How and why do we read? Chemically speaking... Part-1

Reading is a complex cognitive process that involves more than just recognizing symbols on a page. It requires a sophisticated network of neural circuits, chemical messengers, and sensory processes. The center of this activity is attributed to chemistry, particularly the function of neuro-receptors in the brain, which allow the transmission of information necessary for decoding and understanding the text. Reading primarily activates various parts of the brain, especially those concerned with language comprehension and visual processing.

Neurotransmitters, the chemical messengers of the brain, play pivotal roles in this process. Dopamine is associated with the motivational aspect of reading. It rewards cognitive activities by providing feelings of pleasure. When reading is enjoyable or engaging, dopamine levels increase, which not only enhances concentration but also motivates the reader to continue engaging with the text. Serotonin affects mood and memory formation. Higher serotonin levels can enhance mood and improve concentration, thereby facilitating better reading comprehension and retention of information.

Acetylcholine is crucial for attention and learning. It is particularly important in encoding new information into long-term memory and is active during reading to help maintain focus on the text. Reading starts with the eyes, where light must be converted into electrical signals that the brain can interpret. This conversion is a photochemical reaction occurring within the photoreceptors in the retina—rods and cones. Cones are responsible for color vision and function best in bright light.

When exposed to light, the light-absorbing molecule in these cells, rhodopsin, undergoes a structural change. This change triggers a chain of chemical reactions that ultimately convert light into a neural signal. This signal is processed by various areas of the brain to recognize and interpret the shapes and patterns of letters and words. Rods, on the other hand, are more sensitive and work better in low light but are not primarily used for reading under normal conditions.

Hormones also influence the chemistry of reading through their impact on the body's physiological state. For example, cortisol, the stress hormone, can affect concentration. Low to moderate increases in cortisol may heighten alertness and improve the capacity for reading, whereas high levels may impede cognitive function and diminish the effectiveness of reading sessions. Reading is more than a mechanical task; it is a dynamic activity that involves a delicate balance of neurochemicals and hormones. Being able to read under specific conditions can aid in memory retention and focus and enhance the speed of reading. By using dim lights, reducing intake of caffeine, and reading at a stress-free time to make most of your cortisol while reading.

As we discussed, reading releases dopamine and stimulates the pleasure centers of our brain. Because of this, we continue to read, providing incentives. Another reason is the effect of reading on cortisol. Engaging in reading can help balance cortisol levels and promote relaxation, which can become a habit that provides a comforting escape from daily stressors.

Reading is an activity that builds neural plasticity, the brain's ability to change and adapt structurally and functionally in response to experiences. BDNF, a protein in the brain, plays a significant role in this neural plasticity by supporting the survival of existing neurons and encouraging the growth and differentiation of new neurons and synapses. Reading is one of the best cognitive exercises that produces the growth of new neurons and reduces cognitive decline with age.

But why would the mind come up with reading? Why did the mind evolve to seek out patterns in written messages? How and when did it become capable of that? I will explore the answers to these questions in the next part of How and Why Do We Read? Chemically speaking... It will involve the adaptation of mankind after the invention of fire, to how nutrients became more abundant to where we lie now.