![]() Individuals with schizophrenia only reduce the amplitude of S2 by 10–20%, whereas individuals without schizophrenia reduce the amplitude of S2 by 80–90%.Ī subject wearing an electroencephalography cap, a conventional technique for measuring one's reactivity using sensory gating. ![]() High values of the P50 wave indicate a lack of sensory gating. Low values of the P50 wave indicate that sensory gating has occurred. Evidence of the gating can be seen in the P50 wave, occurring in the brain 50 ms after the click. For normal sensory gating, if a person hears a pair of clicks within 500 ms of one another, the person will gate out the second click because it is perceived as being redundant. The paired-click paradigm is a common non-invasive technique used to measure sensory gating, a type of event-related potential. Techniques for measurement Paired-click paradigm ![]() Studies on rats also show the brain stem, thalamus, and primary auditory cortex play a role in sensory gating for auditory stimuli. Research on sensory gating has been primarily occurring in cortical areas where the stimulus is consciously identified because it is a less invasive means of studying sensory gating. Other areas of the brain associated with sensory gating include the amygdala, striatum, medial prefrontal cortex, and mid-brain dopamine cell region ( GABAergic neurons only). Sensory gating is mediated by a network in the brain which involves the auditory cortex (AC), prefrontal cortex, hippocampus, as well as the olfactory cortex, which plays a part in sensory gating phenomenon. The CNS (Central Nervous System), after the pulvinar nuclei deems the information to be irrelevant, acts as an essential inhibitory mechanism that prevents the information from flowing into higher cortical centers. (Both S1 and S2 are commonly referred to auditory stimuli caused by the machines used to test sensory gating.) The pulvinar nuclei in the thalamus function as the gatekeeper, deciding which information should be inhibited, and which should be sent to further cortical areas. In a proven clinical study, it has been found out that the two stimuli (S1 and S2) are transported within 500ms between the clicks and 8 seconds between the pairs, in which S1 is known to generate a trace of memory that lingers presumably in the hippocampal region while the S2 the arrives later to be compared with the first stimuli as it gets inhibited if provided with no new information. The pulvinar nuclei of the thalamus plays a major role in attention, and has a major role in filtering out unnecessary information in regards to sensory gating. Information from sensory receptors make their way to the brain through neurons and synapse at the thalamus. The cocktail party effect demonstrates sensory gating in hearing, but the other senses also go through the same process protecting primary cortical areas from being overwhelmed. The cocktail party effect illustrates how the brain inhibits input from environmental stimuli, while still processing sensory input from the attended stimulus. Previous studies have shown a correlation between sensory gating and different cognitive functions, but there is not yet a solid evidence implying that the relationship between sensory gating and cognitive functions are modality-independent. Sensory gating can also occur in different forms through changes in both perception and sensation, affected by various factors such as "arousal, recent stimulus exposure, and selective attention." Īlthough sensory gating is largely automatic, it also occurs within the context of attention processing as the brain selectively seeks for goal-relevant information. Also referred to as gating or filtering, sensory gating prevents an overload of information in the higher cortical centers of the brain. Sensory gating describes neural processes of filtering out redundant or irrelevant stimuli from all possible environmental stimuli reaching the brain.
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