neurobiology of learning and memory test 3

Bliss and Lomo

discovered LTP; was first recorded in the entorhinal cortex (Dentate Gyrus of the hippocampus)

Weak stimulus was applied and there was a weak response from the area. Strong stimulus was applied at the same area and there was a strong response. The weak stimulus later produced the strong response.

LTP

discovered by Bliss and Lomo by stimulating the preforant path and recording in the dentate gyrus

Moo Ming Poo

Neurons that are out of sync loose their link.

Hebb postulate

Neurons that fire together wire together

Gary Lynch

Increasing AMPA Receptors in the PSD Supports LTP Expression

Ribot's law

Last hired, first fired

Kluver testing hypothesis

that mescaline affected the temporal lobes, so bilaterally removed them

Brown and Schäfer (1888), then later Klüver and Bucy (1937)

noted reduced aggression, fear, and defensiveness in monkeys with amygdala lesions

Brown and Kulik

Flashbulb memories

Reasons that to use LTP to induce memory

LTP is:

Rapidly induced

Long lasting

Drugs that impair memory impair LTP.

Same brain areas and NT systems.

Associative

Theta rhythm can produce LTP.

Reasons to not use LTP to induce memory

LTP is:

LTP "experience" = unnatural stimulus to abnormal tissue

low-intensity, high-frequency electrical event

bypasses all the sensory inputs that normally bring environmental information into the brain.

Slicing tissue has profound effects.

Tissue is preserved in cocktail.

Whitlock et al. (2006)

Inhibitory Avoidance training induces LTP in CA1

Liu et al

Training-induced neuronal activity selectively labels active c-Fos-expressing DG neurons with ChR2-EYFP.

Dox blocks expression

Training with or without shock induces expression

Lasts 5 days, not 30

Sparse labelling not due to low infection rate

DG neurons responded to light stimulation in time-locked manner

Activation of population of DG neurons labelled by ChR2-EYFP is sufficient for memory recall.

Not due to non-specific performance effects

Evidence for "dual memory engram" hypothesis

Karl Lashley

Mass action and equal potentiality

searched for the engram

Distributed network

Dissociations and double dissociations

Santiago Ramón y Cajal

Created incredibly detailed drawings of neurons and neural structure using the Golgi staining method to see the structure.

William James

founder of functionalism;

Described different types of memories:

After images

Primary memory

Secondary memory/Memory proper

Aimed to explain the function and physiological origin of behaviors

Wihelm Wundt

Known as the "Father of experimental Psychology," he established first psychological laboratory in Leipzig, Germany.

Hermann Ebbinghaus

the first person to study memory scientifically and systematically; used nonsense syllables and recorded how many times he had to study a list to remember it well.

initiated empirical research; "Of all liars, the smoothest and most convincing is memory"

Muller and Pilzecker

responsible for perseveration-consolidation hypothesis

made the first experimentally controlled observation that new memories are more easily disrupted than old memories.

William McDougall

accounted for retrograde amnesia ; head injury

People who suffered head injury often cannot remember the events that occurred just prior to the injury but can remember episodes that occurred earlier

Ivan Pavalov

Externalized salivary gland in dogs to collect and measure saliva.

Classical learning (S-S)

Conditional reflex "Psychic Salivation"

Food (US) salivation (UR)

Sound + food salivation

Sound (CS) salivation (CR)

Clark Hull

1884-1952; Field: motivation; Contributions: maintains that the goal of all motivated behavior is the reduction or alleviation of a drive state, mechanism through which reinforcement operates

Behaviorism as a science

Edward Tolman

cognitive psychologist; latent learning and cognitive map

Wolfgang Köhler

He was a psychologist, who, alongside Max Wertheimer, Kurt Koffka, and Edgar Rubin, is known for founding Gestalt psychology theory. In brief, it claims that the whole is different from the sum of its parts. That is, adding up the different elements that constitutes an object or a process is not sufficient arriving at the overall object or process. Gestalt psychology became famous for its studies on perception, wherein art and experimentation were utilized for illustrating perceptive mechanisms. Nevertheless, it was also applied to other research areas. He in particular is credited with coining and studying the insight learning process. This theory posits that people and animals do not learn by operant conditioning or trial and error. Rather, they learn by having an insight or figuring out a solution for their problems. This solution is then applied to their situation. That is, the problem-solving attempts are meaning and purposeful, rather than random strategies carried out on the off-chance of getting lucky and finding out the solution. He published a book called Mentality of the Apes in 1917 in which his experiments with chimps, that illustrated the insight learning process, are described.

Scoville and Milner

Multiple memory systems

Patient H.M

Tolman/Kohler

Cognition and insightful learning

Thorndike/Hull

Instrumental learning (S-R; reinforcement & punishment)

David Olton

radial maze

lesioned brain to find where different types of memory are located

suggested that using converging operations it is possible to eliminate alternative explanations.

Eugenio Tanzi

Agranoff, Davis and Brink

Protein synthesis inhibitors given after training impair memory "fixation"

Flexner and colleagues

Protein synthesis inhibitors given to mice before training impair learning/memory

James McGaugh

Posttraining strychnine enhances memory using epinephrine

The amygdala is in a position to modulate the consolidation of memory through its interactions with other brain areas.

Agranoff

Memory inhibition is dose-dependent.

Memory inhibition is time-dependent.

Memory on day 1 is different from memory on day 4

By blocking protein synthesis on day 1, puromycin impairs memory performance on day 4.

The vagus nerve bridges the peripheral nervous system to the central nervous system through its influence on the .....

amygdala

Neuromodulation of memory

stressful event causes glucocorticoids to cross BBB and act on vagus nerve

vagus nerve acts on NTS

NTS acts on PGI

PGI acts on LC

LC acts on basolateral amygdala

Arc

plays a role in the synaptic plasticity that underlies long-term memory.

Antisense Oligodeoxynucleotides

block expression of Arc protein

post training administration of clenbuterol

enhance long-term memory for the object recognition task

Exposure-based therapies

Patients are repeatedly exposed to reminders of the trauma until they extinguish conditioned fear.

vagus nerve stimulation

is both memory enhancing and anxiety reducing

enhances and accelerates extinction of conditioned fear

protects against reinstatement

PTSD patients have a decreased amount

BDNF

BDNF (brain-derived neurotrophic factor)

required for protien synthesis phase of LTP

signalled centrally through hippocampus during neurogenisis

benzodiazapines

impair memory consolidation

Nader, Schafe & LeDoux (2000)

Fear memories require protein synthesis in the amygdala for reconsolidation after retrieval

hypothesis : Reconsolidation involving protein synthesis is required for retrieved memories to persist.

memory consolidation is disrupted by

ECS or protein synthesis inhibitors

extinction

NO RENEWAL (RECOVERY IN DIFFERENT CONTEXT)

NOT CONTEXT-DEPENDENT

NO REINSTATEMENT EFFECT (RECOVERY AFTER US REMINDER)

NO SPONTANEOUS RECOVERY (AFTER 24 D)

But there are a lot of scientific journals that show evidence against this as well

when impairing reconsolidation the best route is.........

a short termed CS exposure paired with propranolol will give rise to low fear

when enhancing extinction the best route is......

a long termed CS exposure paired with DCS will give rise to low fear

memory renewal

new context or conditioned context

Reinstatement

reappearance of an extinguished response produced by exposure to the US or reinforcer

How addiction and memory are related

Drug use mimics normal learning

drug taking is reinforced

However, motivation for consuming drug exceeds all other motivations

Relapse, hallmark of addiction

Can be triggered by stimuli/cues (reminders)

Storage of information leads to maladaptive neural changes

Hijacking of memory mechanisms by superphysiological conditions

Mesolimbic Pathway

Reinforcement

Nucleus Accumbens

Amygdala

Hippocampus

Mesocortical Pathway

Compulsive behavior

Cingulate gyrus

Orbitofrontal cortex

Nigrostriatal Pathway

Habit

Dorsal striatum (Caudate)

PKMζ

Involved in LTP maintenance, especially in late phase LTP

Extinction training:

↑ expression in infralimbic regions

↓ expression in basolateral amygdala

Both results accelerated in with a 10 minute delay

Estrogen administration enhances

Working memory

Inhibitory and active avoidance

Object and place-recognition memory

Spatial water maze

Memantine

NMDA receptor antagonist

treats Alzheimers

Galantamine

Cholinesterase inhibitors

treats Alzheimer

donzepil does the same

Biomarkers of Alzhimers

Aβ42 Levels DECREASE during progression

Phosophorylated tau Levels INCREASE

total tau levels increase with any brain injury is present

CREB disregulation

in the aged brain

Eric Kandel

Studied the sea slug Aplysia and posited that learning and memory are evidenced by changes in synapses and neural pathways.

Nora Volkow

Matthew Walker

Marc Diamond

Michael (Mick) Rugg

Claudia Kawas

studies plaques and tangles

Pena, Engineer, and McIntyre

Extinction paired with VNS is more rapid than extinction paired with sham stimulation. As it is currently approved by the Federal Food and Drug Administration for depression and seizure prevention, VNS is a readily available and promising adjunct to exposure therapy for the treatment of severe anxiety disorders.

Xue et al

Problem: relapse caused by reinstatement, renewal, spontaneous recovery

Solution: interfere with reconsolidation

Problems with this idea is that it is not practical or safe to administer protein synthesis inhibitors and results from animal models cannot be translated into clinical models

Walker and Stickgold

Sleep cannot be treated as a homogeneous state

Stages of sleep

NREM

REM

Memory, like sleep, is not a single entity

Declarative vs. nondeclarative

Operate in isolation?

Phases

Encoding, consolidation, recall

Staggering number of ways that sleep might affect memory

Koen et al

The relationship between age, neural differentiation, and memory performance

Gold and Van Burskik

Hypothesis: post-trial epinephrine injections should

Add to the normal hormone consequences of the training experience

Mimic the consequences of more intense training

Improve retention performance

Eliminate many performance variables

Gruene

Showed that female rats exhibit darting behavior after fear conditioning more than male rats.

Male rats exhibit freezing after fear conditioning more than female rats.