Local field potential in cortical area MT: Stimulus tuning and behavioral correlations
Local field potential in cortical area MT: Stimulus tuning and behavioral correlations
复制标题
DOI：
10.1523/jneurosci.5052-05.2006
复制
发表时间：
2006-07-26
影响因子：
5.3
通讯作者：
Newsome, William T.
中科院分区：
文献类型：
--
作者：
Liu, Jing;Newsome, William T.
低频电信号像组成局部场电位（LFP）的低频电信号可以在距大脑内的原产地点处检测到。因此，尚不清楚LFP在评估局部功能（例如在皮质柱的空间尺度上）的有用程度。我们通过比较从中间时间区域MT获得的LFP与同时记录的多单位（MU）活性的调整的LFP的速度和方向调整来解决了这个问题。我们发现，LFP可以很好地调整速度和方向，并且与MU活性高度相关，尤其是在伽马频带以外的频率上。 LFP调整对于较低的频率而言，尽管方向的调整延伸到速度较低的频率较低，但速度较低。我们的数据表明，伽马频带和上方的LFP信号在电极尖端的几百微米内反映了皮质柱的空间尺度上的神经处理。与这个概念一致，我们还发现，在速度歧视任务中测得的伽马频带和之上的频率表现出称为“选择概率”的效果，这揭示了神经活动与行为选择之间的关系特别紧密。在LFP中，感知选择的这种签名包括从低频频段（Alpha和Beta）向伽马频段的相对功率转变。尚待确定LFP选择概率是时间签名，与在峰值速率中观察到的常规选择概率效应有关。
Low-frequency electrical signals like those that compose the local field potential (LFP) can be detected at substantial distances from their point of origin within the brain. It is thus unclear how useful the LFP might be for assessing local function, for example, on the spatial scale of cortical columns. We addressed this problem by comparing speed and direction tuning of LFPs obtained from middle temporal area MT with the tuning of multiunit (MU) activity recorded simultaneously. We found that the LFP can be well tuned for speed and direction and is highly correlated with that of MU activity, particularly for frequencies at and above the gamma band. LFP tuning is substantially poorer for lower frequencies, although tuning for direction extends to lower frequencies than does tuning for speed. Our data suggest that LFP signals at and above the gamma band reflect neural processing on the spatial scale of cortical columns, within a few hundred micrometers of the electrode tip. Consistent with this notion, we also found that frequencies at and above the gamma band measured during a speed discrimination task exhibit an effect known as "choice probability," which reveals a particularly close relationship between neural activity and behavioral choices. In the LFP, this signature of the perceptual choice comprises a shift in relative power from low-frequency bands (alpha and beta) to the gamma band. It remains to be determined how LFP choice probability, which is a temporal signature, is related to conventional choice probability effects observed in spike rates.