scholarly journals Experience-dependent plasticity in early stations of sensory processing in mature brains: effects of environmental enrichment on dendrite measures in trigeminal nuclei

2021 ◽  
Author(s):  
Yasmina B. Martin ◽  
Pilar Negredo ◽  
Carlos Avendaño
Keyword(s):  
Sensory Processing ◽  
Environmental Enrichment ◽  
Structural Changes ◽  
Environmental Changes ◽  
Afferent Input ◽  
Adult Rats ◽  
Dendritic Trees ◽  
Trigeminal Nuclei ◽  
Dendritic Length ◽  
Two Populations

AbstractNervous systems respond with structural changes to environmental changes even in adulthood. In recent years, experience-dependent structural plasticity was shown not to be restricted to the cerebral cortex, as it also occurs at subcortical and even peripheral levels. We have previously shown that two populations of trigeminal nuclei neurons, trigeminothalamic barrelette neurons of the principal nucleus (Pr5), and intersubnuclear neurons in the caudal division of the spinal trigeminal nucleus (Sp5C) that project to Pr5 underwent morphometric and topological changes in their dendritic trees after a prolonged total or partial loss of afferent input from the vibrissae. Here we examined whether and what structural alterations could be elicited in the dendritic trees of the same cell populations in young adult rats after being exposed for 2 months to an enriched environment (EE), and how these changes evolved when animals were returned to standard housing for an additional 2 months. Neurons were retrogradely labeled with BDA delivered to, respectively, the ventral posteromedial thalamic nucleus or Pr5. Fully labeled cells were digitally reconstructed with Neurolucida and analyzed with NeuroExplorer. EE gave rise to increases in dendritic length, number of trees and branching nodes, spatial expansion of the trees, and dendritic spines, which were less pronounced in Sp5C than in Pr5 and differed between sides. In Pr5, these parameters returned, but only partially, to control values after EE withdrawal. These results underscore a ubiquity of experience-dependent changes that should not be overlooked when interpreting neuroplasticity and developing plasticity-based therapeutic strategies.

scholarly journals Experience-Dependent Plasticity in Early Stations of Sensory Processing in Mature Brains: Effects of Environmental Enrichment On Dendrite Measures in Trigeminal Nuclei

2021 ◽  
Author(s):  
Yasmina B Martin ◽  
Pilar Negredo ◽  
Carlos Avendaño
Keyword(s):  
Sensory Processing ◽  
Environmental Enrichment ◽  
Structural Changes ◽  
Environmental Changes ◽  
Afferent Input ◽  
Adult Rats ◽  
Dendritic Trees ◽  
Trigeminal Nuclei ◽  
Dendritic Length ◽  
Two Populations

Abstract Nervous systems respond with structural changes to environmental changes even in adulthood. In recent years it has been shown that experience-dependent structural plasticity is not restricted to the cerebral cortex, but also occurs at subcortical and even peripheral levels. We have previously shown that two populations of trigeminal nuclei neurons, trigeminothalamic barrelette neurons of the principal nucleus (Pr5), and intersubnuclear neurons in the caudal division of the spinal trigeminal nucleus (Sp5C) that project to Pr5 underwent morphometric and topological changes in their dendritic trees after a prolonged total or partial loss of afferent input from the vibrissae. Here we examined whether and what structural alterations could be elicited in the dendritic trees of the same cell populations in young adult rats after being exposed for two months to an enriched environment (EE), and how these changes evolved when animals were returned to standard housing for an additional two months. Neurons were retrogradely labeled with dextran amine delivered to, respectively, the ventral posteromedial thalamic nucleus or Pr5. Fully labeled cells were digitally reconstructed with Neurolucida and analyzed with NeuroExplorer. EE gave rise to increases in dendritic length, number of trees and branching nodes, spatial expansion of the trees, and dendritic spines, which were less pronounced in Sp5C than in Pr5 and differed between sides. In Pr5 these parameters returned, but only partially, to control values after EE withdrawal. These results underscore a ubiquity of experience-dependent changes that should not be overlooked when interpreting neuroplasticity and developing plasticity-based therapeutic strategies.

scholarly journals Pathological transitions in myelin membranes driven by environmental and multiple sclerosis conditions

2018 ◽  
Vol 115 (44) ◽  
pp. 11156-11161 ◽  
Author(s):  
Rona Shaharabani ◽  
Maor Ram-On ◽  
Yeshayahu Talmon ◽  
Roy Beck
Keyword(s):  
Multiple Sclerosis ◽  
Phase Transition ◽  
Lipid Composition ◽  
Environmental Conditions ◽  
Structural Changes ◽  
Environmental Changes ◽  
Hexagonal Phase ◽  
Structural Phase ◽  
Structural Modifications ◽  
Transition Points

Multiple sclerosis (MS) is an autoimmune disease, leading to the destruction of the myelin sheaths, the protective layers surrounding the axons. The etiology of the disease is unknown, although there are several postulated environmental factors that may contribute to it. Recently, myelin damage was correlated to structural phase transition from a healthy stack of lamellas to a diseased inverted hexagonal phase as a result of the altered lipid stoichiometry and low myelin basic protein (MBP) content. In this work, we show that environmental conditions, such as buffer salinity and temperature, induce the same pathological phase transition as in the case of the lipid composition in the absence of MBP. These phase transitions have different transition points, which depend on the lipid’s compositions, and are ion specific. In extreme environmental conditions, we find an additional dense lamellar phase and that the native lipid composition results in similar pathology as the diseased composition. These findings demonstrate that several local environmental changes can trigger pathological structural changes. We postulate that these structural modifications result in myelin membrane vulnerability to the immune system attacks and thus can help explain MS etiology.

In Situ Study of The Exposure of Polycarbonate to an Argon Plasma

1995 ◽  
Vol 385 ◽  
Author(s):  
S. Vallon ◽  
B. Drevillon ◽  
F. Poncin-Epaillard ◽  
J. C. Rostaing
Keyword(s):  
Structural Changes ◽  
Argon Plasma ◽  
Silica Layer ◽  
Molecular Weights ◽  
In Situ Study ◽  
Polar Groups ◽  
Unit Scale ◽  
Two Populations ◽  
Polymer Unit

ABSTRACTThe exposure of polycarbonate to an argon plasma is studied using in situ ellipsometry from the UV to the IR, nuclear magnetic resonance and light scattering measurements. An increase in the refractive index and the existence of two populations of different molecular weights show that structural changes occur in the polymer. They are correlated with modifications at the polymer unit scale, such as formation of new polar groups and decrease in dimethyl groups. Two simultaneous reaction mechanisms must be considered to account for these changes. The adhesion of a silica layer on treated polycarbonate is then discussed.

scholarly journals Pairing Cholinergic Enhancement with Perceptual Training Promotes Recovery of Age-Related Changes in Rat Primary Auditory Cortex

2016 ◽  
Vol 2016 ◽  
pp. 1-18 ◽  
Author(s):  
Patrice Voss ◽  
Maryse Thomas ◽  
You Chien Chou ◽  
José Miguel Cisneros-Franco ◽  
Lydia Ouellet ◽  
...  
Keyword(s):  
Auditory Cortex ◽  
Structural Changes ◽  
Primary Auditory Cortex ◽  
Auditory Training ◽  
Tone Frequency ◽  
Perceptual Training ◽  
Adult Rats ◽  
Functional Changes ◽  
Age Related ◽  
Old Rats

We used the rat primary auditory cortex (A1) as a model to probe the effects of cholinergic enhancement on perceptual learning and auditory processing mechanisms in both young and old animals. Rats learned to perform a two-tone frequency discrimination task over the course of two weeks, combined with either the administration of a cholinesterase inhibitor or saline. We found that while both age groups learned the task more quickly through cholinergic enhancement, the young did so by improving target detection, whereas the old did so by inhibiting erroneous responses to nontarget stimuli. We also found that cholinergic enhancement led to marked functional and structural changes within A1 in both young and old rats. Importantly, we found that several functional changes observed in the old rats, particularly those relating to the processing and inhibition of nontargets, produced cortical processing features that resembled those of young untrained rats more so than those of older adult rats. Overall, these findings demonstrate that combining auditory training with neuromodulation of the cholinergic system can restore many of the auditory cortical functional deficits observed as a result of normal aging and add to the growing body of evidence demonstrating that many age-related perceptual and neuroplastic changes are reversible.

scholarly journals Acid–base physiology over tidal periods in the mussel Mytilus edulis : size and temperature are more influential than seawater pH

2019 ◽  
Vol 286 (1897) ◽  
pp. 20182863 ◽  
Author(s):  
Stephanie Mangan ◽  
Rod W. Wilson ◽  
Helen S. Findlay ◽  
Ceri Lewis
Keyword(s):  
Mytilus Edulis ◽  
Environmental Changes ◽  
Interactive Effect ◽  
Marine Biota ◽  
Acid Base ◽  
Tidal Cycles ◽  
Seawater Ph ◽  
Seawater Carbonate Chemistry ◽  
Two Populations

Ocean acidification (OA) studies to date have typically used stable open-ocean pH and CO 2 values to predict the physiological responses of intertidal species to future climate scenarios, with few studies accounting for natural fluctuations of abiotic conditions or the alternating periods of emersion and immersion routinely experienced during tidal cycles. Here, we determine seawater carbonate chemistry and the corresponding in situ haemolymph acid–base responses over real time for two populations of mussel ( Mytilus edulis ) during tidal cycles, demonstrating that intertidal mussels experience daily acidosis during emersion. Using these field data to parameterize experimental work we demonstrate that air temperature and mussel size strongly influence this acidosis, with larger mussels at higher temperatures experiencing greater acidosis. There was a small interactive effect of prior immersion in OA conditions (pH NBS 7.7/pCO 2 930 µatm) such that the haemolymph pH measured at the start of emersion was lower in large mussels exposed to OA. Critically, the acidosis induced in mussels during emersion in situ was greater (ΔpH approximately 0.8 units) than that induced by experimental OA (ΔpH approximately 0.1 units). Understanding how environmental fluctuations influence physiology under current scenarios is critical to our ability to predict the responses of key marine biota to future environmental changes.

Importance of vagal afferents in determining ventilation in newborn rats

1988 ◽  
Vol 65 (3) ◽  
pp. 1033-1039 ◽  
Author(s):  
L. Fedorko ◽  
E. N. Kelly ◽  
S. J. England
Keyword(s):  
Afferent Input ◽  
Vagal Afferents ◽  
Newborn Rats ◽  
Inspiratory Time ◽  
Adult Rats ◽  
Peripheral Chemoreceptor ◽  
Air Breathing ◽  
Ventilatory Pattern ◽  
Threefold Increase ◽  
Bilateral Vagotomy

We studied the effect of acute bilateral vagotomy on ventilation and ventilatory pattern in rats. In 1- to 6-day-old unanesthetized rats, vagotomy resulted in a substantial decrease (38%) in ventilation during air breathing. After vagotomy there was a threefold increase in tidal volume (VT), inspiratory time (TI) doubled, and expiratory time (TE) was six times longer. When studied under isoflurane anesthesia, newborn rats showed decreases in ventilation similar to that observed without anesthesia, whereas anesthetized adult rats had no consistent changes in ventilation. Adult and newborn rats had nearly identical proportionate increases in VT and TI after vagotomy, but TE lengthened to a greater extent in the newborns. Additionally, we demonstrated a significant decrease in ventilation when 100% O2 rather than air was supplied to nonvagotomized unanesthetized newborn rats. Ventilation decreased by 19% after vagotomy under hyperoxic conditions. We conclude that vagal afferent input, probably of pulmonary mechanoreceptor origin, provides positive feedback to respiration in newborn rats and that newborn rats greater than 24 h old also have a degree of peripheral chemoreceptor drive during air breathing.

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