News from Canada: The Neurobiology of Sleep

Dr. Leonid Kayumov, Ph.D.,
Chief Editor of Canadian Edition

Part Two
of Two

Imaging technology is particularly useful for the investigation
of nocturnal seizure disorder (e.g. frontal lobe epilepsy), the
etiology of which remains unknown in the majority of cases.

of a lack of a clearly defined etiology and frequent nonlateralizing
EEG changes, few patients are considered optimal surgical candidates.

With continued
advances in technology, neuroimaging techniques appear to show
the greatest potential, and should lead to a better understanding
of the relation between neural dysfunction, sleep disorders, impaired
alertness and daytime fatigue.

studies are currently being conducted in the area of drowsiness
while driving and fatigue related crashes. Research has shown
a strong association between measures of acute sleepiness and
the risk of a crash-related injury. A large percentage of both
private automobile and commercial vehicle crashes and crash fatalities
are associated with the sleepy driver each year. The identification
of the molecular correlations of sleep and wakefulness are essential
to understanding the restorative processes that occur during sleep,
the cellular mechanisms underlying sleep regulation and the functional
consequences of sleep loss.

Sleep and
waking differ significantly in terms of behavior, metabolism,
and neuronal activity. Recent evidence indicates that sleep and
waking also differ with respect to the expression of certain genes.
Initial results in basic science research on Genomics and brain
chemistry during sleep and sleep disorders has shown exciting

During the
last several years, promising discoveries were made in the area
of the genetics of different sleep disorders. Molecular components
of the mammalian circadian clock system have been recently identified.
It has been shown that an autoregulatory transcriptional feedback
loop appears to form the core circadian rhythm generating mechanisms
in mammals. Two genetic factors have been associated with the
initiation of the circadian loop and another with the closing
of the loop. Identification of these molecular genetic components
may lead to advances in our understanding of circadian rhythms
and how to affect them.

of sleep is a rapidly expanding field, which has profound impacts
on wide-ranging areas of the neurobiology of sleep – from etiology,
diagnosis and treatment, to public education. There is a decline
not only in sex related hormones, but other hormones. Part of
this phenomenon includes the decline of growth hormone in late
middle life and decline of melatonin. The wide ramifications of
this are not fully appreciated, but as knowledge of the role of
melatonin increases, neurobiology implications become more obvious.
The studies showing that the neurohormone
melatonin is an effective chronobiotic in treatment of sleep phase
delay. We have seen individual cases with an off-on-off-on pattern
of melatonin use and associated increase-decrease-increase-decrease
of frequency of epileptic seizures.

Future work
on the neurobiology of sleep will continue to implement the latest
developments in molecular, genetic and neuropharmocological spheres
of basic science with applied clinical practice.