RECRUITMENT OF THE PRE-MOTOR AREA IN HUMAN INDUCTIVE REASONING: AN FMRI STUDYShengfu Lu, Peipeng Liang, Yanhui Yang & Kuncheng Li

Presented by Michael Ycasas

WHAT IS INDUCTIVE REASONING? Defined as the process of inferring a general

rule (conclusion) by observation and analysis of specific instances (premises)

WHAT IS INDUCTIVE REASONING? Defined as the process of inferring a general

rule (conclusion) by observation and analysis of specific instances (premises)

e.g. The Power Rangers were defeated last ThursdayThe Power Rangers were defeated this Thursday

Therefore,the Power Ranger will be defeated next Thursday.

WHAT IS INDUCTIVE REASONING?

e.g.

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PAST STUDIES ON INDUCTIVE REASONING Bilateral rostrolateral PFC, and the right

dorsolateral PFC activation (Christoff et al, 2001)

Left dorsolateral prefrontal gyrus showed greater activity during induction (Goel and Dolan, 2004)

Recruitment of the pre-motor cortex in inductive reasoning (Goel et al., 1997; Goel & Dolan, 2004; Christoff et al., 2001; Parsons & Osherson, 2001)

CONFLICT IN PAST STUDIES PMC’s clear role in induction

CONFLICT IN PAST STUDIES PMC’s clear role in induction

Past experimental method issues:a. Button-pressing taskb. Effect of background knowledge induced

by experimental tasks

METHODS

Rule Acquisition Rule Application

RESULTS Induction Task vs Calculation Task

brain region activations were consistent with past studies - PMC, dorsolateral prefrontal cortex (DLPFC), and others.

RESULTS AND DISCUSSIONGOING BACK TO PMC ISSUES: Was PMC simply activated because of button-

pressing?

RESULTS AND DISCUSSIONGOING BACK TO PMC ISSUES: Was PMC simply activated because of button-

pressing?

RESULTS AND DISCUSSIONWHAT IS THE ROLE OF PMC IN INDUCTION?

Different roles of the left and right PMC

Left – non spatial task

Right – spatial task

(Gitelman et al.,1996; Haxby et al.,1994)

THE ROLE OF THE LEFT PMC IN INDUCTION?PMC AND RELATION SYNTHESIS General and Holistic view of PMC(in relation to

PFC)Trend: Medial PMC (internally guided

movements) vs Lateral PMC (externally guided movements) (Schubotz & Cramon,2003)

Similar trend in dorsolateral prefrontal cortex (DLPFC) (Christoff et al, 2001)

---------------------------------------------------------------------------------------

DLPFC mediate rule application after rule acquisition (Strange et al, 2001)

THE ROLE OF THE LEFT PMC IN INDUCTION?PMC AND RELATION SYNTHESIS General and Holistic view of PMC(in relation to

PFC)Trend: Medial PMC (internally guided

movements) vs Lateral PMC (externally guided movements) (Schubotz & Cramon,2003)

Similar trend in dorsolateral prefrontal cortex (DLPFC) (Christoff et al, 2001)

--------------------------------------------------------------------------------------- DLPFC mediate rule application after rule

acquisition (Strange et al, 2001) Therefore, PMC exhibits the same function as

DLPFC.

THE ROLE OF THE LEFT PMC IN INDUCTION?PMC AND RELATION SYNTHESIS General and Holistic view of PMC(in relation to

PFC)Trend: Medial PMC (internally guided

movements) vs Lateral PMC (externally guided movements) (Schubotz & Cramon,2003)

Similar trend in dorsolateral prefrontal cortex (DLPFC) (Christoff et al, 2001)

--------------------------------------------------------------------------------------- DLPFC mediate rule application after rule

acquisition (Strange et al, 2001) Therefore, PMC exhibits the same function as

DLPFC.

CONCLUSION Inductive Reasoning is a content-based

process

Left PMC – implicit process of relation synthesis

Right PMC – spatial information processing

ISSUES PMC activation due to Short term memory???

PMC may maintain a short term representation of structured dynamics (Geake & Hansen, 2005)

(The NEED to remember the arithmetic rule!!)

OPINION/CRITICISM CORNER

Not persuaded with the conclusion ....

OPINION/CRITICISM CORNER

OPINION/CRITICISM CORNER

2 different brain regions = similar function b/c “they are adjacent” – (reasoning behind Relation Synthesis)??

That is all.

No Questions allowed!!!

OPINION/CRITICISM(S) CORNERIf PMC exhibit 1 then DLPFC exhibit 1DLPFC exhibit 2---------------------------------------------------PMC exhibit 1

OPINION/CRITICISM(S) CORNERIf PMC exhibit 1 then DLPFC exhibit 1,DLPFC exhibit 2---------------------------------------------------PMC exhibit 1

Is the same as saying that.....

If Pregnant then Woman,Woman----------------------------------------------------Pregnant ---x---- not true!