Barnes Samuel J, Franzoni Eleonora, Jacobsen R Irene, Erdelyi Ferenc, Szabo Gabor, Clopath Claudia, Keller Georg B, Keck Tara
Department of Neuroscience, Physiology, and Pharmacology, University College London, 21 University Street, London WC1E 6DE, UK; MRC Centre for Developmental Neurobiology, King's College London, New Hunt's House 4th Floor, London SE1 1UL, UK.
Department of Neuroscience, Physiology, and Pharmacology, University College London, 21 University Street, London WC1E 6DE, UK.
Neuron. 2017 Nov 15;96(4):871-882.e5. doi: 10.1016/j.neuron.2017.09.052. Epub 2017 Nov 5.
Synaptic scaling is a key homeostatic plasticity mechanism and is thought to be involved in the regulation of cortical activity levels. Here we investigated the spatial scale of homeostatic changes in spine size following sensory deprivation in a subset of inhibitory (layer 2/3 GAD65-positive) and excitatory (layer 5 Thy1-positive) neurons in mouse visual cortex. Using repeated in vivo two-photon imaging, we find that increases in spine size are tumor necrosis factor alpha (TNF-α) dependent and thus are likely associated with synaptic scaling. Rather than occurring at all spines, the observed increases in spine size are spatially localized to a subset of dendritic branches and are correlated with the degree of recent local spine loss within that branch. Using simulations, we show that such a compartmentalized form of synaptic scaling has computational benefits over cell-wide scaling for information processing within the cell.
突触缩放是一种关键的稳态可塑性机制，被认为参与了皮层活动水平的调节。在此，我们研究了小鼠视觉皮层中一部分抑制性（第2/3层GAD65阳性）和兴奋性（第5层Thy1阳性）神经元在感觉剥夺后脊柱大小的稳态变化的空间尺度。通过重复的体内双光子成像，我们发现脊柱大小的增加依赖于肿瘤坏死因子α（TNF-α），因此可能与突触缩放有关。观察到的脊柱大小增加并非发生在所有脊柱上，而是在空间上局限于树突分支的一个子集，并且与该分支内近期局部脊柱丢失的程度相关。通过模拟，我们表明这种突触缩放的分区形式在细胞内信息处理方面比全细胞缩放具有计算优势。
