Department of Biomedical Engineering and Neuroscience, University of Rochester, Rochester, NY, USA.
J Comput Neurosci. 2024 Nov;52(4):285-302. doi: 10.1007/s10827-024-00880-4. Epub 2024 Sep 11.
We demonstrate a model of chirp-velocity sensitivity in the inferior colliculus (IC) that retains the tuning to amplitude modulation (AM) that was established in earlier models. The mechanism of velocity sensitivity is sequence detection by octopus cells of the posteroventral cochlear nucleus, which have been proposed in physiological studies to respond preferentially to the order of arrival of cross-frequency inputs of different amplitudes. Model architecture is based on coincidence detection of a combination of excitatory and inhibitory inputs. Chirp-sensitivity of the IC output is largely controlled by the strength and timing of the chirp-sensitive octopus-cell inhibitory input. AM tuning is controlled by inhibition and excitation that are tuned to the same frequency. We present several example neurons that demonstrate the feasibility of the model in simulating realistic chirp-sensitivity and AM tuning for a wide range of characteristic frequencies. Additionally, we explore the systematic impact of varying parameters on model responses. The proposed model can be used to assess the contribution of IC chirp-velocity sensitivity to responses to complex sounds, such as speech.
我们展示了一种在下丘脑中具有啁啾速度敏感性的模型，该模型保留了在早期模型中建立的对调幅（AM）的调谐。速度敏感性的机制是由耳蜗核后腹核的章鱼细胞进行序列检测，生理学研究提出章鱼细胞优先对不同幅度的交叉频率输入的到达顺序做出反应。模型结构基于兴奋性和抑制性输入的符合检测。IC 输出的啁啾敏感性主要由啁啾敏感的章鱼细胞抑制性输入的强度和时间控制。AM 调谐由调谐到相同频率的抑制和兴奋控制。我们提出了几个示例神经元，以证明该模型在模拟广泛特征频率的真实啁啾敏感性和 AM 调谐方面的可行性。此外，我们还探讨了参数变化对模型响应的系统影响。所提出的模型可用于评估 IC 啁啾速度敏感性对复杂声音（如语音）响应的贡献。
