In vitro activity: Noradrenaline modulates the gain of evoked activity, especially in sensory areas. Noradrenaline promotes long-term synaptic plasticity, in addition to these data emphasizing its short-term influence. Noradrenaline would signal ‘gross changes in the environment that produce sensory information strongly violating top-down expectations’ and would, through an enhancement of ‘bottom-up’ information processing at the expense of irrelevant ‘top-down’ expectations, favor behavioral adjustment. Noradrenaline modulates drive and energy and exerts a fine regulation of specific processes including learning, memory, sleep, arousal and adaptation. Noradrenaline system is intimately involved in a range of psychological processes which, when disrupted, lead to the expression of classifiable psychiatric disorders. Noradrenaline appears to be involved in a range of psychological processes, including arousal (vigilance), cognition, learning and sleep regulation, and also in regulating response to stressors which might initiate or exacerbate depressive symptomatology. Noradrenaline deficiency in this pathway may reduce concentration, affect working memory and cause psychomotor retardation, resulting in apathy and depression,while an increase in noradrenaline in this pathway is predicted to alleviate poor concentration, apathy and depression. Noradrenaline effects are complex and depending on experimental conditions (ponto-medullary and medullary preparations) and species (rats or mice), exogenous Noradrenaline mainly facilitates or mainly inhibits the neonatal RRG, with a mixture of α1 facilitatory and α2 inhibitory effects.

Trends Neurosci. 2005 Nov;28(11):574-82.; Int Clin Psychopharmacol. 2003 Jul;18(4):191-202.