Where in the Brain Might Contextual Information Affect Perception

Brain Might Contextual

The information we receive from the surrounding is analyzed in different areas in the brain. These areas are interconnected. Visual impulses reach the occipital lobe in the brain from where they are carried to the somatosensory are in the parietal lobe. The parietal lobe also receives sensory information from other areas of the brain. These stimuli are integrated and stored. The stored information is used to reason similar stimuli in the future. This creates a quicker response in recognition. This theory is consistent to the top down process created by Richard Gregory.

The brain is a complex body organ consisting of two cerebral hemispheres, two cerebellums and a brain stem. The brain stem is a continuation of the spinal cord. It consists of the mid brain, pons and medulla. The brain is made up of complex neurons that transmit impulses to other body organs. These impulses help other organs carry out their functions. Impulses are also transmitted to the brain after which a response is generated and sent back. Each part of the brain has specific functions that are inter-related to other parts of the brain. To understand where contextual image is processed, it becomes important to first review functions of different parts of the brain.

The cerebrum is the largest part of the brain. It consists of the frontal, parietal, temporal and occipital lobes. Each lobe carries out a specific function. The frontal lobe is associated with planning, reasoning, parts of speech, emotions and problem solving. The parietal lobe is responsible for movement, orientation, recognition and perception of stimuli. The occipital lobe is responsible for visual processing and the temporal lobe is responsible for recognition of auditory stimuli and its perception, memory and speech. (Serendip, 2005)

The cerebellum is located posteriorly and is sometimes called the little brain. This part of the brain is mainly responsible for balance. It receives information from the inner ear, sensory and optic nerves which help it to co-ordinate and develop a sense of position. Lesions of the cerebellum impair the brain's ability to analyze impulses from the eye and the ear, hence, a person with a cerebellar lesion loses the ability to precisely time and co-ordinate smooth movements. These patients also lose their sense of position and hence find it difficult to stand straight or walk in a straight line. (Serendip, 2005)

The brainstem is the most important part of the brain. It consists of the respiratory center which directs the basic process of living, that is, respiration. It also controls other basic autonomic functions, such as the heart rate and gastrointestinal motility. The pons, which is a part of the brainstem, controls the level of arousal, alertness or sleep. The brainstem also relays information from the body to the cerebrum and the cerebellum. (Serendip, 2005)

The human brain is always in a state of active learning. Perception, for example, is a complex function that involves the use of our five senses. The information generated is then stored for later use and understanding. The cerebrum and cerebellum are the two brain parts involved in this process. (Hamilton, 2001)

When light stimuli fall on the retina, it relays the information to the cerebrum via the optic nerves. This information reaches the occipital lobe of the brain, for interpretation, from where it is relayed to the parietal lobe. The parietal lobe consists of the somatosensory center which integrates all of the body's senses. The position sense and auditory impulse carried from the ear, touch sensations from the epidermis and gustatory sensations from the tongue are also integrated into the somatosensory center. This not only allows us to understand where objects are in space, but also helps us create a perception, such as a perception of a desk, flower or lamp. This perception might be saved as a memory in the cerebrum. If one of the sensory impulses are eliminated (for example, if the eyes are closed), the memory integrated in the somatosensory area compensates for that deficit. (Hamilton, 2001)

While the basic physiology of perception remains clear, the main problem arises when trying to explain the direct relationship of perception to the information present in the stimulus. One argument considers previous knowledge and the perceiver's expectations as part of the perception building process. Psychologists have devised two processes related to perception, that is, top down process and bottom up process. (Dewey, 2007)

Bottom up processing, also known as data driven process, begins with the stimulus itself. The information is carried from the sensory organ to its respective area in the brain, where it is analyzed and interpreted, after which it is relayed to the somatosensory area in the parietal lobe for integration and perception. According to James Gibson, inventor of this theory, there is enough evidence in the surrounding for us to directly interact with it and create details of perceptions in our minds. (Dewey, 2007)

The top down process involves the use of contextual information. For example, reading a difficult handwriting or understanding wrongly spelled words is easier if the individual is already familiar with those words. This is because recognizing surrounding letters provide a contextual aid to the individual. (Dewey, 2007)

The top down process was a hypothesis invented by the psychologist, Richard Gregory. He considered perception as a process of making inferences about what we perceive through our five senses. According to Gregory, past knowledge and experience is a key factor that determines the process of constructing inferences. The hypothesis we create may not always be correct. For example, on entering a dark room, we may not clearly see the details of an object and may incorrectly perceive it as something else. On turning on the light, the hypothesized data will be confronted by the information received. ("Top-down and bottom-up," 2009)

However, the hypothesized perception created in the brain tends to be appropriate to its place in space. For instance, on entering a dimly lit room, we are more likely to perceive a rectangular object as a loaf of bread rather than a mail box. This is also supporting evidence to the top down process where prior experience, reasoning and past knowledge from the frontal cortex helps the somatosensory area perceive information in relation to the surrounding. Once we see elements that were expected to be seen in a certain environment, the information is rapidly interpreted. This is because on recognizing a few familiar features, the rest of the detail can either verified or expected to be present. (Kavanagh)

Another example of reasoning a perception is seen in dementia. Dementia is a disease of old age where memory is lost. These patients may have defects in perception due to their defect in memory; however, when confronted with reasoning, they are brought back to reality.