02. December 2020 : New publication on the role of α-band activity in tactile stimuli processing
OssandónJ, König P and Heed T (2020)
No evidence for a role of spatially modulated alpha-band activity in tactile remapping and short-latency, overt orienting behavior
J Neurosci 40: 9088-9102
Oscillatory α-band activity is commonly associated with spatial attention and multisensory prioritization. It has also been suggested to reflect the automatic transformation of tactile stimuli from a skin-based, somatotopic reference frame into an external one.
Previous research has not convincingly separated these two possible roles of α-band activity. Here, α-band modulation was assessed with massive univariate deconvolution, an analysis approach that disentangles brain signals overlapping in time and space. Thirty-one male and female human participants performed a delay-free, visual search task in which saccade behavior was unrestricted.
Two significant findings emerged:
First, α-band activity reflected the remapped stimulus location only when touch was task relevant.
Second, α-band modulation occurred too late to account for spatially directed behavioral responses and, thus, only after remapping must have taken place.
These characteristics contradict the prevailing concept that α-band directly reflects automatic tactile remapping processes and rather challenge the idea that α-band activity is directly involved in tactile-spatial transformation, suggesting instead that it reflects delayed, supramodal processes related to attentional reorienting.