Department of Otorhinolaryngology: HNS and Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, USA.
Department of Otorhinolaryngology: HNS and Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, USA.
Cell Rep. 2017 Oct 24;21(4):878-890. doi: 10.1016/j.celrep.2017.10.012.
Neuronal stimulus selectivity is shaped by feedforward and recurrent excitatory-inhibitory interactions. In the auditory cortex (AC), parvalbumin- (PV) and somatostatin-positive (SOM) inhibitory interneurons differentially modulate frequency-dependent responses of excitatory neurons. Responsiveness of neurons in the AC to sound is also dependent on stimulus history. We found that the inhibitory effects of SOMs and PVs diverged as a function of adaptation to temporal repetition of tones. Prior to adaptation, suppressing either SOM or PV inhibition drove both increases and decreases in excitatory spiking activity. After adaptation, suppressing SOM activity caused predominantly disinhibitory effects, whereas suppressing PV activity still evoked bi-directional changes. SOM, but not PV-driven inhibition, dynamically modulated frequency tuning with adaptation. Unlike PV-driven inhibition, SOM-driven inhibition elicited gain-like increases in frequency tuning reflective of adaptation. Our findings suggest that distinct cortical interneurons differentially shape tuning to sensory stimuli across the neuronal receptive field, altering frequency selectivity of excitatory neurons during adaptation.
神经元的刺激选择性是由前馈和反馈兴奋性-抑制性相互作用形成的。在听觉皮层 (AC) 中，脑啡肽 (PV) 和生长抑素阳性 (SOM) 抑制性中间神经元可不同程度地调节兴奋性神经元对频率的反应。AC 中神经元对声音的反应也依赖于刺激的历史。我们发现，SOM 和 PV 的抑制作用随着对音调时间重复的适应而不同。在适应之前，抑制 SOM 或 PV 抑制都会导致兴奋性放电活动的增加和减少。适应后，抑制 SOM 活性主要引起去抑制作用，而抑制 PV 活性仍会引起双向变化。SOM 驱动的抑制作用而非 PV 驱动的抑制作用随适应动态调节频率调谐。与 PV 驱动的抑制作用不同，SOM 驱动的抑制作用引起了频率调谐的增益样增加，反映了适应。我们的发现表明，不同的皮质中间神经元在整个神经元感受野中对感觉刺激的调谐作用不同，在适应过程中改变兴奋性神经元的频率选择性。
