Корковые нейронные механизмы гомеостатических п..

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, 2013,  63,  1, . 1323
Throughout the life span every animal sponta
neously goes through a sequence of distinct be
havioral and brain states. One subdivision of these
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sleep, and REM sleep. Waking is also anything but
a steady state, varying on a time scale of hours,
minutes or even seconds from attentive alert state
to a largely disconnected from the environment
state of restful drowsy waking. However, the activ
ity of the brain does not only reflect the current
level of arousal, ongoing behavior or involvement
in a specific task, but also is influenced by what
kind of activity, and how much sleep and waking
occurred previously. Indeed, being awake and
asleep do not alternate at random, but preceding
sleepwake history and the circadian clock govern
the global and local changes in brain state [10,
43]. Jor example, prolonged waking is invariably
followed by deep restorative sleep, while NREM
sleep episodes alternate on a regular basis with
REM sleep periods. The duration and quality of
waking predicts subsequent sleep intensity, re
flected in highamplitude electroencephalogra
phy )EEL* slow waves )slowwave activity, SWG*,
arising from synchronous fluctuations of the
membrane potential in large neuronal popula
The classical neuroscience view is that brain
Moreover, it is still unknown which molecular,
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sumably arising as a result of physical spread of
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largescale cortical activity and that the record
ings can be performed simultaneously from sever
al cortical areas, and for many hours. \hronic
sleep EEL recording and analysis led not only to
the discovery that sleep consists of two different
stages NREM sleep and REM sleep, but also
that sleep is regulated homeostatically, as mani
fested in an increase in sleep EEL slowwave ac
tivity )0.54 Hz* after waking and its gradual de
cline across the night [10, U1]. However, there are
also some limitations to the EELapproach, such
as volume conduction, poor spatial resolution and
often the impossibility to trace the origin of EEL
waves or their spatiotemporal dynamics to specif
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large part by the time required to bring each suc
cessive neurons to spike threshold [P0]. Important
ly, it was shown
in vitro
in barrel cortex that not only
local cortical, but also thalamic electrical or phar
macological stimulation is able to recruit cortical
ensembles into {` states indistinguishable from
The functional significance of slow wave prop
agation remains unclear. It is possible that the
traveling wave represents a wave of recruitment of
cortical areas into the same cycle of slow oscilla
tion [DP]. The rates of such recruitment may be
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The mechanisms underlying the cortical bista
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Spontaneous and especially prolonged waking
has profound effects not only on brain activity but
also on cognitive functions. Jor example, sleep
deprivation leads to attention lapses, mistakes in
cognitive and memory tasks [41] and microsleeps,
which can have dangerous consequences in tasks
requiring alertness [13]. Surprisingly, neuronal
underpinnings of behavioral deficits after sleep
deprivation remain unknown. G few
ies have found that neuronal excitability and sev
eral other electrophysiological properties of indi
vidual cortical neurons are affected by preceding
sleepwake history [4U, 99]. In turn,
in vivo
cordings of cortical unit activity in freelybehav
ing rats revealed that neurons fire more and more
synchronously after prolonged waking, and less so
after a period of consolidated sleep [95]. More
over, _J` slow waves and their cellular counter
part the periods of generalized neuronal si
lenceoccurred more synchronously across large
distributed cortical territories in early intense
sleep after sleep deprivation [93]. Such changes in
cortical neuronal activity should inevitably affect
cortical function, and specifically the interaction
of the organism with the outside world, manifest
ed, for example, in an altered responsiveness of
cortical neurons to incoming stimuli. One possi
bility is that after prolonged waking the neocortex
switches transiently to a sleeplike mode. In
deed, during acute and chronic sleep deprivation
slower EEL activity, including SWG )0.54 Hz*
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+-/&67 (8";= &/(&&#x/&20;&#x.100;= @AB7C&|&2;�.10;"B  D3 F 1 2013
Destexhe A., Contreras D., Steriade M.
poral analysis of local field potentials and unit dis
charges in cat cerebral cortex during natural wake
and sleep states. }. Neuros
ci. 1999. 19 )11*: 4595
Dijk D.J., Duffy J.F., Czeisler C.A.
\ircadian and
sleepQwake dependent aspects of subjective alertness
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Dringenberg H.C., Vanderwolf C.H.
evoked potentials: behaviordependent modulation
by muscarinic and serotonergic receptors. Xrain
Esser S.K., Hill S.L., Tononi G.
Sleep homeostasis
and cortical synchronization: I. Modeling the ef
fects of synaptic strength on sleep slow waves. Sleep.
Everson C.A., Smith C.B., Sokoloff L.
Effects of pro
longed sleep deprivation on local rates of cerebral
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romodulation of thalamocortical activity. `rog.
Neurotransmitter actions in the
thalamus and cerebral cortex. }. \lin. Neurophysi
McCormick D.A., Pape H.C., Williamson A.
of norepinephrine in the cerebral cortex and thalamus:
implications for function of the central noradrenergic
spindle activity during slow oscillations in human
nonrapid eye movement sleep. }. Neurosci. 2002.
Noda H., Adey W.R.
Neuronal activity in the associ
ation cortex of the cat during sleep, wakefulness and
{nit activity of rat basal forebrain neu
rons: relationship to cortical activity. Neuroscience.
Obal F., Jr., Krueger J.M.
Xiochemical regulation of
nonrapideyemovement sleep. Jront Xiosci.
+-/&67 (8";= &/(&&#x/&20;&#x.100;= @AB7C&|&2;�.10;"B  D3 F 1 2013
in NREM sleep in mice. Grch. Ital. Xiol. 2004. 142
Vyazovskiy V.V., Achermann P., Tobler I.
Sleep ho
meostasis in the rat in the light and dark period.
Vyazovskiy V., Borbely A.A., Tobler I.
vibrissae stimulation during waking induces inter

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