Purchase this article with an account.
Audrey Wong-Kee-You, Spero Nicholas, Chuan Hou; Evidence of audiovisual interactions in the primary auditory cortex. Journal of Vision 2020;20(11):535. doi: https://doi.org/10.1167/jov.20.11.535.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Multisensory processing has been suggested to occur in primary sensory regions (Murray et al., 2016). This is supported by animal studies revealing monosynpatic afferents between the visual cortex and other low-level sensory regions (Cappe & Barone, 2005), and that visual or tactile stimuli can modulate the response of neurons in the auditory cortex (Fu et al., 2004; Lakatos et al., 2007). In humans, DTI studies have revealed fiber tracts connecting the heschl gyrus and the occipital pole (Beer et al., 2013), but it remains unclear whether this connectivity represents multisensory interactions taking place in these early sensory regions. In the current study, we examined whether audiovisual multisensory interactions can be observed in the primary visual (V1) and auditory (A1) cortex in humans, by using source-imaged and frequency tagged SSVEP/AEP. Visual (2 cpd gratings) and auditory (440 Hz pure tone) stimuli were presented at an on/off modulation rate of 3.75 Hz, simultaneously (audiovisual condition) or alone (auditory-alone or visual-alone conditions). For the visual-alone condition, a signal-to-noise ratio (SNR) at 3.75 Hz (the first harmonic component, 1F) greater than 1 was observed in both A1 and V1, while for the auditory-alone condition, an SNR greater than 1 was only observed in A1. These findings suggest that while the visual stimulus elicited a response in both A1 and V1, the auditory stimulus elicited a response only in A1. For the audiovisual condition, an SNR greater than 1 was observed in both A1 and V1. However, the SNR in A1 was greater for the audiovisual condition in comparison to the auditory-alone and visual-alone conditions, suggesting the presence of multisensory enhancement in A1. Overall, our findings point to early multisensory processing in the human A1. The processing of either the auditory and visual stimulus in A1 was enhanced when both stimuli were presented simultaneously.
This PDF is available to Subscribers Only