an increase in median or maxi-
mal life span. —LBR
Aging Cell 10.1111/acel.13488 (2021).NEUROSCIENCE
The dance of sleep
Because of the presence or
absence of consciousness,
sleep and wakefulness are oftenSCIENCE science.org 14 JANUARY 2022 • VOL 375 ISSUE 6577 157PHOTO: PEOPLEIMAGES/ISTOCKPHOTO
thought to be two distinct global
states. These brain states are
characterized by unique intrinsic
activity patterns. Sleep has a self-
organized regimen characterized
by changes in arrangement,
as well as depth or intensity. It
has long been believed that the
preoptic area of the hypothala-
mus is the regulator of brain statechanges. Using optogenetic
stimulation of GABAergic neurons
of the hypothalamus, Yamagata et
al. found that this area affects not
only major state shifts but also
within-state changes of sleep and
wake intensity. The hypothala-
mus thus not only participates
in switching global brain states
but also regulates within-state
intensity. —PRS
Proc. Natl. Acad. Sci. U.S.A. 118 ,
e2101580118 (2021).STRUCTURAL BIOLOGY
Natural solution for
air-water interfaces
Although advances in instrumen-
tation and data processing have
made cryo–electron microscopy
a routine, high-resolution method
for macromolecular structure
determination, experiments are
still often undermined by physical
issues such as protein denatur-
ation at the air-water interface or
preferred orientation of particles.
Fa n et al. found that an amphipa-
thic protein film can block the
air-water interface and change the
surface properties of the sample
support. The authors demon-
strate that this method leads
to thin ice layers and improved
behavior of proteins that have
been challenging to work with
previously. —MAF
Nat. Commun. 12 , 7257 (2021).WEATHER SYSTEMS
Patterns of drying
Ridges of high atmospheric pres-
sure can trap heat in a region for
long periods and contribute to the
occurrence of droughts. Are these
types of highs responsible for the
drying trend in the western United
States that lasted from 1980 to
2018? Zhang et al. identified five
distinct weather patterns that
occur in that region and conclude
that it was a decrease in the fre-
quency of low-pressure troughs,
which are associated with cooler
and wetter conditions, rather
than more high-pressure ridges,
that led to the observed drying.
This trend is likely a consequence
of human activity. —HJS
Geophys. Res. Lett.
Sleep and wakefulness are diff erent brain states regulated by the hypothalamus. 10.1029/2021GL097089 (2021).AGING
Genetics shapes
drug’s effect
The beneficial effects of the
anti-diabetes drug metformin
appear to extend to heart
health, cognitive function, and
even increased health span
and life span in some animal
models. Onken et al. explored
how metformin’s effects varied
in species and strains of worms
in the genus Caenorhabditis,
the genetic diversity of which
approximates that seen
between mice and humans.
This could be informative for
anticipated clinical trials of
metformin’s effects on aging
in humans. However, variability
was rather high. Some strains
had increased life span, but in
some it decreased. A measure
of mobility, taken as an indicator
of health, revealed that in some
genetic backgrounds, health
span could be increased without