Mixed blocked/event-related designs separate transient and sustained activity in fMRI

Visscher, Kristina; Miezin, Francis M.; Kelly, James E.; Buckner, Randy L.; Donaldson, David I.; McAvoy, Mark P.; Bhalodia, Vidya M.; Petersen, Steven E.

doi:10.1016/s1053-8119(03)00178-2

Cited by 224 publications

(218 citation statements)

References 51 publications

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“…The volumes acquired during the six sessions were treated as separate time series. For each series, the variance in the BOLD signal was decomposed with a set of regressors in a general linear model (Friston et al, 1995), using a mixed blocked and event-related design (Visscher et al, 2003). Separate regressors coded for (1) PM encode, (2) PM retrieve, (3) baseline encode, (4) baseline retrieve events, using delta functions aligned to the onset of each event.…”

Section: Discussionmentioning

confidence: 99%

“…Additional boxcar regressors coded for (1) PM storage and (2) baseline storage periods (again with additional regressors in version 2 of the experiment), indicating the period between relevant encoding and retrieval events (mean duration, 10.8 s; range, 5.2-16.2 s). By pseudorandomly manipulating the duration of the storage periods, activity associated with these periods was distinguished from activity associated with the encode and retrieve events (Rowe et al, 2000;Visscher et al, 2003). All regressors were convolved with a canonical hemodynamic response function.…”

Section: Discussionmentioning

confidence: 99%

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Decoding the Content of Delayed Intentions

Gilbert¹

2011

J. Neurosci.

130

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Rostrolateral prefrontal cortex (RLPFC) plays a key role in our ability to postpone the execution of intended behaviors until after another activity has been performed. However, it is poorly understood in computational terms. One crucial question is whether RLPFC represents the content of delayed intentions or plays a nonspecific role. In this human functional magnetic resonance imaging study (n ϭ 32), RLPFC was active while participantsstoreddelayedintentionsduringadistractingongoingtask.Multivariateanalysisshowedthattheintendedcueforfutureactionand the intended behavior could be decoded from distinct posterior brain regions. However, the content of intentions could not be decoded from RLPFC itself. Functional connectivity analysis showed that RLPFC increased its coupling with content-representing regions during intention storage. Furthermore, trials with relatively high RLPFC activity were associated with enhanced decoding. Thus, RLPFC may enable realization of delayed intentions via interactions with posterior brain regions, which represent their content.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Decoding the Content of Delayed Intentions

Gilbert¹

2011

J. Neurosci.

130

View full text Add to dashboard Cite

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“…Transient effects were coded in the GLM with a reference hemodynamic response function modeled as a gamma function (tau ¼ 0.9, n ¼ 4, delay ¼ 2.3; peaking at 5 s post-stimulus) (Boynton et al, 1996). The sustained effects of rehearsal were similarly coded by convolving a block-length boxcar function with this gamma function (Boynton et al, 1996;Visscher et al, 2003). Prior to across-subjects comparisons, fMRI data were spatially normalized to standard stereotactic space using an affine transformation (Duncan et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

“…To explore the effects of prenatal exposure to active maternal smoking on the functioning of neural-circuitrymediating components of mnemonic processing, seven subjects with prenatal exposure and six subjects with no prenatal exposure also underwent fMRI scanning while performing a modified version of a previously described task (Shaywitz et al, 1999;Mencl et al, 2000) that incorporated a mixed design, including block and eventrelated features (Donaldson et al, 2001;Otten et al, 2002;Visscher et al, 2003), to permit separate assessment of neural-circuitry-mediating encoding, rehearsal, and early and delayed recognition of verbal and nonverbal stimuli. Imaging and assessment of verbal and visuospatial memory were performed during the same test session.…”

Section: Assessment Of Brain Functionmentioning

confidence: 99%

Visuospatial Memory Deficits Emerging During Nicotine Withdrawal in Adolescents with Prenatal Exposure to Active Maternal Smoking

Jacobsen

Slotkin

Westerveld

et al. 2005

Neuropsychopharmacol

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Active maternal smoking during pregnancy elevates the risk of cognitive deficits and tobacco smoking among offspring. Preclinical work has shown that combined prenatal and adolescent exposure to nicotine produces more pronounced hippocampal changes and greater deficits in cholinergic activity upon nicotine withdrawal than does prenatal or adolescent exposure to nicotine alone. Few prior studies have examined the potential modifying effects of gestational exposure to active maternal smoking on cognitive or brain functional response to tobacco smoking or nicotine withdrawal in adolescents. We examined visuospatial and verbal memory in 35 adolescent tobacco smokers with prenatal exposure to active maternal smoking and 26 adolescent tobacco smokers with no prenatal exposure to maternal smoking who were similar in age, educational attainment, general intelligence, and baseline plasma cotinine. Subjects were studied during ad libitum smoking and after 24 h of abstinence from smoking. A subset of subjects from each group also underwent functional magnetic resonance imaging while performing a visuospatial encoding and recognition task. Adolescent tobacco smokers with prenatal exposure experienced greater nicotine withdrawal-related deficits in immediate and delayed visuospatial memory relative to adolescent smokers with no prenatal exposure. Among adolescent smokers with prenatal exposure, nicotine withdrawal was associated with increased activation of left parahippocampal gyrus during early recognition testing of visuospatial stimuli and increased activation of bilateral hippocampus during delayed recognition testing of visuospatial stimuli. These findings extend prior preclinical work and suggest that, in human adolescent tobacco smokers, prenatal exposure to active maternal smoking is associated with alterations in medial temporal lobe function and concomitant deficits in visuospatial memory.

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“…In each task block, trials occurred with a variable intertrial interval (2.5-7.5 s in steps of 2.5 s). This design enabled implementation of mixed blocked/event-related analyses for which sustained and transient activation patterns were separately estimated (33,34).…”

Section: Methodsmentioning

confidence: 99%

Flexible neural mechanisms of cognitive control within human prefrontal cortex

Braver

Paxton

Locke

et al. 2009

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

569

677

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A major challenge in research on executive control is to reveal its functional decomposition into underlying neural mechanisms. A typical assumption is that this decomposition occurs solely through anatomically based dissociations. Here we tested an alternative hypothesis that different cognitive control processes may be implemented within the same brain regions, with fractionation and dissociation occurring on the basis of temporal dynamics. Regions within lateral prefrontal cortex (PFC) were examined that, in a prior study, exhibited contrasting temporal dynamics between older and younger adults during performance of the AX-CPT cognitive control task. The temporal dynamics in younger adults fit a proactive control pattern (primarily cue-based activation), whereas in older adults a reactive control pattern was found (primarily probebased activation). In the current study, we found that following a period of task-strategy training, these older adults exhibited a proactive shift within a subset of the PFC regions, normalizing their activity dynamics toward young adult patterns. Conversely, under conditions of penalty-based monetary incentives, the younger adults exhibited a reactive shift some of the same regions, altering their temporal dynamics toward the older adult baseline pattern. These experimentally induced crossover patterns of temporal dynamics provide strong support for dual modes of cognitive control that can be flexibly shifted within PFC regions, via modulation of neural responses to changing task conditions or behavioral goals.dorsolateral PFC ͉ event-related fMRI ͉ inhibition ͉ interference control ͉ working memory

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Mixed blocked/event-related designs separate transient and sustained activity in fMRI

Cited by 224 publications

References 51 publications

Decoding the Content of Delayed Intentions

Decoding the Content of Delayed Intentions

Visuospatial Memory Deficits Emerging During Nicotine Withdrawal in Adolescents with Prenatal Exposure to Active Maternal Smoking

Flexible neural mechanisms of cognitive control within human prefrontal cortex

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