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Bo, K.

Publications and source records attributed to Bo, K..

2 recordsLinked to original sources
bioRxiv2020

Decoding Attention Control and Selection in Visual Spatial Attention

Event-related potentials (ERPs) are used extensively to investigate the neural mechanisms of attention control and selection. The commonly applied univariate ERP approach, however, has left important questions inadequately answered. Here, we addressed two questions by applying multivariate pattern classification to multichannel ERPs in two spatial-cueing experiments (N = 56 in total): (1) impact of cueing strategies (instructional vs. probabilistic) and (2) neural and behavioral effects of individual differences. Following the cue onset, the decoding accuracy (cue left vs. cue right) began to rise above chance level earlier and remained higher in instructional cueing ([~]80 ms) than in probabilistic cueing ([~]160 ms), suggesting that unilateral attention focus leads to earlier and more distinct formation of the attentional set. A similar temporal sequence was also found for target-related processing (cued targets vs. uncued targets), suggesting earlier and stronger attention selection under instructional cueing. Across the two experiments, individuals with higher decoding accuracy during [~]460-660 ms post-cue showed higher magnitude of attentional modulation of target-evoked N1 amplitude, suggesting that better formation of anticipatory attentional state leads to better target processing. During target processing, individual difference in decoding accuracy was positively associated with behavioral performance (reaction time), suggesting that stronger selection of task-relevant information leads to better behavioral performance. Taken together, multichannel ERPs combined with machine learning decoding yields new insights into attention control and selection that are not possible with the univariate ERP approach, and along with the univariate ERP approach, provides a more comprehensive methodology to the study of visual spatial attention.

neuroscience↗
bioRxiv2020

Fear conditioning prompts sparser representations of conditioned threat in primary visual cortex

Repeated exposure to threatening stimuli alters sensory responses. We investigated the underlying neural mechanism by recording simultaneous EEG-fMRI from human participants viewing oriented gratings during Pavlovian fear conditioning. In acquisition, one grating (the CS+) was paired with a noxious noise, the unconditioned stimulus (US). The other grating (CS-) was never paired with US. In habituation, which preceded acquisition, and in final extinction, the same two gratings were presented without the US. Using fMRI-BOLD multivoxel patterns in primary visual cortex during habituation as reference, we found that during acquisition, aversive learning selectively prompted systematic changes in multivoxel patterns evoked by the CS+. Specifically, CS+ evoked voxel patterns in V1 became sparser as aversive learning progressed, and the sparse pattern was preserved in extinction. Concomitant with the voxel pattern changes, occipital alpha oscillations were increasingly more desynchronized during CS+ (but not CS-) trials. Across acquisition trials, the rate of change in CS+-related alpha desynchronization was correlated with the rate of change in multivoxel pattern representations of the CS+. Furthermore, alpha oscillations co-varied with BOLD in the right temporal-parietal junction, but not with BOLD in the amygdala. Thus, fear conditioning prompts persistent sparsification of threat cue representations, likely mediated by attention-related mechanisms.

neuroscience↗