Biology subjects

Boncz, A.

Publications and source records attributed to Boncz, A..

3 recordsLinked to original sources

bioRxiv2024

What are you talking about? Representation of the Topic of Speech in the Human Brain

A sentence outside context provides very restricted information to the listener. Real understanding requires one to be able to place it within the sequence of sentences forming a coherent "story" and just as importantly, within ones general knowledge of the "topic". Here we demonstrate the existence of functional brain networks robustly sensitive to the topic of ca. 6-minute-long coherent newspaper articles. Main network hubs are located in parietal and temporal brain regions. These networks changed very slowly during the course of the article, consistent with their involvement in representing the topic rather than the story aspect of the context. Because even the meaning of words can depend on the topic (see e.g., the word "shuttle" in transportation and weaving) the topic-sensitive network must also be intimately linked with the mental lexicon underlying language comprehension. Significance StatementWhen we listen to someone talking, our brain continuously integrates the speech stream with our general knowledge associated with the topic. While this is a central process of comprehension, it is still unclear how the brain maintains the relevant representations. Here we demonstrate the existence of a cortical network, which is sensitive to the topic of the speech just heard. This network may form the neural substrate for "topic representation" in the brain. Understanding how such representations are maintained and accessed would let us reveal the computations enabling rapid linguistic integration, a key process in human communication.

neuroscience↗

bioRxiv2024

Temporal expectations modulate coupling between frontal and sensory brain areas

Temporal prediction enhances perceptual processing by aligning neural excitability with expected sensory events. While local oscillatory mechanisms are known to support timing, less is understood about how large-scale functional brain networks dynamically coordinate predictive processes. In particular, it remains unclear how functional connectivity (FC)--the integration of information into network hubs--differs during expectation formation (post-cue) versus outcome evaluation (post-target), and how this varies across levels of predictability. To investigate this, we recorded electroencephalogram (EEG) while participants performed a cued auditory target-detection task with varying temporal predictability (80% and 50%). Event-related potential (ERP) results revealed that implicit temporal predictability primarily modulated later evaluative processes (P3b, frontal negativity), rather than early sensory components, consistent with context updating under uncertainty. FC was analyzed using a data-driven approach based on Normalized Directed Transfer Entropy (NDTE) applied to EEG difference waveforms between high- and low-predictability conditions. Connectivity was examined separately for the post-cue and post-target periods to distinguish prediction and evaluation phases. Behaviorally, higher temporal predictability facilitated faster reaction times. Connectivity analyses revealed largely overlapping but somewhat distinct network dynamics for prediction and evaluation phases of the signal processing.

neuroscience↗

bioRxiv2023

The effects of aging and hearing impairment on listening in noise

Listening in a noisy environment (e.g., speech in noise) relies on the fundamental ability to extract coherence from the variable sensory input. This allows the detection active sound sources and their segregation of them from the rest of the scene (figure-ground segregation). Peripheral and central causes of age-related decline of listening in noise were assessed by a tone-cloud-based figure detection task. In two conditions differing in the amount of noise, figure detection performance was equalized between young, normal-hearing, and hearing-impaired elderly listeners by adapting the stimulation separately to the abilities of each person. Based on behavioral measures and event-related brain potentials (ERP), in the absence of cognitive deficits, aging alone does not appear to significantly deteriorate the ability to detect sound sources in noise, although ERPs show delayed perceptual processes and some expected deterioration in attention and/or executive functions. However, even mild hearing impairment substantially reduces the ability to segregate individual sound sources within a complex auditory scene, and susceptibility to masking noise increases together with the severity of the hearing deficit. Significance StatementThis work provides new information about the contributions of central and peripheral causes to the typical age-related decline of listening in a noisy environment. Behavioral and neurophysiological data collected in a well-controlled model of listening in noise suggest that aging alone does not significantly reduce the ability to detect sound sources in a complex auditory scene. However, even mild hearing impairment significantly reduces this ability. The stimulus paradigm used appears to be quite sensitive to hearing loss, making it potentially useful for the early detection of hearing problems.

neuroscience↗