Cognitive Neuroscience of Sleep and Dreaming

Program Director:
J. Allan Hobson, M.D.
Professor of Psychiatry

The goal of the Laboratory of Neurophysiology is to understand the cellular and molecular mechanisms governing the mammalian sleep cycle and to apply that knowledge to the analysis of normal and abnormal psychiatric states. Dr. Hobson is the founding director of the Laboratory, and Drs. Stickgold and Kocsis also lead investigations in this field. The Laboratory has grown and diversified over the last five years and expects to consolidate and enrich its findings over the five year period to come. Having pioneered the study of brain stem neuromodulatory mechanisms underlying the mammalian sleep cycle, the Laboratory now seeks to define and measure the functional consequences of these changes with special reference to mental states of interest, such as dreaming and to how sleep may affect learning and memory. Much of this work remains at the cutting edge of fundamental neuroscience and cognitive neuroscience, and informs theoretical aspects of scientific psychiatry through development of a dynamic neurobiological alternative to psychoanalytic theory.

Laboratory investigators have played a formative role in sleep research at the national and international level. Examples include the recent publication of two comprehensive reviews of basic neurobiology: (1) the lead article in an issue of the Behavioral and Brain Sciences (Volume 23, December 2000) devoted to sleep and dream research; and (2) an invited chapter in the new edition of the Handbook of Neuropsychopharmacology (2002). Dr. Hobson has also revised his chapter on Sleep and Dreaming for the 2nd edition in the Academic Press textbook Fundamental Neuroscience. Dr. Hobson has been a Decade of the Brain lecturer for the Society Neuroscience and the American Academy of Neurology and was invited to give the keynote address at the World Federation of Sleep Research societies in Punta Del Este, Uruguay. Dr. Hobson received the Distinguished Scientist Award of the Sleep Research Society in 1998. Dr. Kocsis, a neurophysiologist, has published peer-reviewed papers in Neuroscience, Journal of Neuroscience, Sleep, and the European Journal of Sleep Research as cited in the bibliography. In future work, these investigators will collaborate in a program of research on sleep dependent changes in hippocampal function, designed to assess the contribution of sleep to excitability and gene product regulation in the hippocampus. In the neurocognitive domain, laboratory investigators led by Dr. Stickgold recently published in Science (2001) an invited review of research on sleep and learning, titled “Sleep, Learning, and Dreams: Offline Memory Reprocessing,” which highlighted their contributions to the field.

The clinical research program of the Laboratory of Neurophysiology is based largely upon the utility of the home-based sleep monitoring system which Laboratory investigators invented and patented as the “Nightcap.” The license to this device is held by Respironics, who have developed a product called the REM View aimed at the Sleep Disorders market. Because the eyelid movement sensors designed for the Nightcap are sensitive to vigilance lapses during waking, Laboratory investigators obtained a second patent for application in monitoring machine operators (including pilots, railway engineers, truck drivers, and most significantly, automobile drivers). The Nightcap has also allowed investigators to collect reliable and valid sleep data from patients with sleep apnea, insomnia, and narcolepsy as well as normal controls. Dr. Pace-Schott has played a prominent role in engineering and carrying out these projects including a collaborative study of truck drivers (with Virginia Tech University) and one of crack-cocaine abusers (with Yale University). A large and highly unique database from studies of normal subjects has also proved to be a valuable source of information for research papers by Laboratory researchers (cf., papers by Dr. Fosse).

Projects and Grant Support

The Laboratory of Neurophysiology maintains an active multi-disciplinary program of research on sleep and dreams, encompassing basic research, cognitive neuroscience and clinical studies. Basic research within the Laboratory includes studies of the anatomy, physiology, pharmacology, and molecular biology of subcortical neurones and circuits (Drs. Hobson and Kocsis). This work is supported by a grant to Kocsis (MH62525). Cognitive neuroscience and studies of dream phenomenology (formal and quantitative) include investigations of the effects of sleep on learning, the effects of learning on sleep, as well as the effects of sleep on other cognitive functions (e.g., semantic priming, perceptual cuing, and semantic memory (Drs. Hobson, Stickgold, Fosse, Walker, Cantero, and Atienza). This work is supported by grants from NIMH to Hobson (MH48832) and fellowships from NSI and sponsoring governments to four international post-docs. Finally, clinical research studies (all involving the Nightcap home-based sleep monitoring system) include the following:

1. Patients with sleep disorders, especially sleep apnea (in collaboration with Dr. Jean Matheson at the Beth Israel Deaconess Hospital (BIDH) Sleep Laboratory),

2. Studies of patients with insomnia before and after treatment (in collaboration with Dr. Greg Jacobs, BIDH),

3. Studies of subjects who are crack- cocaine abusers (in collaboration with Dr. Robert Malison at Yale). This work is sponsored by a grant from NIDA (DA11744) to Dr. Hobson.

4. Studies of vigilance and vigilance lapses in normal subjects and in patients including automobile operation in collaboration with Nissan labs (Drs. Stickgold, Hobson, Pace-Schott).

Theoretical Structure

The broad-based approach of Laboratory investigators to sleep research is unified by two original theory structures, elaborated by Hobson and McCarley in 1975: the activation synthesis hypothesis of dreaming, and the reciprocal interaction model of sleep cycle control. These models, which have stood the test of time, are now enriched by Stickgold’s theory of state dependent alterations in hippocampal cortical information flow. The growth of the Laboratory has been assisted by ten years of participation in the Mind-Body Network of the MacArthur Foundation and by a NASA grant to develop the Nightcap. The current health of the Laboratory is attributable to its solid empirical grounding as a hypothesis-testing science program; its well-connected multidisciplinary approach; the contributions of vigorous, productive, and highly interactive personnel; and diverse and abundant financial support. The Laboratory would be substantially enhanced by an improved infrastructure for basic science at MMHC (i.e., new laboratories). Current collaborations with staff at BWH, CMC, and BID could also form the basis for strengthening the Laboratory’s links to clinical research, hopefully leading to additional clinical applications of research findings and technologies.

The Laboratory of Neurophysiology is currently supervising three post-doctoral fellows: Drs. Roar Fosse, Matthew Walker, and Kenichi Kuriyama.