Locus Coeruleus
The locus coeruleus, or sometimes referred to as LC, exerts major control of both attention and sleep with a high rate of locus coeruleus neuron firing associated with alertness. Very high levels of locus coeruleus firing can result in hyper vigilance or, perhaps, hyperactivity. In some, this can then result in the disorder that is referred to as attention deficit disorder, sometime with hyperactivity.
Through a widespread efferent projection system, the locus coeruleus-noradrenergic system supplies norepinephrine throughout the central nervous system. Recent studies identify a complicated array of behavioral and electrophysiological actions that have in common the facilitation of processing of relevant, or salient, information. This involves two basic levels of action. First, the system contributes to the initiation and maintenance of behavioral and forebrain neuronal activity states that is appropriate for the collection of sensory information, like waking. Second, within the waking state, this system modulates the collection and processing of salient sensory information through an assortment of concentration-dependent actions within cortical and subcortical sensory, attention, and memory circuits. Norepinephrine-dependent modulation of long-term alterations in synaptic strength, gene transcription and other processes suggest a potentially critical role of this neurotransmitter system in experience-dependent alterations in neural function and behavior. The ability of a given stimulus to increase locus coeruleus discharge activity appears independent of affective valence (appetitive vs. aversive). Together, these observations suggest that the locus coeruleus-noradrenergic system is a critical component of the neural architecture supporting interaction with, and navigation through, a complex world. These observations further suggest that dysregulation of locus coeruleus-noradrenergic neurotransmission may contribute to cognitive and/or arousal dysfunction associated with a variety of psychiatric disorders, including attention-deficit hyperactivity disorder, sleep and arousal disorders as well as certain affective disorders, including post-traumatic stress disorder. Independent of an etiological role in these disorders, the locus coeruleus-noradrenergic system represents an appropriate target for pharmacological treatment of specific attention, memory and/or arousal dysfunction associated with a variety of behavioral or cognitive disorders.
Sources:
Dec. 12, 2005. planetpuna.com.
Dec. 12, 2005. biopsychiatry.com. University of Wisconsin.
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