The olfactory network of larval Xenopus laevis regenerates accurately after olfactory nerve transection.

Across vertebrate species, the olfactory epithelium (OE) exhibits the uncommon feature of lifelong neuronal turnover. Epithelial stem cells give rise to new neurons that can adequately replace dying olfactory receptor neurons (ORNs) during developmental and adult phases and after lesions. To relay olfactory information from the environment to the brain, the axons of the renewed ORNs must reconnect with the olfactory bulb (OB). In Xenopus laevis larvae, we have previously shown that this process occurs between 3 and 7 weeks after olfactory nerve (ON) transection. In the present study, we show that after 7 weeks of recovery from ON transection, two functionally and spatially distinct glomerular clusters are reformed in the OB, akin to those found in non-transected larvae. We also show that the same odourant response tuning profiles observed in the OB of non-transected larvae are again present after 7 weeks of recovery. Next, we show that characteristic odour-guided behaviour disappears after ON transection but recovers after 7-9 weeks of recovery. Together, our findings demonstrate that the olfactory system of larval X. laevis regenerates with high accuracy after ON transection, leading to the recovery of odour-guided behaviour.

Optogenetics Neuromodulation of the Nose.

Recently developed optogenetic technology, which allows high-fidelity control of neuronal activity, has been applied to investigate the neural circuits underlying sensory processing and behavior. The nasal cavity is innervated by the olfactory nerve and trigeminal nerve, which are closely related to common symptoms of rhinitis, such as impairment of smell, itching, and sneezing. The olfactory system has an amazing ability to distinguish thousands of odorant molecules at trace levels. However, there are many issues in olfactory sensing mechanisms that need to be addressed. Optogenetics offers a novel technical approach to solve this dilemma. Therefore, we review the recent advances in olfactory optogenetics to clarify the mechanisms of chemical sensing, which may help identify the mechanism of dysfunction and suggest possible treatments for impaired smell. Additionally, in rhinitis patients, alterations in the other nerve (trigeminal nerve) that innervates the nasal cavity can lead to hyperresponsiveness to various nociceptive stimuli and central sensitization, causing frequent and persistent itching and sneezing. In the last several years, the application of optogenetics in regulating nociceptive receptors, which are distributed in sensory nerve endings, and amino acid receptors, which are distributed in vital brain regions, to alleviate overreaction to nociceptive stimuli, has gained significant attention. Therefore, we focus on the progress in optogenetics and its application in neuromodulation of nociceptive stimuli and discuss the potential clinical translation for treating rhinitis in the future.

Chemical reception in vertebrate olfaction: evidence for multiple transduction pathways

Odorant detection takes place at the receptor neurons of the olfactory epithelium and odorant discrimination relies in an important degree on these chemosensory cells. Here we review the evidence for the participation of multiple transduction pathways in the mechanisms of odor recognition in olfactory neurons

Examen clínico de los pares craneales de interés odontológico / Clinical examination of the cranial pairs of dental interest

El objetivo principal de este trabajo consiste en presentar al lector una descripción de las técnicas de examen neurológico de los pares creneales que están en relación con el ejercicio de la odontología, como lo son el nervio oftálmico, trigémino, facial, glosofaríngeo, neumogástrico espinal e hipogloso

Origin of the telencephalic spindles of the toad Bufo paracnemis

Spindles (8-11 Hz and up to 100 uV in amplitude) recorded on the surface of the surface of the telencephalic hemispheres and olfaactory bulbs of the conscious toad disappear after transection between these two structures, indicating that their presence depends onm the integrity of their interconnections. Spindles continue to be present, although in reduced numbers, after transection between the hemispheres and the diencephalon, indicating that caudal regions are not essential for generating spindles but modulate the neurons responsible for spindle genesis. In contrast, the olfactoryy nerves, in addition to their known phasis activity on the spindles, exert a tonic action since after their section there is a change in the duration and amplitude of component waves