SCIENCE science.org 29 OCTOBER 2021 • VOL 374 ISSUE 6567 547PHOTO:AMBER ALHADEFF
By Amber L. AlhadeffW
hy do we behave differently when
we haven’t eaten? How do we
know when to stop eating? How
do the foods that we eat influence
our brain activity? Over the past
several decades, we have discov-
ered many of the mechanisms that underlie
the neural control of food intake and how
hunger changes our perception of the world
( 1 , 2 ). However, the brain constantly receives
updates on the physiological condition of
the body, and so it is also essential to un-derstand how interoceptive sensory signals
that arise from the body influence neural
activity in the brain’s feeding centers. This
component has received comparatively less
scholarly attention. My work has sought to
connect hunger circuits in the brain with
inputs and outputs from the rest of the
body, with the goal of discovering how neu-
rons that encode hunger are modulated by
what we eat and how their neural
activity can change our behavior.HUNGER FILTERS PERCEPTION
How does hunger influence the
perception of competing signals?
To tackle this question, we first ex-
amined how hungry mice respondto different kinds of sensory stimuli. We
found that food deprivation causes a pro-
found reduction in behavioral responses to
long-term inflammatory pain and itch in
mice but leaves intact the ability to respond
to acute thermal and mechanical stimuli ( 3 ,
4 ). These findings demonstrate the specific-
ity with which hunger can filter different
kinds of noxious sensory information.
We next leveraged our knowl-
edge of the neurons that underlie
hunger to investigate the neural
circuits that mediate the effect of
food deprivation on pain behavior.
Hypothalamic agouti-related pro-
tein (AgRP)–expressing neurons are
critical for food intake control inMonell Chemical Senses Center, Philadelphia, PA 19104,
USA. Email: [email protected]NEUROSCIENCEThe power
of hunger
Interoceptive sensing and
hunger neurons have a role
in the control of behavior
PRIZE ESSAY
Pain responses are blunted in lab mice that are
deprived of nutritive foods such as these high-fat pellets.