Multisensory responses in a belt region of the dorsal auditory cortical pathway

Abstract

A basic function of the cerebral cortex is to receive and integrate information from different sensory modalities into a comprehensive percept of the environment. Neurons that demonstrate multisensory convergence occur across the necortex but are especially prevalent in higher order association areas. However, a recent study of a cat higher order auditory area, the dorsal zone (DZ) of auditory cortex, did not observe any multisensory features. Therefore, the goal of the present investigation was to address this conflict using recording and testing methodologies that are established for exposing and studying multisensory neuronal processing. Among the 482 neurons studied, we found that 76.6% were influenced by non‐auditory stimuli. Of these neurons, 99% were affected by visual stimulation, but only 11% by somatosensory. Furthermore, a large proportion of the multisensory neurons showed integrated responses to multisensory stimulation, constituted a majority of the excitatory and inhibitory neurons encountered (as identified by the duration of their waveshape) and exhibited a distinct spatial distribution within DZ. These findings demonstrate that the DZ of auditory cortex robustly exhibits multisensory properties and that the proportions of multisensory neurons encountered are consistent with those identified in other higher order cortices.

A comparison of multisensory features of two auditory cortical areas: primary (A1) and higher-order dorsal zone (DZ)

“…One of the major goals of the present study was to compare multisensory processing in A1, a core auditory area, with that found in area DZ, which is a higher-order region of the auditory cortical belt. The present results (and previous studies: Bizley et al 2007 ; Bizley and King 2009 ; Meredith and Allman 2015 ; Merrikhi et al. 2022 ) show that multisensory processing occurs at the neuronal level in both A1 and in DZ.…”

“…In contrast, bimodal multisensory neurons were predominant in DZ, where 68.9% of neurons showed multisensory properties. In the context of the anatomical distribution of the different neuron response types, while the several of the neuron classes showed a differential anatomical distribution in DZ ( Merrikhi et al. 2022 ), such anatomical organizational effects were not demonstrated for A1.…”

“…2005 ). A recent investigation ( Merrikhi et al. 2022 ) demonstrated that a large proportion (>76%) of DZ neurons exhibited visual and/or somatosensory influences and such convergence generated multisensory integration.…”

Effects of developmental alcohol exposure on cortical multisensory integration

“…It is possible that the different inhibitory cell types show different degrees of MSI or may show region‐specific properties. In contrast to the PV neurons in the rodent RL area (Olcese et al, 2013), inhibitory neurons in the dorsal zone of the cat auditory cortex exhibited similar degrees of MS enhancement than excitatory ones (Merrikhi et al, 2021).…”

Development of Multisensory Processing in Ferret Parietal Cortex.

“…In addition, multisensory neurons can respond to multisensory stimulation without exhibiting MSI, but with responses that fail to achieve a statistically significant difference from their most effective unisensory response (e.g., see (Perrault Jr et al , 2005)). Such non-significant response changes, however, can contribute to substantial effects at the population level (Merrikhi et al , 2022a;Merrikhi et al , 2022b) although their developmental presentation is not known. Furthermore, the AES area is a conglomerate region consisting of 3 different sensory representations, each with their own connectional features and functional properties (for review, see (Meredith et al , 2018)).…”