The spotlight of attention is more like a strobe, say researchers
Long time mediators are familiar with this. When you drill down attention to smaller and smaller time resolution, eventually you notice that attention flickers.<p>Buddhist Abhidhamma sutra describes this phenomenon. Smallest flicker of consciousness is called ceta. 
I think 250 ms is closer to vithi (kind of small molecule of mind- moments), than ceta.<p><a href="https:&#x2F;&#x2F;plato.stanford.edu&#x2F;entries&#x2F;abhidharma&#x2F;" rel="nofollow">https:&#x2F;&#x2F;plato.stanford.edu&#x2F;entries&#x2F;abhidharma&#x2F;</a><p>&gt; We have seen that the Abhidharma’s analysis of sentient experience reveals that what we perceive as a temporally extended, uninterrupted flow of phenomena is, in fact, a rapidly occurring sequence of causally connected consciousness moments or cittas<p>...<p>&gt; The Sarvāstivādins use the term “moment” (kṣaṇa) in a highly technical sense as the smallest, definite unit of time that cannot be subdivided, the length of which came to be equated with the duration of mental events as the briefest conceivable entities. There is no Sarvāstivādin consensus on the length of a moment, but the texts indicate figures between 0.13 and 13 milliseconds in modern terms<p>(My personal subjective estimate is something like to 40 ms)