The Arousal Spectrum

One’s state of arousal is more complicated than simply being “awake” or “asleep.” Rather, arousal exists as if on a dimmer switch, with many phases along the spectrum. Where on the spectrum one lies is influenced by several key neurotransmitters: histamine, dopamine, norepinephrine, serotonin, and acetylcholine, as well as GABA and orexin (not shown). When there is good balance between too much and too little arousal [depicted by the gray (baseline) color of the brain], one is awake, alert, and able to function well. As the dial shifts to the right there is too much arousal, which may cause hypervigilance and consequently insomnia at night. As arousal further increases this can cause cognitive dysfunction, panic, and in extreme cases perhaps even hallucinations. On the other hand, as arousal diminishes individuals may experience inattentiveness, cognitive dysfunction, sleepiness, and ultimately sleep.

Copyright © Neuroscience Education Institute. All rights reserved.

[attis]

Nice summary. It would also be useful to have a lecture about the different mechanisms through which substances and conditions alter arousal.

[DanielleBernstein-cs]

need more in depth videos Dr. Stahl :)

[attis]

Also, there is a typo in the video (understimulation shoud read overstimulation on the right side)

[saudesono-dr.marciobezerra]

Dear Professor Stahl, within this spectrum of arousal, where would mental fatigue fit in?