Recovery of glomerular morphology in the olfactory bulb of young mice after disruption caused by continuous odorant exposure.

Olfactory glomeruli are the first synaptic site of the olfactory system and are formed by the convergence of axons of the same type of sensory neurons onto the olfactory bulbs of the brain. Although the anatomical organization of glomeruli is conserved across species, their particular role in olfactory processing remains uncertain. We studied the composition and maintenance of glomeruli by means of a genetic model, mI7-IRES-tauGFP knock-in young mice, where the cytoskeleton of sensory neurons expressing the mI7 olfactory receptor is tagged with green fluorescent protein. Animals were continuously exposed to heptaldehyde, a cognate ligand of the mI7 receptor, from postnatal days 5-10. We hypothesized that continuous odorant exposure will induce changes in glomerular morphology, and that this can be recovered if the normal odorant environment is reestablished within the early postnatal period. We assessed changes in the distribution of mI7 axons in glomerular morphology, as well as possible changes in the number of the mI7 olfactory sensory neurons. Following odorant exposure the well-defined convergence of mI7 fibers into a single glomerulus was disrupted, producing numerous neighboring glomeruli partially innervated by mI7 fibers. After the normal odor environment was reestablished the number of glomeruli partially innervated by mI7 fibers decreased significantly. Moreover, we found that multiple supernumerary mI7 glomeruli were formed. Our results confirm the significant role of sensory input in glomerular formation and maintenance. Additionally, we show that the developing olfactory system actively maintains glomerular morphology, suggesting the importance of this for olfactory processing.

The body as constitutive element phenomenology and psychoanalysis on our view of ourselves and others.

The aim of this manuscript is to highlight that from the phenomenology and psychoanalysis point of view, the meaning of the notion of the body is different from the medical biologicist discourse. In psychoanalysis, the body is an erogenized body. It is constituted as an object for another self. Similarly, in phenomenology, the body is an own body in first instance. It is the body of a self, rather than a living body and a material body. Both positions enable us to understand how this conceptualization of the body is essential in any human field. Especially in the clinic, the position of the subject before the other will lead to a specific form of intervention. From this understanding of the human body, both phenomenology and psychoanalysis confirm that the biologicist understanding of the body, presumed by all psychological and medical practices, is insufficient.

Chromaffin cell transplants: from the lab to the clinic.

Chromaffin cell transplants have been explored since the early 1980s as a promising alternative in different pathological states, mainly Parkinson's disease and chronic pain. Advances are significant since transplants have been performed in humans. The general mechanism of these transplants relies in the capacity of chromaffin cells to act as mini-pumps that release amines and peptides. Different strategies are being used to improve the efficacy of transplants. However, a remaining hurdle is to determine the viability across time and the interaction with the microenvironment of the graft. We analyzed previous and current results finding that although there is a lot of positive evidence, there is also a lack of molecular studies that support behavioral results. The present review gives an update on recent advances of chromaffin cell transplants and their future in the clinic.

Precision rodent whisker stimulator with integrated servo-locked control and displacement measurement.

We developed a high speed voice coil based whisker stimulator that delivers precise deflections of a single whisker or group of whiskers in a repeatable manner. The device is miniature, quiet, and inexpensive to build. Multiple stimulators fit together for independent stimulation of four or more whiskers. The system can be used with animals under anesthesia as well as awake animals with head-restraint, and does not require trimming the whiskers. The system can deliver 1-2 mm deflections in 2 ms resulting in velocities up to 900 mm/s to attain a wide range of evoked responses. Since auditory artifacts can influence behavioral studies using whisker stimulation, we tested potential effects of auditory noise by recording somatosensory evoked potentials (SEP) with varying auditory click levels, and with/without 80 dBa background white noise. We found that auditory clicks as low as 40 dBa significantly influence the SEP. With background white noise, auditory clicks as low as 50 dBa were still detected in components of the SEP. For behavioral studies where animals must learn to respond to whisker stimulation, these sounds must be minimized. Together, the stimulator and data system can be used for psychometric vigilance tasks, mapping of the barrel cortex and other electrophysiological paradigms.