SENSATION AND PERCEPTION Introduction: Imagine you are hiking into a valley on the tops of various mountains. You strenuously reach the top of a particular peak. Breathing heavily, you let out a sigh in triumph as you reach the top. Around yourself, you see a lake surrounded by the valley on three sides. Embracing the wind rush against your face, you shout out loud, hello and listen for an echo. This nature scene just brought the lesson at hand to focus: sensation and perception. Sensation is when a stimulus response, something that causes a physical or mental response, is received by one of the various sense organs of the body (eg. the eye, ear, nose, tongue, and skin/touch) and transfer into the brain into the brain. Each of the structures and systems that make up our senses have specialized structures called sensory receptors. A cell or group of cell that receives stimuli: sense organ. These receptors are specialized cells that receive an incoming stimulus through a sense system and are able to translate this stimulus into an electrical impulse the brain can use. Special sensory neurons are located at these receptors, capable of translating the stimulus into an electrical impulse the brain can interpret. Perception refers to how we take sensory input and translate it into something that can be interpreted and organized by our brain. The way you are perceiving the environment around you involves your brain communicating with all your senses. The echo you hear, the way youre able to tell the lake is surrounded by mountains, are all examples of the way we use perception. In psychology, sensation and perception are stages of processing of the senses in human and animal systems, such as vision, auditory, vestibular, and pain senses. These topics are considered part of psychology, and not anatomy or physiology, because processes in the brain so greatly affect the perception of a stimulus. Included in this topic is the study of illusions such as motion after effect, color, constancy, auditory illusions, and depth perception. Sensation is the function of the low-level biochemical and neurological events that begin with the impinging of a stimulus upon the receptor cells of a sensory organ. It is the detection of the elementary properties of a stimulus. Perception is the mental process or state that is reflected in statements like I see a uniformly blue wall representing awareness or understanding of the real-world cause of the sensory input. The goal of sensation is detection, the goal of perception is to create useful information of the surroundings. In other words, sensations are the first stages in the functioning of senses to represent stimuli from the environment, and perception is a higher brain function about interpreting events and objects in the world. Stimuli from the environment are transformed into neural signals which are then interpreted by the brain through a process called transduction. Transduction can be likened to a bridge connecting sensation to perception. SENSATION - refers to sensing our environment through touch, taste, sight, sound, and smell (the 5 senses). This information is sent to our brain and thats when perception comes into play. A cause of excitement, a mental process (as seeing, hearing or smelling) resulting from the immediate external stimulation of a sense organ often as distinguished from a conscious awareness of the sensory process. PERCEPTION - is the way we interpret these sensations and therefore make sense of everything around us. Sensation couldnt exist without perception and perception couldnt exist without sensation. Theyre not the same but theyre related. SPECIFICATION OF SENSORY STIMULATED Each sensory organ is stimulated by a specific form of external energy or internal energy. For example, the eye is stimulated by electromagnetic energy called light waves; the ear is stimulated by the sound waves; and the skin senses of touch and pain are stimulated by pressure. TRANSDUCTION OF TRANSMISSION PROCESS TO THE BRAIN Stimuli from the environment are transformed into neural signal which are the interpreted by the brain through a process. For example; as we have learned, the eye respond s to light waves and the ear responds to sound waves. But light and sound are foreign language to the brain. Thus, for our sensations to be useful, the energy, whatever its form , must be changed by the sense organs into a form that the brain can understand. This conversion process is called transduction. It takes place at the receptor cells which receive the energy produced by the stimulus and converts it into electrochemical energy, the brain’s language. For example, when mechanical energy in the form of sound waves stimulates the receptors (a cell or group of cell that receives stimuli: sense organs) in the ear, this energy is changed to nerve impulses, which are really electrochemical energy. This electrochemical energy passes along the auditory nerve to the auditory area of the brain, where sensations of hearing are induced. Transduction in the nervous system typically refers to stimulus alerting events wherein a physical stimulus is converted into an action potential, which is transmitted along axons towards the central nervous system where it is integrated. A receptor cell converts the energy in a stimulus into a change in the electrical potential across its membrane. It causes the depolarization of the membrane to allow the action potential to be transducted to the brain for integration. TRANSDUCTION – is a action or process of transducing (to convert energy or a message into another form essentially sense organs transducing physical energy into a nervous signal. THRESHOLD (conclusion, edge or point) – is the approximate point at which a stimulus become strong enough to produce a response in an individual. The point at which a physiological or psychological effect begins to be produced (has a high threshold for pain). A level, point or value above which something is true or will take place and below which it is not or will not. An absolute threshold is the smallest detectable level of a stimulus and the least amount of stimulus necessary to produce a response in a person. For example, in an experiment on sound detention, researchers may present a sound with varying levels of volume. The smallest level that a participant is able to hear is the absolute threshold.
Posted on: Fri, 17 Jan 2014 04:38:58 +0000
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