I read this on a news site, "Neuroscience tells us that humans are flooded with over 11 million bits of information per second, yet we only actually process about 50 bits per second on a good day.
This means we filter out most of the incoming information. The Autonomic Nervous System or “ANS” filters out whatever you have been trained to ignore, have not been trained to pay attention to, or don’t find important at the time.
In short, we tend to fixate on those things we think are important at the exclusion of most other things. "

It makes it easy to understand how those of us with dysfunctional 'brain filtering' can become so overwhelmed. When our brain fixates on a single issue, it also can become overwhelming, like the various ways we can detect our own heart beat.

Or.............

Our Cognitive issues disallow our 'brain filtering' to recognize what should or should not be filtered, and we become overwhelmed by all the little tidbits intruding upon the single focus we are trying to work.

Best wishes.........

The filtering happens before the cognitive processing/response can address the stimuli. The neuro-physiological term for this problem is a failure in the sensory "gating" as in open a gate or close a gate to control the flow of information.

My reference was more in line with this article, in that the gates aren't always open or closed, and the overstimuli do have effect on us all in some manner cognitively, since we do have injured brains, and our autonomic systems have become dysfunctional in the majority of cases, with upper neck injuries.

Similar ideology had been suggested in chronic pain sufferers in past Pain Management groups also, in reference to specific neurological regional pain issues.... thats when they started using Neurontin in Pain Management in the past.

Just some thoughts..........