Nase Gabriele, Singer Wolf, Monyer Hannah, Engel Andreas K
Abteilung Neurophysiologie, Max-Planck-Institut für Hirnforschung, 60528 Frankfurt, Germany.
J Neurophysiol. 2003 Aug;90(2):1115-23. doi: 10.1152/jn.00480.2002. Epub 2003 Apr 17.
Synchronization of neuronal discharges has been hypothesized to play a role in defining cell assemblies representing particular constellations of stimulus features. In many systems and species, synchronization is accompanied by an oscillatory response modulation at frequencies in the gamma-band. The cellular mechanisms underlying these phenomena of synchronization and oscillatory patterning have been studied mainly in vitro due to the difficulty in designing a direct in vivo assay. With the prospect of using conditional genetic manipulations of cortical network components, our objective was to test whether the mouse would meet the criteria to provide a model system for the study of gamma-band synchrony. Multi-unit and local field potential recordings were made from the primary visual cortex of anesthetized C57BL/6J mice. Neuronal responses evoked by moving gratings, bars, and random dot patterns were analyzed with respect to neuronal synchrony and temporal patterning. Oscillations at gamma-frequencies were readily evoked with all types of stimuli used. Oscillation and synchronization strength were largest for gratings and decreased when the noise level was increased in random-dot patterns. The center peak width of cross-correlograms was smallest for bars and increased with noise, yielding a significant difference between coherent random dot patterns versus patterns with 70% noise. Field potential analysis typically revealed increases of power in the gamma-band during response periods. Our findings are compatible with a role for neuronal synchrony in mediating perceptual binding and suggest the usefulness of the mouse model for testing hypotheses concerning both the mechanisms and the functional role of temporal patterning.
神经元放电的同步化被认为在定义代表特定刺激特征组合的细胞集合中发挥作用。在许多系统和物种中,同步化伴随着γ波段频率的振荡反应调制。由于设计直接的体内检测方法存在困难,这些同步化和振荡模式现象背后的细胞机制主要在体外进行了研究。鉴于有条件地对皮质网络成分进行基因操作的前景,我们的目标是测试小鼠是否符合为γ波段同步化研究提供模型系统的标准。从麻醉的C57BL/6J小鼠的初级视觉皮层进行多单元和局部场电位记录。针对神经元同步化和时间模式,分析了移动光栅、条形和随机点图案诱发的神经元反应。使用的所有类型的刺激都很容易诱发γ频率的振荡。光栅的振荡和同步强度最大,当随机点图案中的噪声水平增加时,振荡和同步强度会降低。互相关图的中心峰值宽度对于条形最小,并随着噪声增加,在相干随机点图案与噪声为70%的图案之间产生显著差异。场电位分析通常显示在反应期γ波段的功率增加。我们的发现与神经元同步化在介导感知绑定中的作用一致,并表明小鼠模型对于测试关于时间模式的机制和功能作用的假设是有用的。