Untying My Tongue

Untying My Tongue by Raynise Cang

Imaging Circuit Activity in the Rat Brain with Fast Neural EIT and Depth Arrays

Few techniques are specialized for neuroscience at the 'mesoscopic' level of neural circuits. Fast neural electrical impedance tomography (fnEIT) is a novel imaging technique that offers affordability, portability, and high spatial (∼100 μm) and temporal (1 ms) resolution. fnEIT with depth arrays offers the opportunity to study the dynamics of circuits in the brains of animal models. However, current depth array geometries are not optimized for this imaging modality. They feature small, closely packed electrodes with high impedance that do not provide sufficient SNR for high resolution EIT image reconstruction. They also have a highly limited range. It is necessary to develop depth arrays suitable for fnEIT and evaluate their performance in a representative setting for circuit neuroscience. In this study, we optimized the geometry of depth arrays for fnEIT, and then investigated the prospects of imaging thalamocortical circuit activity in the rat brain. Optimization was consistent with the hypothesis that small, closely spaced electrodes were not suitable for fnEIT. In vivo experiments with the optimized geometry then showed that fnEIT can image thalamocortical circuit activity at a high enough resolution to see the activity propagating from specific thalamic nuclei to specific regions of the somatosensory cortex. This bodes well for fnEIT's potential as a technique for circuit neuroscience

Nesting Environment Provides Sex-Specific Neuroprotection in a Rat Model of Neonatal Hypoxic-Ischemic Injury

Hypoxic-ischemic (HI) encephalopathy is a devastating injury that occurs when the fetal brain is deprived of oxygen and blood to a degree that may lead to neurological damage, seizing and cerebral palsy. In rodents, early environmental enrichment that promotes maternal care-taking behavior (mCTB) can improve neurobehavioral outcomes and protect against neurological decline. We hypothesized that an enhanced nesting environment would improve mCTB as measured by pup weight gain, and support greater HI recovery in developing rats. Pregnant dams (E15-16) were introduced to either control Standard Facility (SF) housing or closed nestbox (CN) conditions and maintained in larger cages through pup weaning. On postnatal day (PND) 7, male and female Long-Evans rat pups (N = 73) were randomly sorted into one of two surgical conditions: control and HI. HI pups received isoflurane anesthesia and right carotid artery ligation, a 2-h rest followed by 90 min exposure to a moist hypoxic (92% N, 8% O2) chamber. Pups (PND 8) were weighed daily, and tested on the Morris Water Maze (MWM) task (PND 35-50). Results demonstrate significant differences afforded to male and female pups based on weight measure, where CN-rearing modifies pre-weaning adolescent weights in females and increases post-weaning weights in males and females by an average of 10 g. Following successful MWM training and acquisition (PND 35-37), both male and female CN-raised animals demonstrated faster latency to find the hidden platform (HP) during HP trials (PND 38-42) and appeared to freely explore the MWM pool during an additional probe trial (PND 43). Moreover, after sacrifice (PND 60), CN rearing created sex-specific alterations in brain-derived neurotrophic factor (BDNF), glial-derived neurotrophic factor (GDNF) immunopositive cell staining of the dorsomedial striatum and CA1 of the hippocampus. CN-rearing afforded HI males higher BDNF levels in the striatum and produced greater GDNF levels in the hippocampus of HI-injured females. These results suggest that early life environmental enrichment positively modifies nesting environment, increases weight gain, as well as spatial learning and memory in a sex-specific directionality. Our findings also implicate correlative changes in corticolimbic neurotrophin protein levels in the CN-reared animals that may contribute to these benefits

Centcelles y el praetorium del comes Hispaniarum Asterio en Tarraco

This article presents a new chronological and functional interpretation for the Late Roman building of Centcelles (Tarraco), which hinges on an archaeological and architectural analysis of the building, according to the historical and archaeological context of the period. The arguments presented allow one to date the building in the first half of the 5th century, and to identify it as the central area of a Late Roman military camp located next to the urban centre of Tarraco, the city that appears in written sources as being the base for the Imperial armies which tried to reintegrate the whole Hispania to the legitimate power in the West during most of the 5th century. We have at our disposal an exceptional document for the period: Consentius’ Epistle 11, thanks to which we know about the comes Hispaniarum Asterius staying in Tarraco ca. 420 and his residence, the praetorium, where he himself lived together with his daughter and the army which went with him to the campaign. We propose to identify Centcelles with the military base of Asterius and the army in Tarraco. We also put forward some preliminary considerations regarding the decoration of the domed room, still in progress, in accordance with the new function and chronology.Se presenta una nueva propuesta de interpretación cronológica y funcional para el edificio tardorromano de Centcelles (Tarraco), que descansa en el análisis arqueológico y arquitectónico del edificio, de acuerdo con el contexto histórico–arqueológico del período. Los argumentos aportados nos llevan a datar el edificio en la primera mitad del siglo V y a identificarlo como el área central de un campamento tardío emplazado junto al núcleo urbano de Tarraco, ciudad que aparece mencionada en los textos como la base de operaciones de los ejércitos imperiales que durante buena parte del siglo V intentaron reintegrar el conjunto de Hispania al poder legítimo de Occidente. Contamos para este período con un documento excepcional, la Epístola 11 de Consencio, donde se nos informa de la presencia en Tarraco, hacia el año 420, del comes Hispaniarum Asterio y su residencia, el praetorium, donde vivía con su hija y el ejército que le acompañaba en la campaña. Nuestra propuesta plantea identificar Centcelles con el campamento base de Asterio y su ejército en Tarraco. Se presentan, también, algunas consideraciones preliminares sobre la decoración de la sala de la cúpula de acuerdo con la nueva función y cronología, todavía en un estadio incipiente de desarrollo

Effet du voisinage phonologique sur la performance en mémoire de travail verbale au cours du vieillissement

L’objectif de cette recherche est d’observer l’effet du voisinage phonologique (VPH) sur la performance en mémoire de travail (MdT) verbale au cours du vieillissement. Deux mots sont voisins lorsqu’ils ne diffèrent que par un phonème. Nous retrouvons des interprétations contradictoires du phénomène de voisinage phonologique et la différence d’effet entre plusieurs groupes d’âge a peu été étudiée. Trois groupes d’âge ont effectué une tâche d’empan complexe avec une manipulation du voisinage phonologique: des adultes jeunes entre 20 et 35 ans, des adultes entre 35 et 55 ans et des adultes âgés entre 60 et 70 ans. Nous trouvons un effet facilitateur du VPH sur les performances en MdT verbale, mais aucune différence d’âge n’est relevée..