Behavioral gain following isolation of attention

Abstract

Stable sensory perception is achieved through balanced excitatory-inhibitory interactions of lateralized sensory processing. For example, left limb tactile stimulation inhibits somatosensory processing of the right limb tactile stimulation (Palmer et al., 2012 [1]) and inhibitory non-invasive brain stimulation to left attention regions increases right hemispheric attention processing (Hilgetag et al., 2001 [2]). In real world experience, sensory processing is rarely equal across lateralized processing regions, resulting in continuous rebalancing. We predicted rebalancing lateralized sensory processing following prolonged imbalance could cause a rebound in the opposite direction. Here, we isolated covert attention to one visual field with a 30-minute attention-demanding task and found an increase in attention in the opposite visual field after intervention. We suggest a rebound in lateralized attention in the previously unattended visual field due to an overshoot in attention rebalancing. Our finding of visual field specific attention increase could be critical for the development of clinical rehabilitation for patients with a unilateral lesion and lateralized attention deficits. Both homeostatic (Wu et al., 2020 [3]) and Hebbian plasticity (Pugh & Raman, 2006) [4] may have a role in the interplay between lateralized attention processing regions after visual attention imbalance, which is a crucial avenue of future research. Furthermore, applying our data as a case study for lateralized sensory processing, our results suggest a fundamental characteristic of lateralized processing interaction, which may be useful rehabilitation of unilateral stroke, outside of visual attention.

Improving visual attention following right hemisphere stroke: A preliminary study

“…Similarly, here participants with RCVA were required to fixate centrally and attend rightward, toward their unimpaired visual space, to perform a demanding sustained attention task. We predicted an improvement in leftward attention, as was previously found in neurotypical individuals (Edwards et al, 2021). We expected that patients with less leftward inattention would experience a greater impact of intervention, as severity of leftward inattention tends to negatively correlate with successful intervention (Gillen et al, 2005).…”

“…Interestingly, our participants with mild to no leftward inattention showed increased tracking in comparison to the control condition both to the left and right of fixation. The right-sided increase was not initially hypothesized, as no such change was previously shown in neurotypical individuals (Edwards et al, 2021). In neurotypical individuals, a gain in attention was only found in the visual space opposite to where the participant attended for a prolonged duration.…”

“…Unilateral Multiple Object Tracking. Unilateral MOT was employed to isolate attention to the (ipsilesional) right of fixation during the intervention (Edwards et al, 2021).…”

“…Here, we present preliminary results on a potential new leftward attention-enhancing method which provides “proof of concept” for future development of rehabilitation interventions. In neurotypical individuals, we previously found 30 minutes of sustained unilateral attention resulted in an increase in attention in the opposite visual space (Edwards et al, 2021). It is plausible the attention increase was caused by an overshoot in activity as lateralized attention processing regions rebalance following prolonged imbalance (Edwards et al, 2021).…”

“…In neurotypical individuals, we previously found 30 minutes of sustained unilateral attention resulted in an increase in attention in the opposite visual space (Edwards et al, 2021). It is plausible the attention increase was caused by an overshoot in activity as lateralized attention processing regions rebalance following prolonged imbalance (Edwards et al, 2021). When attention is directed to one side of visual space with a centrally held fixation for a prolonged period, attention to the other visual space may be actively suppressed.…”