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Allan Hobson has spent decades researching sleep and dreams. In this book he takes on exactly the right project for a neuropsychoanalytic audience: integrating what he knows about the brain with important questions regarding psychopathology and drug action. In this review I will describe some of his ideas, and then explain what is controversial about them.
The first part of the book describes the “AIM model” of alterations in consciousness. (This is a book for general, educated readers. A complex academic version of the AIM model is presented in Behavioral and Brain Sciences by Hobson, Pace-Schott and Stickgold, 2000.) With the AIM model, Hobson suggests that the brain oscillates between states by changing three independent properties: level of brain activation (A), whether input is outside or inside (I), and type of neuromodulation (M). For example, during REM sleep the brain is highly activated; input is purely internal; acetylcholine is the brainstem driver of cortical function, while brainstem serotonin and norepinephrine are inhibited.
As neuroscience advances, one can begin to see the biological underpinnings of clinical phenomena. For example, Hobson shows some of the changes which occur in the brains of cats as they dream. He describes PGO waves. Cholinergic neurons of the pedunculopontine region of the pons (P) begin seizure-like spiking discharges at the onset of REM. Neuronal pathways run rostrally to the geniculate bodies (G) and occipital cortex (O). The pedunculopontine stimuli substitute for retinal input which occurs in cats which are awake. Hence he demonstrates the neurological basis of the shift from external world input to purely internal input during the dream state.
Using his understanding of the effect of cat brainstem changes which produce alterations in consciousness, Hobson is able to hypothesize about likely effects of these alterations in humans, both with psychotropic medications and with drugs of abuse. He describes a patient whom he was t