Brain control
The brain controls all aspects of our functioning, from the moment we were conceived until the last of our breath. Much of what we do is not a result of just one action or function of the brain but a series of simultaneous processes that all work at the same time to be able to accomplish a task. In this particular scenario wherein an individual, like myself for example, is in the middle of a room and has a table and two different colored balls, red on the left side and green on the right, is asked by another person to pick up the ball placed on the left side with my left hand.
After which the instructor, which is behind the table asks what color is the ball that I picked. In accomplishing the aforementioned tasks, my brain will go through several processes that might seem insignificant when looked at in real time due to the immediate and rapidly firing neurons happening in an instant that we are not even aware that these minute details are happening. I am in the middle of the room; I know where my position is. Being aware of one’s position also requires that the brain recognize where I am. The parietal lobe of the cerebrum is responsible for orientation and movement (Serendip).
This part of the brain will be able to tell me that I am in the middle because one of its functions is to construct a spatial coordinate system to represent the area where I am to be found. The cerebrum is the largest part of the brain that is thought to control higher brain function like that of thought and action (Serendip). This information will reach our brain through an ascending pathway. The afferent fibers will travel through the posterior column, like other functions such as sterognosis, graphesthesia, among many others (University of Idaho).
The stimulus will travel through the spinal cord and will find itself interpreted in the somatosensory cortex of the parietal lobe (University of Idaho). After interpretation, I will now know my position and where I am. In addition to that, I see where I am. Without seeing my surroundings, I may not be able to actually predict my spatial location, which is the middle of the room. I know that I am in the middle of the room because I see the room and I was able to calculate that my position is in the middle of this big box of a room.
This stimulus, particularly the visual one, wherein I was able to see the room and all of its contents, including the table in front of me with the two balls and another person behind the table will be perceived by the visual area of the brain, which is the occipital lobe (Serendip). I can see where the objects are because there are light rays being reflected off them and these rays enter my eyes and pass through my lens. The image that will be projected through my lens will be an inverted version of what I see and this information will be sent to my retina (Montgomery).
Inside the retina there are rod and cone cells that will produce signals to be relayed onto the optic nerve and reach the lateral geniculate nucleus (Montgomery). The details of the objects and the person I see in front of my will travel to selected areas of the primary visual cortex and then to other areas of the cortex that would process the global aspects of the objects and the person in front of me like their shape, color, or movement (Montgomery). The person behind the table will ask me to pick up the left ball with my left hand. I will hear his instructions.
The temporal lobe of the cerebrum is the one to process the auditory stimuli that I receive as he said in his command. My ears will catch the sound and the auditory nerve will receive the stimuli and bring this to auditory nucleus of thalamus, which is the medial geniculate nucleus (Washington University School of Medicine). This will project to the primary auditory cortex in the temporal lobes. After hearing and processing his command, I will now move my left hand to pick up the left ball. I already know which ball I am to pick up with my left hand as I saw the balls and the table and I interpreted its position relative to mine earlier.
Now all I have to do is move my hands and pick it up. The primary motor cortex found in the precentral gyrus, is the area of the cerebrum that will process this movement (Dubuc). First off, I have already signaled my parietal and frontal lobes to alert my attentiveness in processing his command. Once I know that it is my left hand, which should pick the ball and not my right hand, I can tell my left hand to move already and this involves activation of the supplementary and premotor cortical areas and the application of these information from subcortical structures to the primary motor complex (Dubuc).
A closer look at how this happens is through the passing of the stimulus to the corticospinal tract. The corticospinal tract is responsible for stimulating motor neurons located in the spinal cord that are responsible for movement of the axial muscles of body in addition to the arms and legs (Dubuc). The lateral system pathway is followed to produce this movement and the pathway involves passing through the fibers of the lateral corticospinal tract continuing onto the spinal cord before reaching the motor neurons (Dubuc). However, a unique process is occurring in the junction between the medulla and the spinal cord.
Fibers coming from the lateral corticospinal tract cross the midline before continuing their way onto the opposite side of the spinal cord, and is called decussation (Dubuc). The cerebellum also plays a role in movement. The learned movement sequences are stored in the cerebellum, in addition to the coordination of movements and its fine-tuning, avoiding clumsy and large movements (Dubuc). This will help me know how to actually move my left hand and to avoid unnecessary movements. As I am now moving my left hand to reach the left ball, I know from my long-term memory what a ball is and what it looks like.
I also know from memory which is left and which is right. The hippocampus is the part of the brain that is known to store our long-term memory. After knowing what a ball is and which is left and which is right, these information will be transferred from our short-term memory to our long-term memory. Information that we need to summon up every time is considered to be categorized as a long-term memory such as names, dates, colors, among many others. Long-term memory is of three types and color is categorized under semantic memory, that contains facts which we do not need an effort to recall (Aetna, Inc. ).
The acquisition of memory happens when we learn the different colors and we learn to distinguish which is the left side from the right. Consolidation of this information will make us remember the colors and directions more. Then when needed, we will be able to easily recall this information. Since I have already identified which is the ball on my left and I have been able to move my left arm now to pick up the left ball, I can answer what color the ball is. According to the information given, the left ball is colored red. I know from my stored long-term memory and from what I see that the ball on the left side is red.
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html>. Serendip, “Brain Structures and their Functions. ” Brain and behavior. 2005. Serendip. 22 Feb 2009 <http://serendip. brynmawr. edu/bb/kinser/Structure1. html>. University of Idaho, “Ascending Pathways. ” A self-study module to be used for Med Sci 532. 2004. University of Idaho. 22 Feb 2009 <http://www. sci. uidaho. edu/med532pathways/>. Washington University School of Medicine, “AUDITORY AND VESTIBULAR PATHWAYS. ” Neuroscience Tutorial. 1997. Washington University School of Medicine. 22 Feb 2009 <http://thalamus. wustl. edu/course/audvest. html>.
