PSY 340 - EXAM 4

Ch 12, 13, 14

Unconditioned stimulus

naturally occurring stimulus that triggers a response automatically

EX: meat powder 

Unconditioned response

natural reaction to UCS

EX: salivation

Neutral stimulus

stimulus that initially produces no response

EX: Bell

Conditioned stimulus

once-neutral stimulus that now triggers a learned response

EX: bell

Conditioned response

a learned reaction to a conditioned stimulus

EX: salivation

Acquisition 

process of learning the association between NS and UCS 

Extinction

when the CS is presented repeated without UCS and the CR fades

Spontaneous recovery

the reappearance of a learned response after extinction

Generalization 

responding to similar stimuli 

Discrimination

learning to respond only to a specific stimulus

Operant conditioning

learning through consequences of voluntary behavior

Positive Reinforcement

adding something pleasant to increase behavior 

EX: vending machine giving a snack when you insert money

Negative Reinforcement

removing something unpleasant to increase behavior

EX: fastening seatbelt to stop beeping 

Positive punishment

adding something unpleasant to decrease behavior

EX: scolding a child for drawing on walls

Negative Punishment

removing something pleasant to decrease behavior

EX: no dessert after being rude

Engram

physical representation of learning

neural trace of memory 

Equipotentiality

all cortical areas can take over for damaged areas

Mass action

the brain works as a whole for complex learning

Lashley

experimented with rats running mazes after removing different parts of their cortex to see where memory was stored

Lateral Interpositus Nucleus (LIP)

part of cerebellum crucial for learning conditioned responses

without this activity, no new learning occurs

Red Nucleus

midbrain structure controlling performance (movement)

needed to PERFORM response (not LEARN it)

Short-term memory 

temporary holding system, requires rehearsal 

EX: remembering a phone number briefly

Working memory

active version of STM for processing info, prefrontal cortex

EX: doing mental math

Delayed response task 

test for working memory 

EX: monkey waits before responding 

Long-term memory

durable storage system, stimulated with cues/hints

EX: remembering bday from years ago

Consolidation

process of storing STM into LTM

Flashbulb memory 

highly vivid memory of an emotion event 

Rehearsal 

repetition to maintain STM 

Korsakoff’s Syndrome

Cause: Thiamine (B1) deficiency —> can’t metabolize glucose

Brain damage: mammillary bodies, hippocampus

Symptoms: apathy, confusion, amnesia, confabulation

Mechanism: loss of neurons in memory circuits

Common in: malnutrition & alcoholism

LANDS & LATE

Limbic-predominant Amnesic Neurodegenerative Syndrome

Limbic-predominant Age-related TDP-43 Encephalopathy

TDP-43

protein; if build-up = cause LATE

Alzheimer’s Disease

progressive and irreversible brain disorder that causes memory loss, cognitive decline, and behavioral changes

50% of ppl over 85 have this

Stages of Alzheimer’s

1. Normal outward behavior: no noticeable symptoms

2. Very mild changes: occasional forgetfulness

3. Mild decline: difficulty remembering recent events

4. Moderate decline: trouble with complex tasks (managing money, travel, etc)

5. Moderately severe decline: needs help with daily activities

6. Sever decline: major personality and memory changes and confusion

7. Very sever decline: loss of ability to communicate, move, or recognize loved ones

Alzheimer’s symptoms

• memory loss

• difficulty communicating or finding words 

• confusion about time and place 

• misplacing belonging 

• mood swings, poor judgement 

• social withdrawal 

• changes in vision or spatial awareness 

Genetic components of Alzheimer’s

• Down Syndrome: gene for amyloid precursor protein —> increased risk

• Early onset (before 65) have mutated APP and PSEN1/2 genes

Environmental factors of Alzheimer’s

50% of late onset have no known relative w disease 

Risk factors of Alzheimer’s

• physical inactivity

• smoking and alcohol abuse

• air pollution exposure

• head injuries 

• social isolation 

• low education levels (less cognitive reserve) 

• obesity, HTN, diabetes 

• depression

• hearing impairment 

• high cholesterol after age 40

• untreated vision loss

Biological mechanisms of Alzheimer’s

• Amyloid-beta proteins clump between neurons, forming plaques (these block neural communication and trigger inflammation in brain) 

• Tau protein become twisted and form tangles (this disrupts transportation within neuron —> producing MEG3 —> causes cell-death via necrosis) 

Alzheimer’s treatment

Increase acetylcholine levels

Curcumin (from turmeric) help reduce amyloid buildup

Infant amnesia

inability of adults to recall memories from before age 3 or 4 

Why?

• language skills aren’t fully developed yet 

• hippocampal growth and brain aren’t matured yet 

• infants lack a stable sense of self 

H.M. (Henry Molaison)

Suffered from severe epilepsy so he surgically removed hippocampi which stopped his seizures but his memory decreased 

Effects of HM on diff types of memories 

• Anterograde amnesia (couldn’t form new long-term memories)

• Retrograde amnesia (lost some memories from just before surgery)

• Working memory (remained the same)

• Episodic memory (severely impaired)

• Implicit & Procedural memory (intact) 

• Explicit memory (impaired) 

Hippocampal functions 

• supports declarative memories (memory for facts) 

  • damage leads to amnesia or memory loss

• constantly communicates with cerebral cortex to consolidate memories

  • produces “sharp-wave ripples” strengthen and store episodic memories very well

• spatial memory (helps us remember and navigate spaces) 

Sharp-wave ripples

brief bursts of synchronized neural activity between hippocampus and cerebral cortex

Hippocampal spatial memory cells

• Place cells 

  • activated when animal is in a specific location and it receives input from entorhinal cortex (which has grid cells that form a coordinate system for space) 

• Time Cells 

  • activates at specific moments during a task/experience 

Striatum (basal ganglia)

supports procedural and habit learning (especially probabilistic learning, which is the brain learning patterns based on reward and feedback)

Amygdala

involved in emotional memory, especially fear learning and conditioning

Parietal lobe

helps w/ “piecing info together” integrating sensory details into coherent memories and concepts 

Temporal lobe

support sematic memory (facts)

Aplysia

marine invertebrate (sea slug) used in neuroscience 

very few neurons

touch results in the withdrawal response 

Withdrawal reflex

when you touch an aplysia, it’ll withdraw its gills 

can be modified by experience (habituation & sensitization) 

Habituation

decrease in response to a repeated, harmless stimulus 

Sensitization

increase in response following a strong or harmful stimulus

Long-term Potentiation (LTP)

long-lasting increase in synaptic strength following rapid, repeated stimulation of a synapse

postsynaptic neuron becomes more reactive

Properties of LTP

• Specificity: only the synapse that receives stimulation is strengthened

• Cooperativity: several weak inputs can combine to produce LTP

  • Associativity: pairing weak input with strong one strengthens both

Long-term Depression (LTD) 

long-term weakening of synaptic strength, occurs when synapses are rarely active while surrounding neurons are active 

Biochemical mechanisms of LTP

LTP depends on neurotransmitter glutamate, which binds to two receptors:

• AMPA: opens Na+ channels —> depolarizes the cell

• NMDA: normally blocked by Mg2+ but when dendrite is depolarized, glutamate can bind

How LTP happens

1. Glutamate binds to AMPA: Na+ enters and depolarizes dendrite 

2. NMDA channel opens: Mg2+ block removed —> Ca2+ enters postsynaptic cell 

3. Ca2+ triggers enzymes (like CaMKII) —> activated CREB (a gene-regulating protein) 

4. These changes causes the neuron to make more AMPA and NMDA receptors, make new dendritic branches/synapses, and strengthen existing connections

5. BDNF (brain-derived neurotrophic factor) further enhances these effects, promoting neuron growth and survival 

6. Retrograde transmitter (NO) acts as a positive feedback neurotransmitter

LTP & Behavior

• Abnormal NMDA receptor —> poor learning 

• More NMDA receptors —> improved learning 

• No AMPA receptors —> no LTP or memory 

• Drugs that block LTP —> blocks learning 

• Drugs that enhances LTP —> improves learning 

Left Hemisphere

Interpreter, specialized for language, scientific facts, right hand

Right hemisphere 

specialization in music awareness, artistic ability, 3D spatial reasoning, imagination/creativity, emotional tone of language, & left hand

Contra-lateral connections

left hemisphere controls right hand and visual field while right hemisphere controls left hand and visual field 

Lateralization

each hemisphere does some tasks more efficiently, even though they cooperate

Commissures

axon pathways that connect the left an right hemispheres (allow sensory, motor, emotional, and memory information to be shared) 

Corpus callosum

commissure

primary information highway between hemispheres

enables coordinating movement

Anterior commissure

smaller than corpus callosum

connects anterior parts of hemisphere

involved in pain sensation, emotion, and some aspects of olfaction

Hippocampal commissure

connects right and left hippocampi

important for memory formation and spatial navigation

Corpus callosum

main information highway between hemispheres

responsible for communication between sides of body

Visual Connections to Hemispheres

what is visible at any moment 

both eyes can see both visual fields 

right visual field goes to left half of both retinas (which goes to left hemisphere) vice versa 

Auditory Connections to Hemispheres

each ear receives sound waves from just one side of head but sends information to both sides of brain

Absence of Corpus Callosum 

• prevents exchange of information between hemisphere 

  • it’s cut as treatment for sever epilepsy —> split brain behavior

Plenum Temporale  

section of temporal cortex that is plays a role in auditory and language processing

Language

system of communication involving spoken, written, or gestured symbols arranged according to a grammar

• must have symbols that carry meaning

• must be independent of situation it’s being used

• must have possibility to produce new symbols/signals to represent ideas

Phonological loop

a working memory system used for speech sounds 

language evolution 

language likely evolved after mouth/hand gestures 

Evidence against the idea that language is a result of intelligence 

• undamaged brains can still have impaired language 

• impaired intelligence can still have normal language (EX: williams syndrome)

Language acquisition device (LAD)

by Noam Chomsky

• children learn language naturally and quickly, without formal teaching 

• they learn more than what they are explicitly taught (poverty of stimulus argument) 

• suggests humans are biologically prepared for language 

  • FoxP2 gene

FoxP2 gene

gene associated with speech and language development (located on chromosome 7) which is involved in motor control of speech organs (jaw & throat) 

Critical periods for language learning

there’s a sensitive developmental window during childhood where the brain is especially ready to learn language. 

Language production

ability to produce spoken language (speaking) 

brain area: broca’s area

Language comprehension

ability to understand language (hearing)

brain area: wernicke’s area

aphasia

sever language impairment caused by brain damage, usually to left hemisphere

Non-fluent aphasia

person knows what they want to say but struggles to form words

Fluent aphasia

speech is fluent and smooth, but does not make sense

Dyslexia

learning disorder that involves a significant impairment in reading ability

more common in boys and English-language readers

more symmetrical cerebral cortex

cause: sound processing impairment, and attention differences 

Dysphonic dyslexia

trouble sounding out words

Dyseidetic dyslexia 

trouble recognizing whole words by sight 

Mind-brain relationship 

how the mind and brain relate to each other 

is the mind the same as the brain, or something separate? 

Dualism

the mind and body (brain) are separate things 

Rene Descartes 

Monism 

only one kind of substance exists 

Materialism: all is physical

mentalism: only the mind exists

identity: mind and brain are the same things, but with different names 

Masking 

visual technique used to study which stimuli enter consciousness 

awareness depends not just on sensory input, but on continued synchronized brain activation (coordinated, widespread neural firing)

Binocular rivalry

when each eye is shown a different image, you don’t see a blend, instead your conscious awareness switches back and forth between the two images 

Threshold Phenomenon

There’s a minimum level of neural activation required for a stimulus to become conscious

Phi Phenomenon

visual illusion where static images shown rapidly in sequence appear to move

Attention

• concentration of mental activity

• associated with increased neural activity

• required for highest perceptual accuracy

Inattentional blindness 

when people fail to perceive an obvious stimulus because attention is focus elsewhere

Agonist

Mimics or increases effects of a neurotransmitter

Antagonist

Blocks or takes away from effects of the neurotransmitter

Affinity

ability to bind a receptor

Efficacy

how well the drug activates the receptor