Bounds Hayley A, Adesnik Hillel
Department of Neuroscience, University of California, Berkeley.
The Helen Wills Neuroscience Institute.
bioRxiv. 2024 Aug 19:2024.08.18.608496. doi: 10.1101/2024.08.18.608496.
Observation of neural firing patterns can constrain theories for the types of activity patterns that the brain uses to guide behavior. However, directly perturbing these patterns, ideally with great specificity, is required to causally test any particular theory. We combined two-photon imaging and cellular resolution optogenetic photo-stimulation to causally test how neural activity in the mouse visual cortex is read out to detect visual stimuli. Contrary to expectations, targeted activation of highly sensitive neural ensembles did not preferentially modify behavior compared to random ensembles, contradicting a longstanding hypothesis for how neural activity drives stimulus detection. Instead, the main predictor of a targeted neural ensemble's impact on perception was its effect on network activity. This argues that downstream regions summate visual cortex activity without preferentially weighting more informative neurons to make sensory detection decisions. Comparing mouse behavioral performance to decoding models of neural activity implies that mice employ this simple, albeit suboptimal strategy to solve the task. This work challenges conventional notions for how sensory representations mediate perception and demonstrates that specific neural perturbations are critical for determining which features of neural activity drive behavior.
对神经放电模式的观察能够限制关于大脑用于指导行为的活动模式类型的理论。然而，要对任何特定理论进行因果检验，就需要以高度特异性直接扰动这些模式。我们结合双光子成像和细胞分辨率光遗传学光刺激，来因果检验小鼠视觉皮层中的神经活动是如何被读取以检测视觉刺激的。与预期相反，与随机神经元集群相比，高度敏感神经集群的靶向激活并没有优先改变行为，这与关于神经活动如何驱动刺激检测的长期假设相矛盾。相反，靶向神经集群对感知影响的主要预测因素是其对网络活动的影响。这表明下游区域对视觉皮层活动进行累加，而在做出感官检测决策时不会优先权衡信息更丰富的神经元。将小鼠行为表现与神经活动解码模型进行比较表明，小鼠采用这种简单但并非最优的策略来解决任务。这项工作挑战了关于感觉表征如何介导感知的传统观念，并证明特定的神经扰动对于确定神经活动的哪些特征驱动行为至关重要。
