Learning

References:

1. Packard M, Knowlton B, Learning and memory functions of the basal ganglia, Annual Reviews neuroscience, Vol 25, 563-593, 2002

2. Clark, RE, Squire, LR, Classical Conditioning and Brain Systems: The role of awareness, Science, Vol 280, pp. 77-81, 1998

3. Knowlton B, Mangels JA, Squire LR, A Neostriatal habit learning system in humans, Science, Vol 273, 1399-1402, 1996

4. Willingham DB, Salidis J, Gabrieli J, Direct comparison of neural systems mediating conscious and unconscious skill learning, Journal of Physiology, pp 1452-1460, 2001

intact in amnesiaex: motor/habitual skillsex: word priming studiesex: simple CS

Squire, 2004

Working MemoryDLPFC Parietal

(striatum=caudate+putamendiencephalon=thalamus and vicinity)

Explicit Memory– memory of facts and experiences that one can

consciously know and declare– hippocampus- neural center in limbic system

that helps process explicit memories for storage

Implicit Memory– retention without conscious recollection– motor and cognitive skills– dispositions- conditioning

Non-declarative memory:

Occurs through modifications within specialized performance systems.

May be revealed through deactivation of systems through which learning originally occurred.

It is dispositional, being expressed through performance rather than recollection. So it can not be true or false.

Priming

Defn: A change in the processing of stimulus due to prior exposure torelated stimulus.

Types:Perceptual priming:Study versus test phases use stimuli from same or different modalities.(visual, auditory, words). Example tasks: word-fragment completion, picture naming. Effect is more observed when both stimuli are from the samemodality Conceptual priming:Study versus test phases use associative pairs. Example tasks: word-associationgeneration, category-examplar generation. Effect is more observed when studyphase enhances stimulus meaning.

Lesions:Amnesic patients exhibit normal performance in all these example priming tasks.as long as the task requires implicit recall. When the task requires explicit recall(for ex: cued recall) amnesic patients failed

Basal ganglia damage patients also show intact priming

Repetition priming (Gabrieli, 1998)

Systems:

Looks like separate areas in neocortex mediate perceptual and conceptual priming. For perceptual priming, modality specific areas, for conceptualpriming, amodal association cortices are in action.

For example, in visual word-stem completion,, bilateral occipital cortex activation occurs. In abstract/concrete decisions about words, L frontalcortex activity is reported.

For example in AD (Alzheimer's), association cortices are affected, resultingwith intact perceptual but impaired conceptual priming. Also patients with right occipital lesions show intact conceptual priming but impaired visualword-identification.

Repetition priming in a given domain reflects experience-induced changesin the same neural networks that subserved initial processing in that domainFor ex: in fMRI, activity decreases when priming occurs

Skill Learningand basal ganglia

Procedural/Skill memory (Gabrieli, 1998)

Defn: acquisition, retention, retrieval of knowledge expressed through experience induced changes in performance

Tests: implicit tests where no direct reference is made to the experience(ex: skill learning, repetition priming, conditioning)Sensorimotor skills: rotary pursuit, mirror tracing...

Lesions: Sensorimotor and perceptual skills such as reading are intact in amnesic patients who have poor declarative memory

Basal ganglia damage impairs:sensorymotor skill learning (ex: Parkinson's)cognitive skills such as probabilistic classification

Cerebellar damage impairs mirror tracing

One hypothesis indicates basal-ganglia is effective in open-loop skill learning (skills related to planning of movements) cerebellum is effective in closed-loopskill learning (continuous external feedback about errors in movement)

* While a skill is being learned, the area of brain responsible for skill-relatedfunction is predominantly active. Once the skill is learned, separate areasof brain are engaged, but the activity in the early skill-learning areas diminish.

Ex: in piano players, contra-lateral motor area activates while complex fingermovements are practiced. In non-musicians, premotor (BA 6) activate whilemovements are practiced, but when movements are learned the activity inBA6 diminishes .

Ex: Similarly, in finger tapping experiments, a decrease occurs in cerebellar activation with the learning of finger-tap sequences

Probabilistic Learning

Probabilistic Learning

Knowlton, 1996

Probabilistic Learning

Knowlton, 1996

Weather prediction

Survey questionsabout experiment

Probabilistic LearningErdeniz, 2007

Parkinson Patients vs Controls Non-Monetary Feedback

Irrelevant Information TaskFrequency of Blue Choice

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1 2 3 4 5

Blocks

Freq

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y of

Blu

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Parkinson Patients

Controls

Erdeniz, 2007

Irrelevant Information Task PD Reaction Time Graph

400

600

800

1000

1200

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1 2 3 4 5

Blocks

Rea

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Parkinson Patients

Normal Controls

Parkinson Patients vs Controls Non-Monetary Feedback

Erdeniz, 2007

Parkinson Patients vs Controls Non-Monetary Feedback

Erdeniz, 2007

WM and Basal Ganglia are at competition

Stimulus-Response Learning

Willingham, 2002

Stimulus-Response Learning

Willingham, 2002

Stimulus-Response Learning

Willingham, 2002

Stimulus-Response Learning

Willingham, 2002

Classical Conditioning

• Involves making connections between two forms of stimuli:– Unconditional (US): reliably provokes a response

• Response is termed unconditional (UCR)– Conditional (CS): neutral: does not provoke the

response– Pair the CS and UCS over many trials– Does the CS alone produce a response?

Reflex (delay) conditioning: (Gabrieli, 1998)Experiment: CS 250-500 ms tone, US airpuff, both terminate together.US initiates eyeblink. After CS is learned, eyeblink occurs without airpuff.

Electrophysiology: Hippocampus and cerebellum activity correlateswith this behavior

Lesion: Hippocampal lesions do not impair delay conditioning but cerebellar lesions abolish this response (humans and rabbits)

Delay eyeblink conditioning is impact in amnesic patients with bilateralmedio-temporal (MTL) or bilateral thalamic lesions or in patients with basal-ganglia damage

Trace conditioning (complex):

Experiment: CS 250-500 ms tone, US airpuff, delay between the end ofCS and onset of US. Delay is 500-1000 msec

System: Same system active in declarative memory: MTL

Lesion: Delay eyeblink conditioning is impaired in amnesic patients with medio-temporal (MTL) damage (also in animals)

Cerebellum is good enough for delay conditioning

Clark, 1998

Classical Conditioning

Clark, 1998

Classical Conditioning

Worthy of note

Katrin Amunts

n= 30 control, 21 pianistsMRI:T1 1.17 mm

Piano training changes the depth of your central sulcus

ILPG measure