of the CNS from highest to lowest level
cerebral cortex
diencephalon
cerebellum
brain stem
spinal cord
spinal level action stays low in the processing level and s a simple relationship between sensory input and motor output
some examples include:
- organization of reflexes
- simple responses to sensory input
- flexion/extension patterns associated with leg movements
waht kind of movemetn is the brain stem involved in?
- postural control and locomotion
- contains sensory and motor pathways
reticular formation: regulates arousal
what motions is the basal ganglia involved in
- action selecation
- preparation of movement
- execution of movement
- seequencing of movement
- movement control (force)
- interanlly guided movements (self- initiated or remembered)
-** reinforcement/reward based learning (dopamine is released here)**
where is dopamine released?
basal ganglia
parkinsons affects what part of the brain
basal ganglia
what occurs at the corticobasal ganglia loop?
- inhibition of unwanted movements
- excitation of desired movements (dopamine)
what occors at the basal ganglia brainstem system
- gait and balance
- integration with cerebellum
automatic control
basal ganglia has the direct and indirect pathways - what is the role of each
direct: MSIT
- turning off the inhibition (substantia nigra- through gaba) produces planned movement
indrect: MSENIT
- turns on the inhibition (substantia nigra- through glutamate). cessation of planned movement
cerebellum
input from the spinal cord:
input from the cortex:
other roles in motor control
input SP: gets feedback about movement and then refines
input cortex: info on planning movements
- coordinates motor responses
- error detection and correction
- involved in motore learning
- involved in externally (especially visual) guided movementes
what are the 3 subdivisions of the cerebellum?
spinocerebellum:
cerebrocerebellum:
vestibulocerebellum:
primary function of spinocerebellum
monitor and fine-tune limb movements.
- this is achieved by proprioceptive input from the dorsal column pathway of the spina lcord, the cranial treigeminal nerve, the visual and auditory systems as well as the spinocerebellar tract
primary function of cerebrocerebellum
- concerned with planning future movements and als osome purely cognitive functions such as matching verbs to nouns (“run” for the “track”)
Diencephalon
thalamus: role
relay station –> mail room
- accepts and sifts all sensory info
- processes info from the spinal cord, cerebellum and brainstem
involved in:
- leraning
- long term goal oriented behavior
- arousal
- memory
- abstract thinking
diencephalon:
hypothalamus: role
links nervous system to endocrine system
- hormonal control and regulates areas for thirst, hunger, body temp, water balance, BP
hypothalamus has input to where?
- brainstem (visceral, somatic)
- limbic system
- cerebral cortex
- retina
- non- neural inputs: blood temp, osmolarity, hormone levels
hypothalamus has oututs to where?
- thalamus for cortical targets (neural)
- to autonomic nervous system (neural)
- to pituitary gland (neural and neuroendocrinal)
premotor cortex roles
**planning and initation of movements related to external events **
- activates multiple muscles at multiple joints, which gives rise to more coordinated movements (refining)
- visually guided movements
- recieves input from cerebellum
supplementary motor are (SMA) role
- planning and initaion of internally guided movements (motivation)
- remembered or self guided movements
- imagined/mentally rehearsed tasks
- receives input from basal ganglia
remember basal gangalia has direct and indirect pathways, either producing planned movement or inhibiting planned movement
SMA + premotor cortex both areas interact with:
- sensory processing areas
- primary motor cortex
how does the SMA and premotor cortex work together?
both are involved in the motor cortex - they are the two non primary motor cortexes of the motor cortex that are located in the frontal lobe.
the SMA is involved in the executions of sequensing movements, attainment of motor skills AND premotor cortex helps planning the movement
What is a similarity betwen
basal ganglia, cerebellum and primary motor cortex
all perform speed and force of movement
primary motor cortex
- contains a complex map of the body
- receives input from multiple sources
- outputs to motor neurons; contriubtes to corticospinal tract (~50%)
- primarily creates single joint movments
- controls force and speed of movement
somatosensory system
conscious perception of pressure, touch, pain, temp, position, movement and vibration
- a 3 neuron system, relays sensations detected in the periphery and conveys them via pathways through the spinal cord, brainstem, and thalamic relay nuclei to the sensory cortex in the parietal lobe
- includes neurons from teh lower to highest level of the CNS hierarchy
- signals from periphery –> integration and interpretation in association cortex
somatosensory input
somatosensory cortex :
thalamus:
spinal cord level:
ascending pathways:
somatosensory cortex:
- conscious awareness of sensory input
- cross modality integration
- localization of movemetn in specific body areas
- beginning of spatial processing
thalamus:
- all sensory input goes here
- processing and distribution of all sensory input
spinal cord level:
- reflexes
- modulation of central pattern genreator out put (how much force is used)
ascending pathways:
- two systems faciliatate parallel processing and some redundancy ( good to have different ways to get into to the brain)
somatosensory cortex
- major processing area for all somatosensory modalities; marks beginning of conscious awareness of somatosensation
- processes incoming info to increase contrast sensitivity (vision)
- ID and discriminate between different objects through touch
primary vs secondary somatosensory cortex
primary: kinesthetic and touch info from contralateral side of body, organzied in a somatotopic manner
secondary: won’t talk about in this class- just know it exsists
somatosensory homunculus
meidal is genitals/toes/foot and moving laterally to leg, trunk, neck, arm, elobw, hand, eye, nose, face, tongue, pharynx, intra abdominal
somatosensory system - peripheral receptors
muscle spindle
- intrafusal muscle fibers
- group Ia and II afferent neurons
- gamma motor neurons
- stretch reflex loop
golgi tendon organs
joint receptors
cutaneous receptors
muscle spindle
spindle shaped sensory receptors located in the muscle belly of skeletal muscles
consists of:
- very small muscle fibers call intrafusal fibers
- sensory neuron endings - Group Ia and group II afferent
- gamma motor neuron endings
role of muscle spinles in motor control
detect both absolute muscle length and changes in muscle length
helps finely regulate muscle length during movement
- our CNS programs how far a muscle can stretch, muscle spindle allows us to “play” with that a little more
give an example ofthe stretch reflex loop
gastrocnemius muscle is stretched –> muscle spindle Ia afferents in muscle are excited –> alpha motor neurons ofthe gastrocnemiu are excited –> simultaneously Ia inhibitory interneuron to antagonist muscle –> contraction occurs
our body is tryingto prevent an injry
Golgi tendon organs (GTO)
- spindle shpaed, located at the muscle tendon junction (closer to tendon)
- afferent info only via Ib afferent fibers (not subjectot CNS modulation)
- sensitive to tension changes from either strethc or contraction of muscle
- inhibits its own muscle and excites anatagonist (opposite of muscle spindle)
the GTO protects muscles from?
- injury
- constantly mointors muscle tension
- modulates muscle output in responses to fatigue
except
- GTO’s of extensor muscles of the LE are active during stance phase of locomotion, exciting extensor muscles and inhibiting flexor muscles until unloaded
how does PNF work with the deep golgi tendon reflex?
shuts the antagonist down and allows for more length
what is required for a complete and accurate detection of movements?
combination of skin, joint and muscle receptors is required for a complere and accurate detection of movements
there are many joint receptors and they will proivde a danger signal when?
provide a danger signal aobut extreme joint motion as a defense
cutaneous receptors - 3 of them
mechanoreceptors –> pressure
thermoreceptors –> temp
nociceptors –> pain
what are 2 vestibular contributions to motor control?
gaze stabilization
- vestibulo-ocular reflex (VOR)
balance and posture
- orientation with respect to gravity
- rapid change in position
(helps us understand w/moving vs. gravity, think like car sickness)
What is the vestibulo-ocular reflex (VOR)
gaze stabilization
- maintains a visual image on the retina during head turning
- reflex adjestment of eye position when there is movement of the head
(eyes and head move in opposite direction, like eyes stay still while had moves)
cerebral cortex and sensory processing
frontal:
parietal:
temporal:
occipital:
- controls volunary movement
- perception of sensory INput
- auditory perception, memory, abstract thought and judgement
- visual perception
sensory processing - posterior parietal lobe
receives input from?
coordinates vision how?
may be a storage site for?
- receives input from somatosensory areas, visual system, and premotor ares
- coordinates visual (spatial) info with movement (involved w/ visualy guided movements)
- may be storage site for motor programs
clinical considerations
patient may have only one part of visula system in poor conditions… make sure ______ _________ is fixed on object during new task
central vision
what is going on
sensory map and info on the task
- kinesthetic sensation and other sensory organs
make a movement plan
- parietal lobe
- sma and pre motor cortex
plant is sent
- motor cortex (muscle groups are specified)
- cerebellum and a basal ganglia (modify and refine)
muscles are activated
- desending motor pathways - spinal cord - motor neurons
movement is updated
- cerebellum
- sensation
- spinal reflexes ( GTO, muscle spindle)
then info is sent back to motor cortex/cerebellum to modify and refine
