Sensation is a preliminary stage of perception and corresponds to the primary sensory impression by the neuroanatomical sense organs. All the processing processes, such as mainly the emotional evaluation of the sensory impression, turn sensation into perception in the brain.
What is sensation?
At the beginning of perception is sensation or sensory perception. The sense organs receive stimuli. Human perception is a highly complex process consisting of many individual processes. Along with wakefulness, selective attention and motivation, the emotional component is one of the most relevant concepts within the perceptual process. The emotional and intellectual perception processing steps modify what is perceived and at the same time are influenced back by the perception process. At the beginning of perception is sensation or sense perception. The sense organs receive stimuli. The sensation is a preliminary stage of the actual perception. It is only through the intellectual and emotional steps that perception is actually experienced instead of merely felt. Conscious perception takes place in the cerebral cortex and is sometimes most strongly controlled by the limbic system. The limbic system corresponds to the central location for human emotions. How different people feel about a particular perception can vary greatly. The limbic system controls innate and acquired human behavior and is considered the place of origin of motivation, drives, and emotions such as fear, anger, or joy and displeasure. The limbic system contains the entire learning experience of a person. The fact that two people perceive situations differently is due to this connection. A perception is evaluated by the limbic system subjectively and on the basis of the individual previous experience. These evaluation processes result in a certain experience of what is perceived. This experience distinguishes perception from sensation, which corresponds exclusively to the primary sensory impression of the organs.
Function and task
The sensation of perception is the totality of perception minus the processes of intellectual and emotional processing. Few things influence humans subconsciously as strongly as the emotional instructions of the limbic system. The limbic system is essentially involved in perceptual processes and thus, for example, takes care of the selection, processing, evaluation and storage of any information from the sensory organs. Countless stimuli are constantly flowing into the human being. From the brain‘s point of view, these stimuli are a vast amount of information. The fact that the human being nevertheless filters out from the abundance of information exactly the stimuli that are currently relevant and suitable for the state of mind is partly due to the limbic system. The limbic system favors and disfavors certain stimuli. Preference is given above all to information that has an emotional content. Emotions stimulate the limbic system. All stimuli in connection with an emotional image penetrate the filter more easily and thus reach the consciousness sooner. Perceptual sensation in the sense of emotional involvement in what is perceived is an important key to perceptual ability. The emotional content of a perception plays a special role in connection with the olfactory system, responsible for the sense of smell. Olfactory perceptions have sometimes the strongest emotional component. The bulbus olfactorius is connected to the amygdala via the stria lateralis. Odor stimuli thus reach the lateral hypothalamus, basal forebrain, and orbitofrontal cortex. Some projections target the olfactory tubercle and septum. It is within the latter circuit that the sensation of an odor is generated. The emotion component of perceived odors depends primarily on the amygdala, which mediates feelings. The olfactory system is the only perceptual system that projects directly to the center for emotion and for this reason is considered the most emotional sensory system of all. Ultimately, however, the emotion content and thus the experience of the perception also plays an essential role for all other perceptual systems. For example, stimulus information with an emotional link can be processed and remembered more easily. Such information can be stored explicitly in semantic memory and at the same time implicitly in episodic memory.The emotional and intellectual content distinguishes perception as a product of all its processes from the initial sensation, which corresponds exclusively to the primary and thus raw sensory impression of the neuroanatomical perceptual structures. The sensation of perception is practically the first step of the perceptual chain. Only then is the current sensory impression compared with prestored information, processed, classified, and interpreted.
Diseases and complaints
Perceptual sensation has clinical relevance primarily when it is subject to disorders. In this context, such disturbances relate exclusively to disorders of the primary sensory organs. For example, receptors may be defective or have limited function after mutations. Receptor defects result in a disturbed primary sensory impression at the sensory organ. In such a phenomenon, not only the sensation of perception as the first step in the chain of perception is disturbed. Also the following steps sometimes cannot take place, because the sensory impression is not processed at all and thus does not lead to the experience of perception. The sensory perception of the visual system is pathological, for example, if the retina degenerates and thus no photoreceptors are available for visual sensation. Sensory disturbances can also affect the sense of touch and then often become noticeable in the form of a lack of sensation in the form of tingling or numbness. Sensory disorders of this type are not related to the receptors themselves, but to defects in the afferent nerve pathways to the brain. In relation to perception, we can ultimately always speak of sensory disorders when the cause of a perceptual disorder is to be found outside the brain and thus before the processing procedures of perception. Thus, true sensory disorders with respect to perception are predominantly caused by diseases or injuries of the neuroanatomical sensory organs and their nerve connections into the central nervous system.
