Extensive Individual Differences in Brain Activations Associated with Episodic Retrieval are Reliable Over Time

Miller, Michael B.; Horn, John D. Van; Wolford, George; Handy, Todd C.; Valsangkar-Smyth, Monica; Inati, Souheil; Grafton, Scott T.; Gazzaniga, Michael S.

doi:10.1162/089892902760807203

Cited by 143 publications

(121 citation statements)

References 47 publications

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“…Each of these networks involves different anatomical areas, and each has its own time course of development. Although the general anatomy of each network is relatively fixed, there are clearly individual anatomical variations (22) and behavioral differences in the efficiency of their operation (13).…”

Section: Resultsmentioning

confidence: 99%

Mapping the genetic variation of executive attention onto brain activity

Fan

Fossella

Sommer

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

415

250

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Brain imaging data have repeatedly shown that the anterior cingulate cortex is an important node in the brain network mediating conflict. We previously reported that polymorphisms in dopamine receptor (DRD4) and monoamine oxidase A (MAOA) genes showed significant associations with efficiency of handling conflict as measured by reaction time differences in the Attention Network Test (ANT). To examine whether this genetic variation might contribute to differences in brain activation within the anterior cingulate cortex, we genotyped 16 subjects for the DRD4 and MAOA genes who had been scanned during the ANT. In each of the two genes previously associated with more efficient handling of conflict in reaction time experiments, we found a polymorphism in which persons with the allele associated with better behavioral performance showed significantly more activation in the anterior cingulate while performing the ANT than those with the allele associated with worse performance. The results demonstrate how genetic differences among individuals can be linked to individual differences in neuromodulators and in the efficiency of the operation of an appropriate attentional network.A popular theory of cognitive control suggests that the dorsal anterior cingulate is part of a network involved in handling conflict between neural areas (1, 2). In support of this general idea, a number of neuroimaging studies have shown activation of the dorsal anterior cingulate in tasks requiring people to respond to one dimension of a stimulus rather than a strong conflicting dimension (1-3). One task in which this has been found (1, 4) involves the person responding to the direction of a central arrow when flanking arrows could point either in the same (congruent) or the opposite (incongruent) direction.The Attention Network Test (ANT) uses the flanker task to measure conflict and shows strong activation in the dorsal anterior cingulate (4, 5). Because the cingulate is modulated by the ventral tegmental dopamine system (6-8), we previously tested 200 normal persons with the ANT and genotyped them for a number of genes related to the dopamine system (9). We found polymorphisms in two genes were significantly related to the efficiency of conflict. These were the dopamine D4 receptor gene (DRD4) and monoamine oxidase a (MAOA) genes.In the current study, we ran 16 unselected normal subjects on the ANT with event-related functional MRI (fMRI). We collected cheek cells to search for polymorphisms in the two genes which we previously found to be related to performance on the conflict network of the ANT (9). We considered only alleles possessed by at least six of our subjects, and which we thought might influence dopamine modulation within the conflict network. There were sufficient data to test one such polymorphism in each of the two previously identified genes. One of these is a 30-bp repeat polymorphism in the promoter of the MAOA gene. The other is a single-nucleotide insertion͞deletion polymorphism in the 5Ј region of the DRD4 gene.One of the a...

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Section: Resultsmentioning

confidence: 99%

Mapping the genetic variation of executive attention onto brain activity

Fan

Fossella

Sommer

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

415

250

View full text Add to dashboard Cite

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“…Whereas it is trivial to demonstrate prefrontal activation in working memory tasks, previous work has shown that there are frequently interindividual differences in the spatial location of activation (Miller et al, 2002;Wei et al, 2004). This could dilute observed effects in this region with multi-subject voxel-by-voxel analysis.…”

Section: Methodsmentioning

confidence: 92%

Functional Imaging of Working Memory after 24 Hr of Total Sleep Deprivation

Chee¹,

Choo²

2004

J. Neurosci.

441

316

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The neurobehavioral effects of 24 hr of total sleep deprivation (SD) on working memory in young healthy adults was studied using functional magnetic resonance imaging. Two tasks, one testing maintenance and the other manipulation and maintenance, were used. After SD, response times for both tasks were significantly slower. Performance was better preserved in the more complex task. Both tasks activated a bilateral, left hemisphere-dominant frontal-parietal network of brain regions reflecting the engagement of verbal working memory. In both states, manipulation elicited more extensive and bilateral (LϾR) frontal, parietal, and thalamic activation. After SD, there was reduced blood oxygenation level-dependent signal response in the medial parietal region with both tasks. Reduced deactivation of the anterior medial frontal and posterior cingulate regions was observed with both tasks. Finally, there was disproportionately greater activation of the left dorsolateral prefrontal cortex and bilateral thalamus when manipulation was required. This pattern of changes in activation and deactivation bears similarity to that observed when healthy elderly adults perform similar tasks. Our data suggest that reduced activation and reduced deactivation could underlie cognitive impairment after SD and that increased prefrontal and thalamic activation may represent compensatory adaptations. The additional left frontal activation elicited after SD is postulated to be task dependent and contingent on task complexity. Our findings provide neural correlates to explain why task performance in relatively more complex tasks is better preserved relative to simpler ones after SD.

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“…However, no matter how the brain is measured, it is obvious that the brain's natural state is inherently variable (see "Variance" in Fig. 1) (Arieli et al, 1996;Miller et al, 2002;Laskaris et al, 2003;Neumann et al, 2003;Huettel et al, 2004;Faisal et al, 2008;McIntosh et al, 2008). Current evidence suggests substantial intrasubject variability in the blood oxygen leveldependent (BOLD) signal within and across testing sessions, but BOLD signal variance is often discounted as merely reflecting issues with task, image acquisition and preprocessing, statistical power, reliability, or other nuisance effects (Aguirre et al, 1998;Miller et al, 2002;Neumann et al, 2003;Huettel et al, 2004;Smith et al, 2005;Andrews-Hanna et al, 2007;Jones et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Blood Oxygen Level-Dependent Signal Variability Is More than Just Noise

Garrett¹,

Kovačević²,

McIntosh³

et al. 2010

J. Neurosci.

359

442

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Functional magnetic resonance imaging (fMRI) research often attributes blood oxygen level-dependent (BOLD) signal variance to measurement-related confounds. However, what is typically considered "noise" variance in data may be a vital feature of brain function. We examined fMRI signal variability during fixation baseline periods, and then compared SD-and mean-based spatial patterns and their relations with chronological age (20 -85 years). We found that not only was the SD-based pattern robust, it differed greatly, both spatially and statistically, from the mean-based pattern. Notably, the unique age-predictive power of the SD-based pattern was more than five times that of the mean-based pattern. This reliable SD-based pattern of activity highlights an important "signal" within what is often considered measurement-related "noise." We suggest that examination of BOLD signal variability may reveal a host of novel brain-related effects not previously considered in neuroimaging research.

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Extensive Individual Differences in Brain Activations Associated with Episodic Retrieval are Reliable Over Time

Cited by 143 publications

References 47 publications

Mapping the genetic variation of executive attention onto brain activity

Mapping the genetic variation of executive attention onto brain activity

Functional Imaging of Working Memory after 24 Hr of Total Sleep Deprivation

Blood Oxygen Level-Dependent Signal Variability Is More than Just Noise

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