TRACTS Flashcards
Corticobulbospinal FUNCTION
Descending
Modulates sensory input and spinal reflexes
Arises from parietal lobe
Corticospinal PATHWAY
Motor cortex -> through IC -> down into midbrain cerebral peduncles -> medullary pyramids -> top of spinal cord to decussate -> form lateral and anterior corticospinal tracts
Lateral Vestibulospinal FUNCTION
Posture and balance
Lateral Vestibulospinal PATHWAY
Vestibular apparatus inputs –> Vestibular nuclei -> ipsilateral projection to antigravity muscles
Reticulospinal FUNCTION
General arousal of spinal cord, autonomic control, drive to respiration
Reticulospinal PATHWAY
Reticular formation -> bilaterally down cord
Connects neurones from respiratory and vasomotor centres in medulla with preganglionic neurons where they synapse for autonomic control
Rubrospinal FUNCTION
Cerebellar commands carried to cord
Rubrospinal PATHWAY
Input from cerebellum -> red nucleus in midbrain -> cord
Tectospinal FUNCTION
Co-ordinates head and eye voluntary movements
Activating reflex movements of the head in response to visual and auditory stimuli
Tectospinal PATHWAY
Superior colliculus/Optic tectum -> contralateral cervical spinal cord -> laminae 6-8
Medial Vestibulospinal tract FUNCTION
DCML continuation
Mediates reflex co-ordination of the head and neck muscles with the extraocular eye muscles maintaining objects in view despite body movements
Dorsal Spinocerebellar PATHWAY
Afferents from muscle spindles and Golgi tendon organ -> brainstem -> cerebellum inferior peduncle input
Ipsilateral
Dorsal Spinocerebellar FUNCTION
Carries information from proprioceptors (joints, Golgi tendon organs and muscle spindles)
Ventral Spinocerebellar PATHWAY
Crosses in spinal cord then crosses again in brainstem
- to cerebellum
Ventral Spinocerebellar FUNCTION
Carries information about the state of reflexes in the cord
Anterior/neo Spinothalamic tract
- decussation to anterior SPT
- innervate VPL and VPM nuclei of thalamus
- also VPI nucleus of thalamus
- also lateral nuclei of thalamus
- also somatosensory thalamus
Anterior/Neo SPT -> central lateral nuclei of thalamus -> ?
- Anterior cingulate cortex (emotion/motivation)
- PF cortex and striatum -> cognitive function and strategy
Anterior neo SPT -> VPL/VPM nuclei of thalamus -> ?
- somatosensory cortex -> localisation and physical intensity of stimulus
Anterior SPT -> somatosensory thalamus ->
Secondary somatosensory cortex
Anterior/neo SPT?
Discriminative aspects of pain
- reflex withdrawal
- first to be involved
Lateral/Paleo SPT?
- mainly C fibres but some A-delta innervate projection neurons in lamina 1
- decussate posterior/medial parts of thalamus
- to mediodorsal nucleus and posterior thalamus
Lateral/paleo SPT -> mediodorsal nucleus ->
ACC
Lateral/SPT -> posterior thalamus ->
Anterior/rostral insula
emotion, quality, autonomic integration
Lateral/paleo SPT Function
Second involved
Punishing aspects of pain
- say ouch it hurts
What else does the lateral/paleo SPT project to produce unpleasant plain?
- limbic system
subjective sensations of pain and pleasure
LST collateral projection significance?
Stimulated general arousal and focussing attention of painful region
- LST travels upwards projecting to reticular formation, PAG and amygdala
What is the role of the different projections in collateral projections?
RF (arousing and alerting cortex)
PAG (descending pain modulation)
Amygdala (Limbic activation, visceral autonomic integration)
