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Brain Function

Monday July 20, 2020
Brain Function

Learn about the role of the brain – the most complex organ in the human body, its defence system and the importance of diet to achieve healthy brain function.

It may sound extraordinary, but the human brain is the most complex known structure in the universe.

The human brain is the command centre of the central nervous system and is connected to every part of the human body via a complex system of nervous information through the spinal cord and nerves.  This provides a network of connections, signals, and feedback so that the brain can continually monitor the body, respond, and issue commands for optimal function.  The organ is composed of fats and proteins and on average weighs around 1.4kgs.

However, the brain is not just the chief controller but also provides intelligence, learning, memory recall, besides creativity, emotion, movement and balance, speech, visual and audio perception plus sleep.

The significance of the brain is demonstrated by how the body guards this vital organ. Although the brain is protected by the skull, it is suspended in cerebrospinal fluid, which acts as a cushion, and it is protected by the blood brain barrier.  The blood brain barrier will accept the passage of certain compounds, such as nutrients and oxygen, hormones, and fluids into the brain, but its purpose is to protect the brain from infection causing or damaging substances.

The Functions of the Brain

Attention and concentration

Attention and concentration are similar, with subtle differences.  Attention is the ability for an individual to remain working on a task.  While concentration is the maintenance of attention despite of, and in response to cues.


Intelligence is the ability to acquire and apply knowledge.  As individuals our capacity for intelligence varies and so IQ tests (intelligence quotient) provide a method of assessment. 


The use of the imagination to produce original ideas such as inventions, or art.  It further includes methods, philosophy, or concepts.


Psychologists state that humans have 6 basic emotions, they are happiness, surprise, anger, sadness, fear, and disgust, and that any other emotion is made from these basic constructs.  Interestingly, each of the basic emotions come from unique brain region activation, for example, happiness activates several brain regions that include the right frontal cortex, praecuneus, left amygdala and left insula, whereas sadness activates the right occipital lobe, left insula, left thalamus, amygdala and hippocampus.


Memory can be described as the acquisition of knowledge, idea or experience, plus the storage and recall of information.   The brain activates different regions in response to the type of information that is being processed, but what is consistent across the brain regions is that the neurotransmitter that signals and activates the brain cells within the regions.  This is acetylcholine, a compound we talk about a lot in the nootropic blogs.


Movement can be voluntary or as reflex functions.  Voluntary movement is a result of signals transmitted from the brain through the nervous system to the muscles in response to an intention triggered by the environment.  The movement that is created is fed back via the central nervous system to the brain.  

For example, picking up an item.  Whereas reflexes are not voluntary but hardwired responses governed by the autonomic nervous system.  The reflex is generated from a sensation which produces a specific motor action.  Think about when you touch something hot, you pull your hand away immediately.  


Constructing speech is a complex process, one that is often taken for granted, that involves a network of brain areas that each contribute in a unique manner.   The central nervous system is responsible for signalling to enable speaking.  It is a complex interplay that includes the recall of information, construction of sentences, vocals and facial movement alongside visual and auditory feedback besides interpretation and potentially a response.


Organ function

The organs, such as heart, liver and kidneys, are controlled though the autonomic nervous system.  Take the heart as an example, signals pass along the nervous pathways to the heart and back to the brain.  The heart function can be altered by the reflex activation of the cardiac autonomic nerves in response to baro-, chemo- and nasopharyngeal receptors located throughout the cardiovascular system.  Further influence comes via the central autonomic commands such as those associated to stress, exercise, wakefulness, and sleep.


Balance is coordinated through ongoing position detection, feedback, and adjustment via signals through the autonomic nerves system between the inner ear, eyes, muscles and brain.  It is the cerebellum brain region that acts as the control centre and works to stop us falling over.

Visual and audio perception

Like organ function, vision and hearing are controlled by the autonomic nervous system via the retinal light receptors for vision and vibration receptors within the eardrum.  As with speech the brain activates other areas to percept the scene.  Top-down processes such as attention, expectations and prior knowledge facilitate scene perception.

Sleep cycle

Sleep is led by circadian rhythm, a cycle that is influenced by light and dark phases of the day.  It is the interpretation of the stages of light that trigger secretions of hormones to initiate waking, or the onset of sleep and feedback to our biological clock within the brain.  

Our master biological clock is located in the hypothalamus, a cluster of around 20,000 nerve cells called the suprachiasmatic nucleus.  These cells receive input from the eyes and send out signals about the time of day.  And so, this explains why using blue backlit devices in the evening affect sleep as they trick the brain into thinking that the sun is rising.

Diet and the Brain

Diet plays a huge role in brain functioning.  To function in a normal manner the brain requires a constant blood supply, rich in oxygen, glucose and nutrients.  In fact, the brain requires a diverse array of nutrients.

It is widely reported that the brain requires glucose, which are derived from starchy carbohydrate foods, such as root vegetables, wholegrains, potatoes and fruit, to provide brain energy. When glucose is not available the brain can function on fats stored as body fat.

While brain signalling, the replacement of old or injured brain cells and cellular structure can occur when adequate B vitamins, especially B2, B6, B12, folate and choline, magnesium, zinc, vitamins C, D and E, calcium, selenium, copper and iron are consumed. Plus, pigmented phytonutrients that include flavonoids and carotenoids, in addition to phospholipids and omega-3 essential fatty acids are necessary.  

Subsequently, it is understandable that eating a diet that is adequately diverse to contain all the necessary nutrients can be difficult and for the provision of nutrients not in the diet a food supplement may be useful.

For advice and information on supporting your diet to feed your brain, please visit your local independent health store. You can find your nearest one by visiting:

Author: Jenny Carson is a Nutritional Practitioner and Technical Services Manager at Viridian Nutrition. She holds a BSc honours degree in Nutritional Science and is a Master of Research (MRes) in Public Health.

Related articles:

 Brain Health


 The Ageing Brain


 Top Brain Nutrients


 What are Nootropics?


 The Omega Factor


 Healthy Food Healthy Brain


Nina Dronkers, Jennifer Ogar, Brain areas involved in speech production, Brain, Volume 127, Issue 7, July 2004, Pages 1461–1462.
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Kondo, H. M., van Loon, A. M., Kawahara, J. I., & Moore, B. C. (2017). Auditory and visual scene analysis: an overview. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 372(1714), 20160099.
Schwartz A. B. (2016). Movement: How the Brain Communicates with the World. Cell, 164(6), 1122–1135.
Silvani, A, et al. 2016. Brain–heart interactions: physiology and clinical implications. Phil. Trans. R. Soc. A. 374:20150181
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