Sleep and anesthesia resemble in many ways at a first glance. The most prominent common feature
of course is the loss of consciousness i.e. the loss of awareness of external stimuli. However
a closer look at the loss of consciousness reveals already a difference between sleep and
anesthesia: anesthesia is induced by an anesthetic drug whereas we may fall asleep without
external cause. Other questions may arise about the difference of the two effects: do we dream
during surgery under anesthesia do we feel pain during sleep? Essentially we may ask: what is
common and what are the differences between sleep and anesthesia? To answer these questions we
may take a look at the neural origin of both effects and the involved physiological pathways.
In which way do they resemble? Moreover we ask what are the detailed features of normal sleep
and general anesthesia as applied during surgery and which features exist in both phenomena? If
yes in which way? To receive answers to these questions it is necessary to consider several
experimental techniques that reveal underlying neural mechanisms of sleep and anesthesia.
Moreover theoretical models of neural activity may model both phenomena and comes up with
predictions or even theories on the underlying mechanisms. Such models may attack several
different description levels from the microscopic level of single neurons to the macroscopic
level of neural populations. Such models may give deeper insight into the phenomena if their
assumptions are based on experimental findings and their predictions can be compared to
experimental results. This comparison step is essential for valuable theoretical models. The
book is motivated by two successful workshops on anesthesia and sleep organized during the
Computational Neuroscience Conferences in Toronto in 2007 and in Berlin 2009. It aims to cover
all the previous aspects with a focus on the link to experimental findings. It elucidates
important issues in theoretical models that at the same time reflect some current major
research interests. Moreover it considers some diverse issues which are very important to get
an overview of the fields. For instance the book discusses not only neural activity in the
brain but also the effects of general anesthesia on the cardio-vascular system and the spinal
cord in the context of analgesia. In addition it considers different experimental techniques
on various spatial scales such as fMRI and EEG-experiments on the macroscopic scale and single
neuron and LFP-measurements on the microscopic scale. In total all book chapters reveal aspects
of the neural correlates of sleep and anesthesia motivated by experimental data. This focus on
the neural mechanism in the light of experimental data is the common feature of the topics and
the chapters. In addition the book aims to clarify the shared physiological mechanisms of both
phenomena but also reveal their physiological differences.
