Townsend Rory G, Solomon Selina S, Martin Paul R, Solomon Samuel G, Gong Pulin
School of Physics.
Australian Research Council Centre of Excellence for Integrative Brain Function.
J Neurosci. 2017 Oct 18;37(42):10074-10084. doi: 10.1523/JNEUROSCI.1538-17.2017. Epub 2017 Sep 14.
Visual stimuli can evoke waves of neural activity that propagate across the surface of visual cortical areas. The relevance of these waves for visual processing is unknown. Here, we measured the phase and amplitude of local field potentials (LFPs) in electrode array recordings from the motion-processing medial temporal (MT) area of anesthetized male marmosets. Animals viewed grating or dot-field stimuli drifting in different directions. We found that, on individual trials, the direction of LFP wave propagation is sensitive to the direction of stimulus motion. Propagating LFP patterns are also detectable in trial-averaged activity, but the trial-averaged patterns exhibit different dynamics and behaviors from those in single trials and are similar across motion directions. We show that this difference arises because stimulus-sensitive propagating patterns are present in the phase of single-trial oscillations, whereas the trial-averaged signal is dominated by additive amplitude effects. Our results demonstrate that propagating LFP patterns can represent sensory inputs at timescales relevant to visually guided behaviors and raise the possibility that propagating activity patterns serve neural information processing in area MT and other cortical areas. Propagating wave patterns are widely observed in the cortex, but their functional relevance remains unknown. We show here that visual stimuli generate propagating wave patterns in local field potentials (LFPs) in a movement-sensitive area of the primate cortex and that the propagation direction of these patterns is sensitive to stimulus motion direction. We also show that averaging LFP signals across multiple stimulus presentations (trial averaging) yields propagating patterns that capture different dynamic properties of the LFP response and show negligible direction sensitivity. Our results demonstrate that sensory stimuli can modulate propagating wave patterns reliably in the cortex. The relevant dynamics are normally masked by trial averaging, which is a conventional step in LFP signal processing.
视觉刺激能够引发神经活动波,这些波会在视觉皮层区域的表面传播。这些波在视觉处理中的相关性尚不清楚。在这里,我们在麻醉的雄性狨猴的运动处理内侧颞叶(MT)区域的电极阵列记录中测量了局部场电位(LFP)的相位和幅度。动物观看以不同方向漂移的光栅或点场刺激。我们发现,在单个试验中,LFP波传播的方向对刺激运动的方向敏感。在试验平均活动中也可检测到传播的LFP模式,但试验平均模式表现出与单个试验中不同的动态和行为,并且在不同运动方向上相似。我们表明,这种差异的出现是因为刺激敏感的传播模式存在于单个试验振荡的相位中,而试验平均信号则由叠加的幅度效应主导。我们的结果表明,传播的LFP模式可以在与视觉引导行为相关的时间尺度上代表感觉输入,并增加了传播活动模式在MT区域和其他皮层区域服务于神经信息处理的可能性。传播波模式在皮层中广泛观察到,但其功能相关性仍然未知。我们在这里表明,视觉刺激在灵长类动物皮层的运动敏感区域的局部场电位(LFP)中产生传播波模式,并且这些模式的传播方向对刺激运动方向敏感。我们还表明,在多个刺激呈现上平均LFP信号(试验平均)会产生捕获LFP反应不同动态特性且显示出可忽略不计的方向敏感性的传播模式。我们的结果表明,感觉刺激可以在皮层中可靠地调节传播波模式。相关动态通常被试验平均所掩盖,而试验平均是LFP信号处理中的常规步骤。