Biology subjects

Meschede-Krasa, B.

Publications and source records attributed to Meschede-Krasa, B..

4 recordsLinked to original sources

bioRxiv2024

Representation of Verbal Thought in Motor Cortex and Implications for Speech Neuroprostheses

Speech brain-computer interfaces show great promise in restoring communication for people who can no longer speak1-3, but have also raised privacy concerns regarding their potential to decode private verbal thought4-6. Using multi-unit recordings in three participants with dysarthria, we studied the representation of inner speech in the motor cortex. We found a robust neural encoding of inner speech, such that individual words and continuously imagined sentences could be decoded in real-time This neural representation was highly correlated with overt and perceived speech. We investigated the possibility of "eavesdropping" on private verbal thought, and demonstrated that verbal memory can be decoded during a non-speech task. Nevertheless, we found a neural "overtness" dimension that can help to avoid any unintentional decoding. Together, these results demonstrate the strong representation of verbal thought in the motor cortex, and highlight important design considerations and risks that must be addressed as speech neuroprostheses become more widespread.

neuroscience↗

bioRxiv2021

EEG-Based Focus Estimation Using Neurable's Enten Headphones and Analytics Platform

We introduce Neurables research on focus using our recently developed Enten EEG headphones. First we quantify Entens performance on standard EEG protocols, including eyes-closed alpha rhythms, auditory evoked response and the P300 event-related potential paradigm. We show that Entens performance is on-par with established industry-standard hardware. We then introduce a series of experimental tasks designed to mimic how focus might be maintained or disrupted in a real-world office setting. We show that (A) these tasks induce behavioral changes that reflect underlying changes in focus levels and (B) our proprietary algorithm detects these changes across a large number of sessions without needing to adjust the model per participant or recording session. Through manipulation of our experimental protocol, we show that our algorithm is not dependent on gross EMG artifacts and it is driven by changes in EEG. Finally, we evaluated the models performance on the same subject across several days, and show that performance remained consistent over time. Our model correctly captured 80% {+/-} 4.1% of distractions present in our experiments with statistical significance. This indicates that our model generalizes across subjects, time points, and conditions. Our findings are based on EEG data collected from 132 participants across 337 sessions and 45 different experiments.

neuroscience↗

bioRxiv2019

Spatiotemporal input reorganization and enhancement of input-output gain sharpen cortical direction selectivity during development

Some neural circuits are constructed through an overproduction of initial connections followed by activity-dependent refinement. Under this paradigm, functional receptive fields would be expected to be narrowed from a diffuse immature condition to a sharper mature condition. Alternatively, neural activity might lead to formation of new connections, leading to expansion of an initially compact receptive field. In the simple cells of the ferret visual cortex undergoing developmental enhancement of direction selectivity, we found evidence for a mixed mechanism: an expansion of the spatiotemporal receptive fields along the temporal dimension combined with a narrowing in space-time through a marked loss of inputs with certain space-time selectivities. Further, the resulting increase in subthreshold direction selectivity was accompanied by increases in near-spike-threshold excitability and input-output gain that resulted in dramatically increased spiking responses. Increases in subthreshold membrane responses and the increased input-output spiking gain were both necessary to explain firing rates in experienced ferrets. These results demonstrate that cortical direction selectivity develops through a combination of plasticity in synaptic and cell-intrinsic properties.

neuroscience↗

bioRxiv2019

An early phase of instructive plasticity in visual cortex before the typical onset of sensory experience

While early experience with moving stimuli is necessary for the development of direction selectivity in visual cortex of carnivores, it is unclear whether experience exerts a permissive or instructive influence. To test if the specific parameters of the experienced stimuli could instructively sculpt the emergent responses, visually naive ferrets were exposed to several hours of experience with unusual spatiotemporal patterns. In the most immature ferrets, cortical neurons developed selectivity to these patterns, indicating an instructive influence. In animals that were 1-10 days more mature, exposure to the same patterns led to a developmentally-typical increase in direction selectivity. We conclude that visual development progresses via an early phase of instructive plasticity, when the specific patterns of neural activity shape the specific parameters of the emerging response properties, followed by a late phase of permissive maturation, when sensory-driven activity merely serves to enhance the response properties already seeded in cortical circuits.

neuroscience↗