Electrical Neuroimaging of Voluntary Audiospatial Attention: Evidence for a Supramodal Attention Control Network

Abstract

Previous attempts to investigate the supramodal nature of attentional control have focused primarily on identifying neuroanatomical overlap in the frontoparietal systems activated during voluntary shifts of spatial attention in different sensory modalities. However, the activation of the same neural structures is insufficient evidence for a supramodal system, as the same brain regions could interact with one another in very different ways during shifts of attention in different modalities. Thus, to explore the similarity of the functional networks, it is necessary to identify the neural structures involved and to examine the timing and sequence of activities within the network. To this end, we used an electrical neuroimaging technique to localize the neural sources of electroencephalographic signals recorded from human subjects during audiospatial shifts of attention and to examine the timing and sequence of activities within several regions of interest. We then compared the results to an analogous study of visuospatial attention shifts. Similar frontal and parietal regions were activated during visual and auditory shifts of attention, and the timing of activities within these regions was nearly identical. Following this modality-independent sequence of attention-control activity, activity in the relevant sensory cortex was enhanced in anticipation of the response-relevant target. These results are consistent with the hypothesis that a single supramodal network of frontal and parietal regions mediates voluntary shifts of spatial attention and controls the flow of sensory information in modality-specific sensory pathways.

Modulation of response patterns in human auditory cortex during a target detection task: An intracranial electrophysiology study

“…To our knowledge, this is the first study to unequivocally demonstrate target-specific high gamma power increases in this region of non-primary auditory cortex through examination of ECoG recorded directly from PLST. Previous studies have demonstrated high gamma power increases to attended versus non-attended sounds in selective attention tasks (e.g., Green et al, 2011; Doesburg et al, 2012; Mesgarani and Chang, 2012), and we found a similar effect when comparing high gamma activity acquired during attended versus passive listening blocks (subject L237). In contrast to previous studies, however, we identify additional specific effects restricted to target stimuli.…”

Neurophysiological Signals of Ignoring and Attending Are Separable and Related to Performance during Sustained Intersensory Attention

“…The results of our brain source analyses indicate coactivation in both parietal (at junction with associative occipital and temporal cortices) and prefrontal structures along with sensory structures during attend and ignore effects. These associate regions resemble the supramodal network that has been reported to guide attention to operate across attended modalities (Green, Doesburg, Ward, & McDonald, 2011; Green & McDonald, 2008; Driver, Eimer, Macaluso, & Van Velzen, 2003; Eimer, van Velzen, Forster, & Driver, 2003). …”

Primary sensory cortices contain distinguishable spatial patterns of activity for each sense

“…A top–down, attentional modulation of the neural activity in PSCs is not a likely explanation for the correct classification of the responses elicited by non-principal stimuli, because the attentional effects triggered by stimuli of different sensory modalities are not expected to modulate the activity within non-corresponding PSCs in a spatially distinct manner353637. Indeed, a number of studies have shown that stimuli of different modalities activate a single supramodal attentional control network3536, and it is unlikely that its possible top–down modulatory effect on PSCs is spatially different for different sensory modalities.…”

“…Indeed, a number of studies have shown that stimuli of different modalities activate a single supramodal attentional control network3536, and it is unlikely that its possible top–down modulatory effect on PSCs is spatially different for different sensory modalities. The lack of correlation between the differences in subjective ratings of stimulus saliency and two-way classification accuracies also suggests that these were not driven by differences in attentional re-orientation or arousal.…”