Take a moment to notice what your body is touching right now. The texture of fabric against your forearms. The weight of a device in your hand, or the pressure of a seat beneath you. If you are in a room with overhead lighting, there may be a faint, almost inaudible hum. Outside, a car passes. A phone somewhere vibrates. Most people read a list like that and notice nothing in particular — the brain had already sorted those signals below the threshold of attention. For some people, reading it brings six things into simultaneous, slightly insistent awareness.

That difference is not imaginary, and it is not a matter of discipline or focus. It has a measurable neural basis — in how the brain weights incoming sensory information, in the chemistry of circuits that were meant to act as filters, and in the way some nervous systems consistently assign more significance to sensory signals that others’ brains quietly set aside.

What Is the Brain Actually Doing When It Processes a Sensation?

The nervous system is not a passive receiver. Every sensory signal that arrives at the thalamus — the brain’s central relay station — is actively evaluated before it reaches the cortex. The thalamus acts as a gating mechanism, amplifying signals that seem important and suppressing those that do not.

This filtering is mediated in large part by the thalamic reticular nucleus, a thin sheet of inhibitory neurons that wraps around the dorsal thalamus. These neurons use GABA, the brain’s primary inhibitory neurotransmitter, to modulate what gets through and what gets dampened. The result is that the cortex receives a curated, prioritized stream of sensory information — not a raw feed of everything the body is registering.

In 2026, researchers Wang and colleagues published findings in the British Journal of Anaesthesia showing that disrupting thalamic reticular nucleus function in mice specifically impaired auditory sensory gating — the brain’s ability to suppress repeated or irrelevant sounds (Wang et al., Br J Anaesth, 2026). When TRN activity was compromised, auditory responsiveness increased measurably. The gate, when opened, let more through.

Predictive processing theory offers a complementary account. In this framework, the brain is constantly generating predictions about what is likely to arrive next, and comparing incoming signals to those predictions. What gets attention is not the signal itself, but the gap between the signal and the prediction. A truly novel or unexpected sensory event gets flagged; a familiar, expected one gets suppressed. The key variable is what researchers call precision: how much weight the brain assigns to incoming signals relative to its prior predictions.

Why Some Nervous Systems Assign More Weight to Sensory Signals

In 2026, a theoretical and empirical review by Greven and colleagues in Trends in Cognitive Sciences examined what is now called sensory processing sensitivity, or SPS — a trait present in an estimated 15 to 30 percent of humans (Greven et al., Trends Cogn Sci, 2026). SPS is characterized by a consistent tendency to process sensory and social information more deeply than average, with correspondingly greater reactivity to both positive and negative environmental stimuli.

Within the predictive processing framework, Greven and colleagues propose that high-SPS individuals consistently assign high precision to incoming sensory signals — that is, they weight what is arriving now more heavily relative to their prior expectations. This is not a deficit in itself. Deeper processing can support richer sensory experience, greater attunement to subtlety, and stronger responses to beauty as well as discomfort. The same trait that makes a loud restaurant feel overwhelming can also make music more vivid.

But it means that the filter is calibrated differently. Signals that the average nervous system weights lightly — the scratch of a seam, the background hum of a room, overlapping conversations — are assigned more significance. More processing resources are committed to them. And more of the cortex hears about them.

The underlying chemistry connects to the same inhibitory pathways examined in the TRN research. A 2021 study by Wood and colleagues published in Translational Psychiatry found that children with sensory over-responsivity showed overactive brain responses and reduced modulation of thalamocortical connectivity, correlated with an imbalance between excitatory and inhibitory neurochemicals in those circuits (Wood et al., Transl Psychiatry, 2021). The excitatory side of the thalamocortical loop appears less effectively braked.

How Common Is Heightened Sensory Responsivity — and Who Experiences It?

Sensory over-responsivity, the more acute end of this spectrum — characterized by strong, sometimes distressing reactions to sensory stimuli that most people find neutral — affects 15 to 20 percent of children in the general population, according to a 2026 study by Luo and colleagues published in the Journal of the American Academy of Child and Adolescent Psychiatry (Luo et al., JAACAP, 2026). That figure is from one of the largest studies on the subject to date: data from 15,728 participants across five independent datasets, including 4,195 children with fMRI scans from the Adolescent Brain Cognitive Development study, with a replication sample of 4,190.

Among children with conditions associated with attention difficulty, anxiety, or autism spectrum characteristics, rates of sensory over-responsivity were substantially higher — a majority of children in those diagnostic groups showed measurable SOR. But the research is clear on a point worth stating plainly: SOR is not exclusive to any diagnosis. It appears across the full range of cognitive and developmental profiles, including in children with no formal diagnosis at all.

This matters because it shifts how we understand sensory sensitivity. It is not a symptom that belongs to a particular category. It is a characteristic of some nervous systems that can coexist with many different presentations — and that can affect daily life significantly even when it is not a named part of a clinical picture.

Adult sensory processing sensitivity follows a similar distribution. Estimates across multiple studies suggest that 15 to 30 percent of the general adult population scores in the high-SPS range on validated measures, with the trait appearing to have heritable components as well as environmental and developmental influences (Greven et al., Trends Cogn Sci, 2026).

What Large-Scale Brain Imaging Reveals About Sensory Over-Responsivity

The Luo 2026 study went beyond behavioral assessment to examine neural correlates directly. Using resting-state and task-based fMRI data, the researchers identified functional connectivity patterns that were both specific to SOR and replicable across independent samples — a relatively high bar in neuroimaging research.

Children with higher SOR showed altered connectivity in thalamocortical circuits, consistent with what the Wood 2021 findings suggested at the neurochemical level. The imaging data pointed to differences that were brain-wide in some respects and circuit-specific in others — not a single localized change, but a pattern involving multiple regions involved in sensory processing and integration.

The Wang 2026 TRN findings add mechanistic precision to this picture. When the thalamic reticular nucleus is functioning optimally, it gates what the thalamus sends on to the cortex. In the Wang study, disrupting TRN function in an animal model specifically degraded the brain’s ability to filter out repeated auditory stimuli — the same kind of habituation failure that people with sensory over-responsivity often describe, where a sound that others stop noticing remains present and effortful.

Taken together, the imaging and mechanistic research converge on a consistent picture: sensory over-responsivity is associated with a filtering system that is differently calibrated, not one that is simply broken. The circuits are doing what circuits do — they are just doing it with a different threshold, a different balance of excitation and inhibition, and a different assignment of priority.

When Sensory Sensitivity Appears in Chronic Conditions — the Migraine Example

Sensory over-responsivity is not exclusively a developmental phenomenon. It also appears as a prominent feature of some chronic neurological conditions, migraine being among the most well-studied.

Between migraine attacks, many people with migraine show altered responses to sensory stimuli — light, sound, and smell are processed differently than in those without migraine, a pattern that becomes dramatically amplified during an attack. A 2020 review by Coppola and colleagues in the Journal of Neural Transmission documented clinical, neurophysiological, and neuroimaging evidence for altered cortical processing of sensory stimuli in migraine — including evidence of reduced habituation to sensory input (Coppola et al., J Neural Transm, 2020). Where a healthy nervous system dampens a repeated stimulus over time, the migraine-susceptible nervous system may not.

This is sometimes described as a failure of cortical habituation — the sensory gating process that normally quiets down after a signal has been registered as non-threatening. The same input keeps drawing a response. Over repeated exposure and over time, this altered processing contributes to the central sensitization that characterizes chronic migraine: the nervous system becomes progressively more reactive to inputs it was once able to handle.

Migraine is one illustration of a broader point. Sensory sensitivity is not a fixed trait — it sits on a continuum that is influenced by nervous system state, sleep, stress, hormonal factors, and the cumulative history of how sensory processing has been working over weeks and months. The architecture is not destiny; it is a starting point that interacts with everything else the nervous system is managing.

What the Evidence Does — and Does Not — Establish

Several limitations apply to this body of research and are worth naming directly.

Most of the imaging studies, including parts of the Luo 2026 work, are cross-sectional — they describe associations at a point in time, not causal sequences over time. That SOR is associated with altered thalamocortical functional connectivity does not tell us whether the connectivity difference precedes the behavioral sensitivity, follows from it, or reflects a third factor. Longitudinal studies that follow the same individuals across development are needed to answer that question.

The prevalence figures — 15 to 20 percent for SOR in children, 15 to 30 percent for high SPS in adults — are group-level statistics. They describe distributions across populations, not predictions for any individual. A person who experiences strong sensory sensitivity is not a data point in an epidemiological study; the percentage figures say nothing about any one person’s specific profile.

Sensory processing sensitivity, as measured by validated questionnaires, and sensory over-responsivity, as measured by behavioral observation and parent report, are related but distinct constructs that are not always defined consistently across studies. Research on their relationship is still developing.

Finally, none of this research establishes that sensory sensitivity is a disorder requiring correction. It is a characteristic of some nervous systems — one that can present challenges in environments calibrated for average sensory tolerance, but that is not inherently pathological. The question of how to work with a more sensitive nervous system, rather than against it, is one that individuals, families, and clinicians are better positioned to think through with that framing in mind.