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PSY - P 304 : FINAL EXAM
Circadian Rhythm |
a daily cyclical change in behavioral and physiological processes (circadian= "about a day") |
Suprachiasmatic Nucleus (SCN) |
Act as a brands internal clock
-Generates circadian rhythyms in a genetically controlled manner
-Single cell extracted from the SCN produces action potential in rhythmic pattern
-Damage to SCN disrupts circadian rhythyms |
Zeitgeber |
a stimulus (like the morning sun) that acts to reset the biological clock |
Zeitgeber Stimlulus |
light sensitive retinal ganglion cells send axons to the suprachiasmatic nucleus to provide an input that rests the biological clock every morning |
Without Zeitgeber |
(e.g. animal living in complete darkness) circadian rhythyms have a cycle slightly longer than 24 hrs (~25 hrs) |
Lesions of the Suprachiasmatic Nucleus |
-After lesions animal more active in the darks, but sleep cycle loses its rhythm
-Withs lights off, sleep cycle becomes completely random |
Awake |
-Alpha (8-12 Hz) relaxed state
-Beta (13-30 Hz) aroused state |
Stage 1 Sleep |
Theta (3.5-7.5 Hz) transitions between sleep and wakefulness |
Stage 2 Sleep |
Theta (3.5-7.5 Hz) sleep spindles
K complexes |
Stage 3 (slow wave) Sleep |
Delta (<3.5 Hz) deepest sleep |
REM Sleep |
Beta (13-30 Hz)
Rapid Eye Movements
No muscle tones most associated with dreams |
Restorative Theory of Sleep |
sleep provides a chance for the body/brain to repair what & tear
-prolonged mental activity is increased sleep that night
-high levels of growth hormones released during sleep that facilitates repair of damaged tissues
-sleep strengthens immune system
-provides a time for metabolites to be rinsed from the brain tissue |
Sleep alters cleaning efficiency of CSF |
-Interstitial space (space between neurons, glia, blood vessels, etc) expands during sleep, allowing greater flow of CSF
-Greater CSF flow cleans out metabolites from the brain (including some associated with Alzheimers Disease) |
Energy Conservation Theory |
sleep conserves energy during a time (nighttime) in which it would be difficult to replace the calories spent forging/hunting for food (hibernation is an extreme example of this) |
Niche Adaption |
quiet period makes it easier to remain undetected by predators |
Facilitation of Learning |
sleep allows for a period of memory consolidation & clean-up |
Preliminary findings |
-Memories of learned facts (names, vocabulary, etc) reinforced in deep sleep
-PAttern recognition (grammas, logic, etc) reinforced by REM sleep
-Motor skills (musicians, athletes) reinforced by Stage 2 sleep |
Dreams |
often occur during REM sleep |
REM Sleep Dreams |
-Associated with narrative storyline
~Often bizarre/illogical, but accepted unquestioningly
-Perceptions and actions within the dreams are associate with activation in associated brain areas
~Motorneurons are inhibited so that the dream is not acted out (REM-related paralysis, except for eye movements) |
non-REM dreams |
-Less of a narrative component
~Often a simple feeling or emotion
-Sometimes associated with:
~somnambolism: sleep-walking
~night terrors: dreams associated with abstract feelings of intense dread/fear (not nightmares) |
Theories of dream meaning |
Freudian theory, Action-Synthesis Theory, Evolved Threat-Rehearsal Theory |
Freudian Theory |
dreams reflect unconsious conflicts within the mind of the dreamer, in a symbolic for disguised to avoid direct confrontation with conflict
~No evidence supports this |
Action-Synthesis Theory |
dreams reflect the brain's (left hemisphere interpreter's?) attempt to create a narrative to explain the random firing of neurons that occurs during the dream, with the deactivation seen in the frontal lob contributing to the illogical nature of dream |
Evolved Threat-Rehearsal Theory |
dreams provide a virtual simulation of threatening or unusual circumstances so the strategies for coping can be tested and rehearsed |
Reticular Formation |
located in brainstem from the midbrain to medulla, sends axons throughout the brain |
Functions of Reticular Formation |
-recieves visual, auditory and somatosensory input (hence their alerting effects)
-stimulation of reticular formation awakens a sleeping animal; lesions make an animal drowsy/sleepy |
Ventrolateral preoptic areas (VLPA) |
located in the basal forebrain rostral to hypothalamus
-elctrical stimulation of VLPA evokes slow-wave sleep |
Control of REM Sleep |
peribrachial area of the pons: controls the onset of REM sleep |
Peribrachial area of Pons |
stimulation of it induces REM sleep; lesions decrease the occurrence of REM sleep |
REM-related Muscle Atonia |
Produced by inhibitory neurons in nucleus magnocelluraris |
REM Behavior Disorder (REM without atone) |
-results for lesions of the nucleus magnocelluraris
-defect in the neural system that causes REM-related paralysis results in the animal acting out its dreams |
Narcolepsy |
neurological disorder characterized by the urge to fall asleep at inappropriate times |
Cataplexy |
complete loss of muscle tone during the awake stat, related to a hyper excitability of the neurons of the nucleus magnocellularis
|
Recent findins in Narcolepsy |
found to be related to a deficiency in the neuromodultor orexin (hypocretin)
-possible autoimmune disease eliminates hypocretin neurons in humans, genetic defect of hypocretin receptors in dogs |
What an emotion includes |
1. A subjective feeling
2. A behavioral response
3. A physiological reaction |
Racial Expression Suggests Basic Emotions |
-strong cross-cultural similarities
-suggests a biological basis for expressive emotions |
Neural Circuits for Facial Expressions |
Genuine Smile and Volitional Smile |
Genuine Smile |
Circuit passes through orbitofrontal cortex & hypothalamus
- A genuine smile (Duchenne Smile) also includes a tightening of muscle around the eyes (Duchenne muscles), causing a slight squint |
Volitional Smile |
Circuit passes through Primary Motor Cortex |
Volitional Facia Paralysis |
right hemisphere is lesioned and left side is paralyzed
-only right side of face response to making volitional smile
-genuine smile works fine |
Emotional facial paralysis |
left hemisphere lesioned and right side paralyzed
-hase muscle strength to move muscles on both sides of mouth
-genuine smile only engages left side of face |
Dominance of Production of Facial Expression |
Right Hemisphere show dominance for production of facial expressions |
Theories of Subjective Feeling of Emotions |
Common Sense View,
Cannon-Bard Theory, James-Lange Theory, Schachter's Cognitive Theory |
Common Sense View |
is that the subjective feeling is experiences first, then this drives the autonomic response
~good evidence that this is incorrect |
Cannon-Bard Theory |
an emotional event simultaneously evokes the feeling of the emotion and the physical changes that accompany it |
The James-Lange Theory |
How we feel depends on the interpretation of the physical changes (autonomic, behavioral) that occur in body as response to an emotional event |
James-Lange Theory |
-Environmental event triggers behavioral, autonomic, and endocrine response
-Feedback from responses produces feelings of emotions |
Schacters Cognitive Theory |
The physical changes evoked by an emotional event are attributed to the prevailing environmental conditions, leading to an emotional feeling that corresponds |
Testing of Schacters Theory |
Misattribution of arousal is shows evidence of this theory |
Misattribution of Arousal |
Misattribution of Arousal participants who were misinformed or uniformed about the cause of their arousal felt either angry or euphoric, depending on whether a confederate was angry or euphoric |
Limbic System |
traditionally associated with emotion
-Limbic=border between forebrain and brainstem |
Amygdala |
-almond shaped structure buried in the temporal lobe
-processes emotional significant of stimuli
-key structure in fear and anxiety
-single unit recordings and fMRI show cells that are responsive to emotional situations/stimuli
-Stimulation evokes behavioral effects of strong emotional states (e.g fear or rage) |
Kluver-Bucy Syndrome |
Unusual social behavior and emotional responses:
-emotional bluntness/tameness
-tendencey to approach objects that should elicit a fear reponses
-hyperorality
-hypersexuality |
Amygdala Damage in Humans (Patient S.M) |
-Rare genetic disease causing bilateral amygdala damage
-General fearlessness
-Little autonomic nervous system activation to fearful stimuli
-Impaired at recognizing and drawing fearful expression |
Amygdala & Fear Conditioning |
can condition a fear response in stimuli that would not usually invoke a fear response |
Damage to Amygdala |
impairs fear conditioning |
Orbital & Medial Prefrontal Cortex |
-regulates emotions according to circumstances
-can override initial appraisal of emotional stimuli
-control impulses to approach/withdraw |
Phineas Gage |
demonstrated that damage to orbital and medial prefrontal cortex caused erratic emotions: frequent outbursts of anger, rage, couldn't inhibit inappropriate behavior |
Frontal Lobotomies |
-surgical procedures that isolates the prefrontal cortex from rest of brain
-Developed by Antonio Moniz as treatment for various psychiatric disease (e.g. schizophrenia) won the Nobel Prize
Walter Freeman perform thousands in 1940s-60s
-Typically cause loss of emotions, passivity, difficulty planning, reduced initiative, impulsivity |
Medial Forebrain Bundle & Nucleus Accumbens |
Pleasure/Reward Center in the brain |
Hypothalamic Attack Area |
-Region in hypothalamus associated with aggression
-Single unit recordings show increase in activity before/during aggressive behaviors, decrease mating
-Artificial stimulation prompts aggressive behaviors |
Neuropharmacological Basis of Aggression |
-Testosterone increases in many species
-Relationship in humans less clear
-Experience & dominance can affect testosterone levels; winners show higher levels than losers |
Birth position and aggression in female rats |
Number of male "neighbors" in the womb affects levels of aggression in female rats
-Increases in aggression in 2M females relative to 0M and 1M
-Thought to be due to increases in prenatal androgens that spread between neighbors |
Serotonin and Aggressive Behavior |
-Serotonin (5-HT) decreases aggression
-Low serotonin levels in primates associated with risk taking and aggression
-Monkeys with low serotonin end up dying earlier, either from injuries resulting from aggressive behavior or accidents due to risky behavior |
Learning |
changes that occur within the brain to allow the acquisition of new information for long-term storage |
Memory |
the storage and retrieval of information previously acquired through learning |
Information Processing Model of Memory |
Sensory Memory, Working Memory (short-term memory), and Long-term Memory |
Sensory Memory |
A trace of the sensory inout for a brief period
-High capacity & very short duration (up to few seconds)
-Easy accessible, but vulnerable |
Working Memory (short-term memory) |
Attentive/conscious processing occurs here. Information can enter from both sensory memory and LTM
-Small capacity and short duration (seconds, or minutes w active rehearsal)
-Easy accessible, but vulnerable |
Long-Term Memory (LTM) |
The stored representation of knowledge gained from previous experience
-Large capacity and indefinite duration (up to decades/lifetime)
-Difficult to access, but durable |
Types of Memory |
Declarative Learning, Implicit Learning |
Declarative Learning |
learning facts and info of which we can be aware (what we normally think of as memory)
-Episodic memory and semantic memory |
Episodic Memory |
autobiographical memories |
Smenatic Memory |
generalized memory of facts |
Nondeclarative learning |
memory about perceptual and motor procedures of which we are typically unaware
-Priming, Motor (skill) learning, and Associative learning (Conditioning) |
Priming |
exposure to one stimulus alters response to another |
Motor (skill) learning |
learning how to control the body in order to respond appropriately |
Associative learning (conditioning) |
learning the relationship between stimuli (classical conditioning), or between behaviors and outcomes (operant or instrumental conditioning) |
Unconditioned stimulus (US) |
A stimulus that reflexivily elicits a response, without prior learning |
Unconditioned response (UR) |
the response reflexively elicited by unconditioned stimulus, without prior learning |
Neutral stimulus |
a stimulus that elicits no reflexive response |
Conditioned stimulus (CS) |
a stimulus that elicits a particular response only after learning |
Conditions response (CR) |
the response to a conditioned stimulus, after learning has occurred |
Synaptic plasticity |
the basis of learning involving a change in the synaptic structure or biochemistry that alters the efficiency of the synapse in a positive or negative way (Plasticity=the capacity for being molded of altered) |
Hebbian Rule |
a synapse is strengthened if it is repeatedly active when the postsynaptic neuron fires
"Neurons that fire together, wire together" |
Long-Term Potentiation (LTP) |
a mechanism by which synaptic connections are strengthened, allowing for a larger excitatory postsynaptic potential (EPSP) in the postsynaptic neuron (Potentiation=to strengthen or make more potent) |
NMDA receptors |
-ion channel opens when bout w/ glutamate neurotransmitter
-but channel blocked by Mg2+ ion
-unless neuron is depolarized already (pushing Mg2+ away) when glutamate is bound
-Na+ and Ca2+ can enter
~depolarizes neuron
~Ca2+ acts as a 2nd messenger |
Effects of LTP |
-causes the insertion of additional glutamate receptors into postsynaptic membrane
-causes structural changes of the synapse that lead to the creation of new synapse
-causes creation of the neuromodulator Nitric Oxide, which diffuses to presynaptic neuron and enhances glutamate release |
Evidence for Role of LTP in Learning |
-LTP prominent in brain areas involved in learning
-Drugs that block LTP also impair learning abilities
-Drugs that facilitate LTP also enhance learning abilities
-Mice genetically-enhanced to have more NMDA receptors have better learning abilities (Doogie mice) |
Instrumental (Operant) Conditioning |
is in which the likelihood that an act will be performed depends on the consequences of the reinforcing stimuli that follows |
Biological Basis of Reinforcement |
positive reinforcement is associate with the release of the neurotransmitter dopamine in the "Reward Centers" of the brain (e.g. nucleus accumbent, ventral segmental area)
-Food, sex, $$$. addictive drugs
-Amount of dopamine released sets a reinforcers reward value
~more dopamine= more effective reward |
Long-Term Declarative Memory |
relies on the hippocampus and medial temporal lobe |
Morris Water Maze |
Environmental cues in room provide info that permits animal to orient themselves in space and learn the location of hidden platform |
Hippocampus and Spatial Navigation |
PET scan showing activation of right hippocampal formation from subjects navigating through town |
Medial Temporal Lobectomy (Patient H.M: Henry Molaison) |
-underwentd surgery for severe epileptic seizures
-bilateral removal of medial temporal lobe, including hippocampus
-almsot total loss of the ability to encode new long term memories
-but preserved short term memory..can hold normal conversations, intact reading ability, and other skills that require only temporary maintenance of info |
Medial Temporal Lobe Lesion of Clive Wearing |
-In 1985 damage to the medial temporal lobe due to an encephalitis infection
-Profound anterograde and retrograde amnesia
-Can still play the piano, although he has no recollection of ever having been trained |
Amnesia |
a profound impairment of memory as the result of brain injury; the extent of both retrograde and anterograde amnesia depends on severity of injury |
Retrograde Amnesia |
can't remember events prior to brain damage |
Anterograde Amnesia |
can't later remember events that occur after brain damage |
Anterograde Amnesia as Evidence for a Consolidation Process |
H.M. had:
-normal long-term memory of distant past
-normal short-term memory (could carry on conversation, could remember numbers w/ rehearsal, et.)
-but could not for new long-term memories
~Thus hippocampus involved in consolidation |
Consolidation |
process by which immediate memories become lasting (long-term) memories |
Memory Storage |
-hippocampus needed for consolidation, but not where memories are stored
-memories are though to be stored in cortex |
Consolidation view of memory |
is when memories are consilidated from short-term to long-term and retrieved for use |
Reconsolidating view of memory |
memories are retrieved from long-term memory for use and then reconsolidated back to long-term memory |
Reconsolidation |
allows for memory disruption in memory |
Anisomycin |
prevents reconsolidation only after recollection of the information so that the info is forgotten |
Reconsolidation allows |
for memory distortions |
Motor Learning |
relies primarily on the cerebellum and the basal ganglia |
Alzheimers Disease |
a degenerative disorder (cause unknown) that results in a progressive dementia, loss of memory, confusion, hallucinations, motor deficits and eventual death
- Wide sulci indicate thinning cortex due to cell death
-associated with neuronal degeneration, neuritic plaques, and neurofibrillary tangles |