Abnormal Habituation of the Auditory Event-Related Potential P2 Component in Patients With Schizophrenia

Working memory and processing speed abilities are related to habituation and change detection in school-aged children: An ERP study

High cognitive performance is related to efficient brain processing while accomplishing complex cognitive tasks. This efficiency is observed through a rapid engagement of the brain regions and the cognitive processes required for task accomplishment. However, it is unclear if this efficiency is also present in basic sensory processes such as habituation and change detection. We recorded EEG with 85 healthy children (51 males) aged between 4 and 13 years old, while they listened to an auditory oddball paradigm. Cognitive functioning was evaluated using the Weschler Intelligence Scales for Children Fifth Edition and the Weschler Preschool & Primary School for Intelligence Fourth Edition. Auditory evoked potentials (AEPs) analyses and repeated measure analysis of covariance as well as regression models were performed. The analysis revealed that P1 and N1 repetition effects were observed across levels of cognitive functioning. Further, working memory abilities were related to repetition suppression on the auditory P2 component amplitude, while faster processing speed was related to repetition enhancement on the N2 component amplitude. Also, Late Discriminative Negativity (LDN) amplitude, a neural correlate of change detection, increased with working memory abilities. Our results confirm that efficient repetition suppression (i.e. greater reduction in amplitudes with greater levels of cognitive functioning) and more sensitive change detection (greater amplitude changes of the LDN) are related to the level of cognitive functioning in healthy children. More specifically, working memory and processing speed abilities are the cognitive domains related to efficient sensory habituation and change detection.

Habituation, Adaptation and Prediction Processes in Neurodevelopmental Disorders: A Comprehensive Review

Habituation, the simplest form of learning preserved across species and evolution, is characterized by a response decrease as a stimulus is repeated. This adaptive function has been shown to be altered in some psychiatric and neurodevelopmental disorders such as autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD) or schizophrenia. At the brain level, habituation is characterized by a decrease in neural activity as a stimulation is repeated, referred to as neural adaptation. This phenomenon influences the ability to make predictions and to detect change, two processes altered in some neurodevelopmental and psychiatric disorders. In this comprehensive review, the objectives are to characterize habituation, neural adaptation, and prediction throughout typical development and in neurodevelopmental disorders; and to evaluate their implication in symptomatology, specifically in sensitivity to change or need for sameness. A summary of the different approaches to investigate adaptation will be proposed, in which we report the contribution of animal studies as well as electrophysiological studies in humans to understanding of underlying neuronal mechanisms.

Visuo-auditory stimuli with semantic, temporal and spatial congruence for a P300-based BCI: An exploratory test with an ALS patient in a completely locked-in state

BACKGROUND

Brain-computer interfaces (BCIs) are a promising tool for communication with completely locked-in state (CLIS) patients. Despite the great efforts already made by the BCI research community, the cases of success are still very few, very exploratory, limited in time, and based on simple 'yes/no' paradigms.

NEW METHOD

A P300-based BCI is proposed comparing two conditions, one corresponding to purely spatial auditory stimuli (AU-S) and the other corresponding to hybrid visual and spatial auditory stimuli (HVA-S). In the HVA-S condition, there is a semantic, temporal, and spatial congruence between visual and auditory stimuli. The stimuli comprise a lexicon of 7 written and spoken words. Spatial sounds are generated through the head-related transfer function. Given the good results obtained with 10 able-bodied participants, we investigated whether a patient entering CLIS could use the proposed BCI.

RESULTS

The able-bodied group achieved 71.3 % and 90.5 % online classification accuracy for the auditory and hybrid BCIs respectively, while the patient achieved 30 % and chance level accuracies, for the same conditions. Notwithstanding, the patient's event-related potentials (ERPs) showed statistical discrimination between target and non-target events in different time windows.

COMPARISON WITH EXISTING METHODS

The results of the control group compare favorably with the state-of-the-art, considering a 7-class BCI controlled visual-covertly and with auditory stimuli. The integration of visual and auditory stimuli has not been tested before with CLIS patients.

CONCLUSIONS

The semantic, temporal, and spatial congruence of the stimuli increased the performance of the control group, but not of the CLIS patient, which can be due to impaired attention and cognitive function. The patient's unique ERP patterns make interpretation difficult, requiring further tests/paradigms to decouple patients' responses at different levels (reflexive, perceptual, cognitive). The ERPs discrimination found indicates that a simplification of the proposed approaches may be feasible.

From Sound Perception to Automatic Detection of Schizophrenia: An EEG-Based Deep Learning Approach

Deep learning techniques have been applied to electroencephalogram (EEG) signals, with promising applications in the field of psychiatry. Schizophrenia is one of the most disabling neuropsychiatric disorders, often characterized by the presence of auditory hallucinations. Auditory processing impairments have been studied using EEG-derived event-related potentials and have been associated with clinical symptoms and cognitive dysfunction in schizophrenia. Due to consistent changes in the amplitude of ERP components, such as the auditory N100, some have been proposed as biomarkers of schizophrenia. In this paper, we examine altered patterns in electrical brain activity during auditory processing and their potential to discriminate schizophrenia and healthy subjects. Using deep convolutional neural networks, we propose an architecture to perform the classification based on multi-channels auditory-related EEG single-trials, recorded during a passive listening task. We analyzed the effect of the number of electrodes used, as well as the laterality and distribution of the electrical activity over the scalp. Results show that the proposed model is able to classify schizophrenia and healthy subjects with an average accuracy of 78% using only 5 midline channels (Fz, FCz, Cz, CPz, and Pz). The present study shows the potential of deep learning methods in the study of impaired auditory processing in schizophrenia with implications for diagnosis. The proposed design can provide a base model for future developments in schizophrenia research.

Generalization of sustained neurophysiological effects of short-term auditory 13-Hz stimulation to neighboring frequency representation in humans

A fuller understanding of the effects of auditory tetanization in humans would inform better language and sensory learning paradigms, however, there are still unanswered questions. Here, we probe sustained changes in the event-related potentials (ERPs) to 1020Hz and 980Hz tones following a rapid presentation of 1020Hz tone (every 75 ms, 13.3Hz, tetanization). Consistent with the previous studies (Rygvold, et al., 2021, Mears & Spencer 2012), we revealed the increase in the P2 ERP component after tetanization. Contrary to other studies (Clapp et al., 2005; Lei et al., 2017) we did not observe the expected N1 increase after tetanization even in the experimental sequence identical to Clapp. et al., 2005. We detected a significant N1 decrease after tetanization. Expanding previous research, we showed that P2 increase and N1 decrease is not specific to the stimulus type (tetanized 1020Hz and non-tetanized 980Hz), suggesting the generalizability of tetanization effect to the not-stimulated auditory tones, at least to those of the neighboring frequency. The ERPs tetanization effects were observed for at least 30 min - the most prolonged interval examined, consistent with the duration of long-term potentiation, LTP. In addition, the tetanization effects were detectable in the blocks where the participants watched muted videos, an experimental setting that can be easily used in children and other challenging groups. Thus, auditory 13-Hz stimulation affects brain processing of tones including those of neighboring frequencies.