de Bruijn cycles for neural decoding

Aguirre, Geoffrey K.; Mattar, Marcelo G.; Magis-Weinberg, Lucía

doi:10.1016/j.neuroimage.2011.02.005

Cited by 82 publications

(54 citation statements)

References 27 publications

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“…Second, functional runs consisted of 5 presentations of each event as well as 6 self-paced perceptual baseline trials. Third, de Bruijn sequences were used for stimulus ordering (Aguirre et al, 2011). A unique sequence was used for each run (randomized across subjects), and we selected sequences that ended with perceptual baseline trials to allow the hemodynamic response of the 2nd to last trial of the run to approach baseline prior to run completion.…”

Section: Methodsmentioning

confidence: 99%

“…A unique sequence was used for each run (randomized across subjects), and we selected sequences that ended with perceptual baseline trials to allow the hemodynamic response of the 2nd to last trial of the run to approach baseline prior to run completion. Carry-over sequences, such as de Bruijn sequences, match the number of times that each stimulus precedes every other stimulus, thus controlling for stimulus carry-over effects and theoretically increasing the detection power in between-run pattern analysis (Aguirre, 2007; Aguirre et al, 2011). The length of carry-over sequences was prohibitively large for Experiment 1, but the reduction of stimulus conditions allowed an entire de Bruijn sequence to be presented within a short run (for an argument for using short runs for pattern analysis see: Coutanche and Thompson-Schill, 2012; Davis and Poldrack, 2013).…”

Section: Methodsmentioning

confidence: 99%

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The influence of low-level stimulus features on the representation of contexts, items, and their mnemonic associations

Huffman

Stark

2017

NeuroImage

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Since the earliest attempts to characterize the “receptive fields” of neurons, a central aim of many neuroscience experiments is to elucidate the information that is represented in various regions of the brain. Recent studies suggest that, in the service of memory, information is represented in the medial temporal lobe in a conjunctive or associative form with the contextual aspects of the experience being the primary factor or highest level of the conjunctive hierarchy. A critical question is whether the information that has been observed in these studies reflects notions such as a cognitive representation of context or whether the information reflects the low-level sensory differences between stimuli. We performed two functional magnetic resonance imaging experiments to address this question and we found that associative representations observed between context and item (and order) in the human brain can be highly influenced by low-level sensory differences between stimuli. Our results place clear constraints on the experimental design of studies that aim to investigate the representation of contexts and items during performance of associative memory tasks. Moreover, our results raise interesting theoretical questions regarding the disambiguation of memory-related representations from processing-related representations.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

The influence of low-level stimulus features on the representation of contexts, items, and their mnemonic associations

Huffman

Stark

2017

NeuroImage

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“…This allowed us to measure both fMRI adaptation and the direct effect for each item in a continuous sequence. The order of the stimuli was determined using a de Bruijn sequence (Aguirre et al, 2011). Given the nine stimuli and a null-trial, a k=10, n=3 de Bruijn sequence was sought, using a trial duration of 1600 ms, and three separate neural models (i.e., value, color and shape) (Fig.…”

Section: Methodsmentioning

confidence: 99%

Value Is in the Eye of the Beholder: Early Visual Cortex Codes Monetary Value of Objects during a Diverted Attention Task

Persichetti¹,

Aguirre²,

Thompson-Schill³

2015

Journal of Cognitive Neuroscience

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A central concern in the study of learning and decision-making is the identification of neural signals associated with the values of choice alternatives. An important factor in understanding the neural correlates of value is the representation of the object itself, separate from the act of choosing. Is it the case that the representation of an object within visual areas will change if it is associated with a particular value? We used fMRI adaptation to measure the neural similarity of a set of novel objects before and after subjects learned to associate monetary values with the objects. We used a range of both positive and negative values to allow us to distinguish effects of behavioral salience (i.e., large versus small values) from effects of valence (i.e., positive versus negative values). During the scanning session, subjects made a perceptual judgment unrelated to value. Crucially, the similarity of the visual features of any pair of objects did not predict the similarity of their value, so we could distinguish adaptation effects due to each dimension of similarity. Within early visual areas we found that value similarity modulated the neural response to the objects following training. These results show that an abstract dimension, in this case monetary value, modulates neural response to an object in visual areas of the brain even when attention is diverted.

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“…There were 9 trials for each task instruction within a block, with each task instruction presented in a pseudo-randomized, counterbalanced order using De Bruijn sequences for each block 31 .…”

Section: Methodsmentioning

confidence: 99%

Task relevance modulates the cortical representation of feature conjunctions in the target template

Reeder

Hanke

Pollmann

2017

Sci Rep

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Little is known about the cortical regions involved in representing task-related content in preparation for visual task performance. Here we used representational similarity analysis (RSA) to investigate the BOLD response pattern similarity between task relevant and task irrelevant feature dimensions during conjunction viewing and target template maintenance prior to visual search. Subjects were cued to search for a spatial frequency (SF) or orientation of a Gabor grating and we measured BOLD signal during cue and delay periods before the onset of a search display. RSA of delay period activity revealed that widespread regions in frontal, posterior parietal, and occipitotemporal cortices showed general representational differences between task relevant and task irrelevant dimensions (e.g., orientation vs. SF). In contrast, RSA of cue period activity revealed sensory-related representational differences between cue images (regardless of task) at the occipital pole and additionally in the frontal pole. Our data show that task and sensory information are represented differently during viewing and during target template maintenance, and that task relevance modulates the representation of visual information across the cortex.

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de Bruijn cycles for neural decoding

Cited by 82 publications

References 27 publications

The influence of low-level stimulus features on the representation of contexts, items, and their mnemonic associations

The influence of low-level stimulus features on the representation of contexts, items, and their mnemonic associations

Value Is in the Eye of the Beholder: Early Visual Cortex Codes Monetary Value of Objects during a Diverted Attention Task

Task relevance modulates the cortical representation of feature conjunctions in the target template

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