How brain learns new skills

The skills needed to perform any activities are stored in the brain as procedural memories. Researchers from the Gladstone Institutes uncovered how a special type of neuron improves the efficiency of this type of learning. The scientists wanted to show how the specialized brain cells, called fast-spiking interneurons, cause movement disorders, such as Tourette's syndrome, dystonia, and dyskinesia.

The team, led by Gladstone Senior Investigator Anatol C. Kreitzer, PhD, was trying to understand the basic mechanisms of the basal ganglia, which are a group of interconnected neurons in the brain that control movement and are associated with decision-making and action selection. Fast-spiking interneurons represent only about 1 percent of the neurons in that brain region, but are known to have an outsized role in organizing the circuit activity.

The leading hypothesis in the field was that these interneurons were involved in motor control, and that their loss might be related to movement disorders. They discovered that the interneurons are much more important for learning and memory, and potentially more closely related to psychiatric disease than movement disorders.

The team found that the interneurons play a fundamental role in brain plasticity, which is the brain's ability to strengthen or weaken connections between neurons. By doing so, the brain can store information and procedural memory.

The fast-spiking interneurons act like gatekeepers for plasticity. They restrict when plasticity can occur, meaning that they can prevent changes in the connection strength between neurons. This is crucial for learning and memory and, more specifically, for enabling the basal ganglia to remember how to perform tasks.

In other parts of the brain, these same neurons are known to be crucial for processing sensory input, such as vision or touch, and their dysfunction is associated with bipolar disorder and schizophrenia. Fast-spiking interneurons could be a key factor in controlling the efficiency of the learning process in those systems as well.
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Development of brain networks

According to new research, the brains of smart people are wired differently, it allows them to absorb important facts quickly – while blocking out irrelevant information. Scientists used MRI scans on many volunteers to shed light on the nature of intelligence. They had already identified areas of the brain that control IQ and now they have uncovered the mechanism behind it. Researchers said it is possible for people to make themselves more intelligent with brain training games.

Researchers discovered that regions interact more closely in brainy individuals – while others disconnect themselves. In more intelligent people, certain regions are clearly more strongly involved in the exchange of information between different 'sub networks' of neurons. This enables important information to be communicated faster, and more efficiently. On the other hand, the researchers also identified areas that are disconnected, or 'de-coupled', from the rest of the brain in brighter people.
They believe this results in better protection against distracting and irrelevant material.

It is possible that due to their biological predispositions, some individuals develop brain networks that favour intelligent behaviours or more challenging cognitive tasks. However, the frequent use of the brain for cognitively challenging tasks may positively influence the development of brain networks. Smart thinking requires various portions of the brain working together like different parts of an engine.

Differences in academic success and professional careers are attributed to a considerable degree to cognitive abilities. Higher level thinking are rooted in the patterns of integration among parts of the brain called functional modules.It combined the brain scans from the participants with an analysis of mathematical graphs of their networks of neurons to come up with the first neurobiological basis of human intelligence.

 The two brain regions involved in the cognitive processing of 'task relevant' information - the anterior insula and the anterior cingulate cortex - are connected more efficiently to the rest of the brain. Another brain region, the junction area between temporal and parietal cortex that has been related to the shielding of thoughts against irrelevant information, is less strongly connected to the rest of the network.

The different topological embedding of these regions into the brain network could make it easier for smarter persons to differentiate between important and irrelevant information – which would be advantageous for many cognitive challenges. This is similar to a social network which consists of multiple sub-networks, for example: families, or circles of friends. Within these sub-networks or modules, the members of one family are more strongly interconnected than they are with people from other families or circles of friends.

Human brain is functionally organised in a very similar way. There are sub-networks of brain regions – modules that are more strongly interconnected among themselves while they have weaker connections to brain regions from other modules. Researchers examined whether the role of specific brain regions for communication within and among brain modules varies with individual differences in intelligence- whether a specific brain region supports the information exchange within their more than information exchange with other families, and how this relates to individual differences in intelligence.
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Cell can makes or breaks your habits

Some habits are useful and healthy like drinking enough water everyday, eating of fruits and vegetables while habits like eating a cookie every day after work, smoking after meal and excess consumption of alcohol are not healthy.

Neuroscientists have identified a single type of neuron in the brain that serves as a master controller of habits. The team found that habit formation increases the activity of this influential cell, and that shutting it down with a drug is enough to break habits in sugar-seeking mice.

This cell exerts its control through a web of connections to more populous cells that are known to drive habitual behavior. This cell is a relatively rare cell but heavily connected to the main neurons that relay the outgoing message for this brain region. We find that this cell is a master controller of habitual behavior, and it appears to do this by re-arranging the message sent by the outgoing neurons.

The scientists trained healthy mice to receive a tasty treat every time they pressed a lever. Many mice developed a lever-pressing habit, continuing to press the lever even when it no longer dispensed treats. The team compared the brain activity of mice who had developed a lever-pressing habit with those who hadn't. They focused on an area deep within the brain called the striatum, which contains two sets of neural pathways: a "go" pathway, which incites an action, and a "stop" pathway, which inhibits action.

They discovered that the go and stop pathways were stronger in habit-driven mice. Habit formation also shifted the relative timing of the two pathways, making the go pathway fire before the stop. The fast-spiking interneuron in striatum FSI might serve as master conductor of the widespread changes in the outgoing neurons activity. The FSI belongs to a class of neurons responsible for relaying messages located between other types of neurons in a particular brain region.

Though FSIs make up about only one percent of the cells in the striatum, they grow long branch-like tendrils that link them up to the 95 percent of neurons that trigger the stop and go pathways. Forming a habit appeared to make the FSIs more excitable. After giving the mice a drug that decreases the firing of FSIs, they discovered that the stop and go pathways reverted to their previous brain activity patterns, and the habit behavior disappeared. Harmful behaviors like compulsion and addiction in humans might involve corruption of the normally adaptive habit -learning mechanisms.
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Sleep and caffeine can reduce post operative pain

Sleep is essential for good mental and physical health, insufficient sleep increases the risk for several chronic diseases. Pre and postoperative sleep disturbances worsen pain. Caffeine in coffee and other beverages blocks the actions of adenosine in the brain. Adenosine is an endogenous sleep inducer.

Insufficient sleep enhances pain perception. Using a rat model of surgical pain, the research team tested whether prior sleep deprivation increases postoperative pain and caffeine blocks the increase in postoperative pain caused by sleep deprivation.

Researchers sought to identify a potential brain mechanism by which disrupted sleep worsens pain. The effect of sleep deprivation on pain sensitivity in operated and intact rats was virtually eliminated by pharmacologically blocking the action of adenosine in a brain region in the anterior hypothalamus known to regulate sleep, which is connected to major pain-related areas.

Extended wakefulness prior to surgery significantly enhanced postoperative pain behaviors and extended recovery time after surgery. Caffeine mitigate this effect. It blocked the increase in surgical pain caused by previous sleep loss.

 Caffeine might prevent the increase in pain sensitivity by blocking part of the neurochemical changes induced by sleep deprivation in specific brain areas that control sleep and wakefulness, and project to pain-related sites.
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