Chapter 12 Flashcards
Classical conditioning
- who proposal to explain learning here?
- Ivan Pavlov
- Pairing two stimuli changes the response to
one of them- Some stimuli naturally
provoke responses
- Some stimuli naturally
Instrumental conditioning
- Ex?
a.k.a., operant conditioning
* Response followed by reinforcer or punishment
LASHLEY’S SEARCH
- What is ENGRAM?
physical representation of
learning
* E.g., a connection between two brain areas
* Shows learning and memory do not rely on a single cortical area
- Lashley’s principles of the nervous system
- Equipotentiality: all parts of the cortex contribute equally to complex functioning behaviors (e.g., learning)
- Mass action: the cortex works as a whole and more cortex is better
- Thompson et al. search for ENGRAM:
- LIP?
- conclusion of Thompson et al. search
Maybe engram is in cerebellum?
Lateral interpositus nucleus (LIP) = central
for learning
* Responses increase as learning proceeds
* BUT… a change in a brain area doesn’t
necessarily mean that learning took place in
that area
Thomson concluded learning occurred in the LIP
Cerebellar damage
- Cerebellar damage makes no conditioned eyeblinks.
- Damage to cerebellum impairs learned responses only if response requires precise timing
Types of Memory
-Short-term memory
* Memory of events that have just
occurred
* Has limited capacity
* Fades quickly if not rehearsed
-Long-term memory
* Memory of events from times
further back
* Unlimited capacity
* Long-term memories persist
CONSOLIDATION OF MEMORY
What Researchers propose?
Researchers propose all the information enters short-term memory
* Brain consolidates it into
long-term memory
- Later research weakened the distinction between short- and long-term memory
* Not all short-term long-
term
* Time needed for
consolidation varies
Emotionally significant memories form quickly
- Locus coeruleus norepinephrine in cortex + dopamine in hippocampus
- Emotion epinephrine and cortisol to activate amygdala & hippocampus
Flashbulb memories
Are emotionally significant memories with a lot of details and vivid.
Working memory
proposed as alternative to short-term memory, is a temporary storage of information to actively
attend to it + work on it for a period of time.
During WM task a reverberating circuit holds the information
What we do?
we Store abbreviated information of a sequence of task (ex. EAESSE)
Brain fog
Is a type of a Amnesia:
E.g., following COVID-19 or cancer treatments
* COVID virus causes a powerful reaction by the immune system
Cause period of forgetfulness, confusion, slow thinking, and impaired concentration.
Inflammatory cytokines damage BBB-What happen?
* Consequences?
extra microglia activation
= memory and concentration problems.
Impairs the blood flow to the brain-What happen?
* Consequences?
shrinkage of gray matter in
cerebral cortex + decreased myelin
* memory loss, and concentration difficulty.
Alzheimer’s disease
Gradually progressive loss of
memory, often during old age
* Affects 50% of people over 85
and 5% of people 65-74
* Early onset influenced by genes,
most cases are late onset
- No drug is currently effective for Alzheimer’s disease
Infants Alzheimer
- Hypotheses?
- Universal experience- not a disorder
- Children do form memories, the question is why we forget them
- Changes in hippocampus and growth of new neurons
- Infants do not store memories as well as they can when older
- Rapid learning in early childhood displaces memories formed in infancy
- H.M.: famous case study for what?
- Short-term/working remained intact?
- Hippocampus removed to prevent epileptic seizures
- After, H.M. had difficulty forming new long-term memories
- Yes Short-term/working remained intact because the patient can retain info by using mental repeated but forgot if it is distracted (Short-term/working work)
A N T E R O G R A D E
A M N E S I A
Inability to create new memories after the event that caused the amnesia
R E T R O G R A D E
A M N E S I A
- Loss of previous memories or before the event that caused the amnesia
H.M. showed both types after the surgery!
H.M.- INTACT WORKING MEMORY
- H.M.’s short-term or working memory remained intact
- Remember a # 15 min. with no distraction
- When distracted, memory was gone in seconds
H.M.’s memory impairments STORAGE OF LONG-
TERM MEMORY
- Unable to state the correct date or his current age
- Read the same magazine repeatedly without losing interest
- Could recall only a few fragments of events in the recent past
- Did not recognize himself in a photo, but did recognize himself in a mirror
Semantic memory
- Memories of factual information
- H.M. was able to form a few weak semantic
memories
Episodic memory
- Memories of personal events
- H.M. could not describe any event since his surgery
- H.M. had severely impaired episodic memory
Explicit memory
declarative,
memories that need a lot effort because are for remember events.
Implicit memory
non-declarative
Memories that are make automatically, like habits and abilities.
- E.g., another patient and three nurses (the patient hat preference for a nurses the was kind and he was capable of remember think of her like because she is sweet)
Hippocampus relates most strongly to episodic memories
- Episodic memories include context.
- Coordinates representations from various cortical areas.
- When retrieving episodic memory, activity in and around the hippocampus synchronizes with activity in several cortical areas.
Procedural memory
It is the development of motor skills and habits, and also is a type of implicit memories.
Examples
* H.M. learned to read words written backward (as in a mirror)
* K.C. learned to use Dewey decimal system to sort books and is employed part time at a library
Episodic memories need information exchange between
hippocampus &
cortex
Memory reactivation:
hippocampus & cerebral cortex bounce messages back
and forth with sharp-wave ripples
Ripples help…
Ripple patterns during….
- Ripples help to reexperience an event
- Ripple patterns during memory recall resemble those that occurred during original learning
- Radial mazes
- Morris water maze task
What this tasks shows?
Damage to hippocampus impairs
abilities on special tasks like those.
Place Cells
Time Cells
- Place cells turned to a particular spacial location.
Time cells response a particular point in a sequence of time.
The striatum
Is part of a Basal ganglia, and Habits & likelihood of events under a set of circumstances relies on striatum.
(habits develop slowly and depend of your striatum)
striatum orients behaviors relative to your body
The striatum distinction of hippocampus?
Striatum learns habits (implicit) and hippocampus learns declarative (explicit) memories
- Most tasks activate both systems
- Hippocampal learning at the beginning of a task, but once the task becomes “habitual”/”automatic,” more emphasis on the striatum
Hebbian synapse
- example
-critical for what?
increases in effectiveness because of simultaneous activity
in the presynaptic and postsynaptic neurons
- “Cells that fire together wire together”
- May be critical for associative learning
Aplysia
is a marine invertebrate (Large neurons) used in multiple studies of learning, are important for undertant the mechanisms of habituation and sensitization.
HABITUATION IN APLYSIA
Decrease in response to repeatedly presented stimuli accompanied by no
other change in stimuli.
- Depends upon change in synapse between sensory and motor neurons
- Sensory neurons fail to excite motor neurons as they did previously
SENSITIZATION IN APLYSIA
- Increase in response to a mild stimulus as a result to previous exposure to
more intense stimuli - Changes at identified synapses include:
- Serotonin released from a facilitation neuron blocks potassium channels in
the presynaptic neuron - Prolonged release of transmitters from that neuron results in prolonged
sensitization.
Long-term potentiation (LTP)
occurs when one or more axons bombard a dendrite with stimulation
Leaves synapses “potentiated”..
for a period of time and the neuron is more responsive
THE 3 PROPERTIES OF LONG-TERM POTENTIATION
define them..
Specificity
* Only synapses onto a cell that have been highly active become strengthened
Cooperativity
* Simultaneous stimulation by two or more axons produces LTP much more strongly that does repeated stimulation by a single axon
Associativity
* Pairing a weak input with a strong input enhances later responses to weak input
