THE BRAIN: KNOW IT… 1/3

Until recently, scientists believed we were trapped with the brain we were born with and we could neither change it nor improve upon it. Over the last few decades, large strides have been taken in understanding how the brain functions, revolutionizing previously held beliefs. Daily advances continue in the study of the brain, learning, reasoning, and memory formation. The more we discover, the more questions we have, and the more we want to know.

Incredibly complex, our brains define who we are and what we do.

Neuroscience covers the study of the whole nervous system, with the primary focus on the brain. The study of the nervous system includes structure to function, development to degeneration, health, and disease. Neuroplasticity and Neurogenesis are two concepts of the same science.

Neurogenesis is the more amazing ability of the brain to grow new neurons. It facilitates the brain’s adaptive response to new stress by integrating new neurons into related areas.

Neuroplasticity, also known as brain plasticity, is the ability of the brain to form new connections and pathways and change how its circuits are wired. Its ability to change its activity in response to intrinsic or extrinsic stimuli by reorganizing its structure, functions, or connections.

Neuroplasticity has revolutionized all our previous beliefs.

Neuroplasticity examples in everyday life:

-Remembering the name of somebody you met yesterday.

-Creating art, music, or writing.

-Learning a new way to get to the store.

-Understanding the rules of a new board game.

-Figuring out how to use a new mobile phone.

Every human experience in this world is based on information received through our senses: sight, touch, hearing, taste, and smell. Some memories seem sealed into our brains, others are fleeting recollections, while others are forgotten over time.

What affects the importance and duration of these memories?

Memories — They represent intense positive or negative emotions. This occurs through the activation of the AMYGDALA. It enhances attention, perception, and retention; triggering the release of stress hormones, adrenaline, and cortisol, to boost alertness and memory encoding.

Although negatively stressful circumstances should equally be enhanced, they tend to have the opposite effect on memory. They rather alter the way our brain processes information, changing from a flexible, holistic approach to a more rigid stimulus/response (fight/flight) reaction. In such situations, unpleasant experiences only enhance memory formation for places — a cue to avoid potential threats.

Memory pathways — The more a neural pathway is activated, the stronger the synaptic connections become. Then, when a thought enters our head, we involuntarily recall previous related experiences and knowledge. Thus, our minds funnel our thoughts along well-established neural pathways.

Access to memories — Say you had a pleasant experience with an old friend, a meal together. It involves the activation of all the senses, including the setting. These components would have activated various parts of the NEOCORTEX and stored the experience in the HIPPOCAMPUS. As this memory is consolidated over time, its storage will be distributed in different parts of the NEOCORTEX.

The HIPPOCAMPUS is critical, serving as the index. Memory is like a digital database or an old-school office filing cabinet. Something triggers a search of the database, and we retrieve and recall the memory. When your friend mentions this pleasant memory, because of synaptic plasticity and strengthened connections, this visual seed is enough to access the scene in the HIPPOCAMPUS’s index to recall the memory as a whole, and it instantly directs neuronal traffic back to the appropriate circuits of the NEOCORTEX, reactivating all the senses and the setting as well.

Measuring memory and its capacity — The human brain consists of about one billion neurons. Each neuron forms about 1,000 connections to other neurons, amounting to more than a trillion connections. If each neuron could only help store a single memory, running out of space would be next to impossible. Yet neurons combine so that each one helps with many memories at a time, exponentially increasing the brain’s memory storage capacity to something closer to around 2.5 petabytes (or a million gigabytes). For comparison, if your brain worked like a digital video recorder in a television, 2.5 petabytes would be enough to hold three million hours of TV shows. You would have to leave the TV running continuously for more than 300 years to use up all that storage.

A “petabyte” means 1,024 terabytes. So, the average adult human brain can accumulate the equivalent of 2.5 million gigabytes!

The brain’s exact storage capacity for memories is difficult to calculate. First, we do not know how to measure the size of memory. Second, certain memories involve more details and thus take up more space; other less important memories are forgotten and thus free up space. Additionally, some information is just not worth remembering in the first place.

This is good news because our brains can keep up as we seek new experiences over our lifetime. If the human life span were significantly extended, could we fill our brains?

You’ll have to ask me in another 100 years!

Memory storage and motor memories — In 1953, a patient named Henry Molaison had his HIPPOCAMPUS surgically removed during an operation in the United States to treat his epilepsy. His epilepsy was cured, and Molaison lived a further 55 healthy years. However, after the surgery he was only able to form episodic memories; he was completely unable to permanently store new information. Consequently, Molaison’s memory became limited to events that occurred years before his surgery, in the distant past. He was still able to improve his performance on various motor tasks, even though he had no memory of ever encountering or practicing them. This indicated that although the HIPPOCAMPUS is crucial for laying down memories, it is not the site of permanent memory storage and isn’t needed for motor memories.

The study of Henry Molaison was revolutionary because it showed that multiple types of memory exist. We now know that rather than relying on the HIPPOCAMPUS, implicit motor learning occurs in other brain areas — the BASAL GANGLIA and CEREBELLUM.

“Understanding this system has implications for almost any disorder that affects memory, from schizophrenia, depression, and epilepsy to traumatic brain injury and post-traumatic stress disorder,” says Charan Ranganath, a neuroscientist at the University of California. “We’re really interested in understanding the ability to use knowledge to make decisions.”

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THE BRAIN: GROW WITH IT …2/3

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Sammy RNAJ — sammy.rnaj.writer@gmail.com — WhatsApp +96170499352