• Title/Summary/Keyword: ascending reticular activation system

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Correlation Between Sensory Modulation and Arousal : A Literature Review (감각조절과 각성의 관련성에 대한 문헌고찰)

  • Hong, Eunkyoung
    • The Journal of Korean Academy of Sensory Integration
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    • v.13 no.2
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    • pp.75-84
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    • 2015
  • Objective : The aim of this study was to provide mechanism information of a link between arousal and sensory modulation to increase understanding of neurophysiological study. Subject : Optimal arousal state of a child is an important issue in sensory integration therapy. Limbic system and reticular formation are related to sensory modulation by sensory input. Sensory inputs processes from reticular formation to cortex via ascending reticular activation system for moderate arousal. A lot of neurotransmitters such as cholinergic neurons and monoamin neurons help this processes. Mechanism of arousal was measured by functions of central nervous system (CNS) and autonomic nervous system (ANS) using objective tools such as an electroencephalogram (EEG) and electrodermal responses. Functions of CNS and ANS showed differences between normal children and children with disabilities. Optimal sensory input using sensory integration therapy for children with disabilities helps to act reticular formation, limbic system, and cortex and to maintain appropriate arousal. Conclusion : Such quantitative studies by using neurophysiological methods provide evidence for sensory integration therapy.

The Neuroanatomy and Psychophysiology of Attention (집중의 신경해부와 정신생리)

  • Lee, Sung-Hoon;Park, Yun-Jo
    • Sleep Medicine and Psychophysiology
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    • v.5 no.2
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    • pp.119-133
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    • 1998
  • Attentional processes facilitate cognitive and behavioral performance in several ways. Attention serves to reduce the amount of information to receive. Attention enables humans to direct themselves to appropriate aspects of external environmental events and internal operations. Attention facilitates the selection of salient information and the allocation of cognitive processing appropriate to that information. Attention is not a unitary process that can be localized to a single neuroanatomical region. Before the cortical registration of sensory information, activation of important subcortical structures occurs, which is called as an orienting response. Once sensory information reaches the sensory cortex, a large number of perceptual processes occur, which provide various levels of perceptual resolution of the critical features of the stimuli. After this preattentional processing, information is integrated within higher cortical(heteromodal) systems in inferior parietal and temporal lobes. At this stage, the processing characteristics can be modified, and the biases of the system have a direct impact on attentional selection. Information flow has been traced through sensory analysis to a processing stage that enables the new information to be focused and modified in relation to preexisting biases. The limbic and paralimbic system play significant roles in modulating attentional response. It is labeled with affective salience and is integrated according to ongoing pressures from the motivational drive system of the hypothalamus. The salience of information greatly influences the allocation of attention. The frontal lobe operate response selection system with a reciprocal interaction with both the attention system of the parietal lobe and the limbic system. In this attentional process, the search with the spatial field is organized and a sequence of attentional responses is generated. Affective, motivational and appectitive impulses from limbic system and hypothalamus trigger response intention, preparation, planning, initiation and control of frontal lobe on this process. The reticular system, which produces ascending activation, catalyzes the overall system and increases attentional capacity. Also additional energetic pressures are created by the hypothalamus. As psychophysiological measurement, skin conductance, pupil diameter, muscle tension, heart rate, alpha wave of EEG can be used. Event related potentials also provide physiological evidence of attention during information process. NI component appears to be an electrophysiological index of selective attention. P3 response is developed during the attention related to stimulus discrimination, evaluation and response.

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