Brain rhythms shift and deploy attention

Abstract

17One of the most central cognitive functions is attention. Its neuronal underpinnings have primarily been 18 studied during conditions of sustained attention. Much less is known about the neuronal dynamics 19 underlying the processes of shifting attention in space, as compared to maintaining it on one stimulus, 20 and of deploying it to a particular stimulus. Here, we use ECoG to investigate four rhythms across large 21 parts of the left hemisphere of two macaque monkeys during a task that allows investigation of 22 deployment and shifting. Shifting involved a strong transient enhancement of power in a 2-7 Hz theta 23 band in frontal, pre-motor and visual areas, and reductions of power in an 11-20 Hz beta band in a 24 fronto-centro-parietal network and in a 29-36 Hz high-beta band in premotor cortex. Deployment of 25 attention to the contralateral hemifield involved an enhancement of beta power in parietal areas, a 26 concomitant reduction of high-beta power in pre-motor areas and an enhancement of power in a 27 [60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76] Hz gamma band in extra-striate cortex. Effects due to shifting occurred earlier than effects due to 28 deployment. These results demonstrate that the four investigated rhythms are involved in attentional 29 allocation, with striking differences between shifting and deployment between different brain areas. 30Significance 31 We are often confronted by many visual stimuli, and attentional mechanisms select one stimulus for in-32 depth processing. This involves that attention is shifted between stimuli and deployed to one stimulus 33 at a time. Prior studies have revealed that these processes are subserved by several brain rhythms. 34Therefore, we recorded brain activity in macaque monkeys with many electrodes distributed over large 35 parts of their left hemisphere, while they performed a task that involved shifting and deploying attention. 36We found four dominant rhythms: theta (2-7 Hz), beta (11-20 Hz), high-beta (29-36 Hz) and gamma 37 (60-76 Hz). Attentional shifting and deployment involved dynamic modulations in the strength of those 38 rhythms with high specificity in space and time. 42the mechanisms that control the shifting and deployment of attention are not yet fully understood. This 43 is in part due to the fact that most respective studies compare attention conditions with no regard to 44 temporal change, assuming static attention to different stimuli. Such approaches are blind to the 45 temporally dynamic processes that construct an attentional state. Here, we investigate those dynamic 46 processes, distinguishing between attentional shifting and attentional deployment. We define attentional 47 shifting as the process that shifts attention in general, irrespective of the target stimulus or the shift 48 direction; we define attentional deployment as the process that allocates attention to one out of two 49 simultaneously present but spatially separate stimuli. There are a few studies that have investigated design to dissociat...

A mechanism for inter-areal coherence through communication based on connectivity and oscillatory power

“…This predicts that gamma Granger values from V1 to other areas should increase by the same factor if V1 gamma power increases. It is known that V1 gamma power increases after the presentation of an attentional cue (post-cue period) ( Richter et al., 2019 ; Bosman et al., 2012 ). Consistent with SSM model predictions, Granger-causal influences from V1 to higher areas increased by approximately the same factor across all areas in the post-cue period (1.76; Pearson’s R = 0.99; Figure S3 ).…”

Brain rhythms define distinct interaction networks with differential dependence on anatomy

“…Offline, the signals were re-referenced to remove the common recording reference through local bipolar derivations, i.e., sample-by-sample differences, between neighboring electrodes. Note that this procedure also allows rejection of headstage-specific noise and greater signal localization ( Richter et al., 2019 ). Bipolar derivations were obtained for all pairs of immediately neighboring electrodes on the same lane of the ECoG grid, which were also recorded through the same headstage ( Bastos et al., 2015b ).…”

The role of anatomical connection strength for interareal communication in macaque cortex

“…sample-by-sample differences, between neighboring electrodes. Note that this procedure also allows rejection of headstage specific noise and greater signal localization (Richter et al, 2019). Bipolar derivations were obtained for all pairs of immediately neighboring electrodes on the same lane of the ECoG grid, which were also recorded through the same headstage (Bastos et al, 2015b).…”