LAUSR

A small population of brainstem neurons connects breathing behavior to brain arousal. Breathing is one of the perpetual rhythms of life that is often taken for granted, its apparent simplicity belying the complex neural machinery involved. This behavior is more complicated than just producing inspiration, as breathing is integrated with many other motor functions such as vocalization, orofacial motor behaviors, emotional expression (laughing and crying), and locomotion (1, 2). In addition, cognition can strongly influence breathing. Conscious breathing during yoga, meditation, or psychotherapy can modulate emotion, arousal state, or stress (3). Therefore, understanding the links between breathing behavior, brain arousal state, and higher-order brain activity is of great interest. On page 1411 of this issue, Yackle et al. (4) identify an apparently specialized, molecularly identifiable, small subset of ∼350 neurons in the mouse brain that forms a circuit for transmitting information about respiratory activity to other central nervous system neurons, specifically with a group of noradrenergic neurons in the locus coeruleus (LC) in the brainstem, that influences arousal state (see the figure). This finding provides new insight into how the motor act of breathing can influence higher-order brain functions.