Sensory Physiology (Karius) Flashcards
what kind of channels do touch receptors have and what opens them?
sodium channel
opened with deformation of the cell membrane
in sensory neurons the start of the action potential is called what
generator potential
what are 2 ways to start an action potential
if the stimulus is strong enough or lasts long enough
what is the best studied touch receptor
pacinian corpuscle
how does the pacinian corpuscle receptor work
when touch something all layers of the membrane are deformed, fluid inside membranes
-leads to opening of mechanosensitive Na+ channels on the membrane and influx of sodium
what happens if the stimulus to a touch receptor is maintained
action potential gradually die away as adaption occurs
-due to redistribution of the fluid in the corpuscle
what happens with adaption after removal of the stimulus
and what is it called
triggers AP as ending reforms, this is an afterdischarge
what is a receptive field
area from which stimulation produces activation of the neuron
what are 2 ways to code for intensity of stimulus
number of action potentials
pattern of APs
coding stimulus intensity
a change of about ___% is usually required for conscious recognition of the change
10%
perceived intensity vs actual intensity depends on what
-2 types
type of sensory receptor
- muscle senses are 1 to 1
- cutaneous is more variable
dorsal columns are important for
proprioceptive and discriminative (fine touch)
spinothalamic tract is important for
thermal, nociceptive, and coarse touch (less specific)
pre-synaptic inhibition, neuron A,B,C
when C is activated it releases GABA which causes Cl- to enter neuron A and hyperpolarize the cell. not as much calcium can now come in and less NT is released from Neuron A
-reduces AP potential in cell B
where does pre-synaptic inhibition occur?
-purpose?
between neighboring receptors at the first synapse in their pathway
-increases brain’s ability to localize signal
each column in the cortex deals with ____ sensory modality in ___ part of the body
one, one
sensory information arrives at what of the 6 layers in the cortex for a column via __
4 via thalamus
neighboring coluns receive info from the ____ part of the body but ___ modality
same, different sensroy modality
-ex: copuscle touch and thermoreceptor
S1 and S2 damage causes what
if S1 damaged S2 doesn’t work
if S2 damaged, does not affect S1
somatic sensory area 1 location
post-central gyrus
broadman’s area 1,2,3
somatic sensory area 2 location
wall of lateral fissure
S1 function
integration of the information for position sense as well as size, shape discrimination
- not complete
- feeds processing to S2
S2 function
required for cognitive touch
- stereognosis
- comparisons between 2 different tactile sensations
- determine whether something becomes a memory
parieto-temporal-occipital association cortex required for what
-receives input from where
required for high-level interpretation of sensory inputs
-receives input from diff sensory cortical areas, including S1 and S2
