How the Brain Links Different Information Together

CITEC researcher Dr. Nienke Debats studying the brain’s capabilities

The sensory organs are constantly passing along a great deal of information. The brain is able to link together information from the environment that is related to each other. This makes perception more precise. But how does the brain actually know what information belongs together? This is Dr. Nienke Debats’ field of research.

CITEC researcher Dr. Nienke Debats deals with how the brain combines sensory stimuli from the environment with the actions of the person who senses the stimuli. Photo: CITEC/Bielefeld University The brain functions so smoothly and effectively that most people are not even aware of what this organ actually does. When holding a warm cup of tea in your hand, for instance, you see the cup and, at the same time, feel the heat on your hand. “The brain is able to recognize very well that these sensations belong together, and therefore links them with each other,” says Dr. Nienke Debats.

This is especially remarkable given that the brain does not get an image of the cup, only the electrical stimuli that the sensory organs transmit via the nerves. “Based on this, the brain develops structured perception,” explains the researcher. She conducts research on this topic as a member of “Cognitive Neurosciences,” a research group headed by Professor Dr. Christoph Kayser that is part of the Faculty of Biology as well as the Cluster of Excellence CITEC, both at Bielefeld University.

The Brain Puts Certain Sensations Together

The sensory organs register a multitude of stimuli at any given moment: while you are holding the teacup, the wool sweater you’re wearing may scratch and a breeze might sweep over your fingers. “The majority of these sensory signals don’t have anything to do with each other, and are just signals coming from around the cup,” explains Dr. Debats. “But the brain is very effective at determining what of all this information belongs together.”

It is also important to connect information when creating the sensations ourselves: drumming on a tabletop with your fingers, for example, almost automatically brings together the sensory stimuli from your fingers with the sound. “This is particularly interesting to me,” says Debats. If you hold a flashlight, you know exactly which bouncing beam of light belongs to it, even when there is another beam of light from another flashlight. This is also important when you have to move something to a certain point, such as a cursor on a screen.

The Brain Connects the Hand and Cursor Together

: In the experiments, participants have to move a cursor, for example, without being able to see their hand. Then they have to guess where their hand moved to – and they often get the position wrong. Photo: CITEC/Bielefeld University How exactly the brain puts actions and sensory stimuli together still remains unclear. “We therefore did various experiments with a trackpad in which we manipulated the cursor,” says Debats. The cursor moved somewhat differently than the hand, and in the experiment, the study participants were not able to see their own hands. When they then had to guess where their hand had moved to, they were almost always wrong. The same was also true when they had to guess where the cursor was. “This effect was less pronounced when the cursor moved in a curve, thus differing from the hand movement.”

Their conclusion: the brain connects the movement of the cursor on the screen together with the position of the hand on the trackpad. The brain is no longer able to perceive the position of the cursor independently from the position of the hand. “This happens even when the study subject knows that the cursor has been manipulated,” says Debats. “In some situations, it can be a disadvantage for the brain if it can no longer perceive the hand and cursor independently of each other,” says the researcher.

An additional finding was also intriguing for Nienke Debats: a subgroup of study participants who had indicated that they played a lot of computer games was comparatively more successful in the experiment. “One theory for this is that these individuals, because of their experience, are much better at parsing out this information.”

The CITEC research group “Cognitive Neuroscience” conducts basic research on the question of how the brain deals with such information. This question is relevant in many different areas: some hospitals, for instance, use robot-assisted systems in which surgeons “operate” on a screen using a type of joystick. “When working with such systems, it is important to be able to consciously separate sensory information from both the hand and eye from one another,” says Debats. “And who knows: maybe someday we’ll even train surgeons with video games.”  

Dr. Nienke Debats, Bielefeld University
Cluster of Excellence CITEC / “Cognitive Neuroscience” research group
Telephone: +49 521 106-5704

Written by: Maria Berentzen