Spatiotemporal dynamics of sensory neuron and Merkel-cell remodeling are decoupled during epidermal homeostasis.

As the juncture between the body and environment, epithelia are both protective barriers and sensory interfaces that continually renew. To determine whether sensory neurons remodel to maintain homeostasis, we used two-photon imaging of somatosensory axons innervating Merkel cells in adult mouse skin. These touch receptors were highly plastic: 63% of Merkel cells and 89% of branches appeared, disappeared, grew, regressed and/or relocated over a month.

Touch Receptors Undergo Rapid Remodeling in Healthy Skin.

Sensory tissues exposed to the environment, such as skin, olfactory epithelia, and taste buds, continuously renew; therefore, peripheral neurons must have mechanisms to maintain appropriate innervation patterns. Although somatosensory neurons regenerate after injury, little is known about how these neurons cope with normal target organ changes. To elucidate neuronal plasticity in healthy skin, we analyzed the structure of Merkel-cell afferents, which are gentle touch receptors, during skin remodeling that accompanies mouse hair-follicle regeneration.

Population-Level Representation of a Temporal Sequence Underlying Song Production in the Zebra Finch.

The zebra finch brain features a set of clearly defined and hierarchically arranged motor nuclei that are selectively responsible for producing singing behavior. One of these regions, a critical forebrain structure called HVC, contains premotor neurons that are active at precise time points during song production. However, the neural representation of this behavior at a population level remains elusive.

Functional Segregation of Cortical Regions Underlying Speech Timing and Articulation.

Spoken language is a central part of our everyday lives, but the precise roles that individual cortical regions play in the production of speech are often poorly understood. To address this issue, we focally lowered the temperature of distinct cortical regions in awake neurosurgical patients, and we relate this perturbation to changes in produced speech sequences. Using this method, we confirm that speech is highly lateralized, with the vast majority of behavioral effects seen on the left hemisphere.