Glad you found it interesting!

I haven't heard that specific term, but it sounds very similar to what Huxley hypothesised in the doors of perception, and has certainly been an influence on many eminent contemporary thinkers and scientists.

It also sounds similar to Predictive Processing, which hypothesises that the brain encodes top down expectations about its sensory environment, and receives bottom up sensory information. These top down expectations (which are shaped by previous experiences) act as a guide to what we attend to in this bottom-up information flow. If it's relevant, we will attend to the information, allowing it to shape our subsequent expectations. If it's irrelevant, the information will simply go unnoticed. This, to me, is the neuroscientific equivalent of the 'reducing valve' that Huxley frequently talked about.

Relevant again to psychedelics, it's also been shown that these top down expectations are 'relaxed' as a consequence of using psychedelics, which can be analogous to widening the bottleneck of conscious experience. With little expectations (or filter) within the brain, the colours of the flowers in the front garden that have gone unnoticed for months suddenly permeate your consciousness, and become immensely fascinating under the influence of psychedelics!