Decussation occurs when fibers in the body cross from one side of the structure to the other and cross the midline and travel through the spinal cord to the opposite side of their origins. In neural physiology, decussation occurs to enhance communication to carry out neural functions. The main reason why the crossing occurs at midline is to control coordination of motor activity which is essential for locomotion. Decussation which only happens in vertebrates is not just an evolutionary characteristic that the vertebrates develop but also characteristics with functionality advantage. The decussation main functional advantage is the enable the vertebrae to have precise movement of their extremities and further the development of decussation is fundamental for the motor capacities that vertebrae have. Therefore the crossing of fiber at the midline is not just a random evolutionary quirk, but a is an essential aspect in understanding the control of locomotion in the body
The relationships between brain size and level of intelligence among humans and other species have never been well defined. Despite human having exceptional cognitive capabilities, they do not have the biggest brain size in the animal kingdom. Big brains that people correlate to being intelligence could merely mean that they have more neurons and hence the greater processing power increasing their intelligence level. This is because according to evolution a Neanderthal had bigger brains than modern man and their intelligence ways way lower and on the other side men have bigger brains than women, but this does not mean men are smarter than women. Hence, the size of the brain does not influence their level of intelligence.
However, the brain structure correlates with intelligence more that size. Thicker cortices which are the wrinkly outer layer of the brain has been associated with higher intelligence levels for intelligence among people as it is responsible for higher level functions such computational capacity (Dicke & Roth, 2016). Subcortical regions are involved with memory, special awareness, decision making, and emotion. This indicates that the size of different parts of the brain determines an individual’s intelligence.
Muscle memory is not from the muscles as most people often think, but it forms as a procedural memory whereby the brain stores the memory of the activities that are done repeatedly. Repetition of the same action improves the muscle memory making it easier for people to carry out specific tasks without much thinking. Thus practice and repetition of a task form muscle memory. Certain brain areas are associated with muscle memory such as motor cortices, cerebellum, striatal areas and thalamus which facilitate motor learning that is achieved through long-lasting neuronal changes.
One of my muscle memories is playing the piano. As a middle school student, I attended piano classes through which I perfected my pianist skills. Having not played piano since middle school, I thought that the skills had diminished; however, in my sophomore year I signed up for in a piano contest which I eventually emerged the winner. This shows that the practice of piano in middle school resulted in muscle memory which I utilized in my piano competition. Therefore, muscle memory develops as a task is done in repetition and practice sharpens the memory.
Dicke, U., & Roth, G. (2016). Neuronal factors determining high intelligence. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, 371(1685), 20150180.