Limbic system
The limbic system was a set of brain structures which seemed to support a variety of cerebral functions including emotion.

In 2153, T'Pol was infected with a microbe which caused damage to her limbic system by triggering pon farr ()

In 2372, the neuropeptide levels in Tuvok's limbic systems decreased by 15 per cent, after a mind meld with Lon Suder. ()

In 2375, Julian Bashir believed that a slight elevation in Sarina Douglas' norepinephrine levels was probably due to limbic overcompensation for the new thalamic connections. ()

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Biological systems