KAAP220 Lecture Notes - Primary Motor Cortex, Prefrontal Cortex, Phineas Gage
11 May 2018
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Lecture 22
• The Brain continued
• Each sensory and motor region of the cerebral cortex is connected to an association area - region
that interprets the sensory data that comes in, puts meaning to it, and coordinates motor output
• Visual cortex
• Primary visual cortex - most posterior portion of occipital lobe; where all vision perceived from the
retina is directed
• Visual association area - just anterior to primary visual cortex; interprets the visual information
coming into the primary visual cortex
• Integrative centers of cerebral cortex
• Areas that take information from association areas and then deliver to motor area
• Primarily direct motor activities
• Receive information from association areas, decide what to do with it, coordinate response, send it
to the motor area to make the response occur
• Analytic functions
• In areas of both hemispheres
• But wernicke’s and Broca’s are in the left
• Frontal eye field
• In precentral gyrus
• Controls learned eye movements; for example, scanning lines of text from the left top to right
and down the lines
• Prefrontal cortex - in anterior portions of frontal lobes; integrates information from sensory
association areas; performs intellectual functions like planning, logic, reasoning, personality -
“where’s your filter?” The prefrontal cortex is your filter; notes what situation you’re in and
what the consequences of your actions may be; damage to prefrontal cortex typically results in
change of behavior and loss of self-control; functions in working memory
• Phineas Gage
• Broca’s area (motor speech area) - speech production; regulates breathing as we’re talking and
allow contraction of the muscles in the larynx and oral cavity to allow us to form and say words;
if this is damaged, you can make sounds but the skeletal muscle is no longer contracting to form
specific words; you know what you want to say and all you hear is moaning; know what they
want to say but they can’t say it
• Wernicke’s area - language association and comprehension; receiving information from
somatosensory association areas and allows us to understand the meaning behind what others
and ourselves are saying; if damaged, you can form words but you don’t make sense; depends on
why/what other areas are damaged, sometimes they don’t know but sometimes they do know
what they want to say
• Hemispheric lateralization - regional specialization of each hemisphere; even though it looks like
they’re both the same; specific functions happen only on the left or right
• Left cerebral hemisphere - specialized language areas (like Broca’s and Wernicke’s); language-
based skills (like reading, writing, speaking); premotor cortex for hand movements is larger on
left side in right-handed people than in left-handed people; analytical tasks, such as math and
logic
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Transmits crude/general touch, not very specific; and pressure from the body, pain and temperature from the body too. First-order neuron from a receptor to the spinal cord; same posterior root; ascends into the posterior white columns of the spinal cord into the medulla where it synapses. Very similar in pathway just not crossing in the spinal cord; 1st order synapses on 2nd order in medulla where it crosses to the other side: spinocerebellar pathway. Proprioceptive information from muscle spindles, tendons, and joint capsules. 1st order neuron from a proprioceptor into the spinal cord, synapses on 2nd order neuron, which ascends up and goes to the cerebellum - some 2nd order neurons cross and some do not; all ascend to the cerebellum. Allows us to know where our bodies are in space and coordinate our movement based on that information: somatic motor pathways - descending pathways, always involve at least 2 motor neurons.
