Which neurotransmitter controls arousal in the brain

Some researchers have compared the neurological mechanism that controls these rapid transitions to the "flip-flop switch" in an electrical circuit. In the brain, the mechanism that maintains stability through mutual inhibition is triggered by changes in factors such as the body's drive for sleep or the circadian alerting signal.

When one of these forces becomes strong enough, it drives the transition to the opposite state. The same "flip-flop switch" analogy also describes the brain mechanisms involved in switching between rapid eye movement REM sleep and non-rapid eye movement NREM sleep.

However, different neurotransmitters and different groups of neurons in the brainstem are involved in the transitions between REM and NREM sleep. People generally require several minutes to calm down and relax enough to fall asleep, and the deepest stages of sleep typically occur 20 or more minutes after sleep onset.

However, sleep onset and associated loss of consciousness can occur in an instant. This is particularly obvious in very tired people who can fall asleep at inconvenient and sometimes dangerous times, such as when driving a car. Similarly, waking up from sleep can occur very quickly, for example in response to an alarm clock, although it typically takes people much longer to become fully alert after awakening.

There are many internal factors such as homeostatic sleep drive and circadian rhythms and environmental factors such as noise that influence the likelihood of falling asleep or waking up. For example, a powerful sleep drive builds up with prolonged wakefulness and shifts the balance toward sleep. How this occurs is not precisely known, but adenosine is one of the chemicals thought to accumulate during prolonged wakefulness.

When it does, it serves to induce sleep by inhibiting wake-promoting neurons. Interestingly, caffeine inhibits the actions of adenosine and therefore helps maintain wakefulness. GABA works to inhibit neural signaling. If it inhibits cells too much, it can lead to seizures and other problems. But this neurotransmitter also plays an important role in brain development. New research suggests that GABA helps lay down important brain circuits in early development.

Neurochemicals like oxytocin and vasopressin are also classified as neurotransmitters. Made and released from the hypothalamus, they act directly on neurons and have been linked to pair-bond formation, monogamous behaviors, and drug addiction. Hormones like estrogen and testosterone can also work as neurotransmitters and influence synaptic activity.

Other neurotransmitter types include corticotropin-releasing factor CRF , galanin, enkephalin, dynorphin, and neuropeptide Y. Enkephalin, for example, is released with glutamate to signal the desire to eat and process rewards.

It was once believed that only neurons released neurotransmitters. In , researchers found that glial cells release glutamate into synapses in the hippocampus, helping synchronize signaling activity. Astrocytes, a star-shaped glial cell, are known to release a variety of different neurotransmitters into the synapse to help foster synaptic plasticity, when required.

Researchers are working diligently to understand the contributions of these different cell types—and the neurotransmitter molecules they release—on how humans think, feel, and behave. Download this page as a PDF. Hearing is a mechanical sense. It turns physical movement into the electrical signals that make up the language of the brain, translating these vibrations into what we experience as the world of sound.

All of our senses give us vital information about our surroundings, but the one we rely on most is vision. Accordingly, the physical apparatus for gathering visual information—the eye—and the brain circuits that process this information are more complex than corresponding systems for the other senses.

The human brain is a network of networks: an intricate, integrated system that coordinates operations among billions of cells. Although strokes are sudden, the brain injury they inflict typically evolves over the course of hours or even days.

Prompt, effective treatment is critical. People take SNRIs to relieve symptoms of depression, anxiety, chronic pain, and fibromyalgia.

Some evidence indicates that people can increase serotonin naturally through:. A precursor to serotonin, called 5-hydroxytryptophan 5-HTP , is available as a supplement. While some studies have shown promising results, further research is needed to understand possible side effects of 5-HTP supplements. There is no proven way to ensure that neurotransmitters are balanced and working correctly. However, having a healthful lifestyle that includes regular exercise and stress management can help, in some cases.

Before trying a supplement, ask a healthcare provider. Supplements can interact with medications and may be otherwise unsafe, especially for people with certain health conditions. Health conditions that result from an imbalance of neurotransmitters often require treatment from a professional. See a doctor regularly to discuss physical and mental health concerns.

Endorphins are chemicals produced naturally in the body to cope with pain or stress. Learn about how they affect mood disorders and other conditions. Although these two…. Oxytocin is a hormone that plays an important role in the female reproductive system, particularly with childbirth and breast-feeding. Known as the…. Dopamine and serotonin, or the 'happy hormones,' play key roles in mood, depression, and appetite, among other things.

Learn about similarities…. While some chemical imbalances can be a factor in certain symptoms of mental health conditions, they do not tell the whole story. Learn more about the…. What are neurotransmitters?

Medically reviewed by Nancy Hammond, M. What are the key types? Key types of neurotransmitters. Brain Res Bull 16 — Selective GABAergic innervation of thalamic nuclei from zona incerta.

Eur J Neurosci 16 — State-dependent gating of sensory inputs by zona incerta. J Neurophysiol 96 — Feedforward inhibitory control of sensory information in higher-order thalamic nuclei. J Neurosci 25 — Efferent connections of the internal globus pallidus in the squirrel monkey: I. Topography and synaptic organization of the pallidothalamic projection.

Projections from the substantia nigra pars reticulata to the motor thalamus of the rat: single axon reconstructions and immunohistochemical study. J Comp Neurol 3 — The mediodorsal nucleus of the thalamus in rats — I. Neuroscience 70 — Abolition of spindle oscillations in thalamic neurons disconnected from nucleus reticularis thalami. J Neurophysiol 54 — Selective optical drive of thalamic reticular nucleus generates thalamic bursts and cortical spindles.

Nat Neurosci 14 — Spontaneous activity of neurones of nucleus reticularis thalami in freely moving cats. Evidence for two types of firing pattern during the sleep-waking cycle in the reticular thalamic nucleus of the cat. Exp Neurol 72 — Reticularis thalami neurons revisited: activity changes during shifts in states of vigilance.

J Neurosci 6 — Serotonin and noradrenaline excite GABAergic neurones of the guinea-pig and cat nucleus reticularis thalami. State-dependent architecture of thalamic reticular subnetworks. Cell — Guarding the gateway to cortex with attention in visual thalamus. Nature —4. Kayahara T, Nakano K. The globus pallidus sends axons to the thalamic reticular nucleus neurons projecting to the centromedian nucleus of the thalamus: a light and electron microscope study in the cat. Brain Res Bull 45 — Topographical connections of the substantia nigra pars reticulata to higher-order thalamic nuclei in the rat.

Brain Res Bull 87 —8. Basal forebrain and mesopontine tegmental projections to the reticular thalamic nucleus: an axonal collateralization and immunohistochemical study in the rat.

GABAergic projection from the basal forebrain to the visual sector of the thalamic reticular nucleus in the cat. Cortical input to the basal forebrain. Neuroscience 79 — Electrophysiological evidence for the existence of a posterior cortical-prefrontal-basal forebrain circuitry in modulating sensory responses in visual and somatosensory rat cortical areas. The effect of prefrontal stimulation on the firing of basal forebrain neurons in urethane anesthetized rat.

Brain Res Bull 75 — Pinault D, Deschenes M. Control of Hz firing of reticular thalamic cells by neurotransmitters. Neuroscience 51 — Voltage-dependent Hz oscillations in rat reticular thalamic neurons in vivo. Focal stimulation of the thalamic reticular nucleus induces focal gamma waves in cortex. J Neurophysiol 79 —7. The intralaminar and midline nuclei of the thalamus. Anatomical and functional evidence for participation in processes of arousal and awareness. Brain Res Brain Res Rev 39 — Thalamic microinjection of nicotine reverses sevoflurane-induced loss of righting reflex in the rat.

Anesthesiology — Thalamic microinfusion of antibody to a voltage-gated potassium channel restores consciousness during anesthesia. Temporal patterning of pulses during deep brain stimulation affects central nervous system arousal. Behav Brain Res — Shaker-related potassium channels in the central medial nucleus of the thalamus are important molecular targets for arousal suppression by volatile general anesthetics.

J Neurosci 33 — Altered activity in the central medial thalamus precedes changes in the neocortex during transitions into both sleep and propofol anesthesia. Neuroscience 64 — Fritschy JM, Mohler H.

GABAA-receptor heterogeneity in the adult rat brain: differential regional and cellular distribution of seven major subunits. Electrophysiological and behavioral effects of zolpidem in rat globus pallidus. Exp Neurol — Acta Pharmacol Sin 29 —8. Distribution of central omega 1 benzodiazapine1 and omega 2 benzodiazapine2 receptor subtypes in the monkey and human brain. An autoradiographic study with [3H]flunitrazepam and the omega 1 selective ligand [3H]zolpidem.

J Pharmacol Exp Ther 1 — Schiff ND. Recovery of consciousness after brain injury: a mesocircuit hypothesis. Trends Neurosci 33 :1—9. Clinical and imaging evidence of zolpidem effect in hypoxic encephalopathy. Ann Neurol 62 1 —5. Whyte J, Myers R. Incidence of clinically significant responses to zolpidem among patients with disorders of consciousness: a preliminary placebo controlled trial.

Am J Phys Med Rehabil 88 —8. GABA A alpha-1 subunit mediated desynchronization of elevated low frequency oscillations alleviates specific dysfunction in stroke — a case report. Clin Neurophysiol — Can J Neurol Sci 38 —4. Zolpidem and restoration of consciousness. Am J Phys Med Rehabil 93 — Somatotopic maps within the zona incerta relay parallel GABAergic somatosensory pathways to the neocortex, superior colliculus, and brainstem.

Urbain N, Deschenes M. Motor cortex gates vibrissal responses in a thalamocortical projection pathway. Neuron 56 — Cortical control of zona incerta. J Neurosci 27 — GABAergic and cholinergic basal forebrain and preoptic-anterior hypothalamic projections to the mediodorsal nucleus of the thalamus in the cat.

Neuroscience 85 — Cellular bases of neocortical activation: modulation of neural oscillations by the nucleus basalis and endogenous acetylcholine. J Neurosci 12 — Biol Psychiatry 71 — A parvalbumin-containing, axosomatic synaptic network in the rat medial septum: relevance to rhythmogenesis. Eur J Neurosci 19 — NMDA receptor ablation on parvalbumin-positive interneurons impairs hippocampal synchrony, spatial representations, and working memory.

Neuron 68 — GABAergic basal forebrain neurons that express receptor for neurokinin B and send axons to the cerebral cortex. Immunolocalization of the voltage-gated potassium channel Kv2. Sleep 36 — Phase segregation of medial septal GABAergic neurons during hippocampal theta activity.

J Neurosci 24 39 —9. Firing properties of anatomically identified neurons in the medial septum of anesthetized and unanesthetized restrained rats. J Neurosci 26 — High-frequency gamma electroencephalogram activity in association with sleep-wake states and spontaneous behaviors in the rat. Neuroscience 76 — Gross DW, Gotman J. Correlation of high-frequency oscillations with the sleep-wake cycle and cognitive activity in humans. Neuroscience 94 — Neuroscience 92 — Distribution and role of Kv3.

Contributions of Kv3 channels to neuronal excitability. Ann N Y Acad Sci — Kocsis B, Li S. In vivo contribution of h-channels in the septal pacemaker to theta rhythm generation. Eur J Neurosci 20 — Hippocampal theta rhythm is reduced by suppression of the H-current in septohippocampal GABAergic neurons.

Third group of neostriatofugal neurons: neurokinin B-producing neurons that send axons predominantly to the substantia innominata. Role of neurokinin B in the control of female puberty and its modulation by metabolic status. Cholinergic excitation of septohippocampal GABA but not cholinergic neurons: implications for learning and memory. J Neurosci 20 10 —8. Excitatory effects of muscarine on septohippocampal neurons: involvement of M3 receptors. Nicotine recruits a local glutamatergic circuit to excite septohippocampal GABAergic neurons.

Eur J Neurosci 18 — Optogenetic stimulation of basal forebrain cholinergic neurons promotes cortical activation both directly and indirectly. Alreja M, Liu W. J Physiol Pt 1 — Alreja M. Excitatory actions of serotonin on GABAergic neurons of the medial septum and diagonal band of Broca. Synapse 22 — Hypocretin increases impulse flow in the septohippocampal GABAergic pathway: implications for arousal via a mechanism of hippocampal disinhibition. J Neurosci 22 17 — J Neurosci 24 — Gaykema RP, Zaborszky L.

Parvalbumin-containing neurons in the basal forebrain receive direct input from the substantia nigra-ventral tegmental area.

Brain Res —9. Increased gamma- and decreased delta-oscillations in a mouse deficient for a potassium channel expressed in fast-spiking interneurons. J Neurophysiol 82 — Increased motor drive and sleep loss in mice lacking Kv3-type potassium channels. Genes Brain Behav 3 — Kv3 potassium channels control the duration of different arousal states by distinct stochastic and clock-like mechanisms.

Ablation of Kv3. J Neurosci 28 — Sleep-waking discharge patterns of median preoptic nucleus neurons in rats. J Physiol 2 — Characterization and mapping of sleep-waking specific neurons in the basal forebrain and preoptic hypothalamus in mice. Sakai K. Sleep-waking discharge profiles of median preoptic and surrounding neurons in mice.