Kok Melanie A, Stolzberg Daniel, Brown Trecia A, Lomber Stephen G
Graduate Program in Neuroscience, University of Western Ontario, London, Canada; Brain and Mind Institute, Department of Psychology, University of Western Ontario, London, Canada; Cerebral Systems Laboratory, University of Western Ontario, London, Canada;
Brain and Mind Institute, Department of Psychology, University of Western Ontario, London, Canada; Cerebral Systems Laboratory, University of Western Ontario, London, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Canada; and.
J Neurophysiol. 2015 Jan 15;113(2):475-86. doi: 10.1152/jn.00682.2014. Epub 2014 Oct 22.
Current models of hierarchical processing in auditory cortex have been based principally on anatomical connectivity while functional interactions between individual regions have remained largely unexplored. Previous cortical deactivation studies in the cat have addressed functional reciprocal connectivity between primary auditory cortex (A1) and other hierarchically lower level fields. The present study sought to assess the functional contribution of inputs along multiple stages of the current hierarchical model to a higher order area, the dorsal zone (DZ) of auditory cortex, in the anaesthetized cat. Cryoloops were placed over A1 and posterior auditory field (PAF). Multiunit neuronal responses to noise burst and tonal stimuli were recorded in DZ during cortical deactivation of each field individually and in concert. Deactivation of A1 suppressed peak neuronal responses in DZ regardless of stimulus and resulted in increased minimum thresholds and reduced absolute bandwidths for tone frequency receptive fields in DZ. PAF deactivation had less robust effects on DZ firing rates and receptive fields compared with A1 deactivation, and combined A1/PAF cooling was largely driven by the effects of A1 deactivation at the population level. These results provide physiological support for the current anatomically based model of both serial and parallel processing schemes in auditory cortical hierarchical organization.
目前听觉皮层分层处理的模型主要基于解剖学上的连接，而各个区域之间的功能相互作用在很大程度上仍未得到探索。先前对猫进行的皮层失活研究探讨了初级听觉皮层（A1）与其他层次较低水平区域之间的功能互惠连接。本研究旨在评估当前分层模型多个阶段的输入对麻醉猫听觉皮层高阶区域——背侧区（DZ）的功能贡献。将冷冻环放置在A1和后听觉场（PAF）上方。在分别单独和同时对每个场进行皮层失活期间，记录DZ中多单元神经元对噪声爆发和音调刺激的反应。无论刺激如何，A1的失活都会抑制DZ中的峰值神经元反应，并导致DZ中音调频率感受野的最小阈值增加和绝对带宽减小。与A1失活相比，PAF失活对DZ放电率和感受野的影响较弱，并且在群体水平上，A1/PAF联合冷却主要受A1失活的影响驱动。这些结果为当前基于解剖学的听觉皮层分层组织中串行和平行处理方案的模型提供了生理学支持。
