Soto Gabriel, Kopell Nancy, Sen Kamal
Department of Biomedical Engineering, Boston University, 44 Cummington Street, Boston, MA 02215, USA.
J Neurophysiol. 2006 Dec;96(6):2972-83. doi: 10.1152/jn.00459.2006. Epub 2006 Aug 9.
Two fundamental issues in auditory cortical processing are the relative importance of thalamocortical versus intracortical circuits in shaping response properties in primary auditory cortex (ACx), and how the effects of neuromodulators on these circuits affect dynamic changes in network and receptive field properties that enhance signal processing and adaptive behavior. To investigate these issues, we developed a computational model of layers III and IV (LIII/IV) of AI, constrained by anatomical and physiological data. We focus on how the local and global cortical architecture shape receptive fields (RFs) of cortical cells and on how different well-established cholinergic effects on the cortical network reshape frequency-tuning properties of cells in ACx. We identify key thalamocortical and intracortical circuits that strongly affect tuning curves of model cortical neurons and are also sensitive to cholinergic modulation. We then study how differential cholinergic modulation of network parameters change the tuning properties of our model cells and propose two different mechanisms: one intracortical (involving muscarinic receptors) and one thalamocortical (involving nicotinic receptors), which may be involved in rapid plasticity in ACx, as recently reported in a study by Fritz and coworkers.
听觉皮层处理中的两个基本问题是，丘脑皮层回路与皮层内回路在塑造初级听觉皮层（ACx）的反应特性方面的相对重要性，以及神经调质对这些回路的影响如何影响网络和感受野特性的动态变化，从而增强信号处理和适应性行为。为了研究这些问题，我们在解剖学和生理学数据的约束下，开发了一个AI区III层和IV层（LIII/IV）的计算模型。我们关注局部和整体皮层结构如何塑造皮层细胞的感受野（RFs），以及不同的、已确定的胆碱能对皮层网络的影响如何重塑ACx中细胞的频率调谐特性。我们确定了关键的丘脑皮层和皮层内回路，这些回路强烈影响模型皮层神经元的调谐曲线，并且对胆碱能调制也很敏感。然后，我们研究网络参数的差异胆碱能调制如何改变我们模型细胞的调谐特性，并提出两种不同的机制：一种是皮层内机制（涉及毒蕈碱受体），另一种是丘脑皮层机制（涉及烟碱受体），这两种机制可能参与ACx中的快速可塑性，正如弗里茨及其同事最近在一项研究中所报道的那样。
