Cognitive control, hierarchy, & the rostro-caudal organization of the prefrontal cortex

David Badre

Department of Cognitive & Linguistic SciencesDepartment of Psychology

Brown University

What does neural systems level data tell us?

• Action hierarchy may not require a hierarchical system

• Complex actions can be represented hierarchically

Sandwich for lunch

Make sandwich Pack sandwich

Slicing bread Spreading Mayonnaise

Etc…

Action and the Frontal Lobes

• Frontal lobe dysfunctionInability to organize or plan a sequence of behaviors(Shallice and Burgess, 1991)

Vulnerability to action slips(Schwartz et al., 1998)

Rostro-Caudal Axis of the Frontal Cortex

• Perception-Action cycle (Fuster, 1997; 2001; 2004)

• Human Neuroimaging EvidenceRelational complexity(Christoff & Gabrieli, 2000; Christoff et al., 2003)

Temporal organization of behavior(Koechlin et al., 2003; Koechlin & Jubault, 2006;

Koechlin & Summerfield, 2007)

Fuster, 2004

Talk Outline

• FMRI evidence of hierarchy along rostro-caudal PFC

• Disruption of PFC hierarchy

• Learning at different levels of PFC hierarchy

Prefrontal Cortex and Cognitive Control

Cognitive control processes represent contextual information to bias relevant representations over competitors.

Hypothesis 1: Manipulate control by varying competition

Response 1 Response 2

Cue Cue

Response 1 Response 2

Cue 1 Cue 2

Response 2 Response 1

Cue 1 Cue 2

Hypothesis 2: Regional differences in PFC are determined by the level of abstraction of competing action representations.

Level 1: Competition among Responses

12 3

4

Badre and D’Esposito, JOCN, 2007

Level 1: Competition among Responses

1 Response(no competition)

1 1 22 Responses

3 Response Levels

1 2 3 44 Responses

Level 1: Competition among Responses

-.4

0

.4

.8

1 2 3 4 5 6 7 8 9 101112

4 Responses2 Responses1 Response

TR

PS

C

Badre and D’Esposito, JOCN, 2007

Level 2: Competition among Features

1

1 - Positive

22 - Negative

Features

Badre and D’Esposito, JOCN, 2007

3 Feature Levels

Level 2: Competition among Features

1 Feature 2 Features 4 Features

Level 2: Competition among Features

TR

-.1

0

.1

.2

1 2 3 4 5 6 7 8 9 101112

4 Features2 Features1 FeatureP

SC

Level 3: Competition among Dimensions

1

1 - Match along relevant dimension

22 - Mismatch along relevant dimension

DimensionsOrientation

TextureShapeSize

Badre and D’Esposito, JOCN, 2007

3 Dimension Levels

Level 3: Competition among Dimensions

1 DimensionOrientation Orientation Texture

2 Dimensions

ShapeOrientation

SizeTexture

4 Dimensions

Level 3: Competition among Dimensions

-.2

0

.2

.4

.6

1 2 3 4 5 6 7 8 9 101112

4 Dims2 Dims1 Dim

TR

PS

C

Badre and D’Esposito, JOCN, 2007

Level 4: Competition among “Contexts”

Size Texture Shape Orientation

Recent Instructions

3 Context Levels

100% mapping 50% mapping 25% mapping

Badre and D’Esposito, JOCN, 2007

Level 4: Competition among “Contexts”

0

.04

.08

0 .5 .25Mapping Frequency

Sus

tain

edA

dj iP

SC

Interim Conclusions

• FMRI evidence of hierarchy along rostro-caudal PFC

• Disruption of PFC hierarchy

– Hierarchical system in PFC engaged by competition in action system– Hierarchy ranked by level of abstraction of representations