Like with all aspects of the human experience, things are interpreted on a spectrum. Each and every person internalizes external stimuli differently. It is for this reason that we all have preferences in foods, textures, sounds, and more. What underlies these sensitivities to experience is the complex interaction of neural networks throughout the brain. These systems are unique to each individual and lead to different levels of processing. There are several proposed mechanisms to explain the neurological basis of sensory processing sensitivities.
Sensory sensitivity could be due to increased “noise” in sensory processing areas of the brain. So what does this mean? Well, most neurons in your body have a natural level of baseline activation regardless of external stimuli. For example, a nerve fiber connected to a muscle might send 10 signals a second regarding the state of that muscle, but can increase to 1000 signals a second when the muscle is being flexed. The underlying level of activation is often referred to as “noise” because it is usually unimportant to the signal being sent. This proposed mechanism suggests that individuals with sensory sensitivities may have a higher baseline level of noise, leading to overwhelming signals when sensory systems are activated. Another possible mechanism for sensory sensitization is that genetic and epigenetic differences lead to larger, more pronounced neuronal firing in response to sensory stimuli. Moreover, it is thought that these larger firing patterns can recruit larger populations of neurons, further amplifying the experience (Ward, 2019; Ward & Del Rio, 2020).
The study of sensory sensitivities becomes incredibly important when examining ways to make the world more accessible to individuals with diverse neurological backgrounds. Autism spectrum disorder, Post-Traumatic Stress Disorder, Schizophrenia, and many other neuropsychiatric conditions involve hypersensitization to environmental perceptions (Acevedo et al., 2018). By examining the neurological and genetic correlates to low sensory thresholds, scientists are searching for molecular targets that can be used to provide sensory relief for individuals struggling with sensory overload (Qian et al., 2020).