The Neuroscience of Altered States

Real Neurons

Neurotransmitter being transported in vesicles (purple spheres) to
the synaptic cleft.

Basic Functional Anatomy of Neurons


The Action Potential is the fundamental carrier of neural information. When stimulus-inputs to a neuron exceed a certain critical threshold, , a sodium (K+) \ potasium (Na+) chemical pump changes the polarity - the distribution of electrical charges - across its cell membrane in a traveling pulse-like wave (the action potential).



The action potential causes vesicles filled with neurotransmitter to migrate to the synaptic cleft (the gap between neurons). By binding to receptor sites on the far side of the cleft, the neurotransmitter, depending upon its chemical composition, contributes to either exciting or inhibiting an action the next neuron down the line. That neuron will in turn "fire" - generate its own action potentail -  if the sum of excitatory and inhibitory impulses from all of the neurons that synapse onto it reaches the critical threshold.


Simulated Neurons

Basic Structural Anatomy of the Brain

Basic Functional Anatomy of the Brain


The Recticular Activating System (RAS)

(Regulates arousal, states of conscious awareness, and unconscious states, including waking, dreaming, and dreamless sleep)



Neurotransmitter Pathways Involved in Waking-Dreaming-Dreamless Sleep Cycle


EEG patterns (in Dutch)


Hobson's Activation-Input-Modulation (AIM) Model







Excerpts_from_Hobson: Dreaming and the Brain