Biology subjects

Ciesla, K.

Publications and source records attributed to Ciesla, K..

2 recordsLinked to original sources

bioRxiv2024

Resting-state functional connectivity changes following audio-tactile speech training

Understanding speech in background noise is a challenging task, especially if the signal is also distorted. In a series of previous studies we have shown that comprehension can improve if simultaneously to the auditory speech, the person receives speech-extracted low-frequency signals on fingertips. The effect increases after short audio-tactile speech training. Here we use resting-state functional magnetic resonance, measuring spontaneous low-frequency oscillations in the brain while at rest, to assess training-induced changes in functional connectivity. We show enhanced connectivity within a right-hemisphere cluster encompassing the middle temporal motion area (MT), and the extrastriate body area (EBA), and lateral occipital cortex (LOC), which before training is found to be more connected to bilateral dorsal anterior insula. Furthermore, early visual areas are found to switch from increased connectivity with the auditory cortex before, to increased connectivity with an association sensory/multisensory parietal hub, contralateral to the palm receiving vibrotactile inputs, after. Also the right sensorimotor cortex, including finger representations, is more connected internally after training. The results alltogether can be interpreted within two main complementary frameworks. One, speech-specific, relates to the pre-existing brain connectivity for audio-visual speech processing, including early visual, motion and body regions for lip-reading and gesture analysis in difficult acoustic conditions, which the new audio-tactile speech network might be built upon. The other refers to spatial/body awareness and audio-tactile integration, including in the revealed parietal and insular regions. It is possible that an extended training period may be necessary to more effectively strengthen direct connections between the auditory and sensorimotor brain regions, for the utterly novel speech comprehension task. The outcomes of the study can be relevant for both basic neuroscience, as well as development of rehabilitation tools for the hearing impaired population.

neuroscience↗

bioRxiv2024

Neuronal basis of audio-tactile speech perception

Since childhood, we experience speech as a combination of audio and visual signals, with visual cues particularly beneficial in difficult auditory conditions. This study investigates an alternative multisensory context of speech, and namely audio-tactile, which could prove beneficial for rehabilitation in the hearing impaired population. We show improved understanding of distorted speech in background noise, when combined with low-frequency speech-extracted vibrotactile stimulation delivered on fingertips. The quick effect might be related to the fact that both auditory and tactile signals contain the same type of information. Changes in functional connectivity due to audio-tactile speech training are primarily observed in the visual system, including early visual regions, lateral occipital cortex, middle temporal motion area, and the extrastriate body area. These effects, despite lack of visual input during the task, possibly reflect automatic involvement of areas supporting lip-reading and spatial aspects of language, such as gesture observation, in difficult acoustic conditions. For audio-tactile integration we show increased connectivity of a sensorimotor hub representing the entire body, with the parietal system of motor planning based on multisensory inputs, along with several visual areas. After training, the sensorimotor connectivity increases with high-order and language-related frontal and temporal regions. Overall, the results suggest that the new audio-tactile speech task activates regions that partially overlap with the established brain network for audio-visual speech processing. This further indicates that neuronal plasticity related to perceptual learning is first built upon an existing structural and functional blueprint for connectivity. Further effects reflect task-specific behaviour related to body and spatial perception, as well as tactile signal processing. Possibly, a longer training regime is required to strengthen direct pathways between the auditory and sensorimotor brain regions during audio-tactile speech processing.

neuroscience↗