BIO 365S Lecture Notes - Lecture 11: Receptive Field, Sensory System, Parietal Lobe
Large vs. Small receptive fields: Convergence
Sensitive vs. insensitive parts – convergence.
Big converge = lots of receptors on skin, but signal conduction when
converges (only one neuron processes the 3 different receptors). High
resolution = low/no convergence.
More sensitive = different neurons activating separate pathways to the
brain.
Have limited amount of neuron, cannot afford to make every body part
so sensitive, so certain body parts have convergence and some have
low sensitivity.
Perception of something is based on neuronal activity. For
convergence, no matter which colored area you touh, it does’t
matter (pro = save neuron for areas you care about; cons = low
resolutio), so you feel like it’s all oig i fro the sae area.
Divergence = one receptive field, one neuron responsible for it. When
activate, brain will know exactly which area specifically. High resolution,
BUT uses a lot of neuron for this area.
CNS must distinguish 4 properties of a stimulus:
1.Nature/modality
2.Location
3.Intensity
4.duration
5 senses = transfer stimulus into action potential. All the action
potetial are the sae eause they’re the sae size, so they all eed
to be able to code the 4 properties/information above.
1.If action potential comes from 1st/2nd/etc. senses, each is responsible
for a different physical stimulus.
3. Taste, touch, smell = already have location defined because of the
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one area that you concentrate the sensory info at.
All 5 senses = can tell location.
2. Where signal comes from; for visual system, not too difficult; for
auditory it’s harder eause sound coming from left or right goes
through both ears (brain must be able to resolve this because you
yourself knows where the sound came from = sound coming from left
goes to left first, and going to the right will take 1 ms slower to create
an action potential, so brain catches the time difference; if sound
traels as fast as light the this o’t ork)
FYI: Interaural time differences for
different positions around the head
Center part = more pressure than peripheral.
Brai ats to e % sure, do’t at to guess = through euro
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Document Summary
Big converge = lots of receptors on skin, but signal conduction when converges (only one neuron processes the 3 different receptors). More sensitive = different neurons activating separate pathways to the brain. Have limited amount of neuron, cannot afford to make every body part so sensitive, so certain body parts have convergence and some have low sensitivity. Perception of something is based on neuronal activity. For convergence, no matter which colored area you tou(cid:272)h, it does(cid:374)"t matter (pro = save neuron for areas you care about; cons = low resolutio(cid:374)), so you feel like it"s all (cid:272)o(cid:373)i(cid:374)g i(cid:374) fro(cid:373) the sa(cid:373)e area. Divergence = one receptive field, one neuron responsible for it. When activate, brain will know exactly which area specifically. But uses a lot of neuron for this area. Cns must distinguish 4 properties of a stimulus: 5 senses = transfer stimulus into action potential.