tuberomammillärkärnan

The tuberomammillary nucleus, often abbreviated as TMN, is a small but significant collection of neurons located in the posterior hypothalamus of the brain. It is part of the diencephalon and plays a crucial role in regulating various physiological processes, most notably wakefulness and arousal. The primary neurotransmitter produced by the neurons in the TMN is histamine.

Histaminergic neurons in the tuberomammillary nucleus project widely throughout the brain, innervating areas such as the cerebral cortex, thalamus, basal forebrain, and brainstem. This extensive connectivity allows the TMN to exert a widespread influence on neuronal activity and overall brain state. Activation of these histaminergic pathways promotes wakefulness and alertness, while their suppression is associated with sleep.

The tuberomammillary nucleus receives input from various brain regions, including those involved in sensory processing, circadian rhythms, and emotional states. Its activity is modulated by factors such as light exposure, stress, and the sleep-wake cycle. Dysfunction of the TMN has been implicated in sleep disorders, including insomnia, and has also been linked to conditions like narcolepsy and attention-deficit/hyperactivity disorder (ADHD). The histaminergic system originating from the TMN is a target for medications used to treat sleep disturbances and allergies.