Learning

1
Learning Memory

• 2. Neural learning

2
Neural learning
Early connectionism

• Essential
• Gazzaniga Ch.7
• Wills, Ch. 1, 2, 5, 6.(not all this week!)
• Suppl
• Schultz Dickinson (2000)
• (www.willslab.co.uk)

Action potentials 1120-1
Hebbian learning
Long-term potentiation
Neurotransmitters 1120-1
Potential summation 1120-1
Prediction error neuroscience
Rescorla-Wagner model
Intro. Connectionism 1121-1
R-W neuron collection
Before
After
During
3
Neuroscience
4
Connectionism
word units
letter units
feature units
T I M E
5
Pavlov (1909)
temporary union i.e. the establishment of a new
connection in the conducting pathways (p.122)
analyzers
Extraordinarily poor dress sense his choice of
colours made his friends laugh and his family
angry (Gantt, 1928, p.14)
6
Donald Hebb (1949)

• When an axon of cell 1 is near enough to excite
  a cell 2 and repeatedly and persistently takes
  part in firing it, some growth process or
  metabolic change takes place in one or both cells
  such that 1's efficacy, as one of the cells
  firing 2, is increased.

Cells that fire together wire together
?w G.a1.a2
7
Hawkins et al. (1983)
Classical conditioning in the sea slug (Aplysia
Californica)
8
Sea slug anatomy
9
(No Transcript)
10
Synaptic changes
11
Slightly more complex learning
A
B-
12
Blocking (Kamin, 1969)

• Phase 1 Phase 2 Phase 3
• A AX Test X
• B- BY Test Y

Cells that fire together wire together
13
Results (from Waelti, Dickinson Schultz, 2001)
X
Y
14
Blocking (Kamin, 1969)

• Phase 1 Phase 2 Phase 3
• A AX Test X
• B- BY Test Y

We learn about cues that predict surprising
outcomes.
Cells that fire together wire together
15
Waelti, Dickinson Schultz (2001)
Microelectrode
Note This is a human brain. Waelti et al.
studied Macacca fascicularis
16
Dopamine neuron response
Phase 1 Phase 2 Phase 3 A AX Test
X B- BY Test Y
17
Hypothetical neural circuit
McLaren (1989)
18
Rescorla Wagner (1972)
We learn about cues that predict surprising
outcomes.
?w G(?-Swa)
AKA Delta rule c.f. Level 1 Cognition Level
2 Language Thought
19
Rescorla Wagner (1972)
?w G(?-Swa)
w1
a1
?1, US present ? 0, US absent
w2
a2
AKA Delta rule c.f. Level 1 Cognition Level
2 Language Thought
20
What next?

• Essential
• Gazzaniga Ch.7
• Wills, Ch. 1, 2, 5, 6.(not all this week!)
• Suppl
• Schultz Dickinson (2000)
• (www.willslab.co.uk)

Correlation 1117-9