The auditory midbrain mediates tactile vibration sensing.

Vibrations are ubiquitous in nature, shaping behavior across the animal kingdom. For mammals, mechanical vibrations acting on the body are detected by mechanoreceptors of the skin and deep tissues and processed by the somatosensory system, while sound waves traveling through air are captured by the cochlea and encoded in the auditory system. Here, we report that mechanical vibrations detected by the body's Pacinian corpuscle neurons, which are unique in their ability to entrain to high frequency (40-1000 Hz) environmental vibrations, are prominently encoded by neurons in the lateral cortex of the inferior colliculus (LCIC) of the midbrain. Remarkably, most LCIC neurons receive convergent Pacinian and auditory input and respond more strongly to coincident tactile-auditory stimulation than to either modality alone. Moreover, the LCIC is required for behavioral responses to high frequency mechanical vibrations. Thus, environmental vibrations captured by Pacinian corpuscles are encoded in the auditory midbrain to mediate behavior.

Diverse states and stimuli tune olfactory receptor expression levels to modulate food-seeking behavior.

Animals must weigh competing needs and states to generate adaptive behavioral responses to the environment. Sensorimotor circuits are thus tasked with integrating diverse external and internal cues relevant to these needs to generate context-appropriate behaviors. However, the mechanisms that underlie this integration are largely unknown. Here, we show that a wide range of states and stimuli converge upon a single Caenorhabditis elegans olfactory neuron to modulate food-seeking behavior. Using an unbiased ribotagging approach, we find that the expression of olfactory receptor genes in the AWA olfactory neuron is influenced by a wide array of states and stimuli, including feeding state, physiological stress, and recent sensory cues. We identify odorants that activate these state-dependent olfactory receptors and show that altered expression of these receptors influences food-seeking and foraging. Further, we dissect the molecular and neural circuit pathways through which external sensory information and internal nutritional state are integrated by AWA. This reveals a modular organization in which sensory and state-related signals arising from different cell types in the body converge on AWA and independently control chemoreceptor expression. The synthesis of these signals by AWA allows animals to generate sensorimotor responses that reflect the animal's overall state. Our findings suggest a general model in which sensory- and state-dependent transcriptional changes at the sensory periphery modulate animals' sensorimotor responses to meet their ongoing needs and states.

Genetic Inhibition of sFRP3 Prevents Glial Reactivity in a Mouse Model of Accelerated Aging.

PURPOSE: Aging is the most significant risk factor for neurodegenerative disorders that are typified by cognitive deficits. Our recent work utilizing BubR1 hypomorphic (BubR1H/H) mice, an accelerated aging model, has revealed that genetic inhibition of the endogenous Wnt pathway inhibitor secreted frizzled related protein 3 (sFRP3) plays a neuroprotective role. Neuroinflammation has been suggested as a pathological hallmark of age-related neurodegeneration mediating cognitive impairment. However, whether sFRP3 inhibition has a neuroprotective effect on neuroinflammatory gliosis in BubR1H/H mice is unknown. METHODS: To investigate neuroprotection from aging-related neuroinflammation by sFRP3 in vivo, we generated double Bub R1H/H;sfrp3 knockout mice and performed immunohistological analysis with cell type-specific markers for astrocytes (glial fibrillary acidic protein), and microglia (ionized calcium-binding adapter molecule 1). Given that the hippocampus is a brain structure critical for learning and memory, and is uniquely affected in aging-related neurodegeneration, we evaluated morphological changes on astrocytes and microglia via confocal imaging. RESULTS: We demonstrate that BubR1H/H mice exhibit significantly increased levels of astrogliosis and an increased trend of microglial activation in the hilus and molecular layer of the young adult hippocampus, thus suggesting that BubR1 insufficiency accelerates glial reactivity. Importantly, our results further show that genetic inhibition of sFRP3 significantly recovers the astrogliosis and microglial activation observed in BubR1H/H mice, suggesting a critical neuroprotective role for sFRP3 in age-related neuroinflammation. CONCLUSION: Our findings suggest that sFRP3 inhibition may represent a novel therapeutic strategy for neurodegeneration.