Biology subjects

Etard, O.

Publications and source records attributed to Etard, O..

3 recordsLinked to original sources

bioRxiv2018

Does the heart forget? Modulation of cardiac activity induced by inhibitory control over emotional memories

Effort to suppress past experiences from conscious awareness can lead to forgetting. It remains largely unknown whether emotions, including their physiological causes, are also impacted by such memory suppression. In two studies, we measured in healthy participants the aftereffect of suppressing negative memories on cardiac response. Results of Study 1 revealed that an efficient control of memories was associated with a long-term inhibition of the cardiac deceleration normally induced by disgusting stimuli. Attempts to suppress sad memories, on the opposite, aggravated cardiac response, an effect that was largely related to the inability to forget this specific material. In Study 2, we found using electroencephalography that a prominent neural marker of inhibitory control, a suppression of the 5-9 Hz frequency band, was related to the subsequent inhibition of the cardiac response. These results demonstrate that suppressing memories also influence the cardiac system, opening new avenues for treating intrusive memories.

neuroscience↗

bioRxiv2018

Real-time decoding of selective attention from the human auditory brainstem response to continuous speech

Humans are highly skilled at analysing complex acoustic scenes. The segregation of different acoustic streams and the formation of corresponding neural representations is mostly attributed to the auditory cortex. Decoding of selective attention from neuroimaging has therefore focussed on cortical responses to sound. However, the auditory brainstem response to speech is modulated by selective attention as well, as recently shown through measuring the brainstems response to running speech. Although the response of the auditory brainstem has a smaller magnitude than that of the auditory cortex, it occurs at much higher frequencies and therefore has a higher information rate. Here we develop statistical models for extracting the brainstem response from multi-channel scalp recordings and for analysing the attentional modulation according to the focus of attention. We demonstrate that the attentional modulation of the brainstem response to speech can be employed to decode the attentional focus of a listener from short measurements of ten seconds or less in duration. The decoding remains accurate when obtained from three EEG channels only. We further show how out-of-the-box decoding that employs subject-independent models, as well as decoding that is independent of the specific attended speaker is capable of achieving similar accuracy. These results open up new avenues for investigating the neural mechanisms for selective attention in the brainstem and for developing efficient auditory brain-computer interfaces.

neuroscience↗

bioRxiv2017

The human auditory brainstem response to running speech reveals a subcortical mechanism for selective attention

Humans excel at selectively listening to a target speaker in background noise such as competing voices. While the encoding of speech in the auditory cortex is modulated by selective attention, it remains debated whether such modulation occurs already in subcortical auditory structures. Investigating the contribution of the human brainstem to attention has, in particular, been hindered by the tiny amplitude of the brainstem response. Its measurement normally requires a large number of repetitions of the same short sound stimuli, which may lead to a loss of attention and to neural adaptation. Here we develop a mathematical method to measure the auditory brainstem response to running speech, an acoustic stimulus that does not repeat and that has a high ecological validity. We employ this method to assess the brainstems activity when a subject listens to one of two competing speakers, and show that the brainstem response is consistently modulated by attention.

neuroscience↗