The human brain is an extraordinary and complex organ using which we breathe, survive, make decisions, make friends, build relations, etc. Every time we do something, electric sparks and chemical reactions in the brain occur. It is also crucial that the brain adapts towards physical and chemical changes. Generally, if we are lost, we have an easy-to-access application called Google Maps to find our way back to where we are supposed to go, according to our transportation type. Likewise, if someone loses a limb, the brain readjusts, and the neurons remap to fill the void and neuron connections responsible for the functions in that particular limb.
How is it possible for the brain to process such a thing? Where does this process occur? What causes the brain to remap? The process occurs in the hippocampus and the cerebral cortex and is called remapping. Remapping is when the neurons update the responses immediately in response to external or internal stimuli (Bisley et al., 2020).
Cortical remapping
The cerebral cortex is responsible for learning, processing, language, memory, reasoning, thought, emotions, intelligence, and personality (Professional, n.d.). Cortical remapping is the process of the brain adjusting to a series of incidents, such as building muscle memory, recovering from an accident, learning new skills, etc.
For example, Vrundha started learning music at the age of 5. During the initial stage, her brain maps to strengthen her listening, vocalising, and music-processing skills. From then on, every time she practises or performs the music, she develops her style of music and presentation, which is also the result of cortical remapping. The remapping occurs throughout her life, boosting her creativity and presentation skills and keeping her memory intact.
Another example of cortical remapping is losing one sense and heightening the other senses. Harsh met with a terrible accident and lost his eyesight. It was distressing for him to adjust and adapt to the new circumstances. One day, he realised he could use his other senses, such as hearing, smelling, and touching, for his basic activities. When the neurons responsible for eyesight are lost, the remaining senses are improved, which is the outcome of cortical remapping.
Hippocampal remapping
The hippocampus in our brain is involved in long-term memory formation, memory retrieval, spatial memory and navigation, emotional behaviour, and hypothalamic function regulation (Osmosis - Hippocampus: What Is It, Location, Function, and More, n.d.; Anand & Dhikav, 2012).
Every one of us tends to confuse a few memories like the holiday trip year or confuse someone’s birthday with another and many such things. It is the effect of retroactive interference, an impairment that occurs by processing new memories and interfering with the existing ones. To guard from such interference, the brain engages in a neural mechanism to promote the formation of new memories (Colgin et al., 2008). This mechanism involves the hippocampus, which is responsible for memorial functions. Place cells in the hippocampus are specialised and are responsible for storing and locating unique patterns of brain activity (Blair et al., 2023). The research group also found that rats avoid certain places corresponding to their worst experiences, whereas administering amnesia-inducing drugs before the work experience made them forget the experience. Place cells are responsible for partial remapping, where the hippocampal network fails to act coherently (Jeffery, 2011).
Diseases such as Alzheimer’s disease, Epilepsy, Cushing’s Disease, Schizophrenia, PTSD, and TBI occur due to damage/atrophy in the hippocampus. The thumb rule of all the mentioned diseases is memory impairment and declined cognitive function. The cells in the hippocampus remap according to external environmental factors and genetic expression (Anand & Dhikav, 2012; McEwen, 1997).
Such functions of the brain amuse scientists to study more about brain functions, diseases, physiology, its relationship with psychology, and many more. There’s no stopping to study the brain due to its complex and amusing nature.
References
[1] Anand, K. S., & Dhikav, V. (2012). Hippocampus in health and disease: An overview. Annals of Indian Academy of Neurology, 15(4), 239. [ https://doi.org/10.4103/0972-2327.104323 ]
[2] Bisley, J. W., Mirpour, K., & Alkan, Y. (2020). The functional roles of neural remapping in cortex. Journal of Vision, 20(9), 6. [ https://doi.org/10.1167/jov.20.9.6 ]
[3] Blair, G. J., Guo, C., Wang, S., Fanselow, M. S., Golshani, P., Aharoni, D., & Blair, H. T. (2023). Hippocampal place cell remapping occurs with memory storage of aversive experiences. eLife, 12. [ https://doi.org/10.7554/elife.80661 ]
[4] Colgin, L. L., Moser, E. I., & Moser, M. (2008, September 1). Understanding memory through hippocampal remapping. Trends in Neurosciences. [ https://doi.org/10.1016/j.tins.2008.06.008 ]
[5] Jeffery, K. J. (2011). Place cells, grid cells, attractors, and remapping. Neural Plasticity, 2011, 1–11. [ https://doi.org/10.1155/2011/182602 ]
[6] McEwen, B. S. (1997). Possible mechanisms for atrophy of the human hippocampus. Molecular Psychiatry, 2(3), 255–262. [ https://doi.org/10.1038/sj.mp.4000254 ]
[7] Osmosis - Hippocampus: What is it, location, function, and more. (n.d.). Osmosis. [ https://www.osmosis.org/answers/hippocampus#:~:text=The%20hippocampus%20is%20involved%20in,to%20the%20objects%20around%20them. ]