How the brain works

Everything that happens in our bodies is controlled by the brain, the most complex structure known to us. A human brain weighs around 1,5 kilos and has more than 100 billion nerve cells. Each of those cells can send signals to thousands of other cells with a speed of 300 km/h.

Functionalities of the brain

The brain controls not only what we pay attention to and think, but also automatic activities such as heartbeat, breathing and temperature. It also handles motor skills, movements, and sensorics, sensations and senses (hearing, vision, smell, etc.) Diseases and injuries that affect these functions are usually referred to as neurological diseases and injuries. The brain also handles our mental health, including through various neurotransmitters. It's called the psychiatric disorders. To fully interpret, understand and interact with the world around us requires a working cognition, e.g. you can talk/find words, remember, orient yourself, be caring and social. Different areas of the brain are responsible for different (cognitive) functions and diseases or injuries here result in a cognitive impairment in the same way that failing function in the pumping capacity of the heart leads to heart failure. If it is a disease that is responsible for the cognitive impairment, they are called cognitive disorders or dementias. You can divide the brain's abilities into six overall functions, "abilities", so-called cognitive domains.

The brain's six overall abilities (cognitive domains)

1. Attention

The first domain, “attention,” or ability to concentrate, is central to sustain all the other cognitive functions. This domain is situated in two regions; the prefrontal cortex in the front lobe and the parietal lobe, further back in the brain.

Symptoms of impaired function: The noticeable effect of damage to the neurotransmitters in these two regions shows it is difficult to maintain a conversation. The person might repeat a phone number or address many times. Mental calculations are difficult to perform, and perhaps it takes some time before the person responds, the so-called “slow response rate.” .

2. Executive functions

This brain region (the frontal lobe) is important for planning and executing tasks.

Symptoms of impaired function: The person can often become initiatorless, have difficulty with complex tasks such as paying bills, using credit cards, following an instruction manual or using various devices that are not usually a problem.

3. Memory

The ability to remember occasions, recall and store information is called memory. A function in the hippocampus, a small region in the brain, controls memory.

Symptoms of impaired ability:Damages to the hippocampus lead the affected person to forget what just happened, what happened yesterday, last week, or what someone just said. Being on time and remembering what day and year it is is also difficult.

4. Language

Understanding (impresario) or expressing oneself (expressive) verbally is another important function of the brain. The function of language sits in the left hemisphere, more specifically in two areas, Broca's area, which has the ability to speak and articulate, and Wernicke's area, which has to do with words and language comprehension.

Symptoms of impaired function: A person with injuries in these areas may have difficulty understanding instructions and what others are saying. The person may also have difficulty finding words and instead often uses euphemisms, general terms or simplifications to express themselves. Perhaps it is more difficult to speak foreign languages that have gone well in the past. To stake out his speech and repeat what others say are other examples of symptoms.

5. Spatial perception and visuospatial ability

Our ability to interpret visual impressions (visuospatial ability) is important since it helps us build a spatial perception. It enables us to navigate and execute hands-on activities.

Symptoms of impaired ability: It’s difficult for people with damages in this region to find their way in new areas and familiar ones. They may have difficulties navigating their body, which leads them to have problems sitting down on a chair or making their way around a room. Unbeknownst to many, sitting down is a complex task, during which visual impression, velocity, muscles, and movement all contribute to a smooth sitting down. All the mentioned issues increase during darker hours since the visual impressions are fewer.

6. Social ability (behavior)

Located in our frontal lobe are functions that are important for our personalities and behaviors. This region controls our impulse control and our emotions.

Symptoms of impaired function: In case of damage to the frontal lobe, the person may have poorer judgment, difficulty perceiving social cues or reading facial expressions. The person can become both more emotional and numb, that is, not react as much as one would expect in different situations. Lack of empathy and insight, agitation (anger and agitation) and altered eating behavior are also examples of other common symptoms. People who have only impaired function in this area, such as frontotemporal dementia (frontal dementia) can often perform relatively well on cognitive tests such as mini mental test, while loved ones notice changes in behavior and personality in particular.

Johan Sundelöf, Senior Physician, Specialist in Geriatrics and Palliative Medicine
Reviewed by: Johan Sundelöf, Senior Physician, Specialist in Geriatrics and Palliative Medicine
Updated: January 22, 2021
Published: 15 December, 2020

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