Biology subjects

Preisig, B. C.

Publications and source records attributed to Preisig, B. C..

3 recordsLinked to original sources

bioRxiv2026

Volitional control of parieto-occipital alpha lateralization via neurofeedback does not influence auditory spatial attention

Auditory spatial attention, the ability to focus selectively on specific sounds while ignoring others, is crucial for everyday listening. Lateralized alpha oscillations over the parieto-occipital cortex have been proposed to act as a crossmodal attentional filter mechanism that allows to gate sensory processing by actively suppressing unattended locations. While prior evidence supports the functional role of this mechanism in visual attention, its role in auditory spatial attention remains debated. In this pre-registered EEG-neurofeedback study, participants were trained for 30 minutes to lateralize alpha power toward the left or right parieto-occipital cortex, while auditory probes from different spatial directions (-90{degrees}, -45{degrees}, 45{degrees}, and 90{degrees}) assessed whether online changes in alpha lateralization influenced auditory processing. Resting-state and task-based alpha lateralization, as well as gaze behavior were measured before and after training. Participants successfully modulated alpha lateralization in the trained direction during neurofeedback. However, shifting alpha lateralization did not cause changes in online auditory processing, as evidenced by the absence of asymmetric changes in auditory evoked responses to lateralized probe tones. Likewise, neurofeedback did not cause persistent changes in alpha lateralization during resting-state and task-based recordings after neurofeedback. Notably, neurofeedback training affected gaze behavior. Shifting alpha lateralization toward the left hemisphere during neurofeedback abolished a pre-existing rightward gaze bias in training responders, pointing to a dissociation between oculomotor and auditory attentional systems. These findings challenge the notion that parieto-occipital alpha lateralization serves as a universal crossmodal spatial gate, and raise important questions about the functional specificity of alpha-based neurofeedback interventions.

neuroscience↗

bioRxiv2021

Categorical encoding of speech sounds: beyond auditory cortices

Which processes in the human brain lead to the categorical perception of speech sounds? Investigation of this question is hampered by the fact that categorical speech perception is normally confounded by acoustic differences in the stimulus. By using ambiguous sounds, however, it is possible to dissociate acoustic from perceptual stimulus representations. Twenty-seven normally hearing individuals took part in an fMRI study in which they were presented with an ambiguous syllable (intermediate between /da/ and /ga/) in one ear and with disambiguating acoustic feature (third formant, F3) in the other ear. Multi-voxel pattern searchlight analysis was used to identify brain areas that consistently differentiated between response patterns associated with different syllable reports. By comparing responses to different stimuli with identical syllable reports and identical stimuli with different syllable reports, we disambiguated whether these regions primarily differentiated the acoustics of the stimuli or the syllable report. We found that BOLD activity patterns in left perisylvian regions (STG, SMG), left inferior frontal regions (vMC, IFG, AI), left supplementary motor cortex (SMA/pre-SMA), and right motor and somatosensory regions (M1/S1) represent listeners syllable report irrespective of stimulus acoustics. Most of these regions are outside of what is traditionally regarded as auditory or phonological processing areas. Our results indicate that the process of speech sound categorization implicates decision-making mechanisms and auditory-motor transformations. HighlightsO_LIAmbiguous dichotic syllables elicit distinct percepts of identical stimuli C_LIO_LIMultivariate searchlight analysis reveals syllabic-category sensitive brain areas C_LIO_LICategorical responses arise in non-auditory cortical areas including motor areas C_LIO_LISMA is a possible locus for transforming sensory signals into perceptual decisions C_LI

neuroscience↗

bioRxiv2019

Dual-site high-density 4Hz transcranial alternating current stimulation applied over auditory and motor cortical speech areas does not influence auditory-motor mapping

BackgroundVerbal repetition of auditory speech requires the mapping of a sensory acoustic input onto articulatory motor plans (auditory-motor mapping). Recent evidence indicates that auditory-motor mapping could rely on low frequency neural synchronization (i.e., theta oscillatory phase coupling) between sensory and motor speech areas.\n\nObjectiveIn the present study, we apply dual-site high-density (HD) Transcranial Alternating Current Stimulation (TACS) above the auditory and motor cortex to induce, or disrupt, theta phase coupling between the two areas. We predicted that functionally coupling the two areas would strengthen auditory-motor mapping, compared with functionally decoupling them. We assessed the strength of auditory-motor mapping using a verbal repetition task.\n\nResultsWe found no significant effect of TACS-induced theta phase coupling on auditory-motor mapping as indexed by verbal repetition performance.\n\nConclusionAuditory-motor mapping may rely on a different mechanism than we hypothesized, for example, oscillatory phase-coupling outside the theta range. Alternatively, modulation of interregional theta-phase coupling may require more effective stimulation protocols, for example, TACS at higher intensities.

neuroscience↗