PSYC 311 Study Guide - Summer 2018, Comprehensive Midterm Notes - Temporal Lobe, Cerebral Cortex, Lesion
12 Oct 2018
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PSYC 311
MIDTERM EXAM
STUDY GUIDE
Fall 2018
PSYC311: Lecture 1: Neuroanatomy 1:
Cerebral Cortex:
- Cortex means “bark” → This is a sheet of cortex made of grey matter (lots of neurons and
computations occur here). We will focus on this area.
- In a primate brain, the cerebral cortex is highly developed → this is because of the higher level
processes are occurring here.
Subcortical levels:
- Found beneath the cerebral cortex and regulates basic biological processes like hunger, thirst,
sleep, alertness, basic movement and reflexes. We won’t be focusing on these in the course.
The Cerebral Cortex has four lobes…
- Occipital lobe, Parietal lobe, Frontal lobe, and Temporal lobe.
Central sulcus:
Located between frontal and parietal lobe. In front
of the central sulcus, there is the pre-central sulcus
(in frontal lobe). In the back, we have the post-
central sulcus (in parietal lobe).
On the pre-central sulcus we have the primary
motor cortex and in the post-central sulcus you
have the primary somatosensory cortex.
These two areas work together → every
movement creates sensory feedback, and this
feedback is necessary to guide motion.
On the pre-central gyrus, there are
cytoarchitectonic areas (columns of neurons). The
motor area contains two and possibly three
specific cytoarchitectonic areas.
The somatosensory cortex contains three specific cytoarchitectonic areas. One is responsible for simple
touch, the other for vibration and the last for somatotopy. (I think).
Penfield:
- Famous for surgical treatment of epilepsy.
- In the 1930s/40s, there was no imaging technology.
- When surgeons opened up the brain, how did they know where they were looking? They needed
to electrically stimulate the areas of the cortex to tell.
- If on the pre-central gyrus, you would get a twitch on a part of the body. If on the post-central
gyrus, the patient would report a funny feeling on a part of their body.
Rasmussen: Took over in the 1960s.
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Feindel: Last trainee of Penfield.
Although Fritsch and Hitzig discovered the motor and somatosensory cortex experimentally in animals, it
was actually Penfield that managed to do it in humans and has created one of the most famous images of
all time → Penfield’s Homunculus → an orderly arrangement of physiological function along the cortex.
Somatotopic representation: Soma (body), topic (place) → each part of the motor cortex represents its
own parts of the body.
If you stimulate the motor cortex on the left hemisphere, you get movement on the right hand. This
represents contralateral representation.
In summary, he discovered two main things:
◼ Different parts of the body are controlled by specific parts of the pre-central gyrus
◼ Motor cortex has contralateral representation.
Although all of us have a central sulcus, they are all slightly different from each other. The folding
patterns are unique like fingerprints.
There is a lot of cortex dedicated to the hands, lips, and mouth in humans. For rats, there is a large space
dedicated to whiskers → it depends on the kind of animal → which parts of the body are important to
them?
If the cortex was a simple sheet, we would be way further ahead in discovery than we are. Unfortunately,
since the intricate folding patterns, it creates complexity and problems in cutting the tissue optimally,
staining it, and relating the sulci to its function etc.
Terminology:
- Gray matter: Mostly neurons
- White matter: Mostly axons
find more resources at oneclass.com
find more resources at oneclass.com
