Sensorimotor control Flashcards
classes of movement
relex
rhythmic motor patterns
voluntary
reflexes
Simplest motor behavior least affected by voluntary control rapid stereotypes involuntary controlled by stimulus sensory processing occurs in spinal cord
Rhythmic motor patterns
once initiation continues automatically until consciously termination
sensory processing occurs sub-cortically
Voluntary
Complex purposeful learnt more practice less conscious sensory processing occurs in cortex
Somatosensory System
Exteroceptive-external environment, pain touch and temperature
Proprioceptive- body position from muscle, tendon and joint capsule
Interoceptive- internal pain, unconscious sensation from deep structures
Pathway
receptor to spinal cord
spinal cord to thalamus
thalamus to cerebral cortex
Vision
Retina
Optic nerve
Optic Tract
Occipital lobe
Hearing
Hair cells cochlea
Vestibulo-cochlear nerve
temporal lobe
Somatic sensation
Skin, muscle, tendon, joint capsule
sensory fibres
sensory tract
parietal lobe
as sensation passes from brainstem to cortex it passes the through the internal capsule
Dorsal column pathway
fine touch tactile sensation and proprioception
1st order neurone-
carries information from the peripheral nerves (located in
the dorsal root ganglia) via the fasciculus cuneatus or via the fasciculus gracilis. They then synapse in the nucleus cuneatus or nucleus gracilis of the medulla oblongata.
2nd order neuron-
within the medulla oblongta the fibres decussate and travel in the contralateral medial lemniscus then synapse to to the thalamus
3rd order neuron-
the ventral posterolateral nucleus of the thalamus
transmits sensory signals , travel through the internal capsule and terminate at the sensory cortex of the post central gyrus of the partial lobe.
Spinothalamic pathway
ascending pathway
perception of temperature
crude tactile sensationtouch and pain
3 neural levels
1st order -
primary neuron from sensory receptor to spinal cord with cell bodies located in dorsal root ganglia and enter the spinal cord throught the Liassauer’s fascicles, then synapses to the ipsilateral dorsal horn
2nd order-
secondary neurons either
ipsilaterally ascend or contralaterally ascend (decussation sending axons across the midline) ascends through brainstem yo
synapses to thalamus
3rd order-
tertiary neurons axons travel through the internal capsule to synapse to the post central gyrus of the cortex somatosensory cortex of the brain
Motor System
Cerebral Cortex Basal Ganglia Brainstem nuclei Cerebellum Spinal motor neurons
to alpha motoneurone which go directly to muscle
Cerebral Cortex
primary motor cortex
premotor cortex
supplementary motor area
conscious control
complex motor and fine precision
communicates with musces via the coticospinal tract
Corticospinal pathway
frontal lobe internal capsule brain stem spinal cord peripheral nerve to muscle
originates in the cerebral cortex in the pre central gyrus from the Primary motor cortex, Premotor cortex and Supplementary motor area the neurones converge and decend through the internal capsule through the brain stem and in the caudal medulla divides into the
lateral cortical tract which decussates in the medulla pyramids and descend into spinal cord synapsing to the ventral horn with lower motor neurone supplying distal muscles.
anterior corticospinal tract which remains ipsilateral descending into the spinal and the decussates through the anterior white commisure then synapse to ventral horn of gray matter supplying proximal muscles.
Corticospinal tract
largest descending motor fibre tract from brain
Acts directly on α motoneurons via fast monosynaptic connection
important for fine finger movements
Basal Gangliaz
central gray matter important in planning controld learning sequencing and coordination of complex movement cohesive functional unit eye movement motivation decision making complex movement
base of the forebrain
planning movement
Cerebellum
produce smooth, coordinated movement and balance through perceptive input from the sensory system and interacts with motor cortex receiving information about movement
controls posture
maintains equilibrium
coordination movement on its own side
Brainstem
contain important centers involved with control of automatic movement
Contains two parallel neuronal systems medial and lateral neuronal system
Medial neuronal system
controls proximal muscles
postural control
Lateral neuronal system
controls distal limb movement
precise movement
Functional
Medial and lateral motoneurons are controlled by separate pathways
Therefore, when trying to facilitate a specific movement, you must activate postural muscles as well as specific “action” muscles.
Spinal cord
lowest level of control
many neuronal circuits mediating automatic movement
influenced by brain above
influence by sensation below
Rehabilitaion
Cortical lesion eg: stroke, head injury Brainstem lesions eg. Multiple Sclerosis, tumour Spinal injury eg. trauma, tumour
