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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 Learning
Erdeniz, 2007
Parkinson Patients vs Controls Non-Monetary Feedback
Irrelevant Information TaskFrequency of Blue Choice
40
50
60
70
80
90
100
1 2 3 4 5
Blocks
Fre
qu
en
cy o
f B
lue C
ho
ice
Parkinson Patients
Controls
Erdeniz, 2007
Irrelevant Information Task PD Reaction Time Graph
400
600
800
1000
1200
1400
1600
1 2 3 4 5
Blocks
Rea
ctio
n T
ime
(mse
c)
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