Replication and extension: Working memory and predictability Unpredictable inferences: LH activation, IFG, pSTG • searching for connections Predictable inferences: Bilateral activation, IFG, pSTG • building on connections Higher WM (n=13) > lower WM (n=13): RH activation, pSTG, IFG, and a little aSTG • building on connections • facile comprehension
Successful integration versus continued activation: STG in High vs. Low WM subs at coherence break, Predictable inferences RH aSTG High WM subs show bilateral (stronger in RH) p<.005 Low WM show LH only, no aSTG
Replication and extension: Working memory and predictability Unpredictable inferences: LH activation, IFG, pSTG • searching for connections Predictable inferences: Bilateral activation, IFG, pSTG • building on connections Higher WM (n=13) > lower WM (n=13): RH activation, pSTG, IFG, and a little aSTG • building on connections • facile comprehension
Conclusions about inferences • Semantic integration builds up as story hints that some event might occur: anterior STG; RH (?) • At coherence break: integration and activation (STG), especially in LH • completing the inference requires selection (IFG) • RH contributes to facile inferencing/comprehension, not just kick in when demands are high
Current projects, Future directions • Shift semantic distance for integration --> shift hemi asymmetry • Closely tie to behavioral markers of inference activation, selection, incorporation – Recall of inferences � – Priming of inferences • Successful integration versus effort of difficult integration – Incorporation (recall study)
Recalled inferences • If inferences recalled, must have been incorporated • Working Memory correlates with – total recall – Recall of inferences – NOT with recall of episodes w/o inferences • Contrast fMRI signal of recalled infs versus recall episode, no infs
Inferences recalled versus Episode recalled, inf not recalled L R Post Ant L R L R R R Bilateral pMTG, stronger in RH RH aSTS, bilat IFG p<.005 , positive only
So what? Knowing where processing occurs informs and constrains what and how it occurs
Bilateral semantic processing: Inferences in language, insight in problem solving OUTLINE: • Drawing inferences from stories -- bilateral comprehension • Three bilateral component semantic processes (to start) • Insight -- bilateral, parallel processing during problem solvin
Bilateral Activation, Integration, and Selection model of semantic processing • Semantic activation - “Wernicke’s area” – Bottom-up lexical-semantic activation: index of semantic representations (pMTG) • Semantic integration - anterior Sup. Temp. Gyrus – Compute semantic overlap - detect or generate (aSTG) • Semantic selection - Inf. Frontal Gyrus – Select among competing activated concepts (IFG)
Why does the RH code more coarsely Asymmetries in neural microcircuitry
Given topographic mapping of brain, broader input/output fields => coarser semantic codin Left Hemisphere Right Hemisphere RULER foot foot TOES CUT Large but weakly activated; Small but strongly activated; Diffuse, including secondary Focused on dominant or and less relevant concepts contextually relevant concepts
RH coarse semantic coding: Increased likelihood of semantic overlap for distant semantic relations foot foot pain glass pain glass
Why a separate area for semantic integration? • Could form associations in “activation” area BUT • Higher level relations, correlated co-occurrence, indir • Ability to extract, attend to, & manipulate relations – Analogous to individual areas within vision (e.g., motion)
Why anterior STS/STG for semantic integration? • Again, neural architecture
Patchy organization and multisensory integration (Beauchamp 2004) L R Post Ant L R
Why anterior STS/STG for semantic integration? • Again, neural architecture • More anterior = longer intrinsic conxns, better to integrate across patches • RH = longer than LH
Important clarifications • Not an “inference area” – Semantic integration - participates in many functions – Not specific to categories of inferences - varies with demand • Tight comparison not reveal whole network – Just areas that differ when storied imply versus explicitly state events • RH and LH cooperate
Bilateral semantic processing: Inferences in language, insight in problem solving OUTLINE: • Drawing inferences from stories -- bilateral comprehension • Three bilateral component semantic processes (to start) • Insight -- bilateral, parallel processing in problem solving
Brain bases of insight during problem solving: Aha! and antecedents Most problems solved with mix of analytic and insight processing • Distinct computations, distributed across hemispheres, allow two approaches to proceed simultaneously (partially interactive) • Hemispheric components, task shielding/switching
Archimedes and the crown King’s crown - gold, or silver Archimedes knew gold and silver differed in density Archimedes knew weight, but couldn’t geometrically measure to obtain volume (and compute density)
Archimedes and the crown Why has story persisted so long?
Archimedes and the crown Why has story persisted so long? • Resonates with our own experiences of solving insight problems solving problems with insight
Archimedes and the crown • Solvers reach impasse (dead-end) - couldn’t measure • Must reinterpret some aspect of problem – Volume by water displacement • Unconscious processing important – If not thinking of crown, how recognize importance of water? • Solution accompanied by “Eureka!”
Insight component processes? Insight solutions associated with • Switching to new strategy or associations (“restructuring”) • Semantic integration -- solvers see connections that previously eluded them – Right hemisphere?
Solving problems with insight Characteristics of both “insight problems” and solving processes similar to characteristics of discourse and comprehension processes for which the Right Hemisphere (RH) seems to make contributions •Drawing inferences, understanding the gist •Getting jokes, metaphors, connotations •2ndary word meanings
Solving problems with insight • Solvers reach impasse (dead-end) • Must reinterpret some aspect of problem • Unconscious processing important • Solution accompanied by “Aha!”
Short insight problems: Remote Associates Test: The RAT (Mednick, 1962) RAT Compound Remote Associate Proble Bowden & Jung Beeman, 1998 child tennis scan lame strike same
RAT Compound Remote Associate Proble Bowden & Jung Beeman, 1998 child tennis scan lame strike same
Aha! experience • Solution appears sudden and obvious • As soon as you think of solution, you “just know” it works for all three words – Comes as a whole, not part by part • (vs strategic, step-by-step testing, etc)
Event-related fMRI design • Insight solutions versus noninsight solutions • Very “tight” comparison – Not reveal whole network of problem solving – Highlights just components that are uniquely engaged (or at least emphasized) for insight solutions
Insight effect in RH anterior Superior Temporal Gyrus: FMRI signal for insight > noninsight solutions. L R Post Ant L R L coronal R axial sagittal p < .005, cluster > 500 mm 3
RH aSTG: Singal change across the active region Signal change for insight Insight effect and noninsight solutions (Ins - non) Percent signal change 0.40 0.40 Percent 0.30 0.30 Signal 0.20 0.20 change 0.10 0.10 0.00 0.00 -0.10 -0.10 -2 2 4 6 8 10 -2 2 4 6 8 10 Time (sec)
Signal change for insight and noninsight solutions, in aSTG across hemispheres “Best” clus Insight 0.25 within each Non Percent signal 0.20 hemisphere 0.15 change 0.10 0.05 0.00 -0.05 LH RH Hemisphere
Parallel study with 128 channel EEG •Temporal specificity •Processing specificity - frequencies
Gamma band insight effects
Insight solving conclusions Insight solutions associated with increased activity in RH aSTG • Binding and conscious accessibility (gamma) over RH aSTG • Preceded by visual gating (alpha) - RH temp/ occipital areas
Insight solving conclusions Insight solutions associated with increased activity in RH aSTG • Binding and conscious accessibility (gamma) over RH aSTG – - Lexical or semantic integration • Preceded by visual gating (alpha) - RH temp/ occipital areas – - Sensory gating indicates cognitive control?
Replication plus… more areas New data set: improved N, scanner, protocol RH aSTG (distant semantic integration) • Anterior Cingulate (monitoring response competition, switching) • Posterior Cingulate - same? • Hippocampus/parahippocampal gyri - memory, reorgnzn?
Insight effect in RH Superior Temporal Gyrus: FMRI signal for insight > noninsight solutions. L R Post Ant L R L coronal R axial sagittal p < .001, cluster > 1000 mm 3 ant and post STG
NONinsight effect in LH Inf. Frontal Gyrus: FMRI signal for NONinsight > insight solutions. LH IFG - dominant semantic retrieval or selection - turns on at problem onset - off at solution, esp’y Insight RH IFG - unusual retrieval / selection - off at problem onset sagittal - on at solution (I>NI, ns) p < .005, cluster > 1000 mm
General vs specific mechanisms - Visual Aha! •
Visual Aha! effect in RH anterior Mid Temporal Gyrus FMRI signal for insight > noninsight recognition L R Post Ant L R L coronal R axial sagittal p < .01, cluster > 500 mm 3
Visual Aha! effect in RH anterior Mid Temporal Gyrus FMRI signal for insight > noninsight recognition L R Post Ant L R L coronal R axial sagittal p < .01, cluster > 500 mm 3
Visual Aha! effect in RH Angular Gyrus: FMRI signal for insight > noninsight recognition L R Post Ant L R L coronal R axial sagittal p < .01, cluster > 500 mm 3 Also: RH Sup Frontal Gyrus
Visual Aha! effect in Bilateral M. Occipital Gyri: FMRI signal for NONinsight > insight recognition L R Post Ant L R L coronal R axial sagittal p < .005, cluster > 500 mm 3
Visual Aha! conclusions • NOT just for verbal problems • Similarities - shared mechanisms (not “insight”, but…) – Insight: top-down, cognitive control, integration – RH -- unconscious, weak but mutually constraining, integration – Recognition comes as a whole, not part by part – Noninsight: bottom-up • Some differences - Angular Gyrus somewhat surprising
General vs specific mechanisms - Visual Aha! •
Insight solving conclusions Insight solutions associated with increased activity in RH aSTG • Binding and conscious accessibility (gamma) over RH aSTG • Preceded by visual gating (alpha) - RH temp/ occipital areas
Insight solving conclusions Insight solutions associated with increased activity in RH aSTG • Binding and conscious accessibility (gamma) over RH aSTG – - Lexical or semantic integration • Preceded by visual gating (alpha) - RH temp/ occipital areas – - Sensory gating indicates cognitive control?
Insight solving conclusions Insight solutions associated with • Semantic integration -- solvers see connections that previously eluded them • When “the light goes on…”
Bilateral Activation, Integration, and Selection model of semantic processing • Semantic activation - “Wernicke’s area” – Bottom-up lexical-semantic activation: index of semantic representations (pMTG) • Semantic integration - anterior Sup. Temp. Gyrus – Compute semantic overlap - detect or generate (aSTG) • Semantic selection - Inf. Frontal Gyrus – Select among competing activated concepts (IFG)
Insight preparation Do different mental states influence how you solve problems? • Brain activity during a “rest period” (fMRI) or at a “Ready?” prompt (EEG), prior to getting a problem • Problems solved with insight versus without insight
Preparation for Insight • Is there a general form of preparation for insight that begins before a problem is presented? • We examined neural activity during the 2 sec immediately before each problem was presented. • Compared neural activity preceding problems solved with insight to activity preceding problems solved without insight.
8-9 Hz 9-10 Hz -3.25 I - T t N - T +3.25
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