Physiology of the Spinal Cord

Question 1

name two physiological functions of the spinal cord

Answer 1

1) initial processing of somatosensory input by the CNS
2) final processing of motor output by the CNS

Question 2

SENSATION AND PERCEPTION

i) what is sensation and what is perception?
ii) what is the range of input for a specific receptor
iii) what three ‘codes’ allow neurons in sensory systems to signal events
iv) what level of convergence is there when high spatial resolution is required? which cells does this occur in?
v) which level of convergence is required to detect weak signals? which cells does it this occur in?
vi) name a reflex that has high divergence

Answer 2

i) sensation = detection by receptors
perception = interpretation by spinal cord and brain circuits

ii) range of input for a specific receptor is narrow
iii) neurons signalling events need a combination of rate (firing frrequency), spatial (how neurons distribute their connections) and temporal (neurons firing in different temporal paterns) codes

iv) high spatial resolution requires low convergence
- this occurs in bipolar cells in the retina

v) need high convergence to detect weak signals
- this occurs in rod and bipolar cells

vi) vestibulo-ocular reflex has high divergence

Question 3

PRIMARY SENSORY RECEPTORS