Jessica Turner, Ph.D. Mind Research Network, Albuquerque, NM Angela Laird, Ph.D. University of Texas...
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Transcript of Jessica Turner, Ph.D. Mind Research Network, Albuquerque, NM Angela Laird, Ph.D. University of Texas...
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What is the relationship between cognitive processes and cognitive
experiments?
Jessica Turner, Ph.D.Mind Research Network, Albuquerque, NM
Angela Laird, Ph.D.University of Texas Health Sciences Center, San Antonio
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ConclusionsMental 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 them
The link between experimental results and the mental function they claim to be “about” needs to be clarifiedNeed 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
DelusionsHallucinationsDisorganization
I. Positive symptomsBlunted affect
Few words (Alogia )No initiative (Avolition )No pleasure (Anhedonia)
II. Negative symptoms
Discontent/depression (Dysphoria )Suicidality
Hopelessness
IV. Affective symptoms
Social/occupational dysfunctionWork/interpersonal relationships
Self-care
AttentionMemory
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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In the extremes
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 model
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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 experimentsBrainMap database: Experiments have
conditions
Describe the conditions of the experimentStimulusInstructionsResponse
And context: Pre/post treatment? Population studied?
And behavioral domain
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Linking mind and behaviorCognitive 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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Sz have attention problems
Controls on average: 77% correctSz on average:
54% correct
Carter et al., Schizophrenia Res. 2010
Disentangling the roles of attention and perception in measuring perceptual thresholds is not easy to do.
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Linking mind and physiologyCognitive 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
The differences in speed and accuracy among these trials relates to voluntary control of attention
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 Neuroscience
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Cognitive neuroimaging and mental function
Localization of function
Effort-related increases in signal
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Cognitive neuroimaging and mental function
Carter et al., Schizophrenia Res. 2010
Controls (L) and SZ (right) increases in BOLD signal for different attentional task conditions.
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Linking mind and brain Brain Map-supported analysis of “executive function” in
schizophrenia Also 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
Minzenberg et al., Arch. Gen. Psychiatry, 2009
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HypothesesWe 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 areas
But also keeps us from asking other questionsCan we treat schizophrenia with cognitive
training?
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OperationalizationThis 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
attention
Perception:Sensory thresholds are defined as the 50% point or 75% point
Executive functionHow many trials do you perseverate in using a rule you’re
being told is wrong?
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InterpretationThe caveats are important!These are plausible alternative explanations
for the experimentFailures of operationalization
Eg. 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 functionExamples from fMRI
It gets messy, when the linking hypotheses aren’t clear
E.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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ConclusionsScience 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.