PSYC 311 Lecture Notes - Lecture 9: Commissurotomy, Optic Chiasm, Michael Gazzaniga
8 Jun 2018
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May 16, 2017
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Lecture 9: Midterm Review
Midterm:
- Will have a coronal section and need to identify the structure
The somatosensory cortex
- Brodmann identified 3 cytoarchitectonic areas on the post- central gyrus (area 3,1,2)
- We now know that there are three different homunculi and that the maps are mirror
images of one another
- Each area is responsible for something slightly different
o Area 3-> the real S2-> Neurons have small receptive fields and respond to tactile
stimulation of contralateral side of body (continuous response if continuous
stimulation, direct somatosensory input)
o Area 1-> Receptive fields are bigger. Neurons seem to code vibrations of tactile
stimulation (e.g. neurons respond when apply and remove stimulus)
o Area 2-> receptive fields are even bigger. Neurons seem to respond to fine
changes in joint position
â–Ş Convergence of information
â–Ş As you move posteriorly, converging information, not as direct input as
area 3
Posterior parietal cortex
- All of this information is sent to the anterior SPL and IPL
- In these areas, neurons don't respond to tactile stimulation anymore
- Rather, research by Japanese investigator Sakata** ( monkey research) shows neurons
there respond to extremely specific body movements ( right hand to left shoulder)
- In other words, there is an integration of information about the body so that neurons
code specific body movements and postures
- It turns out that patients with damage to the pariatal lobes lose their body schema
o Touch your nose
o Where is your right arm in this moment
o Examiner may poit to a drawig ad sa  idetif this od part o our ow
od
o Patients with damage in parietal lobes cannot do these things. They lose the
ability to interpret how their body is organized in space
- Conclusion: therefore, our general understanding of the parietal lobes is that they
integrate somatosensory information from the post central gyrus and visual information
from the occipital lobes to code for the organization of the body in space
- This includes coding for the orofacial musculature -> move the mouth, tougue, face in
specific ways to produce specific sounds for speech -> direct connections with 6 VR
(ventral rostral) and 44 -> therefore damage here could cause problems like those seen
in conduction aphasia -> warrington and Shallice (phonological working memory)
- 6 VR: direct connection to anterior superamarginal gyrus
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Will have a coronal section and need to identify the structure. Brodmann identified 3 cytoarchitectonic areas on the post- central gyrus (area 3,1,2) We now know that there are three different homunculi and that the maps are mirror images of one another. Neurons seem to code vibrations of tactile stimulation (e. g. neurons respond when apply and remove stimulus: area 2-> receptive fields are even bigger. Neurons seem to respond to fine changes in joint position: convergence of information, as you move posteriorly, converging information, not as direct input as. All of this information is sent to the anterior spl and ipl. Rather, research by japanese investigator sakata** ( monkey research) shows neurons. In these areas, neurons don"t respond to tactile stimulation anymore there respond to extremely specific body movements ( right hand to left shoulder) In other words, there is an integration of information about the body so that neurons code specific body movements and postures.
