Day 3: Outline
March 3, 2009 by Dr. Ken Tangen · Leave a Comment
General Psychology
Neurological Psychology
Neurons
Structure & Steps
Dendrite = receptors
Soma = cell body
Nucleus = holds DNA, etc
Axon hillock = connect soma to anon
Axon = thin, long fiber
Depolarization
sudden and rapid change in action potential
changes in permeability of cell membrane
Myelin sheath (Schwann cells) = white, fatty “insulator”
Nodes of Ranvier = gaps in the “sausage”
Axon terminal
Voltage-gated calcium channels = calcium ions enter terminal
Synaptic vesicles
Neurotransmitter
Synaptic cleft
Diffusion
Receptors
Postsynaptic neuron
Re-uptake
Principles
All-or-None Law = either a neuron fires or it does not
It fires if it passes a certain threshold
If it fires, it does so at full strength
Neurons cannot change intensity of an impulse
Neurons can change the rate (# of impulses per sec)
Refractory Period = can’t fire until it recovers (1 millisecond)
Absolute refractory period =can’t fire no matter how much stimulation
Relative refractory period = can fire with lots of stimulation
Thresholds
Super-threshold stimulus = 1 neuron releases enough neurotransmitter to depolarize the post-synaptic neuron in 1 shot
Summation
Multiple sub-threshold releases of neurotransmitter builds up
1. Temporal Summation
One neuron gives several impulses in rapid succession
So rapidly that the neurotransmitter doesn’t dissipate
2. Spatial Summation = many neurons give 1+ impulses
1 cell can code 2+ perceptual experiences
excitation signals one quality; inhibition another
For example:
excitation = blue, inhibition = yellow
excitation = left, inhibition = right
Neurotransmitters
Amino acids
Glutamate 90%
GABA 9%
Other 1%
Acetylcholine
Peripheral nervous system (PNS)
One of many in autonomic nervous system (ANS)
Activate muscles
Only transmitter in somatic nervous system (SNS)
Only transmitter for autonomic ganglia
Central nervous system (CNS)
Low amounts found in:
Alzheimer’s disease
Myasthenia gravis
muscle weakness & fatigue
antibodies against acetylcholine
Monoamines
Histamine
Melatonin
Serotonin
Dopamine
5 types of receptors (D1….D5).
Also acts as a hormone
Released by hypothalamus
Inhibits release of prolactin from pituitary
Low levels of dopamine are seen in:
Parkinson’s
Can’t give dopamine (blood-brain barrier)
Give L-Dopa (levodopa) which can be turned into dopamine
Cocaine
Blocks re-uptake of dopamine
Takes very little stimulation to activate post-synaptic neuron
Quasi-Transmitters (not stored in vesicles)
Purines
chemicals (adenosine and its derivatives)
ATP
GTP
Peptides
larger neurotransmitters
long chains of amino acids
co-enzymes
often co-released
50+ polypeptides and proteins
insulin, prolactin, vasopressin
synthesized in cell body
transported down axon
slow process
not reabsorbed & recycled
exhausted quickly
Ions (zinc)
Gasses
carbon monoxide
nitric oxide
Neuro-receptors
All drugs that affect behavior act on synaptic receptors
Affect people differently
Neuro-receptors
Neurotransmitter differ in number of receptors
acetylcholine
4 types of nicotinic receptors
5 types of muscarinic receptors
dopamine has 5 types of receptors
serotonin has at least 15 types of receptors
Neural Development
create twice as many as necessary
winnowed out just before and after birth
50,000 cells each second for most of intrauterine life
Many neurons last your whole life
other cells die and are replaced
many neurons aren’t replaced when they die
hippocampus neurons CAN grow in adults
generally have less neurons as get older
Brain
2 hemispheres
4 lobes
Occipital lobes
At back of brain
Vision
Geniculo-Striate Pathway
Parietal lobe -dorsal path
Parietal lobes
Located behind the central sulcus
3D representation of world
Perception of stimuli
touch
pressure
temperature
pain
Temporal lobes
Located below the lateral fissure
Recognition of auditory stimuli
Production of speech
Memory for words (left hemisphere)
Memory for events (right hemisphere)
Perception
Frontal lobes
Extremely vulnerable to injury
Large in size
Located up front
Most common region of brain injury
Mild to moderate traumatic brain injury
If damaged:
Loss of simple movements (paralysis)
Can’t plan sequence of complex movements
Can’t complete multi-stepped tasks, such as making coffee
Loss of spontaneity in interacting with others
Loss of flexibility in thinking
Persistence of a single thought (perseveration)
Inability to focus on task (attention)
Mood changes
Difficulty with problem solving
Inability to express language (Broca’s Aphasia)
3 Parts
1. Motor Cortex
precentral gyrus
directs motor coordination
also known as M1
contains Betz cells
large neurons
long axons down the spinal cord
Homunculus
2. Premotor Cortex
processing info on intended movement
sends info to motor cortex
3. Prefrontal cortex
Most anterior
Not short term storage; but if damaged, damaged executive processes
Has 10 or so microscopically different cells
working memory for objects
working memory for spatial locations
3 regions
1. dorsolateral
last part of brain for myelination
still developing at 30 years old
interacts with other parts of brain
location of stimuli
spatial information for sequence learning
sleep deprivation inhibits activity here
tumors produce symptoms similar to schizophrenia
2. orbitofrontal
areas around eye sockets
least explored
least understood
controls : social adjustment, responsibility, mood, drive
controls drug addiction?
Alzheimer’s disease shows neurofibrillary tangles in this area
Lesions: feel no regret, can’t encode new information
3. medial
1. anterior cingulated cortex
activates when working memory is used
forms collar around corpus collosum
regulate heart rate & blood pressure
reward, anticipation, empathy
2. hippocampus
if damaged, amnesia
if small damage, retrograde amnesia
remember before and after the accident, not accident or around it
if bilateral damage, anterograde amnesia = can’t form new memories
consolidation = move from short to long term memory
not necessary to retrieve info; must be working to put into long term
Reproduces patterns during sleep
Hippocampus
Encodes patterns into sparse representations (non-overlapping)
Sparse encoding allows quick learning
Example
Componential encoding of 9×9 pixel = 81 pixels
like cortex: efficient; good for generalization
Sparse encoding uses 13 elements
Trains cortex by repeating pattern over time
Find L in field of Ts
Patterns repeated
Ss unaware of pattern
Without damage, improve over time (priming)
With damage, no improvement
No “thinking” required
Review
There are only 3 things you can learn
10 Tips For Learning
Facts
Lists, names, dates, generic info
Concepts
Heuristics, rules, ideas, principles
Behaviors
Anything you do
5 Paths To Truth
Science
systematic observation
replication = do over and over
levels of measurement
nominal = name
ordinal = rank, rating, 1st, 2nd
interval = temperature, hurtles
ratio = absolute zero; time, distance
independent variable
manipulated by experimenter
“independent” of the subjects
dependent variable
“dependent” on what subjects do
outcome measure
Sensation-Perception
Bottom-up process
Top-down process
Stroop Effect
3 Principles of showing Magnitude (intensity)
4 Principles of Perceptual Efficiency
Illusions
Muller-Lyer illusion = arrows
Delboeuf Illusion = compare outer to inner
Estimation = height of 4-story building overestimated by 25%
Horizontal-Vertical Illusion
