Neurological soft signs, including behavioural manifestations of executing motor coordination and sensory integration tasks, have been considered to be one of the sensitive, specific, reliable and valid biomarkers for schizophrenia spectrum disorders. Recent neuroimaging findings have shown have strong neural bases for their behavioural manifestations in people with schizophrenia. However, most of these studies have focused on motor coordination signs. It is equally important to study other domains of neurological signs such as sensory integration that takes up a crucial role in the cognitive representation of the outside world by integrating signals from different sensory modalities. However, there are surprisingly much fewer studies examining the neural bases of sensory integration in both healthy and clinical samples.
Drs. Jia Huang and Raymond Chan together with their collaborator, Prof. Paola Dazzan, from UK have specifically developed an audiovisual sensory integration paradigm to examine spatial-temporal matching ability in healthy participants. They recruited 37 healthy volunteers from the general public. All participants were requested to undertake a functional imaging task involving spatial dots matching with an auditory tone response inside a brain scanner. They were also examined with the sensory integration items from the Cambridge Neurological Inventory after the completion of the brain scanning.
The results showed that there were activations observed in the bilateral occipital-parietal conjunction and the precentral frontal gyrus when the participants were asked to match spatial-temporal stimuli. However, there was no such activation being observed in the non-matching condition. Moreover, there were significant correlations found between occipital-parietal conjunction integration of information across visual and auditory modalities, and between precentral frontal gryus activation and decision-making of movements. Sensory integration subscale score from the Cambridge Neurological Inventory was also correlated significantly with the activation of the left superior frontal gyrus.
The findings suggest that the bilateral occipital-parietal conjunction cortex may be responsible for matching information input from multiple modalities and may therefore be sensitive to audiovisual sensory integration. The study of sensory integration in healthy volunteers facilitates us to better understand the underlying neural mechanism of sensory integration in neurodevelopmental disorders such as schizophrenia and autism. Dr. Chan’s team is now applying this paradigm to individuals with schizophrenia and autism in order to examine how the neural mechanisms correspond to the clinical manifestations and functional outcomes observed in these clinical groups.
Three regions of interest and their parameters were estimated in the matching-control contrast. The red part represents the right occipital-parietal conjunction cluster. The yellow part represents the combination of the right occipital-parietal conjunction cluster and the right superior parietal lobe anatomically defined in AAL brain structure. The purple part represents the combination of the right occipital-parietal conjunction cluster and the right middle occipital lobe cluster anatomically defined by the AAL brain structure. The right panel represents the parameter estimates extracted from these three ROIs (Mean + SE), showing that the activation of the red part involves both the parietal and occipital cortex, which is therefore labeled as the right occipital-parietal conjunction. (Note: *: p<0.05; **: p<0.01; ***: p<0.001.
This study was supported by a grant from the Beijing Muncipal Science and Technology Grant, the Beijing Training Project for Leading Talents in Science and Technology, National Science Foundation China, “Strategic Priority Research Program (B)” of the Chinese Academy of Sciences, the CAS/SAFEA International Partnership Programme for Creative Research Teams, and CAS Key Laboratory of Mental Health, Institute of Psychology.
The paper is now published in Neuropsychology. Huang, J.# Reinders, A. A. T. S.#, Wang, J., Xu, T., Zeng, Y. W., Li, K., Handley, R., Cheung, E.F. C., Chan, R. C. K.*, Dazzan, P.*. (2018). Neural correlates of audiovisual sensory integration. Neuropsychology, 32(3), 329-336.
Li, Z.#, Huang, J. #, Xu, T.#, Wang, Y., Li, K., Zeng, Y. W., Lui, S. S. Y., Cheung, E. F. C., Jin, Z., Dazzan, P., Glahn, D. C., Chan, R. C. K.* (2018). Neural mechanism and heritability of complex motor sequence and audiovisual integration: A healthy twin study. Human Brain Mapping, 39:1438–1448. DOI: 10.1002/hbm.23935 (# equal contribution) http://onlinelibrary.wiley.com/doi/10.1002/hbm.23935/full