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Mammalian T-type Ca\textsuperscript{2+} channels may act as sleep stabilizers and may help generate the burst firing necessary for the sleep oscillations of deep NREM sleep.  Unfortunately, the three separate mammalian T-type genes all undergo alternative splicing to produce various channel isoforms that each have specific biophysical properties, neuroanatomical and subcellular localizations, and varying abilities to interact with other ion channels.  All these variables combine to make it difficult if not impossible to define a precise physiological role in sleep for T-type channels as a group.  Although Ca\textsubscript{v}3.1 knockout mice lack the slow wave delta  oscillations characteristic of deep sleep and show reduced total sleep\cite{Lee:2004ey}, when the knockout is limited to the rostral midline thalamus, sleep is still reduced, but delta waves are mildly increased\cite{anderson:2005aa}. Another more recent study showed that treatment with the T-type-specific channel blocker TTA-A2 enhances sleep and delta rhythms in wild type mice but not Ca\textsubscript{v}3.1/Ca\textsubscript{v}3.3 double knockout mice\cite{kraus:2010aa}. In other words, manipulation of T-type channels can both enhance and reduce total sleep and deep delta-wave sleep depending on the experimental context. Although perhaps disrespectful of the actual complexity of the situation, the subtle phenotypes of the homozygous viable Ca\textsubscript{v}3 mutant mice are often ascribed to functional compensation among the various Ca\textsubscript{v}3.1-3 isoforms. \textcolor{red}{Maybe a citation here?}  It is surprising, then, that despite its broad and relatively strong expression across adult fly brains, null mutants of the one and only fly T-type channel, DmCa\textsubscript{v}3, are also homozygous viable and lack any overt phenotypes. 
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This wake-promoting function also seems to be independent of the circadian clock, as DmCa\textsubscript{v}3-null mutants show weak but significant rhythmicity in constant darkness and normal oscillation of the core clock gene \emph{period}.  Judging from the complexity of T-type physiology so far reported in mice, it will be interesting to see whether future studies focused on the technically demanding study of isoform-specific expression patterns and isoform-specific rescues in both mice and flies will clarify how T-type channels can at various times both enhance and reduce sleep.