Age-related changes in activation during tip-of-the-tongue: An event-related fMRI study.

1. UNIVERSITY OF CAMBRIDGE ACC younger TOT rates correlate with ACC activity r= -.51* r= -.44 Acknowledgements:We acknowledge The University of Cambridge Behavioural and Clinical Neuroscience Institute, supported by a joint award from the Medical Research Council and the Wellcome Trust; We also thankthe radiographers at the Wolfson Brain Imaging Unit, Cambridge for their help with the study. This research was supported by NIA grant AG 08835 and a Sontag grant from Pomona College to Deborah Burke, and an MRC programme grant and grant from the Newton Trust to L. K. Tyler. Age-related changes in activation during tip-of-the-tongue: An event-related fMRI study. M.A. Shafto1, E.A. Stamatakis1, P.P. Tam1, D.M. Burke3, & L. K. Tyler1,2 1Department of Experimental Psychology , Cambridge, UK 2Wolfson Brain Imaging Center, Cambridge, UK 3Department of Psychology, Pomona College, Claremont, CA Background Results & Conclusions Methods & Analyses Current research: fMRI study of TOTs in younger and older adults Tip-of-the-tongue States (TOTs) • Activity examined for two areas: • 1. Bilateral insula; affiliated with phonological production • 2. ACC, RIFC, RDLPFC; affiliated with conflict monitoring and strategic retrieval during TOT resolution • Activity shown is unique to TOTs: TOT – [Know + Don’t Know] • Temporary inability to produce a well-known word or name • Most frequently involves proper names • Phonological form of name inaccessible while semantic information about person available • Sometimes partial phonological information about word available (e.g., initial phoneme or number of syllables) • Phonological Retrieval Deficit: • Will fMRI support structural findings that the insula is relevant for TOTs? • Will fMRI performance in older adults reflect age-related atrophy in the insula? • Based on structural findings, insula should be more active during TOTs for both young and older adults Young and Older separately • Based on the affiliation of left insula atrophy with age-related increases in TOTs, older adults may differentially recruit contralateral areas during TOTs Bilateral Insula ACC, R DLPFC, R IFC Young Young • Based on Maril et al., (2001), ACC-PFC network should be differentially active during TOTs • 2. ACC-PFC during Resolution: • Will current task replicate the role of ACC-PFC network in TOTs? • Will older adults make less use of the ACC-PFC network during TOTs? Older Older Phonological Retrieval Deficit Hypothesis: • TOTs are the number one memory problem reported by older adults • TOTs particularly increase for proper names • Based on behavioural data that older adults report less partial information and fewer resolution strategies, older adults should show less ACC-PFC activity during TOTs TOT rates increase in old age Both younger and older adults activate insula bilaterally during TOTs, with left lateralized maxima Both younger and older adults activate ACC, R DLPFC, and R IFC during TOTs • Older adults produce more TOTs than young adults butless partial phonological information • TOTs reduced by priming words phonologically relatedto target • Semantic access spared in old age Participants TOT increase caused by Phonological RetrievalDeficit Young versus Older • 29 participants • 15 younger aged 20 -37 (M=24.6, SD=4.45) • 14 older aged 66 -88 (M= 74.5, SD=6.57) • Major language exclusion criteria • Dyslexia self report or diagnosed • Non Native British English / bilingual • Left handed • Major health exclusion criteria • Neurological or hormonal disorder • Recent treatment for psychiatric disorder • Major head trauma • Stroke Young>Old Old> Young Bilateral Insula Regions in right insula active for older > younger, supporting age-related increase in activation during phonological production, and recruitment of contralateral areas Phonological Retrieval Deficit and insula: Structural imaging (Burke et al., 2005) fMRI TOT task ACC, R DLPFC, R IFC Materials Procedure Regions in ACC and R IFC active for younger > older, in keeping with age-related decrease in reported TOT-resolution strategies • Structural analysis correlating grey matter integrity with number of TOTs for each participant. • Left insula associated with phonological production • Age-related atrophy in left insula correlated with increasing TOTs • Age-related atrophy in L insula not correlated with decreasing Ravens matrices performance • 200 famous faces • Pretested to include faces susceptible to TOTs for younger adults, and faces susceptible to TOTs for older adults • Each face presented for 3 sec • 1 sec pause between pictures • Know, Don’t Know, or TOT response made with button press Behaviour-activity correlations 3 sec picture presentation 1 sec pause ... Etc. • Maxima identified for unique TOT activity in L insula, R insula, ACC, RIFC • Activity at maxima correlated with behaviour for young and older separately • *p<.05 Increasing numbers of TOTs for famous faces correlate with grey matter intensity in left insula (Burke et al., 2005) Old Young Left insula Right insula Young and older TOT rates correlate with L insula activity (young marginal p=.075) older TOT rates correlate with R insula activity r= -.47 r= -.22 Participant responds with button press r= -.66* TOT Resolution and ACC-PFC network: Functional imaging (Maril et al., 2001) r= -.65* ... Etc. RIFC younger TOT rates correlate with RIFC activity (marginal p=.083) • Scanning details: 3 Tesla Bruker Medspec Avance S300 system, gradient-echo EPI sequence, TR = 1102 ms, 21 oblique slices, 101 kHz bandwidth and spin echo guided reconstruction • Data analyses: SPM2 software (Wellcome Institute of cognitive Neurology, www. fil.ion.ucl.ac.uk). Contrast images from each subject combined into a group random effects analysis (RFX). • Cognitive model of TOT resolution which emphasizes conflict monitoring and strategic use of partial information to resolve TOTs • Neural model of TOTs proposed implicating ACC-PFC network in conflict monitoring and strategic retrieval processes During TOTs, younger adults activated ACC, RIFC, R DLPFC r= -.46 r= -.29 Behavioural performance Conclusions Response proportions Response times • Age-related decrease in reported partial information and resolution strategies (Burke et al., 1991) • Age-related changes should be reflected in decreased use of ACC-PFC network Older adults report fewer strategies when resolving TOTs Younger and Older adults activate similar networks during TOTs including bilateral insula, ACC, R DLPFC, and R IFC. Older adults show evidence of increased bilateral activation of insula, which may reflect recruitment following atrophy of areas relevant to phonological retrieval (i.e., left insula). Older adults show reduced ACC and RIFC activity during TOTs, which may reflect age-related decreases in the availability of partial information and use of TOT resolution strategies. • TOTs less frequent than Know or Don’t Know responses • TOTs slower than Know or Don’t Know responses • No age effect or interactions for proportions or response times. http://csl.psychol.cam.ac.uk/ ; http://psych.pomona.edu/cogaging/