Lectures 21-25 Flashcards
auditory system
1) signal from the environment (sound)
2) detected by sensory receptors (sensory organ: ears, sensory receptors: hair cells)
3) relayed to brain ( auditory receptors –> hindbrain–>midbrain–>thalamus—>cerebral cortex)
4) perception (language, music, sounds)
properties of sound
pitch and loudness
pitch
determined by frequency of sound wave
higher the frequency (closer together) the higher the pitch
loudness
determined by amplitude of wave
higher the wave the louder the sound
structures of the ear
outer ear, middle ear, inner ear
outer ear
- pinna - external ear structure, functions as funnel to catch sound waves
- ear canal - tunnel from pinna to ear drum, amplifies sound waves and directs them to the ear drum
- ear drum - tissue at the end of the ear canal, vibrated by sound waves and moves the ossicles
Middle ear
- ossicles - tiny bones in the middle of the ear, moved by ear drum, moves oval window of cochlea
Inner ear
- Cochlea - snail-shaped structure in inner ear, filled with fluid, contains auditory receptors, hair cells
- auditory nerve - carries auditory information to the brain
transduction of sound
basilar membrane moves when vibrations from sound waves move through fluid of the inner ear which causes hair cells to move which in turn causes ion channels to open (causing depolarization), hair cells send info to bipolar cells
auditory pathway
hair cells –> bipolar cells which form auditory nerve, auditory nerve goes through hindbrain to inferior colliculus, inferior colliculus projects to medial geniculate nucleus of the thalamus, medial geniculate nucleus –> info to auditory cortex
stronger vibration
louder noise, and the basliar membrane moves more which causes more firing of the auditory nerve
basilar membrane is ____ organized
tonotopically (by pitch)
higher pitch detected closer to oval window
learning
change in behavior as a result of experience
memory
ability to recall or recognize previous experience
- physical change in brain
- mental representation of previous experiences
pavlovian conditioning
neutral stimulus becomes associated with an important one
four components:
1) unconditioned response
2) unconditioned stimulus
3) conditioned stimulus
4) conditioned response
ex: fear conditioning
operant conditioning
using consequences of a behavior to increase or decrease probability that the behavior will occur again
ex: training a cat to open a box using treats
implicit memory
- unconscious memory
- demonstrating knowledge
- procedural learning
- bottom up encoding
explicit memory
- conscious memory
- can retrieve a memory
- declaritive
- top down encoding (info starts at the brain and guides the body)
short term memory
- held briefly
- frontal lobe is important
long term memory
- held indefinitely
- temporal lobe is important
hippocampus is important for what part of memory?
spatial memory - memory of space around you, navigating
(larger the hippocampus better the spatial memory)
frontal lobe is important for what part of memory
many forms of short-term memory
all sensory systems project to the frontal lobe
plasticity
physical changes behind learning and memory
plasticity - habituation
decrease behavioral response to a repeated stimulus
(decrease Ca influx –> fewer vesicles released –> less EPSP on postsynaptic neuron)
plasticity - sensitization
enhanced response to stimulus
(decrease activity of K channels –> neuron stays depolarized for longer)
long term potentiation (LTP)
changes that underlies associative learning, long term enhanced response to a stimulus
- requires glutamate and postsynaptic neuron to be depolarized
- has three mechanisms
the three mechanisms of long term potentiation (LTP)
- activation of NMDA receptors
- Insertion of new AMPA receptors
- changes in dendritic spines
LTP - NMDA
requires depolarization and glutamate, allows Ca to enter the cell
LTP - AMPA receptors
- calcium triggers postsynaptic neuron to insert more AMPA receptors
-Gives more places for Glutamate to bind –> increases EPSPs
LTP - dendritic spines
when LTP occurs, dendrites grow and change shape and so there is more surface area for AMPA and NMDA receptors to go –> increases EPSPs
Amnesia
- loss of memory
- retrograde: loss of past memories
- anterograde: cannot make new memories
three kinds of psychiatric disorders
- psychoses (schizophrenia)
- mood disorders (major depression)
- Anxiety disorders (anxiety duhh)
symptoms of schizophrenia
- delusions: beliefs that distort reality
- hallucinations: distorted perceptions
- negative symptoms: blunted emotions and interest
causes of schizophrenia
genetics or brain changes
brain changes: thinner cortex, low blood flow, or disorganized brain development
major depression symptoms
- prolonged feelings of worthlessness
- disruptions of eating and sleep habits
- slowing of behavior
causes of major depression
brain anatomy may predispose individuals and life experiences can lead to onset of symptoms
treatment of depression
SSRIs (increase serotonin in brain) and Cognitive Behavioral Therapy (identifies dysfunctional thoughts and replaces them with realistic ones)
anxiety disorders
phobias
panic disorders
OCD
PTSD
generalized anxiety disorders
