Using high-resolution 3D electron microscopy and optogenetics, we discovered that lamellar Schwann cells (LSCs) in mouse Pacinian corpuscles form complex, multilayered structures rather than concentric rings. Connected by thousands of desmosomes and gap junctions, LSCs enhance mechanosensitivity by triggering reliable axonal spiking when activated, while inactivation raises thresholds, highlighting their key role in somatosensory processing.
By tracing the transformation between a temporal code to a rate code, with electrophysiological recordings and calcium imaging along all stages of the ascending somatosensory pathway: primary sensory afferents (mechanoreceptors), dorsal root ganglia, dorsal column nuclei, thalamus and cortex, we discovered that major neural signal transformations occur between brainstem and thalamus
Location (somatotopy) and frequency tuning (tonotopy) are highly important properties of neurons in somatosensory pathways. We found that location and frequency tuning for vibration stimulus was organized into highly structured maps in dorsal column nuclei. The distribution of mechanoreceptors and the specificity in dendritic sampling during modality convergence contribute to the emergence.
The oscillatory stimuli of vibration propagate through solid substrates, are sensed by
mechanoreceptors in our body and give rise to perceptual attributes such as vibrotactile pitch. Our findings suggest the existence of a fundamental relationship between the seemingly unrelated concepts of spectral sensitivity and pitch perception in both mouse and human.
Retinotopic maps of many visual areas are thought to follow the fundamental principles described for the primary visual cortex. Here we demonstrate a striking departure from this mapping in the secondary visual area (V2) of the tree shrew best described as a sinusoidal transformation of the visual field, which suggests the cortical circuits implement flexible solutions.
Callosal projections are thought to play a critical role in coordinating neural activity between the cerebral hemispheres in placental mammals, but the rules that govern the synaptic connection remain unknown. Our results demonstrate, for the first time, that functional synaptic clustering in a short dendritic segment could play a role in integrating distinct neuronal circuits.
Circuits in the visual cortex integrate the information derived from separate ON and OFF pathways to construct orderly columnar representations of stimulus orientation and visual space. We showed that cortical columns exhibit an invariant aggregate receptive field structure: a distinct arrangement of ON/OFF inputs enables continuity in the mapping of orientation and visual space.
Methods for evaluating analgesic effect for spontaneous pain are increasingly important because it is reported by most patients with neuropathic pain. We demonstrated PAG stimulation was effective in alleviating spontaneous pain and mechanical allodynia in neuropathic pain. The behavioral index of spontaneous pain used in this study could be useful for therapeutic methods.
