Biology subjects

Marx, M.

Publications and source records attributed to Marx, M..

3 recordsLinked to original sources

bioRxiv2026

Neurofeedback enhances a neural signature of selective attention to speech in cocktail-party settings

Understanding speech in noisy situations is challenging and often fails due to attentional rather than sensory deficits. We report here that neurofeedback can enhance a neural signature of selective attention to speech in a cocktail-party setting. Neural responses to speech were quantified in participants electroencephalogram (EEG) while they attended to one of two audiobooks, presented simultaneously. After each 22s-segment of speech, the participants N1 component was extracted from the temporal response function (TRF). The N1 component is known to be sensitive to attention. During a [~]49-min training session, N1 amplitude values were displayed visually to participants so that they could learn to strengthen their neural responses to target speech and minimise their responses to distracting speech. During neurofeedback training, we found an enhanced N1 component in the response to target audiobooks that was specific to EEG channels used to provide feedback, and not present in a control group that received sham feedback. At right-lateralised fronto-central channels, enhanced N1 components correlated with improvements in a measure of speech comprehension (multiple-choice content questions). These results indicate that neural responses to speech can be regulated through neurofeedback and open up new possibilities to train attentional listening in populations struggling to understand speech in noise.

neuroscience↗

bioRxiv2023

Neural entrainment to both target and distracting speech causally contributes to speech perception in a multi-speaker scenario

Segregating important stimuli from distractors is crucial for successful speech perception. Neural activity synchronized to speech, also termed "neural speech tracking", is thought to be instrumental for this purpose. However, the relative contribution of neural tracking of targets and distractors for speech perception in a setting with multiple competing speakers remained unclear. In 61 human participants, we used transcranial alternating current stimulation (tACS) to manipulate neural tracking of two simultaneously presented sequences of rhythmic speech while participants attended to one of them. A random temporal relationship between speech streams allowed us to disentangle effects of tACS on target and distractor processing, and to examine their combined effect on a behavioural measure of speech perception. We found that the phase relation between tACS and both target and distracting speech modulated word report accuracy to a similar degree. This effect was observed during bilateral tACS over auditory regions, the inferior frontal gyrus (IFG) and, importantly, in a control group that received near-identical cutaneous stimulation but [~]50% reduced brain stimulation. These results imply that, although neural tracking of both target- and distracting speech causally modulates speech perception, the cutaneous stimulation that goes along with tACS can cause phase effects in speech perception that resemble those for conventional tACS. Our finding illustrates the urgent need to control for cutaneous stimulation in tACS studies. Significance StatementNeural activity synchronised to speech ("neural speech tracking") plays an important role in speech perception, yet its exact role in multi-speaker scenarios remains underexplored. We here use tACS to manipulate neural tracking in such scenarios. We find that neural tracking of both target and distracting speech causally modulates speech perception, irrespective of whether tACS is applied to target auditory cortex, inferior frontal gyrus, or in a control condition designed to produce similar cutaneous stimulation, but [~]50% reduced direct brain stimulation. Although our results demonstrate a causal role of neural tracking for speech perception in multi-speaker scenarios, they also illustrate the urgent need to control for effects of cutaneous stimulation in future tACS work on speech perception and beyond.

neuroscience↗

bioRxiv2020

The aggregate effect of implementation strength of family planning programs on modern contraceptive use at the health systems level in rural Malawi

Background To explore the association between the strength of implementation of family planning (FP) programs on the use of modern contraceptives. Specifically, how strongly these programs are being implemented across a health facility’s catchment area in Malawi and the odds of a woman in that catchment area is using modern contraceptives. This information can be used to assess whether the combined impact of multiple large-scale FP programs is leading to change in the health outcomes they aim to improve.Methods and findings We used data from the 2017 Implementation Strength Assessment (ISA) that quantified how much of family planning programs at the health facility and community health worker levels were being implemented across every district of Malawi. We used a summary measure developed in a previous study that employs quantitative methods to combine data across FP domains and health system levels. We tested the association of this summary measure for implementation strength with household data from the 2015 Malawi Demographic Health Survey (DHS). We found that areas with stronger implementation of FP programs had higher odds of women using modern contraceptives compared with areas with weaker implementation. The association of ISA with use of modern contraception was different by education, marital status, and geography. After controlling for these factors, we found that the adjusted odds of using a modern contraceptive was three times higher in catchment areas with high implementation strength compared to those with lower strength.Conclusion Metrics that summarize how strongly FP programs are being implemented were used to show a statistically significantly positive relationship between increasing implementation strength and higher rates of modern contraceptive use. Decisionmakers at the various levels of health authority can use this type of summary measure to better understand the combined impact of their diverse FP programming and inform future programmatic and policy decisions. The findings also reinforce the idea that having a well-supported and supplied cadre of community health workers supplementing FP provision at the health facility can be an important health systems mechanism, especially in rural settings and to target youth populations.View Full Text

scientific communication and education↗