Theta rhythms govern rodent sniffing and whisking, and human language processing. Human psychophysics suggests a role for theta also in visual attention. However, little is known about theta in visual areas and its attentional modulation. We used electrocorticography (ECoG) to record local field potentials (LFPs) simultaneously from areas V1, V2, V4, and TEO of two macaque monkeys performing a selective visual attention task. We found a ≈4-Hz theta rhythm within both the V1–V2 and the V4–TEO region, and theta synchronization between them, with a predominantly feedforward directed influence. ECoG coverage of large parts of these regions revealed a surprising spatial correspondence between theta and visually induced gamma. Furthermore, gamma power was modulated with theta phase. Selective attention to the respective visual stimulus strongly reduced these theta-rhythmic processes, leading to an unusually strong attention effect for V1. Microsaccades (MSs) were partly locked to theta. However, neuronal theta rhythms tended to be even more pronounced for epochs devoid of MSs. Thus, we find an MS-independent theta rhythm specific to visually driven parts of V1–V2, which rhythmically modulates local gamma and entrains V4–TEO, and which is strongly reduced by attention. We propose that the less theta-rhythmic and thereby more continuous processing of the attended stimulus serves the exploitation of this behaviorally most relevant information. The theta-rhythmic and thereby intermittent processing of the unattended stimulus likely reflects the ecologically important exploration of less relevant sources of information.

θ节奏控制啮齿动物的嗅闻和拂打以及人类语言处理。人类心理物理学表明theta在视觉注意力中也有作用。但是，关于视场中的θ及其注意力调节知之甚少。我们使用皮质描记术（ECoG）来同时记录执行选择性视觉注意任务的两只猕猴的V1，V2，V4和TEO区域的局部场电势（LFP）。我们在V1-V2和V4-TEO区域内都发现了一个≈4-Hztheta节奏，并且它们之间的theta同步受到了前馈的直接影响。这些区域大部分的ECoG覆盖率揭示了theta和视觉诱发的γ之间令人惊讶的空间对应关系。此外，伽马功率由θ相位调制。对各个视觉刺激的选择性注意极大地减少了这些节律过程，从而导致V1具有异常强烈的注意效果。微扫视（MS）部分锁定在theta。然而，对于缺乏MS的时期，神经元theta节律趋于更加明显。因此，我们发现特定于V1–V2视觉驱动部分的独立于MS的theta节律，该节律有节奏地调节局部伽马并夹带V4–TEO，并且通过注意会大大降低。我们建议较少的节律性，从而对有人参与的刺激进行更连续的处理，有助于利用这种行为上最相关的信息。对无人参与的刺激进行有节奏的节律性处理，从而进行间歇性处理，可能反映了对不那么重要的信息源的重要生态探索。