How many neurons are sufficient for perception of cortical activity?
How many neurons are sufficient for perception of cortical activity?
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DOI：
10.7554/elife.58889
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发表时间：
2020-10-26
期刊：
影响因子：
7.7
通讯作者：
Häusser M
中科院分区：
文献类型：
--
作者：
Dalgleish HW;Russell LE;Packer AM;Roth A;Gauld OM;Greenstreet F;Thompson EJ;Häusser M
许多关于大脑功能的理论认为，稀疏的神经元子集的活动是感知和行动的基础。为了对可以感知到的神经活动量设置下限，我们使用全光学方法来驱动行为，对小鼠桶皮质中的L2/3锥体神经元的小集合进行有针对性的双光子光遗传学激活，同时用双光子钙成像记录局部网络活动。通过精确地滴定刺激的神经元的数量，我们证明了感知皮层活动的下限是~14个锥体神经元。我们发现激活的神经元数量和行为之间存在陡峭的S形关系，仅在~37个神经元处饱和，并表明这种关系可以随着学习而改变。此外，合奏的激活通过邻近神经元的抑制来平衡。面对强大的网络抑制，这种令人惊讶的感知灵敏度支持稀疏编码假设，并表明皮层感知平衡了最小化噪声影响与有效检测相关信号之间的权衡。
Many theories of brain function propose that activity in sparse subsets of neurons underlies perception and action. To place a lower bound on the amount of neural activity that can be perceived, we used an all-optical approach to drive behaviour with targeted two-photon optogenetic activation of small ensembles of L2/3 pyramidal neurons in mouse barrel cortex while simultaneously recording local network activity with two-photon calcium imaging. By precisely titrating the number of neurons stimulated, we demonstrate that the lower bound for perception of cortical activity is ~14 pyramidal neurons. We find a steep sigmoidal relationship between the number of activated neurons and behaviour, saturating at only ~37 neurons, and show this relationship can shift with learning. Furthermore, activation of ensembles is balanced by inhibition of neighbouring neurons. This surprising perceptual sensitivity in the face of potent network suppression supports the sparse coding hypothesis, and suggests that cortical perception balances a trade-off between minimizing the impact of noise while efficiently detecting relevant signals.