What is the relationship between cognitive processes and co - PowerPoint Presentation

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What is the relationship between cognitive processes and cognitive experiments?

Jessica Turner, Ph.D.Mind Research Network, Albuquerque, NMAngela Laird, Ph.D.University of Texas Health Sciences Center, San Antonio

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Conclusions

Mental functions may be shorthand for complex neural circuitry and function; or they may be emergent properties which cannot be further deconstructedEither way we can build an ontology for themThe link between experimental results and the mental function they claim to be “about” needs to be clarified

Need details of time, location, assumptions, methods.

Need to consider the hypothetical framework; the explicit

operationalizations; the analyses done and not done; and the caveats from the experimental context.

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Core Symptom Clusters in Schizophrenia: Or, why I care about mental function

Delusions

Hallucinations

Disorganization

I. Positive symptoms

Blunted affect

Few words (Alogia )

No initiative (Avolition )

No pleasure (Anhedonia)

II. Negative symptoms

Discontent/depression (

Dysphoria

)

Suicidality

Hopelessness

IV. Affective symptoms

Social/occupational dysfunction

Work/interpersonal relationshipsSelf-care

Attention

Memory

Executive functions

(

eg

, abstraction)

III. Cognitive symptoms

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. Fourth ed. Text Revision. Washington DC: American Psychiatric Association. 2000.Slide courtesy of Dr. Jose Cañive

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The ontological status of mental function over time

IntrospectionismBehaviorismCognitive science

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In the extremes

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Eliminative materialism

Mental functions as concepts will disappear as we understand the brain better

Reality is epiphenomena

All we have is consciousness and everything else is a modelSlide6

Cognitive Paradigm Approach

The mental function experimenters claim to be studying is not as important as how they study it.

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Schema for cognitive experiments

BrainMap database: Experiments have conditionsDescribe the conditions of the experimentStimulusInstructionsResponse

And context: Pre/post treatment? Population studied?

And behavioral domain

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CogPO basics

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Turner and Laird, 2012.Slide9

BrainMap behavioral domains

CogAtlas is similarNot completeNot clear which is whichNot orthogonal

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Linking mind and behavior

Cognitive experiments attempt to measure mental processes

Donders

, 1869.

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SZ have deficits detecting low spatial frequencies

O’Donnell et al., J. Abnormal Psychology 2002.

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Disorganized perception

Louis Wain (1860-1939)

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Sz have attention problems

Controls on average: 77% correct

Sz

on average:

54% correct

Carter et al., Schizophrenia Res. 2010

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Disentangling the roles of attention and perception in measuring perceptual thresholds is not easy to do.Slide14

Linking mind and physiology

Cognitive neuroscience experiments attempt to measure physiological correlates of behavior, indirectly connected to mental processes Attention: What is it?Endogenous (voluntary) attention

vs

Exogenous (involuntary) attention

Posner: Experimental designs for studying voluntary attention

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The differences in speed and accuracy among these trials relates to voluntary control of attentionSlide15

The

spatiotemporal receptive-field map of a single neuron in the unattended mode (top) and attended mode (bottom).

McAdams C J , Reid R C J.

Neurosci

. 2005;25:11023-11033

©2005 by Society for NeuroscienceSlide16

Cognitive

neuroimaging and mental functionLocalization of function

Effort-related increases in signal

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Cognitive

neuroimaging and mental function17

Carter et al., Schizophrenia Res. 2010

Controls (L) and SZ (right) increases in BOLD signal for different

attentional

task conditions. Slide18

Linking mind and brain

Brain Map-supported analysis of “executive function” in schizophreniaAlso known as “cognitive control”41 papers with tasks including delayed match-to-sample or delayed response (including Sternberg item recognition), go/no-go (including AX-CPT), mental arithmetic, N-back, oddball, sequence recall,

Stroop

, Wisconsin Card Sort, and word generation tasks

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Minzenberg

et al., Arch. Gen. Psychiatry, 2009Slide19

Linking mind and brain

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From experiment to mental function

HypothesesOperationalizationAnalysisInterpretation

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Hypotheses

We frame hypotheses within a scientific framework.This rules out some questions as being sillyE.g. we don’t ask about the olfactory role of primary visual areasBut also keeps us from asking other questionsCan we treat schizophrenia with cognitive training?

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Operationalization

This is a key step in linking what we are studying in the abstract to what we are measuring in reality Attention: Performance differences somehow capture what we mean by attentionPerception:

Sensory thresholds are defined as the 50% point or 75% point

Executive function

How many trials do you perseverate in using a rule you’re being told is wrong?

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Analysis

What we do with data is shaped by what we think is acceptable within our framework

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Interpretation

The caveats are important!These are plausible alternative explanations for the experimentFailures of operationalizationEg. A monkey who has figured out another way to get their juice reward or a human who is doing the study in some completely unexpected way

The BOLD signal or other measurement is not sensitive to the differences you want

Or it is sensitive to differences you don’t want (medication)

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Cognitive neuroimaging and mental function

Examples from fMRIIt gets messy, when the linking hypotheses aren’t clearE.g. clinical populations: We know that the BOLD signal doesn’t look the same, and the behavior is different; but what does that mean about mental function per se?

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Conclusions

Science does not work solely by building on logical axioms. There is a theoretical framework behind the formation and interpretation of every experiment.How we think about the experimental design and interpretation is not context-free. Over time, concepts and relationships will disappear and new ones show up

E.g., phlogiston, DNA as a blue print, arguments over nature

vs

nurture, the role of the unconscious in mental dysfunction.Our semantic framework for reasoning within cognitive neuroscience has to take that into account.

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Conclusions

How we characterize mental functions is going to change (again!).The results of cognitive experiments about mental function need to be subscripted by the experimental methods and theoretical framework.

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