Department of Biology, Texas A&M University, College Station, Texas.
Institute for Neuroscience, Texas A&M University, College Station, Texas.
J Neurophysiol. 2022 Sep 1;128(3):634-648. doi: 10.1152/jn.00436.2021. Epub 2022 Aug 17.
In this study, we examined the auditory responses of a prefrontal area, the frontal auditory field (FAF), of an echolocating bat () and presented a comparative analysis of the neuronal response properties between the FAF and the primary auditory cortex (A1). We compared single-unit responses from the A1 and the FAF elicited by pure tones, downward frequency-modulated sweeps (dFMs), and species-specific vocalizations. Unlike the A1, FAFs were not frequency tuned. However, progressive increases in dFM sweep rate elicited a systematic increase of response precision, a phenomenon that does not take place in the A1. Call selectivity was higher in the FAF versus A1. We calculated the neuronal spectrotemporal receptive fields (STRFs) and spike-triggered averages (STAs) to predict responses to the communication calls and provide an explanation for the differences in call selectivity between the FAF and A1. In the A1, we found a high correlation between predicted and evoked responses. However, we did not generate reasonable STRFs in the FAF, and the prediction based on the STAs showed lower correlation coefficient than that of the A1. This suggests nonlinear response properties in the FAF that are stronger than the linear response properties in the A1. Stimulating with a call sequence increased call selectivity in the A1, but it remained unchanged in the FAF. These data are consistent with a role for the FAF in assessing distinctive acoustic features downstream of A1, similar to the role proposed for primate ventrolateral prefrontal cortex. In this study, we examined the neuronal responses of a frontal cortical area in an echolocating bat to behaviorally relevant acoustic stimuli and compared them with those in the primary auditory cortex (A1). In contrast to the A1, neurons in the bat frontal auditory field are not frequency tuned but showed a higher selectivity for social signals such as communication calls. The results presented here indicate that the frontal auditory field may represent an additional processing center for behaviorally relevant sounds.
在这项研究中，我们检查了回声定位蝙蝠的前额皮质区域（FAF）的听觉反应，并对 FAF 和初级听觉皮层（A1）之间的神经元反应特性进行了比较分析。我们比较了 A1 和 FAF 对纯音、下变频调扫频（dFM）和特定物种发声的单个单位反应。与 A1 不同，FAF 不是频率调谐的。然而，dFM 扫频率的逐渐增加引起了反应精度的系统增加，这种现象在 A1 中不会发生。与 A1 相比，FAF 的叫声选择性更高。我们计算了神经元的时频感受野（STRFs）和尖峰触发平均（STAs），以预测对通讯叫声的反应，并解释 FAF 和 A1 之间叫声选择性的差异。在 A1 中，我们发现预测和诱发反应之间存在高度相关性。然而，我们在 FAF 中没有生成合理的 STRFs，基于 STAs 的预测显示出比 A1 低的相关系数。这表明 FAF 中的非线性反应特性比 A1 中的线性反应特性更强。用叫声序列刺激增加了 A1 中的叫声选择性，但在 FAF 中没有变化。这些数据与 FAF 在评估 A1 下游的独特声音特征中的作用一致，类似于提出的灵长类腹外侧前额叶皮层的作用。在这项研究中，我们检查了回声定位蝙蝠的一个额皮质区域对行为相关声音刺激的神经元反应，并将其与初级听觉皮层（A1）进行了比较。与 A1 不同，蝙蝠额听觉场的神经元不是频率调谐的，但对社交信号（如通讯叫声）表现出更高的选择性。这里呈现的结果表明，额听觉场可能代表了一个用于处理行为相关声音的额外处理中心。
