Biology subjects

Mueller-Voggel, N.

Publications and source records attributed to Mueller-Voggel, N..

5 recordsLinked to original sources

bioRxiv2024

Analyzing Differences in Processing Nouns and Verbs in the Human Brain using Combined EEG and MEG Measurements

Language and consequently the ability to transmit and spread complex information is unique to the human species. The disruptive event of the introduction of large language models has shown that the ability to process language alone leads to incredible abilities and, to some extent, to intelligence. However, how language is processed in the human brain remains elusive. Many insights originate from fMRI studies, as the high spatial resolution of fMRI devices provides valid information about where things happen. Nevertheless, the limited temporal resolution prevents us from gaining a deep understanding on the underlying mechanisms. In this study, we performed combined EEG and MEG measurements in 29 healthy right-handed human subjects during the presentation of continuous speech. We compared the evoked potentials (ERPs and ERFs) for different word types in source space and sensor space across the whole brain. We found characteristic spatio-temporal patterns for different word types (nouns, verbs) especially at latencies of 300ms to 1 s. This is further emphasized by the fact that we observe these effects in two pre-defined sub-samples of the data set (exploration and validation sample). We expect this study to be the starting point for further evaluations of semantic and syntactic processing in the brain.

neuroscience↗

bioRxiv2024

Temporal and Hemispheric Dynamics in Neural Processing of Auditory and Speech Stimuli Across Linguistic Complexity: A MEG Source Space Study

In this study we investigated the neural processing of auditory stimuli of varying complexity: a non-linguistic (pure tone), a simple linguistic (phoneme) and a complex linguistic (word) stimulus. We recorded brain activity of 30 healthy, righthanded participants using magnetoencephalography (MEG), and compared the resulting evoked fields (ERFs) in source space in three different time intervals, i.e. early (0-250ms), mid (250-500ms) and late (500-750ms) responses. Our results reveal a bilateral activation during early response and rightlateralized activation in the mid-phase for all stimuli. Hoewever, the late response exhibited lateralization variations. The pure tone predominantly activated the right hemisphere, consistent with pitch processing theories. The phoneme primarily engaged the left hemisphere, supporting its role in phonemic processing. Notably, the word elicited activation in both hemispheres, reflecting phonemic processing on the left and stress patterns on the right. These findings highlight the intricate interplay between temporal processing and hemispheric lateralization in speech perception, emphasizing the importance of stimulus complexity and temporal dynamics in understanding auditory and speech processing.

neuroscience↗

bioRxiv2023

Neurophysiological correlates of Somatosensory tinnitus modulation

Tinnitus is the subjective perception of a sound in absence of corresponding external acoustic stimuli. Research highlights the influence of the sensorimotor system on tinnitus perception. Associated neuronal processes, however, are insufficiently understood and it remains unclear how and at which hierarchical level the sensorimotor system interacts with the tinnitus-processing auditory system. We therefore asked 23 patients suffering from chronic tinnitus (11 males) to perform specific exercises, aimed at relaxing or tensing the jaw area, which temporarily modulated tinnitus perception. Associated neuronal processes were assessed using Magnetencephalography. Results show that chronic tinnitus patients experienced their tinnitus as weaker and less annoying after completion of relaxing compared to tensing exercises. Furthermore, (1) sensorimotor alpha power and alpha-band connectivity directed from the somatosensory to the auditory cortex increased, and (2) gamma power in the auditory cortex, reduced, which (3) related to reduced tinnitus annoyance perception on a trial-by-trial basis in the relaxed state. No effects were revealed for 23 control participants without tinnitus (6 males) performing the same experiment. We conclude that the increase in directed alpha-band connectivity from somatosensory to auditory cortex is most likely reflecting the transmission of inhibition from somatosensory to auditory cortex during relaxation, where concurrently tinnitus-related gamma power reduces. We suggest that revealed neuronal processes are transferable to other tinnitus modulating systems beyond the sensorimotor one that are e.g. involved in attentional or emotional tinnitus modulation and provide deeper mechanistic insights into how and through which channels phantom sound perception might be modulated on a neuronal level. Significance StatementTinnitus describes the perception of auditory phantom sounds. Research suggests that the sensorimotor system impacts on tinnitus perception, associated neuronal mechanisms, however, have remained unclear. Here, chronic tinnitus patients performed exercises with the jaw temporarily reducing (versus increasing) tinnitus perception. Tinnitus reduction was accompanied by an increase of alpha-band connectivity directed from the somatosensory to the auditory cortex and gamma power reduction in the auditory cortex. We suggest that the increase in alpha-band connectivity, when tinnitus is reduced, reflects the transmission of inhibition from somatosensory to auditory cortex, where, in parallel, probably tinnitus related, gamma power reduces. The findings have important implications both for the understanding of phantom sound perception and, more generally, of top-down modulation in healthy and impaired cognition.

neuroscience↗

bioRxiv2023

Decreasing alpha flow releases task-specific processing paths

Directing and maintaining attention toward relevant information and away from non-relevant information is a critical competence of higher-order nervous systems. Here, we used directed connectivity to investigate how the human brain prioritizes appropriate processing paths when participants are performing a behavioral task requiring attention in the visual or the auditory modality. We show that the efficient transfer of information relevant for the task is mediated by a region- and task-specific decrease of alpha band connectivity from parietal and, in case a motor response is required, motor cortex to the relevant sensory cortices. Further, alpha-band connectivity modulations reliably predict alpha power modulations in the task-related sensory cortices, particularly where the task-irrelevant cortex is inhibited via local alpha power increases. We suggest that the task- and region-specific modulation of alpha-band connectivity in the present study is a basic neuronal mechanism orchestrating the allocation of task-relevant neuronal resources related to and possibly underlying the previously reported sensory alpha power modulations in association with the allocation of competing attentional resources.

neuroscience↗

bioRxiv2023

Cortical Activity Associated With Acute Development of Phantom Auditory Percepts via Unilateral Deprivation

Subjective tinnitus describes the experience of hearing phantom sounds (e.g., tones, buzzing, noise). While the majority of those who report having experienced phantom sounds claim that these percepts have not lasted but are transient, some experience this chronically, with others even describing their tinnitus as severe enough to negatively impact their well-being and daily lives. Currently, no permanent solution has been discovered for preventing or curing tinnitus. This is due to several factors, including an insufficient understanding of the mechanisms at play that give rise to such auditory sensations, as well as a lack of research investigating the corresponding changes in neural activity associated with the onset and development of tinnitus. Taking advantage of the high spatial and temporal resolution of magnetoencephalography (MEG), we measured cortical activity associated with the development of acute tinnitus-like percepts induced via unilateral auditory deprivation. Over the course of four days, participants continuously wore a silicone earplug in one ear, which led to the experience of phantom sounds in 15 of 16 participants. Frequency analysis of source-localized continuous MEG data revealed a significant increase of gamma power in primary auditory cortices (A1) during the tinnitus condition (p=0.02), which most likely reflects the neuronal processing correlated with tinnitus perception.

neuroscience↗