3.8.1 Development and localisation of cerebral functions
The Development and Localization of Cerebral Functions throughout the Life Span from the Foetal Stages Onwards
The brain and nervous system of the embryo start to form at just six weeks. The creation of the human brain from the tip of a 3-millimetre neural tube is a biological engineering masterpiece. To reach the more than 100 billion neurons that constitute a newborn baby’s normal complement, the brain must grow at an average pace of roughly 250,000 nerve cells every minute during pregnancy. But it’s not just the rate of growth that makes the production of a human brain mind-boggling. The large number of activities that the brain dependably performs and the specificity with which they are assigned to one or more types of cells or tiny locations in the entire assembly is astounding in their complexity (Ackerman, 1992).
The development of the sophisticated portions of the brain begins during pregnancy and ends around the age of 25.
(Tau, 2010)
The neural tube, which forms during the first month of the embryo’s growth, is the first part of the brain. Around week 6 or week 7, the neural tube shuts, at which point the front brain, midbrain, and hindbrain separate. The cerebrum will fold into the left and right halves of the brain, and these three regions will eventually grow into the brain’s specialised regions.
Millions of new neurons will develop in the brain throughout the first trimester. These neurons interact via synapses to control movement and growth.
In the second trimester, the embryonic brain starts to control how the chest muscles contract and how the diaphragm moves. The brain stem is in charge of these practice breaths, which are similar in nature.
The left brain and right brain will begin to separate when the cerebrum begins to form ridges and grooves. In the third trimester, the cerebellum is the area of the brain that is growing the fastest. aby will start to move more, wriggling fingers and toes, stretching, and kicking since this area controls motor function.
Localisation of function:
According to the concept of “localisation of function in the brain,” particular functions are carried out by distinct parts of the brain.
The hypothesis of “localization of function” is supported by the probability that when a certain portion of the brain is destroyed, the accompanying area of function will also likely suffer. The two hemispheres can communicate with one another thanks to the corpus callosum. Hemispheric lateralisation is the term used to describe how each hemisphere specialises in carrying out particular tasks. They can share information, incorporate it, and process it to an excellent degree via conversing.
The relationship between particular brain regions and particular functions is an area of investigation with plenty of competing ideas. The prefrontal cortex, the motor and somatosensory cortex, the visual cortex, the auditory cortex, Broca’s and Wernicke’s areas, and others all show evidence for the localization of function in the brain (De Luca & Leventer, 2010).
References:
(1) Ackerman, S. (1992). The Development and Shaping of the Brain. [online] www.ncbi.nlm.nih.gov. National Academies Press (US). Available at: https://www.ncbi.nlm.nih.gov/books/NBK234146/.
(2) De Luca, C. R., & Leventer, R. J. (2010). Developmental trajectories of executive functions across the lifespan. In Executive functions and the frontal lobes (pp. 57-90). Psychology Press.
(3) Tau, G.Z. and Peterson, B.S. (2010). Normal Development of Brain Circuits. Neuropsychopharmacology, [online] 35(1), pp.147–168. doi:10.1038/npp.2009.115.