Carrasco Andres, Kok Melanie A, Lomber Stephen G
Brain and Mind Institute, Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada N6A 5C1 Cerebral Systems Laboratory, Department of Psychology, University of Western Ontario, London, ON, Canada N6A 5C2.
Cereb Cortex. 2015 Jan;25(1):84-96. doi: 10.1093/cercor/bht205. Epub 2013 Aug 19.
Interhemispheric communication has been implicated in various functions of sensory signal processing and perception. Despite ample evidence demonstrating this phenomenon in the visual and somatosensory systems, to date, limited functional assessment of transcallosal transmission during periods of acoustic signal exposure has hindered our understanding of the role of interhemispheric connections between auditory cortical fields. Consequently, the present investigation examines the impact of core auditory cortical field deactivation on response properties of contralateral anterior auditory field (AAF) neurons in the felis catus. Single-unit responses to simple and complex acoustic signals were measured across AAF before, during, and after individual and combined cooling deactivation of contralateral primary auditory cortex (A1) and AAF neurons. Data analyses revealed that on average: 1) interhemispheric projections from core auditory areas to contralateral AAF neurons are predominantly excitatory, 2) changes in response strength vary based on acoustic features, 3) A1 and AAF projections can modulate AAF activity differently, 4) decreases in response strength are not specific to particular cortical laminae, and 5) contralateral inputs modulate AAF neuronal response thresholds. Collectively, these observations demonstrate that A1 and AAF neurons predominantly modulate AAF response properties via excitatory projections.
半球间通信与感觉信号处理和感知的各种功能有关。尽管有充分证据表明在视觉和躯体感觉系统中存在这种现象，但迄今为止，在声信号暴露期间对胼胝体间传递的功能评估有限，这阻碍了我们对听觉皮层区域之间半球间连接作用的理解。因此，本研究考察了猫的核心听觉皮层区域失活对同侧前听觉场（AAF）神经元反应特性的影响。在对同侧初级听觉皮层（A1）和AAF神经元进行单独和联合冷却失活之前、期间和之后，测量了AAF对简单和复杂声信号的单单位反应。数据分析显示，平均而言：1）从核心听觉区域到同侧AAF神经元的半球间投射主要是兴奋性的；2）反应强度的变化因声学特征而异；3）A1和AAF投射对AAF活动的调节方式不同；4）反应强度的降低并非特定于特定的皮质层；5）同侧输入调节AAF神经元的反应阈值。总的来说，这些观察结果表明，A1和AAF神经元主要通过兴奋性投射调节AAF的反应特性。
