A
B
SAMPLE DELAY CHOICE
A
B
A
B
1st Reversal 2nd Reversal
etc….0 500 1500
Trial Time (ms)
Conditional Visuomotor Learning Task
Asaad, W.F., Rainer, G. and Miller, E.K. (1998) Neuron, 21:1399-1407.
Time (ms)0 200 400 600 800 1000 1200 1400
Spikes per second
20
30
40
50
SAMPLE DELAY
30
40
50 B - go right
A - go rightA - go left
B - go left
Object and Direction selective PF neuron(nonlinear interaction)
RightLeft RightLeft RightLeft
Movement Direction Stimulus Mapping
Prefrontal cortex :
May mediate learning of arbitrary associations. Many PF neuronscoded both an object and a currently-associated directional response.
During learning, information about the cue object and the action itinstructed gradually merged together in PF activity.
This may reflect the role of the PF cortex in acquiring and representingbehavior-guiding rules, a function crucial for intelligent, adaptivebehavior.
Asaad, W.F., Rainer, G. and Miller, E.K. (1998) Neuron, 21:1399-1407.
Match (bar release)
Nonmatch (bar release)
Match Rule(DMS)
Nonmatch rule(DNMS)
Sample Delay Test
We trained monkeys to switch between two abstract rules: “match” and “nonmatch”
Four samples were used.New objects every day.
Wallis, J.D., Anderson, K.C., and Miller, E.K. (2000) Soc. Neurosci. Abstr.
+ reward
+ low tone
Lever release
Match
+ no reward
+ high toneLever release
Nonmatch
Condition Rule Example Trial
Sample Cue
2D Graph 1
Time (milliseconds)500 1000 1500 2000
Firin
g ra
te (H
z)
5
10
15
20
NONMATCH - no rewardNONMATCH - high tone
MATCH - rewardMATCH - low tone
Sample Delay
A Prefrontal Neuron Tuned to the Match Rule
2D Graph 1
Time (milliseconds)500 1000 1500 2000
Firin
g ra
te (H
z)
0
5
10
15
20
NONMATCH - no rewardNONMATCH - high tone
MATCH - rewardMATCH - low tone
A Prefrontal Neuron Tuned to the Nonmatch Rule
Sample Delay
The prefrontal cortex:
Selectively represents goal-relevant information (focal attention, recall).Synthesizes information from diverse sources to serve a common behavioral goal (sensory inputs, stored knowledge).Is plastic: it neural activity changes to meet behavioral demands.Knits together arbitrary associations between diverse, but behaviorally-related information.Conveys information about the behavioral context in which the animals are engaged and the rules used to guide behavior. This may reflect the role of the PF cortex in acquiring and representing the formal demands of behavior, rules or models of tasks that provide a foundation for complex, intelligent behavior.(Cohen and Servan-Schreiber, 1992; Passingham, 1993; Grafman, 1994;Wise et al., 1996; Dehaene et al., 1998; Miller, 1999, Miller, 2000, Miller and Cohen, 2001).
Active Inactive
The PF cortex and cognitive control
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Active Inactive
The PF cortex and cognitive control
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The PF cortex and cognitive control
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Active Inactive
The PF cortex and cognitive control
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PF cortex
Active Inactive
The PF cortex and cognitive control
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PF cortex
Reward signals(VTA neurons?)
Active Inactive
The PF cortex and cognitive control
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PF cortex
Active Inactive
The PF cortex and cognitive control
Phone ringsAnswer
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At home
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PF cortex
Reward signals(VTA neurons?)
Active Inactive
The PF cortex and cognitive control
Phone ringsAnswer
Don’tanswer
At home
Guest
PF cortex
Active Inactive
The PF cortex and cognitive control
Answer
Don’tanswer
PF cortex
Phone rings
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At home
Active Inactive
The PF cortex and cognitive control
Answer
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PF cortex
At home
Guest
Phone rings
Active Inactive
The PF cortex and cognitive control
Answer
Don’tanswer
PF cortex
At home
Guest
Phone rings
Active Inactive
The PF cortex and cognitive control
Answer
Don’tanswer
PF cortex
Phone rings
Guest
At home
Active Inactive
The PF cortex and cognitive control
Answer
Don’tanswer
PF cortex
At home
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Phone rings
PF cortex
Its integrative anatomy allows it to rapidly acquire a “map” that specifies which pattern of “tracks” (neural pathways) are needed to solve a given task.
The prefrontal cortex may be like a switch operator in a system of railroad tracks:
PF cortex
Its integrative anatomy allows it to rapidly acquire a “map” that specifies which pattern of “tracks” (neural pathways) are needed to solve a given task.
The PF cortex actively maintains this pattern during task performance, allowing feedback signals to bias the flow of activity in other brain areas along those tracks.
The prefrontal cortex may be like a switch operator in a system of railroad tracks:
PF cortex
Its integrative anatomy allows it to rapidly acquire a “map” that specifies which pattern of “tracks” (neural pathways) are needed to solve a given task.
The PF cortex actively maintains this pattern during task performance, allowing feedback signals to bias the flow of activity in other brain areas along those tracks.
The prefrontal cortex may be like a switch operator in a system of railroad tracks:
Attention, retrieval, representation ofrules and goals, response selection, inhibitory control, etc. can be explained by PF bias signals actingon different brain structures.