Thesis Presentation 2014 Final

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11.psdIntroductionInvestigate the impacts of aging on the anterior cingulate cortexDetermine age differences in ACC activation through EEG collection during a modified Stroop task and ICAPredicted that the grand average ERPs, ERSP, and GFA for the ACC IC would differ between younger and older adults Brain activity changes across our lifetime and the impacts of aging on cortical activation can be measured with EEGResearch will focus on the influence of normal aging on the anterior cingulate cortex (ACC)Specifically examining how the ACC responds to making errors/correct decisions in older and younger adults while performing a modified Stroop task*Anterior Cingulate CortexMedial-frontal lobeExecutive functions,emotion, and physiologyRelation to researchFound near the corpus callosum in the medial frontal lobe and is involved in a number of executive functions as well as the regulation of emotional and physiological processes (b.p., heart rate, etc.)Plays a specific role in the anticipation of action prior to performance, in addition to a sensitivity to error detectionThus, the ACC is an ideal structure to investigate the impacts of aging on behaviour*Literature ReviewMager et al. (2007) - Age-related changes in cognitive conflict processing: An event-related potential studyMathewson et al. (2008) - Aging and electrocortical response to error feedback during a spatial learning task West (2004) The effects of aging on controlled attention and conflict processing in the Stroop task Mager et al. (2007) a modified Stroop task was used to focus on stimulus-related interference processeswhile excluding response-related interference. In the ERP, a broad negativity developed after incongruent versus congruent stimuli between 350 and 650 ms. An age-related increase of the latency and amplitude of this negativity was observed. These results indicate age-related alterations in the processing of conflicting stimuli already in middle age.*MethodsLesleys Data/Methods:Participants performed a modified Stroop task while measures of heart rate variability and physical fitness were recordedThe modified Stroop task involved a basic, memory, and super memory condition with a reward and a non-reward component for eachBasic standard Stroop; accept congruent words and reject incongruentMemory same as a above but given a special/predefined congruent word to reject (ex reject incongruent words and GREEN in green)Super Memory same as memory but case sensitive (ex reject incongruent words and GREEN in green, but only if it is in capital letters)Reward vs. non-reward non-reward conditions as above, reward condition involved point system where making errors cost more points (loss) than correct decisions (gains)Scalp data revealed that ERN had no relation to RSA or behaviour (performance), but RSA was related to behaviour * check with Lesley & JaneAdditional Information:Stimulus presentation time 900 msLength of time between stimuli varied randomly between 500, 600, and 700 ms50 practice trials per task (3-6 blocks); 100 trial runs at a time (3-6 blocks of each task)Task order basic, basic reward, memory, memory reward, super memory, and super memory rewardAll data is response locked thus far*ACC Component ClassificationThe ACC component was identified in each of the participants individually by examining the % variance accounted for by the top 7 componentsThe ACC component was determined based on topography related to each component in addition to how much variance within the dataset can be accounted for at the time of the responseOnce all of the ACC components were classified, they were clustered for further analysis*ACC TopographiesACC component clusters mapped onto the scalpYounger on left, older on right*Grand Average ERP ComparisonThese graphs represent the ACC component comparison between the two groups (young vs. older) for both errors and correct responses#1 (blue) represents the younger adults, while #2 (green) is the older adultsCorrects on right, errors on left*ACC Component ERSP Z-ScoresACC component power (ERSP) shown as Z-scores; anything above or below +/-3 is statistically significant*ACC Component ERSP Z-Scores*ACC Component Power Difference15.psd16.psdThe ERSP graphs super-imposed on one another with the significant alpha levels (+/- 3 SD) shown with the transparent barsMain focus is the blue power difference b/w older and younger adults*Global Field AmplitudeGFA for ACC component before baseline correct, same legend as previous slide*GFA Z-Scores and Group DifferenceGroupTime (ms)Z-score Younger74.22-3.905Older91.801.310Difference72.27-6.721GFA for ACC component with baseline correctedYounger red, Older blue, Difference black*Summary & DiscussionACC component responded differently to making correct responses versus errors, and differed between groupsPower and global field amplitude generated by the ACC component was significantly greater in younger adultsSuggests that the ACC component produces less and more diffuse electrical activity with advancing ageStill working on it!*Future DirectionsApplying the ICA approach to the Memory, Super Memory, and monetary incentive components of the modified Stroop taskCompare the results of the ACC component to performance and respiratory sinus arrhythmia (RSA) dataEngaging the ACC through alternative modalitiesBrain activity changes across our lifetime and the impacts of aging on cortical activation can be measured with EEGResearch will focus on the influence of normal aging on the anterior cingulate cortex (ACC)Specifically examining how the ACC responds to making errors/correct decisions in older and younger adults while performing a modified Stroop task*Found near the corpus callosum in the medial frontal lobe and is involved in a number of executive functions as well as the regulation of emotional and physiological processes (b.p., heart rate, etc.)Plays a specific role in the anticipation of action prior to performance, in addition to a sensitivity to error detectionThus, the ACC is an ideal structure to investigate the impacts of aging on behaviour*Mager et al. (2007) a modified Stroop task was used to focus on stimulus-related interference processeswhile excluding response-related interference. In the ERP, a broad negativity developed after incongruent versus congruent stimuli between 350 and 650 ms. An age-related increase of the latency and amplitude of this negativity was observed. These results indicate age-related alterations in the processing of conflicting stimuli already in middle age.*Lesleys Data/Methods:Participants performed a modified Stroop task while measures of heart rate variability and physical fitness were recordedThe modified Stroop task involved a basic, memory, and super memory condition with a reward and a non-reward component for eachBasic standard Stroop; accept congruent words and reject incongruentMemory same as a above but given a special/predefined congruent word to reject (ex reject incongruent words and GREEN in green)Super Memory same as memory but case sensitive (ex reject incongruent words and GREEN in green, but only if it is in capital letters)Reward vs. non-reward non-reward conditions as above, reward condition involved point system where making errors cost more points (loss) than correct decisions (gains)Scalp data revealed that ERN had no relation to RSA or behaviour (performance), but RSA was related to behaviour * check with Lesley & JaneAdditional Information:Stimulus presentation time 900 msLength of time between stimuli varied randomly between 500, 600, and 700 ms50 practice trials per task (3-6 blocks); 100 trial runs at a time (3-6 blocks of each task)Task order basic, basic reward, memory, memory reward, super memory, and super memory rewardAll data is response locked thus far*The ACC component was identified in each of the participants individually by examining the % variance accounted for by the top 7 componentsThe ACC component was determined based on topography related to each component in addition to how much variance within the dataset can be accounted for at the time of the responseOnce all of the ACC components were classified, they were clustered for further analysis*ACC component clusters mapped onto the scalpYounger on left, older on right*These graphs represent the ACC component comparison between the two groups (young vs. older) for both errors and correct responses#1 (blue) represents the younger adults, while #2 (green) is the older adultsCorrects on right, errors on left*ACC component power (ERSP) shown as Z-scores; anything above or below +/-3 is statistically significant**The ERSP graphs super-imposed on one another with the significant alpha levels (+/- 3 SD) shown with the transparent barsMain focus is the blue power difference b/w older and younger adults*GFA for ACC component before baseline correct, same legend as previous slide*GFA for ACC component with baseline correctedYounger red, Older blue, Difference black*Still working on it!*