Linking Implicit and Explicit Memory: Common Encoding Factors and Shared Representations

Turk‐Browne, Nicholas B.; Yi, Do Joon; Chun, Marvin M.

doi:10.1016/j.neuron.2006.01.030

Cited by 224 publications

(214 citation statements)

References 75 publications

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“…Other recent studies have similarly suggested that repetition attenuation is more flexible than previously thought, being affected by attention (14,(40)(41)(42)(43), emotion (44), and response mapping (45). Our new finding is qualitatively distinct from these other forms of modulation, however.…”

Section: Discussionsupporting

confidence: 56%

Spatiotemporal object continuity in human ventral visual cortex

Turk‐Browne

Flombaum

et al. 2008

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

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Coherent visual experience requires that objects be represented as the same persisting individuals over time and motion. Cognitive science research has identified a powerful principle that guides such processing: Objects must trace continuous paths through space and time. Little is known, however, about how neural representations of objects, typically defined by visual features, are influenced by spatiotemporal continuity. Here, we report the consequences of spatiotemporally continuous vs. discontinuous motion on perceptual representations in human ventral visual cortex. In experiments using both dynamic occlusion and apparent motion, face-selective cortical regions exhibited significantly less activation when faces were repeated in continuous vs. discontinuous trajectories, suggesting that discontinuity caused featurally identical objects to be represented as different individuals. These results indicate that spatiotemporal continuity modulates neural representations of object identity, influencing judgments of object persistence even in the most staunchly ''featural'' areas of ventral visual cortex.functional MRI ͉ object persistence ͉ repetition attenuation ͉ spatiotemporal continuity ͉ visual tracking

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Section: Discussionsupporting

confidence: 56%

Spatiotemporal object continuity in human ventral visual cortex

Turk‐Browne

Flombaum

et al. 2008

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

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“…Notably, repetition-related BOLD reductions in the inferior temporal cortices have been found to correlate with altered behavioral performance, indicating a potential origin in later response selection, rather than earlier perceptual encoding (Turk-Browne et al, 2006). However, repetition-related improvements in behavioral performance have been fully dissociated from place-selective BOLD response in the PPA, with the magnitude of PPA attenuation to repeated places unaffected by changes in task demands and task performance (Xu et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

Opposing Influences of Affective State Valence on Visual Cortical Encoding

Schmitz¹,

Rosa²,

Anderson³

2009

J. Neurosci.

165

131

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Positive and negative emotional states are thought to have originated from fundamentally opposing approach and avoidance behaviors. Furthermore, affective valence has been hypothesized to exert opposing biases in cognitive control. Here we examined with functional magnetic resonance imaging whether the opposing influences of positive and negative states extend to perceptual encoding in the visual cortices. Based on prior behavioral research, we hypothesized that positive states would broaden and negative states would narrow visual field of view (FOV). Positive, neutral, and negative states were induced on alternating blocks. To index FOV, observers then viewed brief presentations (300 ms) of face/place concentric center/surround stimuli on interleaved blocks. Central faces were attended, rendering the place surrounds unattended. As face and place information was presented at different visual eccentricities, our physiological metric of FOV was a valence-dependent modulation of place processing in the parahippocampal place area (PPA). Consistent with our hypotheses, positive affective states increased and negative states decreased PPA response to novel places as well as adaptation to repeated places. Individual differences in self-reported positive and negative affect correlated inversely with PPA encoding of peripheral places, as well as with activation in the mesocortical prefrontal cortex and amygdala. Psychophysiological interaction analyses further demonstrated that valence-dependent responses in the PPA arose from opponent coupling with extrafoveal regions of the primary visual cortex during positive and negative states. These findings collectively suggest that affective valence differentially biases gating of early visual inputs, fundamentally altering the scope of perceptual encoding.

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“…That is, during periods when task-specific processing (7) presumably could not be implemented to benefit future performance, task-switching success still could be predicted. Recent advances in neuroimaging have granted researchers the tools to probe states of the mind in such a way that a myriad of subsequent behaviors may be predicted, including attentional control (16), memory (34,35), motor responding (36), and problem solving (37). In studies like these, neural activity preceding task performance commonly is correlated with overall performance, allowing the interpretation that arousal, attention, or task engagement drives the variations in performance.…”

Section: Discussionmentioning

confidence: 99%

Neural predictors of moment-to-moment fluctuations in cognitive flexibility

Leber

Turk‐Browne

Chun

2008

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

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162

152

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Cognitive flexibility is a crucial human ability allowing efficient adaptation to changing task challenges. Although a person's degree of flexibility can vary from moment to moment, the conditions regulating such fluctuations are not well understood. Using a task-switching procedure with fMRI, we found several brain regions in which neural activity preceding each trial predicted subsequent cognitive flexibility. Specifically, as pretrial activity increased, performance improved on trials when the task switched but did not improve when the task repeated. Regions from which flexibility could be predicted reliably included the basal ganglia, anterior cingulate cortex, prefrontal cortex, and posterior parietal cortex. Although further analysis revealed similarities across the regions in how flexibility was predicted, results supported the existence of multiple independent sources of prediction. These results reveal distinct neural mechanisms underlying fluctuations in cognitive flexibility.basal ganglia ͉ fMRI ͉ task switching ͉ cognitive control J uggling several tasks at once, or multitasking, is a fact of everyday life and becomes increasingly salient with the growing use of products such as mobile telephones, wireless e-mail devices, and portable music players. Given the wide array of tasks people successfully pack into their daily routines, the capacity to multitask is among the most remarkable endowments of the human mind. Nevertheless, this capacity, known as ''cognitive flexibility,'' does come at a cost: empirical investigations of task switching consistently show that performance upon switching to a new task is slower and more error prone than performance when repeating a task (1-3). These behavioral costs are difficult to avoid even when subjects are given ample time to prepare for the upcoming task (1, 3), but variations in the size of this switch cost have been observed within experimental sessions (4, 5), suggesting that an individual's flexibility can fluctuate from moment to moment.Unfortunately, it is unclear how fluctuations in flexibility can be predicted, although such knowledge would carry considerable value. From a practical standpoint, for instance, productivity could be maximized by reserving multitasking activities for known periods of high flexibility and scheduling single-task activities for periods of low flexibility. From a theoretical standpoint, identifying the predictors of cognitive flexibility could facilitate a deeper understanding of the mechanisms governing cognitive control.In this study, we used fMRI to predict cognitive flexibility. Because fMRI is noninvasive and imposes minimal additional task demands on subjects, it potentially can reveal variations in flexibility with negligible interference to the task-switching procedure.Our particular aim was to learn if brain activity preceding task cues could predict task-switching performance. Probing before the cue, when the task to be performed has not yet been revealed to subjects, distinguishes our work from previous studies that...

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Linking Implicit and Explicit Memory: Common Encoding Factors and Shared Representations

Cited by 224 publications

References 75 publications

Spatiotemporal object continuity in human ventral visual cortex

Spatiotemporal object continuity in human ventral visual cortex

Opposing Influences of Affective State Valence on Visual Cortical Encoding

Neural predictors of moment-to-moment fluctuations in cognitive flexibility

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