When humans perceive touch, the information is sent to the thalamus and then to the primary somatosensory cortex, the part of the brain that receives sensory input.

A web of sensory neurons in the skin help filter out background sensations

The somatosensory system helps us organize and navigate our surroundings, enabling us to understand our bodies in relation to our environment and also filter out minor sensations that are basically background noise so they aren't overwhelming to our bodies. Meanwhile, viscerosensation—or internal sensation—refers to the internal sensory neuron system that conveys information from internal organs to the brain.

We can sense touch even through a tool

Research published in 2019 indicates that the same brain regions involved in sensing touch on the body also process it when humans use a tool to do the touching. Essentially, it's acting as a sensory extension of the body. (Some users may experience a paywall.)

How the five senses share information with each other

The human body depends on information from the five sensory organs—the eyes, ears, nose, tongue, and skin—to react to the world around it. Each of these organs, in its own way, relies on complex circuitry to send signals back to the central nervous system.

How does the body know where it is in space?

Close your eyes and touch your nose. How did you know where your nose was? How could you tell where your hand was? That's proprioception, the sense that keeps your brain apprised of the body's position and movement. This article explains how this sense works, what happens when people don't have it, and what we know about it.

Sensory memory is information collected from your senses

Lasting seconds before moving into short-term memory or being forgotten, sensory memory aids in environmental awareness and navigation. Key brain regions involved include auditory, somatosensory, gustatory, visual, and olfactory cortices.

When processing light, the brain can perceive colors with no natural wavelength

While some animals are sensitive to many forms of light, humans possess receptors that are sensitive to red, green, and blue wavelengths. These receptors send signals to the brain, which are processed and mixed to produce the array of colors we observe, including magenta, pink, and "supercolors" that lack a corresponding natural wavelength in the visible spectrum.

Humans likely cannot tickle themselves because there's no element of surprise

Unraveling the neural mechanisms of tickling—formally called gargalesis—is an area of active research, but a leading theory about why we can't tickle ourselves is that the brain's somatosensory cortex processes self-touch differently than it does external touch. The cerebellum already anticipated what was going to happen when you move your hand for self-touch, limiting the effectiveness of a self-tickle.

Touch is the first sense a fetus develops in the womb

During gestation, our sense of touch begins to develop around 8 weeks, starting with the development of sensory receptors in the face and, about a month later, in the palms and soles of the feet.

Touch deprivation can heighten anxiety and depression

Pacinian Corpuscles are pressure receptors just under the skin that send signals to the vagus nerve in the brain—that's the cranial nerve which regulates involuntary actions like breathing, heart rate, and the general "fight or flight" response. Activating those receptors can slow the heart, decrease blood pressure, and lead to the release of oxytocin and cortisol. The absence of touch, conversely, can promote negative feelings.

Humans have taste receptors throughout the body, including in the testes and lungs, but we don't taste what they detect because those areas lack taste buds.

Our sense of smell affects what foods taste like and how we perceive it

Scent stimulates our olfactory sensor neurons high in the nasal cavity, and the brain attaches labels to those scents. But when we eat, chemicals from the foods travel from our mouths and throat to those neurons. We have roughly 400 odor receptors, and they can be used to decipher more than 10,000 different odors (or more than one trillion by some calculations), including the nuances of different foods.

Brain-reading devices are helping paralyzed people to touch

In clinical trials, implanted brain-computer interfaces are allowing dozens of individuals with paralysis to control prosthetics that are restoring a range of skills, including drinking coffee and feeding oneself. One area of related prosthetic research is creating a synthetic sense of touch—coupling the brain implant with pressure sensors in prosthetic robotic fingertips to enable an approximation of a sense of touch.

Brain hemispheres control opposite sides of the body without either dominating

Although distinctions exist between the two halves—language processing is left-oriented, and emotions are right-oriented—signals are sent along neural pathways between the hemispheres and across different regions to collectively process information about external stimuli.

How texture affects taste

Texture is the brain's interpretation of several sensations, including pressure, as registered by our teeth, tongue, and finger tips, and sound, as recorded by our ears. Texture also speaks to food particle sizes—smaller than 35 microns contributes to the sensation of creamy—and the balance between flavor and mouth time, such as the crunch of a crispy chip or the bounce of a chewy caramel.

Explore the biology of pain and why the experience of pain may differ widely from one person to another.

If hearing is damaged, the brain may amplify remaining sounds, perhaps causing tinnitus.

Efforts to build touch-enabled machines highlight the complexity of human touch

The challenges that engineers are facing as they try to reproduce a human's ability to touch and also give robots the ability to interpret that kind of sensory flow are furthering our understanding of the myriad intricacies of human touch—and the challenges in emulating it.

The limbic system drives emotion, memory, and survival instincts in the brain.

This interconnected group of brain structures—including the amygdala, hippocampus, thalamus, and hypothalamus—processes emotional responses, regulates bodily functions, and plays a key role in memory and learning.

Octopuses have taste receptors along their tentacles

Octopus suction cups are filled with modified sensory receptors that can bind with a greater variety of materials and transport a wider array of information, such as flavor, from tactile stimuli. These structures allow the animal to search for food as it crawls the ocean floor.

How brain cells carry information

At any moment, there is an electrical storm coursing through your body. Discover how chemical reactions create an electric current that drives our responses to everything from hot pans to a mother’s caress.

Many parts of the body, including the testicles, have bitter, sweet, and umami receptors

Taste receptors—the tiny cells that report the chemical makeup of external stimuli to the brain—in the testicles don't "taste" in the same way as the gustatory ones you use to determine if there's enough sugar in your tea. Research suggests that these "teste" receptors can sense bitter, sweet, and umami compounds and use that chemical input to control physiological processes or (literally) change direction. (Some users may experience a paywall.)

Phantom limb pain may often match the pain or contortion of the injury that led to the limb loss.

Most advanced touch screens rely on electrical charge in your skin

Capacitive touch screens store electrical charges in an electrostatic grid of tiny wires. When we touch the screen a tiny electrical charge is transferred from the screen to the finger to complete a circuit (since skin has positive and negative charges). This connection creates a voltage drop on that point of the screen. Cloth, however, doesn't conduct electricity, which is why humans can't wear thick gloves and operate their smartphones.

The 'sense' of direction comes from two strategies involving unique brain regions

Egocentric navigation utilizes the caudate nucleus and posterior parietal cortex, relying on a person's position in space to determine their direction of movement. Spatial navigation uses landscape features for orientation and is driven by the hippocampus.

Research suggests the brain maintains connections to lost limbs

Decades-old research suggested brain reorganization after amputations, but brain scans show unchanged limb representations. Phantom limb pain may result from such unchanged brain maps, which may enhance prosthetic limb control in brain-computer interface technology.

These cells 'taste' danger, trigger immune responses

Taste receptor-coated tuft cells are found throughout the body, where they communicate with and take part in a growing list of biological processes. In the intestines, these taste receptor-studded cells can sense byproducts of parasite metabolisms. This causes the taste receptors to release chemicals that alert the immune system, order nearby goblet cells to produce mucus, and trigger muscle contractions in attempts to launch the parasites from the intestines.

Recent research found that the brain doesn't seem to massively rewire following amputation—upending earlier beliefs about the cause of phantom limb pain.

Each taste bud has 10 to 50 sensory cells that form a flower-like capsule

At the top of the structure are thin filaments known as "taste hairs" that bind taste-producing substances to the surfaces of the cell, after which corresponding electrical signals are sent to the brain. Adults have 2,000 to 4,000 taste buds on their tongue.

Parents and romantic partners naturally touch at speeds optimizing nerve activation

A small observational research study shows that when parents are asked to caress their infants and volunteers are asked to caress their partners, both groups spontaneously stroke their loved ones at velocities that, on average, fell within the optimal range to stimulate the C-tactile afferent nerve receptors. This wasn't the case when volunteers were asked to do the same with an artificial arm, which they stroked much faster.

Individuals with synesthesia experience involuntarily overlapping sensations

Tasting words or seeing colors in music results from the brain retaining extrasensory connections from infancy. While most lose these neural pathways during development, about 4% of people are synesthetes, maintaining them without realizing it's unusual.

What is the peripheral nervous system?

This nervous system extends throughout the body, where it acts as the informational bridge between the central nervous system, housed in the brain and spinal cord, and the body's muscles and organs. The peripheral nervous system is further divided into the autonomic, enteric, and somatic nervous systems, each of which oversees certain muscle types and processes. This article overviews the anatomy and functions of the peripheral nervous system.

Itching is caused by stimulated nerve cells in the skin

Scratching produces low-level pain signals to the brain, distracting from the itch. Scratching also releases serotonin, a neurotransmitter that creates a happy sensation, which resets the itch signal. This can cause a cyclical itch-scratch cycle.

Mind-controlled bionic arms use nerve implants to restore sensation and movement

Unlike traditional prosthetics that rely on surface electrodes or mechanical parts, this system uses implanted titanium and nerve-connected electrodes to enable a seamless brain-to-arm connection. Patients train in virtual reality with their implanted signals before using the physical prosthesis.

Meet the 12 cranial nerves

Your cranial nerves are a set of 12 paired nerves in your brain. They help your brain and body communicate senses, movement or both.

The most common types of touchscreens are capacitive and resistive

Capacitative screens are coated with a conductive material that creates a uniform electric field, which is disrupted by fingers. This disruption is registered by the device across a grid to determine where contact was made. Resistive screens identify touch when fingers push gap-separated sheets into contact with one another.

The body's master clock has 20,000 neurons

The suprachiasmatic nucleus, the master clock in mammals, has 20,000 neurons that help maintain the light-dark cycle in the body. Among its jobs: It receives light input information from the retina and then signals peripheral body clocks to act on this information, driving everything from body temperature to hunger.

Taste buds have evolved to fill a wide variety of functions

Taste buds do more than let you experience your favorite food. These peripheral organs can sense the chemical makeup, potential toxicity, and fleeting experience of flavor, giving the body a chance to respond to undesirable chemicals or tell the brain that you should reach for another scoop.

Touch helps newborns regulate stress, gain weight, and feel less pain

Conclusions from this 2024 analysis from a team of Danish researchers included that touch interventions were particularly useful for newborns in regulating cortisol levels, helping newborns gain weight, and reducing pain. (Some users may experience a paywall.)