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Glossary of Lecture 13: Psych 345

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Created by jamiegallup

Who was Gustav Fechner?
father of experimental pscyh 1801-1887
Commisures:
projection of fibers that connect structures on the R and L side of the brain: interhemi pathways
Corpus collosum:
largest commisure: large white matter structure
In the medial view of the CC what is seen?
white matter
In the coronal section of the CC what is seen?
bridge of fibers that connects R and L hemi
Rostral region on the CC:
interconncets the L and R orbital frontal cortices
Genu region of the CC:
interconnects the PFCs
Rostral body of the CC:
interconnects the superior frontal and motor cortex
Caudal body of the CC:
interconnects parietal/somatosensory and temporal/auditory
Splenium of the CC:
connects occiptial cortices: Area 18 and 19
Area 17 is __ connected via CC
not
Five regions of the CC:
1. Rostral
2. Genu
3 Rostral Body
4. Caudal Body
5. splenium



Homotopic interhemi connections:
connections within the same region: L V2 connects w/ R V2
Reciprocal connections: project both ways
Heterotopic interhemi connections:
Connect diff regions
L V2 connects R V3
Interhemispheric connections are __
contralateral
What/where pathways are:
intrahemispheric pathways
Intrahemispheric connections are __
ipsilateral
Seziure:
abnormal excessive or synchronous neural activity
Normal brain activity controlled by __ stimulation
external
Normal brain activity goes ___ with seziures and excessive __ ___
wary, electrical storm
Epilepsy:
chronic seziure disorder
Intractable epilepsy:
not responsive to medication and requires surgery
Two types of surgery for epilepsy:
1. focal origin
2. Commissurotomy
Focal origin surgery for epilepsy:
lobectomy - remove scar tissue, lesion/lobe
Generalized intractible seziure disorder:
not focused on particiular spot in the brain and focal surgery will not work
Commissurotomy:
surgical cutting of the commisures to treat generalized seziures
Experimental background of commissurotomy surgery:
1930s on monkeys
reduced spread of epilepsy
How does commisutory surgery reduce epilepsy?
1. reduced response/generation of mirror focus - abnormal activity of one side of the brain ends up to the other hemi b/c of CC
Mirror focus:
Seziure in one hemi will go to homotopic regions b/c of interconnection of the commisures, will have bilateral seziure foci
First human commissurotomy procedure in __ in __ by __ __
NY, 1940s, Van Wagen
Behavioral testing of Van Wagen's pts by Akelaitis revealed:
only minor motor disturbances
What did Akelaitis say of the CC?
no psych functioning b/c only the minor motor disturbances, mixed success in relieving epiliepsy w/ procedure so believe CC has no psych fxn
What did the intact animal in Visual split concept by Sperry and Gazzanig perform as:
Sensory and callosal transfer of info from R to L hemi
Shared b/w hemi b/c each eye projects to each hemi
What did the split chiasm animal in Visual split concept by Sperry and Gazzanig perform as:
Cut chiasm: info from L eye no longer crosses to R hemi
Still have an intact CC, RH still be informed what is in RVF - info shared b/c CC spared
What did the split chiasm and split cc animal in Visual split concept by Sperry and Gazzanig perform as:
no visual transfer
info isolated to the LH and RH no knowledge of what is in the LH
What were the control and experimental groups of the Myers and Sperry cat object learning:
Experimental: split chiasm and CC
put patch on other eye while learning
don't retain or never acquire info about assoc., learning experience of hemi unavaliable to other hemi
Control: results for learning same: patch 1 eye so L eye being trained, both hemis can learn no matter what eye is patched


Conclusion from the Myers and Sperry cat object learning:
CC essential for integrating cognitive experiences (learning) mediated by each hemi
What did the disconnection syndrome reveal?
Separate spheres of cognition w/ split brain pts
Diff hemi fxns
What always gets cut in a commissurotomY?
CC: connects occipital, parietal, frontal and parts of the temporal
What sometimes gets cut in a commissurotomy?
Anterior commissure: sep from CC and connects temporal and limbic system
Hippocampal commisure: part of the fornix that's inadvertantly cut b/c lies under the CC
What never gets cut in a commissurotomy?
Collicular commisure: connects the L and R superior colliculus
Posterior commisure: import for R bilateral pupillary light reflection
Optic chiasm

Callostomy:
pt only has the CC cut
Staged callostomy:
2 consecutive surgeries:
1. only anterior or posterior part of CC cut: more interhemi communication spared - visual info shared b/w hemi
2. Full callostomy if needed

Who gets callosal surgery?
Most effective for anotonic/drop attacks --> seziures that lead to loss of muscle tone and have tonic/grand mal seziures
Partial callostomy reduces: __-__% Complete reduces: __ - __ %
70-80
80-90

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