McLean Somatosensory

4 qualities of stimulus

modality

location

intensity

duration

intensity

firing

duration

adaptation to a prolonged stimulation

slowly adapting

firing whole time

rapidly adapting

firing twice

receptive field

the space within the receptive sheet in which the sensory receptor is located and in which it transduces stimuli

what is in the receptive field

gradient

when is the highest receptive field

center

gets lower as you move to the periphery

AP is proportional to

intensity

what can a neuron tell us_

location and intensity

what do 2nd neurons have_

surround inhibition

what does surround inhibit do_

increase spatial resolution localize the stimulus better

when should you use two point discrimination_

for body regions with the *highest innervation densit*y and amount of cortical area devoted to them

function of medial lemniscus system

proprioception

vibration

contributes to reflexes

medial lemniscus system ‘ 1st

enters dorsal column in spinal cord with sensory afferent info about proprioception

medial lemniscus system ‘ target

primary somatosensory in brain

trigeminothlamic tract

large mechanoreceptors from face trigeminal

synapse at VPM in thalamus

primary somatosensory in cortex |

nociceptors

mediate transduction of pain

thermal receptors

Mediate transduction of cold, cool, warm and hot

spinothalamic

afferent info about pain and temp in dorsal horn

synapses contralateral at medulla ‘ VPL

primary somatosensory

what happens if there is damage to somatosensory cortex_

contralateral sensory deficits

what is cortical map plasticity

ability of the brain to reorganize in response to environment

posterior parietal complex

somatic sensation

where things are from visual inputs

neglect syndrome

body or part of world ignored

agnosia

inability to recognize

astererognosia

loss of ability to perceive the form of object by sense of touch