Chen Chenggang, Remington Evan D, Wang Xiaoqin
Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21025, USA.
bioRxiv. 2025 Aug 19:2025.08.14.669832. doi: 10.1101/2025.08.14.669832.
In auditory cortex, neural responses to stimuli inside receptive fields (RFs) can be further facilitated by behavioral demands, such as attending to a spatial location. It is less clear how off-RF stimuli modulate neural responses and contribute to behavioral tasks. Our recent study revealed a particular form of location-specific facilitation evoked by repeated stimulation from an off-RF location, suggesting behavioral modulation of spatial RFs. To further explore this question, we trained marmosets to attend to sound locations that were either inside or outside the RFs of auditory cortical neurons. The majority of neurons showed increased firing rates at target locations inside their RFs. Interestingly, this increase also occurred outside the RFs, sometimes exceeding the responses at the RF center during passive listening. These task-related off-RF facilitation were much more common in the caudal area than in the rostral area and the primary auditory cortex. A normalization model reproduced the off-RF facilitation using widespread suppression. The model's prediction was confirmed by experimental observations of widespread reductions in firing rate and hyperpolarized membrane potentials for off-RF stimuli. These results suggest that behavioral task demands recruit a broader range of neurons than those that are responsive to a target sound in the passive state.
在听觉皮层中，对感受野（RFs）内刺激的神经反应可因行为需求（如关注空间位置）而进一步增强。目前尚不清楚感受野外（off-RF）的刺激如何调节神经反应并对行为任务产生影响。我们最近的研究揭示了一种由来自感受野外位置的重复刺激诱发的特定形式的位置特异性增强，这表明空间感受野存在行为调节。为了进一步探究这个问题，我们训练狨猴关注听觉皮层神经元感受野内或感受野外的声音位置。大多数神经元在其感受野内的目标位置表现出更高的放电率。有趣的是，这种增加在感受野外也会出现，有时在被动聆听时超过感受野中心的反应。这些与任务相关的感受野外增强在尾侧区域比在头侧区域和初级听觉皮层更为常见。一个归一化模型利用广泛抑制重现了感受野外增强。该模型的预测通过对感受野外刺激导致放电率广泛降低和膜电位超极化的实验观察得到证实。这些结果表明，行为任务需求所调动的神经元范围比被动状态下对目标声音有反应的神经元范围更广。
