Lec 3 Neuro

determinants of speed of afferent somatosensory neurons

amount of insulation, diameter of axon

afferent projections to CNS

specific grey matter regions specific for one sensory system

association areas

sensory info converges to generate unified percept or action

topographic

ordered projection of a sensory surface

ipsilateral

same side of the body

contralateral

opposite side of the body

optic chiasm

site of visual signal cross over

primary visual pathway

geniculostriate

secondary visual pathway

tectopulvinar

left hemifield

sends info to the right thalamus

right hemifield

sends info to the left thalamus

optic tract

bundle of nerves relaying visual info from optic chiasm to LGN thalamic nucleus

retinotopic organization

optic nerve to optic chiasm to optic tracts to LGN

dorsal visual stream

where or how, vision for action

ventral visual stream

what, vision for perception

where does dorsal stream go

towards parietal cortex

where does ventral stream go

toward temporal lobe, connect to memory

vestibular nuclei

relay signals to cerebellum, thalamus, cortex, brainstem nuclei

dorsal horn

sensory neurons enter the spinal cord

ventral horn

motor neurons leave the spinal cord

motor neuron cell bodies

located in the spinal cord

sensory neuron cell bodies

located outside spinal cord in dorsal root ganglion

posterior column

nerves convey fine touch, vibration, and proprioceptive afferent info

first order neuron

axon projects from receptor to medulla

second order neuron

axon crosses the body midline in medulla and projects to thalamic nucleus

third order neuron

axon projects from thalamic nuclei to primary somatosensory cortex

anterior spinothalamic tract

unrefined, poorly localized information about touch

lateral spinothalamic tract

information about noxious stimuli and temperature

dorsal spinocerebellar tract

proprioceptive information from lower limbs (spindle fibres from 1a afferent neurons)

rostral spinocerebellar tract

proprioceptive information from upper limbs

projection of DSCT

to inferior peduncle of cerebellum (cuneocerebellar tract)

projection of RSCT

to inferior peduncle of cerebellum

ventral spinocerebellar tract

proprioceptive information from lower limbs (golgi tendon organs from 1b afferent neurons)

projection of VSCT

to superior peduncle of the cerebellum