PSYC 110 Lecture Notes - Lecture 9: Childhood Amnesia, Hindbrain, Occipital Lobe
27 Jun 2018
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Historic brain ->
Galen: First neurosurgeon
Predominant theory - Animal spirits produced in the heart and flowed to the ventricles where they were
stored and used for movement and sensation. Ventricles were the instrument of the soul, but the brain
tissue itself was the seat of intellect (animal spirits flowed into the brain as well as the nerves) -
considered to the run the body - idea of soul and the soul was in a particular part of your brain. When
they looked at the brain, they saw empty caverns - when it is in an alive person, it is filled with cerebral
spinal fluid but its all drained out in a dead person and they believed that the animal spirits resided
there.
The historic brain (1500 years later):
Rene Descartes - "duality" of the body and soul
Reflexes: sensory simulation --> valves in the ventricles to release animal spirits into hollow nerves
which caused movement
Voluntary behavior - required interaction with the soul, via the pineal gland (only structure in the brain
that does not have 2 halves). Scientists did not agree because the soul couldn't reside there since it was
too small and too ugly.
A nucleus is a cluster of cell bodies in the CNS. Tract is a bundle of axons that course together from one
nucleus to another. They are referred to as white matter because the myelin sheaths around axons
make tracts appear white; nuclei, which are darker are referred to as gray matter.
Methods for studying the human brain:
Observing behavioral deficits that occur when a apart of the brain is destroyed or is temporarily
inactivated
Observing behavioral effects of artificially stimulating specific parts of the brain
Recording changes in neural activity that occur in specific parts of the brain when a person or
animal is engaged a particular mental or behavioral task
V.G Shebalin suffered a stroke that damaged his left cerebral cortex - difficulty expressing himself in
words or understanding what others are saying - created great music
TMS - transcranial magnetic stimulation - copper coil over the scalp that temporarily causes the neurons
to stop firing. Since it is held above the head, only areas accessible are the ones in the cerebral cortex.
Research conducted in Italy - subjects were made to watch other people solve problems - TMS was used
to see which parts of their brains would light up during observation.
EEG used to study the patterns of humans when they are relaxed, aroused, asleep. The change in EEG
after a stimulus is called ERP (event related potential).
Any activity in the brain is followed by an increase in blood flow to that area. Neuroimages - shows
amount of blood flowing through each part of the brain
Positron emission tomography - injecting radioactive material into the blood and seeing radioactivity in
the brain
Function magnetic resonance fMRI - causes hemoglobin to give off radio waves to measure blood
amounts in the brain
PET and fMRI are more effective than EEG - not limited to just skull and can produce pictures of spatial
locations of activity
Methods for studying nonhuman brain:
Easier than humans since can be invasive, done through producing lesions in animal brains, stimulating
the brain using chemical or electrical means, microelectrodes
Nervous system has two hierarchies:
Sensory-perceptual hierarchy: data processing using internal and external environment. Flow of
information is bottom (sensory receptors) to top (perceptual centers in the brain)
Motor-control hierarchy: control of movement, flow of information is top (executive centers
that make the decision) to bottom (areas that turn decisions into muscle movements)
find more resources at oneclass.com
find more resources at oneclass.com
Peripheral Nerves ->
Entire set of nerves. Two types -
Cranial nerves from the brain, 12 pairs - 3 pairs contain sensory neurons, 5 pairs contain motor
neurons, rest 4 contain both
Spinal nerves from the spinal cord, 31 pairs - all contain sensory and motor neurons
Sensory neurons->
Activated at the dendritic ends by sensory stimuli, send action potentials to CNS through their long
axons, sensory inputs from sensory organs to the brain through cranial nerves and sensory input from
the rest of the body through spinal nerves and some cranial nerves (called somatosensation because
they come from all over the body and not just sensory organs)
Motor neurons ->
Cell bodies in the CNS and send signals through cranial and spinal nerves to terminate muscles or
glands. "final common path" - control behavior because they take the brains calculations to the muscles.
Motor neurons act on 2 classes:
Skeletal muscles that are attached to bones and produce observable movements in the body -
neurons make up skeletal portion of peripheral motor system
Visceral muscles that are not attached to bones and do not move, form walls of heart, stomach,
intestine - neurons make up autonomic portion. They don't initiate activity, they modulate them
and can work without neural input such as beating of heart. Come from two divisions ->
sympathetic division responds to stressful situations such as fight or flight (increased heart rate,
blood pressure, blood flow, inhibited digestive processes) and parasympathetic division serves
growth-promoting, energy-conserving functions that are opposite of sympathetic.
Spinal Cord ->
Connects spinal nerves to the brains, organizes simple reflexes and rhythmic movements
Contains ascending tracts - carry somatosensory information from spinal nerves to brain and descending
tracts - motor control commands from brain to muscles
Spinal animals - animals whose spinal cords are separated from their brains, prick a spinal cat with a
needle and it will not show pain because input cannot reach the brain but the cat will withdraw its paw
(flexion reflex) because it is adaptive - moving away from potential danger. In normal cat, it occurs a lot
faster
Spinal cord contains network of neurons that stimulate one another and produce action potentials in a
regular, rhythmic pattern - pattern generators
Pattern generators activate motor neurons in the spinal cord to produce rhythmic sequence of muscle
movements that results in walking, running, flying, swimming
Cerebral Cortex ->
Franz Joseph Gall - there are different pieces in the brain that have their own jobs. 'Phrenology" - figure
of a perfect head
Cortex is functionally specialized
Function is correlated with the size of the cortical area
Well developed cortical areas pushed on skull and produced palpable bumps
Therefore, correlations between traits and bump patterns reveal how the cortex is organized
Came up with the map of where different functions reside in the brain - data was terrible, there was no
truth to the location of the abilities
We now know there are areas of the brain that correlate with abilities - so the idea is not completely off
but the math Gall made was not accurate at all with an actual brain.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Predominant theory - animal spirits produced in the heart and flowed to the ventricles where they were stored and used for movement and sensation. Rene descartes - duality of the body and soul. Reflexes: sensory simulation --> valves in the ventricles to release animal spirits into hollow nerves which caused movement. Voluntary behavior - required interaction with the soul, via the pineal gland (only structure in the brain that does not have 2 halves). Scientists did not agree because the soul couldn"t reside there since it was too small and too ugly. A nucleus is a cluster of cell bodies in the cns. Tract is a bundle of axons that course together from one nucleus to another. They are referred to as white matter because the myelin sheaths around axons make tracts appear white; nuclei, which are darker are referred to as gray matter.
