A Brain Study shows how brain distinguishes between what is important and what is not: Study indicates that during learning various signals from other regions of brain influence learning processes in cortex.

Among all the traffic lights and neon-signs, the brain certainly does a superior job in learning the importance of certain images over others.

Neuroscientist Prof. Sonja Hofer, at the Biozentrum of the University of Basel and University College London, conducted a study to discover how the brain distinguishes between relevant and irrelevant information. The research was recently published in Neuron, stating that as the brain learns new information, considerable modifications take place in neural networks. These changes assist the brain in effectively processing and classifying the bulk of external stimuli it receives every day.

How an individual perceives the environment is significantly related to his past learning experience. For example, skilled drivers don’t need to think too much when they see a road sign since they are experts in understanding traffic situations. As opposed to learners, filtering irrelevant information from relevant stimuli and making sensible traffic choices comes easily to them. Prof. Sonja Hofer’s team investigated the question of how the brain optimizes sensory stimuli through learning.

Brain Differentiates Between Images

Researchers studied the visual cortex of mice – the part of the brain responsible for processing and interpreting visual stimuli. The mice were made to run through a virtual-reality environment, encountering several images. One image had been paired with an award. Within a week of this exercise, the mice learned to differentiate between the images and respond consequently. This learning was represented by the activity of neurons in the visual cortex, the responses of which were monitored and recorded over the course of the run. Initially, the responses developed in the brain were unspecific, but after one week of training, the responses and neurons became much more specific.

Learning Optimises Processing Of Stimuli

“From day to day, the response of the neurons to the images became increasingly distinguishable and reliable,” stated Adil Khan, who is among the two first authors. He assumes that the changes in neural networking improve the assessment of important information and is the underlying cause of why we react so efficiently to visual cues. The researchers also established that a variety of internal and external stimuli influence how effectively it is processed.

“We observed that the response of the nerve cells to the same visual stimuli became less accurate when the mice were engaged in another task, such as having to discriminate between different smells. The visual stimuli then lose their relevance and are no longer so effectively analyzed by the brain,” explained Khan. “Remarkably, the expectation of a stimulus even before it appears, and the anticipation of a reward also altered the activity of specific brain cells. This means that from one moment to the next our brain might process the same stimulus quite differently depending on its importance and relevance.”

Internal signals affect visual perception: It was previously assumed that the visual cortex is the exclusive part of the brain involved with visual processing. However, this brain study indicates that during learning, various signals from other regions of the brain influence the learning processes in the cortex.

“This means that our previously learnt knowledge, our expectations and the context we are in can have a great impact on our visual perception of the environment,” explained Hofer.