Motor and Sensory Inputs to the Brain Flashcards
Major Sensory Inputs to the Brain
Somatosensory (body sense) Pathways Spinocerebellar Pathways Vestibular Inputs Visual Inputs Auditory Inputs
Major Players in Motor Control
Corticalspinal Pathway
Cerebellum and its output pathways
Basal Ganglia and its circuits
Vestibulospinal and Reticulospinal Pathways
Somatosensory (body sense) Pathways
PNS to Spinal Cord to Cerebral Cortex
Dorsal Column Pathway
Lateral Spinothalamic Pathway
Dorsal Column Pathway
i. Conveys information about vibration, discriminative touch, and
conscious proprioception
ii. Makes synaptic “relays” in the brainstem and the thalamus
Lateral Spinothalamic Pathway
i. Conveys information about “fast” pain and temperature sensation
ii. Makes a synaptic “relay” in the thalamus
Spinocerebellar Pathways
PNS to Spinal Cord to Cerebellum
a. Receive sensory information from joint receptors, muscle receptors
b. Provide important information about position of body segments for synergy
of ongoing movements and unconscious proprioception
Vestibular Inputs:
from inner ear (vestibular apparatus) to the brainstem, cerebellum, and cerebral cortex
a. Coordinate eye and head movements
b. Link head movements to postural reflexes
Visual Inputs
from retina to the cerebral cortex and brainstem
a. Allow for processing of visual information
b. Participate in specific visual reflexes (e.g.pupillary light reflex)
Auditory Inputs
from inner ear to the cerebral cortex and brainstem
a. Allow for processing of auditory information
b. Allow for language comprehension
c. Participate in specific auditory reflexes (e.g. orientation reflexes)
The Cerebral Cortex via the Corticospinal Pathway
Cerebral Cortex to the Spinal Cord
a. Voluntary fine motor control
b. Primarily affects flexor muscles
c. When damaged the patient typically has paralysis
The Cerebellum and its output pathways
Cerebellum to cortex and brainstem
a. Coordinates postural adjustments
b. Coordinates on-going movements
c. When damaged the patient can have ataxia
The Basal Ganglia and its circuits
Circuits between the basal ganglia and the cerebral cortex
a. Involved in control of voluntary movements
b. Procedural learning of routine behaviors
c. “Action selection” the selection of a particular motor behavior to execute at
a given time
What happens when Basal Ganglia and its circuits are damaged
When damaged the effect depends on the specific location of the lesion.
Basal ganglia lesions can result in movement disorders such as Parkinson’s and Huntington’s Disease
Vestibulospinal and Reticulospinal Pathways
from brainstem to the spinal cord
a. Control
posture through regulation of primarily extensor musculature
b. When corticospinal and rubrospinal inputs to these pathways are
damaged decerebrate posturing may occur
CNS diseases
Stroke, Alzheimer’s Disease, Epilepsy, Multiple Sclerosis, Parkinson’s
Disease
