Center for Biomedical Imaging and Neuromodulation, Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Rd, Orangeburg, NY 10962, United States.
Department of Psychiatry, New York University School of Medicine, 145 E 32nd St., New York, NY 10016, United States.
Cereb Cortex. 2024 Sep 3;34(9). doi: 10.1093/cercor/bhae373.
Audiovisual (AV) interaction has been shown in many studies of auditory cortex. However, the underlying processes and circuits are unclear because few studies have used methods that delineate the timing and laminar distribution of net excitatory and inhibitory processes within areas, much less across cortical levels. This study examined laminar profiles of neuronal activity in auditory core (AC) and parabelt (PB) cortices recorded from macaques during active discrimination of conspecific faces and vocalizations. We found modulation of multi-unit activity (MUA) in response to isolated visual stimulation, characterized by a brief deep MUA spike, putatively in white matter, followed by mid-layer MUA suppression in core auditory cortex; the later suppressive event had clear current source density concomitants, while the earlier MUA spike did not. We observed a similar facilitation-suppression sequence in the PB, with later onset latency. In combined AV stimulation, there was moderate reduction of responses to sound during the visual-evoked MUA suppression interval in both AC and PB. These data suggest a common sequence of afferent spikes, followed by synaptic inhibition; however, differences in timing and laminar location may reflect distinct visual projections to AC and PB.
已有许多研究表明听觉皮层存在视听（AV）相互作用。然而，由于很少有研究使用能够描绘出区域内净兴奋和抑制过程的时间和分层分布的方法，更不用说跨皮质水平了，因此其潜在过程和回路仍不清楚。本研究在猕猴主动辨别同种个体的面孔和声音期间，记录了听觉核心（AC）和副皮质（PB）皮层中的神经元活动的分层特征，以检查这些特征。我们发现，针对孤立的视觉刺激，多单位活动（MUA）发生调制，其特征为在假定的白质中存在短暂的深 MUA 尖峰，随后在核心听觉皮层中出现中层 MUA 抑制；后者具有明显的电流源密度伴随事件，而前者的 MUA 尖峰则没有。我们在 PB 中观察到类似的促进-抑制序列，其潜伏期较晚。在 AV 联合刺激中，在 AC 和 PB 中，视觉诱发的 MUA 抑制期间，对声音的反应均有中度降低。这些数据表明存在传入尖峰的共同序列，随后是突触抑制；然而，在时间和分层位置上的差异可能反映了 AC 和 PB 中不同的视觉投射。
