26.09.2018

Swedish Researchers Discover an Ancient Part of the Brain Controls Eye Movements

The amount of data from the external world that bombards our brain every single moment is just mind-boggling. For decades now, neuroscientists have been trying to figure out how the human brain can possibly process all of this information.

Recently, a study was published in the journal eLife sheds new light on this fascinating topic. In this study, researchers looked into what parts of our brains register visual information so that we immediately know what to avoid or move towards in our local environment.

This study was conducted by researchers at Sweden's prestigious medical university Karolinska Institutet. The study was headed by the famous Swedish neurophysiologist Sten Grillner.

Those involved in this study discovered that just one very old part of the brain is responsible for interpreting visual information. This section of the brain is called the corpora quadrigemina in scientific discourse. This area is also known more colloquially as the tectum. This whole area is headquartered in the midbrain with neurons throughout the vertebrates that specifically send signals to control movement of the head and the eyes.

Researchers noted that the tectum has an intimate relationship with the visual stimulus that hits the eye's retina. It seems that whenever visual information is taken in by the retina it is then immediately projected onto the tectum and sent to the brain.

Some of the professors involved in the study said that the tectum works to produce a kind of "spatial sensory map." This map helps the brain determine spatial relations between objects that the eyes perceive.

The tectum also works to control our natural head and neck movements. Certain networks within the neural pathways of the tectum can be shut off to control the range of movement both for the eyes and head depending on how the brain registers the retinal field of information.

Researchers also found that if two senses were experienced at the same time from the same place, the tectum became confused with the overload of information. This leads to decreased activity in the neurons, and thus a diminished frequency of triggered physical movements.

This study was actually performed on a very ancient eel-like fish called a lamprey. Many people know these fish from its distinctive funnel mouth. Researchers noted, however, that the nervous systems of these ancient fish share a great deal with the advanced nerve structures of humans and other mammals.

Although this study is very important for neuroscientists interested in how the brain works, it can also help medical professionals better understand various eye conditions. Scientists hope that their research will help people better understand the visual impairments that go along with Parkinson's disease.


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