The Human Brain - Fact or Fiction?

The hippocampus, the region of the brain responsible for learning and spatial memory, contains stem cells that can differentiate into neurons throughout your life (Ming and Song, 2011). Interestingly, scientists have discovered another region of the adult brain able to create neurons - the amygdala (Roeder et al., 2022). This part of the brain is important for emotional memories and processing fear and stem cells in the amygdala have shown to play a role in fear learning. These findings may be associated and used for treatment of depression and anxiety disorders such as PTSD, which are linked to disrupted connection in the amygdala. For example, studies have shown that neuron numbers increase in the human amygdala throughout a person's lifespan, but not in people suffering with autism (Avino et al.).

This topic holds some controversy amongst neuroscientists, as some of them think the theory of adult neurogenesis is not fully proven. There are some conflicting studies and many questions are still unanswered. For instance, it is still believed that neurogenesis in the hippocampus steadily decrease with age, which could play a role in neurodegeneration. In addition, research has shown that impaired adult neurogenesis has impact on Alzheimer's disease (Winner and Winkler, 2015). Therefore, further research in this field can not only help us understand our brain better, but also contribute to treating neurodegenerative diseases.

The story behind this myth started from a study conducted by Rauscher et al. in 1993, in which 36 college students temporarily achieved higher scores on spatial reasoning tests after listening to the Mozart's Sonata (Rauscher et al., 1993). The students sat in silence for 10 minutes or listened to Mozart's Sonata, after which they completed a series of mental tasks, such as being able to remember where an object was located in an array of objects. The results showed that the students who listened to Mozart did a little better on the tests, indicating that listening to Mozart had an impact on better performance.

It is important to note that this study only tested 36 graduate students, not children, and it showed effects on spatial reasoning, not on overall intelligence. However, the media misinterpreted these findings and people believed that playing classical music to babies has a lasting impact on their intelligence. The belief became so popular, that they started producing classical music CDs and DVDs for babies. Furthermore, in 1998, the governor of Georgia added 105,000$ of the state budget to send every new-born baby a tape of classical music, although at this time there were no further studies testing the effects of music on children.

More experiments have been conducted after that, showing small positive effects of listening to classical music on spatial performance, but these effects were also observed in people who listened to other type of music. Thus, there is nothing unique about Mozart, but rather a short-time impact of music on spatial-task performance, which can even be linked to the music's effect on a person's mood.

Although listening to music may not have such impact on intelligence, playing a musical instrument does have an effect by engaging practically every area of the brain at once, evidence of which are MRI scans. Playing an instrument improves cognitive function by increasing the volume and activity of the brain's corpus callosum, the bridge between the two hemispheres. This results in enhanced neuronal communication between the left and right hemispheres of the brain, leading to improved problem-solving, learning, memory and motor skills (Stoklosa and Fisher,2016). Thus, research has shown that playing a musical instrument in childhood is associated with improved thinking skills in older age.

Alcohol causes brain damage in different ways, for instance, by damaging dendrites, which disrupts neuronal signalling. When you drink, alcohol reaches your brain within five minutes and firstly, it triggers the release of endorphins. This is why you start to feel more relaxed and happier after a few glasses. However, if you continue to drink more and more, alcohol starts to interfere with your brain's communication pathways, causing changes in your behaviour, slurred speech and poor coordination, and this can lead to alcohol poisoning.

If we look at the long-term effects of alcohol, associated with heavy/binge drinking, booze can lead to decreased cognitive function, memory issues and brain atrophy. Furthermore, alcohol has a negative impact on neurogenesis, thus even though it does not kill neurons, it interferes with your brain making new ones. Moreover, long-term alcohol abuse is associated with dementia, for instance the Wernicke-Korsakoff syndrome. In this syndrome, the loss of neurons is not caused directly by alcohol, but by deficiency in a vitamin called thiamine. Thus, alcohol can in fact kill brain cells, but not directly. Drinking can have long-lasting effects on developing brains as well, as they are more vulnerable, which can lead to permeant brain damage. This is the reason why you are not allowed to drink alcohol until your early twenties.

Therefore, although alcohol doesn’t directly lead to neuronal death, it still causes damage (usually reversible) to your brain, especially if you drink too much.

What makes our brains fat is the lipid layer, covering the axons of our neurons, through which electrical impulses travel. Myelin sheath serves as an insulating layer of fat, protecting the axon and allowing electrical impulses to transmit much more quickly (up to 50 times faster!). Interestingly, this is why you have white and grey matter - the white matter of your brain contains those myelinated axons, whereas the grey matter consists of the neuronal somas. Therefore, your brain may be your fattiest organ, but it is unique in that it uses this fat as an insulator of electricity, compared to the adipose tissue, in which fat has energetic function.

Moreover, your brain needs additional fat, supplemented by diet, because fatty acids are crucial molecules for proper brain function (Chang et al., 2009). For instance, omega-3 fatty acids are not synthesized in your body, therefore it is essential you get them through food, such as fish or walnuts. Thus, although fat is considered something bad, the right kind of fat is crucial for proper brain function.