By Dr Inga Griškova-Bulanova, Scientist at Vilnius University and Dovilė Šimkutė, PhD Student at the Vilnius University Life Sciences Centre

A recent meta-analysis (a research approach that combines the results of many different studies to draw an overall conclusion) found that problematic internet use can significantly impair a person’s cognitive functions, attention control, various inhibitory processes (including motor inhibition), decision-making processes and their working memory. The speed of the internet, as well as the activities and opportunities resulting from new technologies, are changing too quickly for scientists to keep pace in their studies on how these changes are impacting us. Nonetheless, one thing is clear: our brains are operating in a different world than which they have evolved and prepared for over many millennia.

Online entertainment causes a dopamine release

Every time you receive a favourable comment on a social media post, or if you find a rare token in a game, your brain will receive a dopamine rush that you perceive as pleasure. The brain then remembers the activity that triggered a dopamine rush, so we come to expect that engaging in that activity will give us the same feeling again, even if the behaviour itself is no longer pleasurable.

This is known as a “forecasting error” – where we expect to feel good. Then, if we don’t feel good, we look for new, better, stronger or more exciting stimuli to get the dopamine rush that we want back again.

This is especially true when it comes to using the internet, because it always has something new to offer, whether it is a new game room, a new lottery or a new cute animal video. In contrast to the addiction to psychotropic substances, there is no “dosage” limit in the case of behavioural addictions – in other words, the content of online platforms is not exhaustive and cannot lead to an overdose.

Therefore, one of the prerequisites for the development of this type of addiction is the availability of an addictive stimulus. All the activities taking place on online platforms are available at any time of the day, in any corner of the world. The researchers working in this field have argued that persistent problematic use of the internet has long-term negative effects, while studies have shown links not only to various mental health disorders, but also to structural changes taking place in the brain.

Various parts of the brain are affected

The prefrontal cortex is the operational centre of the brain, which is involved in virtually all cognitive functions. When the prefrontal cortex is impaired, uncontrolled behaviour occurs and this may explain the symptoms experienced by internet addicts. A recent meta-analysis showed that, in the case of one aspect of internet use, i.e. problematic gaming, the prefrontal cortex is seen to be “busy” during such an activity – it exclusively responds to stimuli related to the problematic behaviour and is unable to perform other everyday cognitive functions.

Meanwhile, the insular cortex is an emotional centre of the brain that also collects information about the body, its signals and its condition. It is part of the salience network. The insular cortex is where you develop the desire to consume the resources that you depend on. In addition, problematic internet use strengthens the connections between the prefrontal cortex and another important emotional centre, called the amygdala, which is part of the limbic system. This is linked to impaired emotional self-control. The more addictive that internet use becomes, the greater effect it has on these connections between the prefrontal cortex and the amygdala. In general, the altered connections between the default mode network, salience network, central executive network and the limbic system lead to an automatic response to the addiction-related stimuli and automatic behaviour. 

Unsurprisingly, excessive internet use also affects the areas of the brain responsible for processing visual information, which results in a reduced volume and cortical thickness of the occipital lobe, where the visual cortex is located, as well as weaker connections in the visual attention network that are associated with a reduced ability to focus. Excessive online gaming also affects the areas of the brain responsible for sensorimotor functions, which have been found to have an increased cortical thickness and reduced grey matter. The structural changes in these parts of the brain seem to be dependent on the duration of the internet use or gaming, and they appear to have a cumulative effect.

Moreover, signals in the visual and sensorimotor areas were found to be more synchronised in problematic gamers when compared to subjects that used the internet moderately. This may indicate that the brain activity becomes optimised for frequent actions, such as the movements required for playing the game. In other circumstances, such a process could be considered to be the result of motor skill development or practice.

Emotional and cognitive function disorders

All of the above results were obtained by assessing the subject’s brain when it was at rest. However, functional tests that show the changes in one or another brain function are also important.

The classic Stroop test is often used to study a subject’s attention control. During this test, names of colours are displayed on a computer screen, but the word can be either in the same colour as it describes or in a different colour. For example, the word “green” can be written in green or in red. The subject’s task is then to indicate the colour of the word. When the meaning of the word and its colour do not match, the task becomes more difficult – typically, the subject’s reactions are slower and mistakes are made.

During the test, in the mismatched situations, the group of problematic internet users showed more activity in their anterior and posterior cingulate cortex. This anterior cingulate cortex activity is associated with decision-making, social behaviour and empathy. It is a unique area that is connected to both the “emotional” limbic system and the “cognitive” prefrontal cortex, thereby linking the decision-making and emotional centres of the brain. An increase in activity in this part of the brain while performing a task may indicate a decrease in the subject’s cognitive performance. In addition, increased activity in the posterior cingulate cortex probably means that the brain is unable to get out of the “do-nothing” mode, even when it needs to optimise its attention resources to achieve the specific task at hand.

Conclusion

The internet is now an inevitable part of our everyday lives; however, problematic use of the internet has long-term negative effects. Studies have shown links not only to various mental health disorders, but also to structural changes taking place in the brain. Problematic use of the internet can significantly impair a person’s cognitive functions, attention control, various inhibitory processes (including motor inhibition), decision-making processes and working memory. Therefore, it is important to recognise the signs of excessive or problematic internet use, to consciously and objectively monitor our own internet habits, and to take care to ensure the quality of our real lives.