Biology subjects

Desain, P.

Publications and source records attributed to Desain, P..

4 recordsLinked to original sources

bioRxiv2024

Fast and robust objective EEG audiometry

The current gold standard of audiometry relies on subjective behavioral responses, which is impractical and unreliable for certain groups such as children, individuals with severe disabilities, or the disabled elderly. This study presents a novel electroencephalography (EEG) system that is easy to setup and estimates audiometric thresholds quickly. Air-conduction audiometric thresholds at 250, 500, 1000, 2000, 4000, and 8000 Hz and 5 dB resolution were estimated from ten elderly patients with asymmetric sensorineural hearing loss and five normal hearing young adults using three different systems: the novel EEG system, conventional pure-tone audiometry (PTA), and an automated behavioral test with the same stimulus properties as in the EEG test. EEG data was collected for 15 minutes from 32 semi-dry EEG electrodes. Later, the EEG system was trimmed to 8 electrodes and 7.5 minutes of data with satisfactory results. Correlation and regression analysis validated the hearing thresholds derived from both EEG configurations relative to the behavioral hearing thresholds-Pearsons correlation of 0.82 between PTA and 8-electrode 7.5-minute EEG data. The results of this study open the door to fast and objective hearing threshold estimation with EEG.

neuroscience↗

bioRxiv2022

Inducing a mental context for associative memory formation with real-time fMRI neurofeedback

Memory, one of the hallmarks of human cognition, can be modified when humans voluntarily modulate single neuron or neural population activity using neurofeedback. However, it is currently unknown whether memory is facilitated or impaired after such neural perturbation. In this study, participants memorized objects while we trained them with abstract neurofeedback to modulate their brain activity patterns in the ventral visual stream to represent either faces or houses. The neurofeedback created an implicit face or house context in the brain while memorizing the objects. The results revealed that participants created associations between each memorized object and its implicit context solely due to the neurofeedback manipulation. Our findings shed light onto how memory formation can be influenced by synthetic memory tags with neurofeedback and advance our understanding of mnemonic processing.

neuroscience↗

bioRxiv2020

Exploiting Electrophysiological Measures of Semantic Processing for Auditory Attention Decoding

In Auditory Attention Decoding, a users electrophysiological brain responses to certain features of speech are modelled and subsequently used to distinguish attended from unattended speech in multi-speaker contexts. Such approaches are frequently based on acoustic features of speech, such as the auditory envelope. A recent paper shows that the brains response to a semantic description (i.e., semantic dissimilarity) of narrative speech can also be modelled using such an approach. Here we use the (publicly available) data accompanying that study, in order to investigate whether combining this semantic dissimilarity feature with an auditory envelope approach improves decoding performance over using the envelope alone. We analyse data from their Cocktail Party experiment in which 33 subjects attended to one of two simultaneously presented audiobook narrations, for 30 1-minute fragments. We find that the addition of the dissimilarity feature to an envelope-based approach significantly increases accuracy, though the increase is marginal (85.4% to 86.6%). However, we subsequently show that this dissimilarity feature, in which the degree of dissimilarity of the current word with regard to the previous context is tagged to the onsets of each content word, can be replaced with a binary content-word-onset feature, without significantly affecting the results (i.e., modelled responses or accuracy), putting in question the added value of the dissimilarity information for the approach introduced in this recent paper.

neuroscience↗

bioRxiv2018

Semantic Probing: Feasibility of using sequential probes to decode what is on a user’s mind

In this paper, we investigate the feasibility of using multiple sequential probe words to decode their relatedness to an active semantic concept on a users mind from the respective electrophysiological brain responses. If feasible, this relatedness information could be used by a Brain Computer Interface to infer that semantic concept, by integrating the knowledge of the relationship between the multiple probe words and the unknown target. Such a BCI can take advantage of the N400: an event related potential that is sensitive to semantic content of a stimulus in relation to an established semantic context. However, it is unknown whether the N400 is suited for the multiple probing paradigm we propose, as other intervening words might distract from the established context (i.e., the target word). We perform an experiment in which we present up to ten words after an initial target word, and find no attenuation of the strength of the N400 in grand average ERPs and no decrease in classification accuracy for probes occurring later in the sequences. These results lay the groundwork for the development of a BCI that infers the concept on a users mind through repeated probing.

neuroscience↗