Department of Biomedical Engineering, University of Minnesota Minneapolis, MN, USA.
Front Neural Circuits. 2013 Apr 25;7:77. doi: 10.3389/fncir.2013.00077. eCollection 2013.
Descending projections from the cortex to subcortical structures are critical for auditory plasticity, including the ability for central neurons to adjust their frequency tuning to relevant and meaningful stimuli. We show that focal electrical stimulation of primary auditory cortex in guinea pigs produces excitatory responses in the central nucleus of the inferior colliculus (CNIC) with two tonotopic patterns: a narrow tuned pattern that is consistent with previous findings showing direct frequency-aligned projections; and a broad tuned pattern in which the auditory cortex can influence multiple frequency regions. Moreover, excitatory responses could be elicited in the caudomedial portion along the isofrequency laminae of the CNIC but not in the rostrolateral portion. This descending organization may underlie or contribute to the ability of the auditory cortex to induce changes in frequency tuning of subcortical neurons as shown extensively in previous studies.
皮层到皮质下结构的下行投射对于听觉可塑性至关重要，包括中枢神经元调整其频率调谐以适应相关和有意义的刺激的能力。我们表明，豚鼠初级听觉皮层的聚焦电刺激在中脑下丘核（CNIC）中产生两种音调模式的兴奋性反应：与先前显示直接频率对齐投射的发现一致的窄调谐模式；以及在该模式中，听觉皮层可以影响多个频率区域。此外，可以在 CNIC 的等频层的尾内侧部分而不是在头侧外侧部分中引出兴奋性反应。这种下行组织可能是听觉皮层诱导皮质下神经元频率调谐变化的能力的基础或贡献，如先前的广泛研究所示。
