This month's episode features Mark Humphries, author of "The Spike: An Epic Journey Through the Brain in 2.1 Seconds." We explore how the brain uses electrical signaling in surprising ways, beginning with a look at how an action potential (aka. "the spike") is produced. Then we consider what Humphries calls "the dark neurons," which are neurons that rarely generate spikes. We explore their role and also how it relates to the brain's spontaneous activity. One of the more surprising recent discoveries in neuroscience is that most of the brain's activity does not appear to be caused by external stimuli. It is not a passive receiver of information and this has profound implications for our understanding of things like how the brain generates conscious experience. This episode is for listeners of all backgrounds. Links and References: The Spike: An Epic Journey Through the Brain in 2.1 Seconds by Mark Humphries Humphries Lab at the University of Nottingham Please visit http://brainsciencepodcast.com for additonal references and episode transcripts. Please Visit Our Sponsors: TextExpander at textexpander.com/podcast NordVPN at nordvpn.com/brainscience Announcements: Brain Science comes out on 4th Friday each month. Support Brain Science by buying Are You Sure? The Unconscious Origins of Certainty by Virginia "Ginger" Campbell, MD. (Autographed copies are available) Learn more ways to support Brain Science at http://brainsciencepodcast.com/donations Sign up for the free Brain Science Newsletter to get show notes automatically every month. You can also text brainscience to 55444 to sign up. Check out the free Brain Science Mobile app for iOS, Android, and Windows. (It's a great way to get both new episodes and premium content.) Send email to brainsciencepodcast@gmail.com or post voice feedback at http://speakpipe.com/docartemis. Connect on Social Media: Twitter: @docartemis Facebook page: http://www.facebook.com/brainsciencepodcast Contact Dr. Campbell: Email: brainsciencepodcast@gmail.com Voicemail: http://speakpipe.com/docartemis