bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sensory and cortical activation of distinct glial cell subtypes in the somatosensory thalamus of young rats
Authors: Parri H. Rheinallt , Gould Timothy M. , Crunelli Vincenzo 
Published: July 2010

AbstractThe rodent ventrobasal (VB) thalamus receives sensory inputs from the whiskers and projects to the cortex, from which it receives reciprocal excitatory afferents. Much is known about the properties and functional roles of these glutamatergic inputs to thalamocortical neurons in the VB, but no data are available on how these afferents can affect thalamic glial cells. In this study, we used combined electrophysiological recordings and intracellular calcium ([Ca2+]i) imaging to investigate glial cell responses to synaptic afferent stimulation. VB thalamus glial cells can be divided into two groups based on their [Ca2+]i and electrophysiological responses to sensory and corticothalamic stimulation. One group consists of astrocytes, which stain positively for S100B and preferentially load with SR101, have linear current–voltage relations and low input resistance, show no voltage‐dependent [Ca2+]i responses, but express mGluR5‐dependent [Ca2+]i transients following stimulation of the sensory and/or corticothalamic excitatory afferent pathways. Cells of the other glial group, by contrast, stain positively for NG2, and are characterized by high input resistance, the presence of voltage‐dependent [Ca2+]i elevations and voltage‐gated inward currents. There were no synaptically induced [Ca2+]i elevations in these cells under control conditions. These results show that thalamic glial cell responses to synaptic input exhibit different properties to those of thalamocortical neurons. As VB astrocytes can respond to synaptic stimulation and signal to neighbouring neurons, this glial cell organization may have functional implications for the processing of somatosensory information and modulation of behavioural state‐dependent thalamocortical network activities.
Environmental impoverishment and aging alter object recognition, spatial learning, and dentate gyrus astrocytes
Authors: Diniz Daniel G. , Foro César A. R. , Rego Carla M. D. , Gloria David A. , De Oliveira Fabio R. R. , Paes Juliana M. P. , De Sousa Aline A. , Tokuhashi Tatyana P. , Trindade Lucas S. , Turiel Maíra C. P. , Vasconcelos Erick G. R. , Torres João B. , Cunnigham Colm , Perry Victor H. , Da Costa Vasconcelos Pedro F. , Diniz Cristovam W. P. 
Published: July 2010

AbstractEnvironmental and age‐related effects on learning and memory were analysed and compared with changes observed in astrocyte laminar distribution in the dentate gyrus. Aged (20 months) and young (6 months) adult female albino Swiss mice were housed from weaning either in impoverished conditions or in enriched conditions, and tested for episodic‐like and water maze spatial memories. After these behavioral tests, brain hippocampal sections were immunolabeled for glial fibrillary acid protein to identify astrocytes. The effects of environmental enrichment on episodic‐like memory were not dependent on age, and may protect water maze spatial learning and memory from declines induced by aging or impoverished environment. In the dentate gyrus, the number of astrocytes increased with both aging and enriched environment in the molecular layer, increased only with aging in the polymorphic layer, and was unchanged in the granular layer. We suggest that long‐term experience‐induced glial plasticity by enriched environment may represent at least part of the circuitry groundwork for improvements in behavioral performance in the aged mice brain.
Two types of Ca2+ channel linked to two endocytic pathways coordinately maintain synaptic transmission at the Drosophila synapse
Authors: Kuromi H. , Ueno K. , Kidokoro Y. 
Published: July 2010

AbstractEndocytosis at the presynaptic terminal is initiated by Ca2+ influx through voltage‐gated Ca2+ channels. At the Drosophila neuromuscular junction, we demonstrated two components of endocytosis linked to distinct Ca2+ channels. A voltage‐gated Ca2+ channel blocker, (R)‐(+)‐Bay K8644 (R‐BayK), selectively blocked one component (R‐BayK‐sensitive component) without affecting exocytosis, while low concentrations of La3+ preferentially depressed the other component (La3+ ‐sensitive component). In a temperature‐sensitive mutant, shibirets, at non‐permissive temperatures, dynamin clusters were found immunohistochemically at the active zone (AZ) during the R‐BayK‐sensitive endocytosis, while they were detected at the non‐AZ during the La3+‐sensitive endocytosis. Immunostaining of the Ca2+ channel α2δ subunit encoded by straightjacket (stj) was found within the AZ, and a mutation in stj depressed the R‐BayK‐sensitive component but enhanced the La3+ ‐sensitive one, indicating that the α2δ subunit is associated with the R‐BayK‐sensitive Ca2+ channel. Filipin bound to the non‐AZ membrane and inhibited the La3+ ‐sensitive component, but not the R‐BayK‐sensitive one. We concluded that the R‐BayK‐sensitive component of endocytosis occurred at the AZ and termed this AZ endocytosis. We also concluded that the La3+ ‐sensitive component occurred at the non‐AZ and termed this non‐AZ endocytosis. These two types of endocytosis were modulated by various drugs towards opposite directions, indicating that they were differentially regulated. During high‐frequency stimulation, AZ endocytosis operated mainly in the early phase, whereas non‐AZ endocytosis operated in the late phase. Thus, intense synaptic transmission is coordinately maintained by synaptic vesicle recycling initiated by Ca2+ influx through the two types of Ca2+ channel.
Neuronal disinhibition in the trigeminal nucleus caudalis in a model of chronic neuropathic pain
Authors: Martin Yasmina B. , Malmierca Eduardo , Avendaño Carlos , Nuñez Angel 
Published: July 2010

AbstractThe mechanisms underlying neuropathic facial pain syndromes are incompletely understood. We used a unilateral chronic constriction injury of the rat infraorbital nerve (CCI‐IoN) as a facial neuropathic model. Pain‐related behavior of the CCI‐IoN animals was tested at 8, 15 and 26 days after surgery (dps). The response threshold to mechanical stimulation with von Frey hairs on the injured side was reduced at 15 and 26 dps, indicating the presence of allodynia. We performed unitary recordings in the caudalis division of the spinal trigeminal nucleus (Sp5C) at 8 or 26 dps, and examined spontaneous activity and responses to mechanical and thermal stimulation of the vibrissal pad. Neurons were identified as wide dynamic range (WDR) or low‐threshold mechanoreceptive (LTM) according to their response to tactile and/or noxious stimulation. Following CCI‐IoN, WDR neurons, but not LTM neurons, increased their spontaneous activity at 8 and 26 dps, and both types of Sp5C neurons increased their responses to tactile stimuli. In addition, the on–off tactile response in neurons recorded after CCI‐IoN was followed by afterdischarges that were not observed in control cases. Compared with controls, the response inhibition observed during paired‐pulse stimulation was reduced after CCI‐IoN. Immunohistochemical studies showed an overall decrease in GAD65 immunoreactivity in Sp5C at 26 dps, most marked in laminae I and II, suggesting that following CCI‐IoN the inhibitory circuits in the sensory trigeminal nuclei are depressed. Consequently, our results strongly suggest that disinhibition of Sp5C neurons plays a relevant role in the appearance of allodynia after CCI‐IoN.
Developmental increase in D1‐like dopamine receptor‐mediated inhibition of glutamatergic transmission through P/Q‐type channel regulation in the basal forebrain of rats
Authors: Momiyama Toshihiko 
Published: July 2010

AbstractWhole‐cell patch‐clamp recordings of non‐N‐methyl‐d‐aspartate glutamatergic excitatory postsynaptic currents (EPSCs) were carried out from cholinergic neurons in slices of basal forebrain (BF) of developing rats aged 21–42 postnatal days to elucidate postnatal developmental change in Ca2+ channel subtypes involved in the transmission as well as that in dopamine D1‐like receptor‐mediated presynaptic inhibition. The amplitude of EPSCs was inhibited by bath application of ω‐conotoxin GVIA (ω‐CgTX; 3 μm) or ω‐agatoxin‐TK (ω‐Aga‐TK; 200 nm) throughout the age range examined, suggesting that multiple types of Ca2+ channel are involved in the transmission. The EPSC fraction reduced by ω‐CgTX decreased with age, whereas that reduced by ω‐Aga‐TK increased. Inhibition of the EPSCs by a D1‐like receptor agonist, SKF 81297 (SKF; 30 μm) increased with age in parallel with the increase in ω‐Aga‐TK‐induced inhibition. An activator of the adenylyl cyclase (AC) pathway, forskolin (FK; 10 μm) inhibited the EPSCs, and FK‐induced inhibition also increased with age in parallel with the increase in SKF‐induced inhibition. Throughout the age range examined, SKF showed no further inhibitory effect on the EPSCs after ω‐Aga‐TK‐ or FK‐induced effect had reached steady‐state. These findings suggest that D1‐like receptor‐mediated presynaptic inhibition of glutamate release onto cholinergic BF neurons increases with age, and that the change is coupled with a developmental increase in the contribution of P/Q‐type Ca2+ channels as well as a developmental increase in AC pathway contribution.
Stability of subicular place fields across multiple light and dark transitions
Authors: Brotons‐Mas Jorge R. , Montejo Noelia , O’Mara Shane M. , Sanchez‐Vives Maria V. 
Published: July 2010

AbstractAlthough hippocampal CA1 place cells can be strongly modulated by visual inputs, the effect of visual modulation on place cells in other areas of the hippocampal formation, such as the subiculum, has been less extensively explored. Here, we investigated the role of visual inputs on the activity of subicular place cells by manipulating ambient light levels while freely‐moving rats foraged for food. Rats were implanted with tetrodes in the dorsal subiculum and units were recorded while the animal performed a pellet‐chasing task during multiple light‐to‐dark and dark‐to‐light transitions. We found that subicular place fields presented a somewhat heterogeneous response to light–dark transitions, with 45% of pyramidal units showing stable locational firing across multiple light–dark–light transitions. These data suggest that visual inputs may participate in spatial information processing by the subiculum. However, as a plurality of units was stable across light–dark transitions, we suggest that the subiculum supports, probably in association with the grid cells of the entorhinal cortex, the neurocognitive processing underlying path integration.
Night‐time neuronal activation of Cluster N in a day‐ and night‐migrating songbird
Authors: Zapka Manuela , Heyers Dominik , Liedvogel Miriam , Jarvis Erich D. , Mouritsen Henrik 
Published: July 2010

AbstractMagnetic compass orientation in a night‐migratory songbird requires that Cluster N, a cluster of forebrain regions, is functional. Cluster N, which receives input from the eyes via the thalamofugal pathway, shows high neuronal activity in night‐migrants performing magnetic compass‐guided behaviour at night, whereas no activation is observed during the day, and covering up the birds’ eyes strongly reduces neuronal activation. These findings suggest that Cluster N processes light‐dependent magnetic compass information in night‐migrating songbirds. The aim of this study was to test if Cluster N is active during daytime migration. We used behavioural molecular mapping based on ZENK activation to investigate if Cluster N is active in the meadow pipit (Anthus pratensis), a day‐ and night‐migratory species. We found that Cluster N of meadow pipits shows high neuronal activity under dim‐light at night, but not under full room‐light conditions during the day. These data suggest that, in day‐ and night‐migratory meadow pipits, the light‐dependent magnetic compass, which requires an active Cluster N, may only be used during night‐time, whereas another magnetosensory mechanism and/or other reference system(s), like the sun or polarized light, may be used as primary orientation cues during the day.
Neural correlates of binaural masking level difference in the inferior colliculus of the barn owl (Tyto alba)
Authors: Asadollahi Ali , Endler Frank , Nelken Israel , Wagner Hermann 
Published: July 2010

AbstractHumans and animals are able to detect signals in noisy environments. Detection improves when the noise and the signal have different interaural phase relationships. The resulting improvement in detection threshold is called the binaural masking level difference. We investigated neural mechanisms underlying the release from masking in the inferior colliculus of barn owls in low‐frequency and high‐frequency neurons. A tone (signal) was presented either with the same interaural time difference as the noise (masker) or at a 180° phase shift as compared with the interaural time difference of the noise. The changes in firing rates induced by the addition of a signal of increasing level while masker level was kept constant was well predicted by the relative responses to the masker and signal alone. In many cases, the response at the highest signal levels was dominated by the response to the signal alone, in spite of a significant response to the masker at low signal levels, suggesting the presence of occlusion. Detection thresholds and binaural masking level differences were widely distributed. The amount of release from masking increased with increasing masker level. Narrowly tuned neurons in the central nucleus of the inferior colliculus had detection thresholds that were lower than or similar to those of broadly tuned neurons in the external nucleus of the inferior colliculus. Broadly tuned neurons exhibited higher masking level differences than narrowband neurons. These data suggest that detection has different spectral requirements from localization.
Unitized representation of paired objects in area 35 of the macaque perirhinal cortex
Authors: Fujimichi Ryoko , Naya Yuji , Koyano Kenji W. , Takeda Masaki , Takeuchi Daigo , Miyashita Yasushi 
Published: July 2010

AbstractThe perirhinal cortex, which is critical for long‐term stimulus–stimulus associative memory, consists of two cytoarchitectonically distinct subdivisions: area 35 (A35) and area 36 (A36). Previous electrophysiological studies suggested that macaque A36 is involved in both association and retrieval processes during a visual pair‐association task. However, the neuronal properties of macaque A35 have never been examined because A35 is located in a very narrow region, which makes it difficult to systematically record single‐unit activity from there. In the present study, we overcame this technical difficulty for targeting A35 by combining magnetic resonance imaging‐guided in‐vivo localization with postmortem histological localization. This two‐track approach enabled us to record from 181 A35 neurons in two macaque monkeys while they performed a pair‐association task. Among these neurons, 64 showed stimulus‐selective responses during the cue period (cue‐selective neurons), whereas 18 did during the delay period (delay‐selective neurons). As in A36, the responses of cue‐selective neurons in A35 to paired associates were correlated. In both areas, these correlations were stronger in neurons showing delay selectivity than in those without delay selectivity. Notably, delay‐selective neurons in A35 responded similarly to the optimal stimulus and its paired associate, whereas delay‐selective neurons in A36 discriminated between them. However, these neurons in both areas discriminated the primary pair, consisting of the optimal stimulus and its paired associate, from other pairs, indicating that selectivity across pairs was maintained between the two areas. These results suggest that delay‐selective neurons in A35 represent these paired stimuli as a single unitized item rather than two associated items.
Toxic cascades: multiple anthropogenic stressors have complex and unanticipated interactive effects on temperate reefs
Authors: Shears Nick T. , Ross Philip M. 
Published: July 2010

Ecology Letters (2010) 13: 1149–1159AbstractIn a changing environment multiple anthropogenic stressors can have novel and non‐additive effects on interacting species. We investigated the interactive effects of fishing and harmful algal blooms on the predator‐sea urchin‐macroalgae trophic cascade. Fishing of urchin predators had indirect negative effects on macroalgae, whereas blooms of epi‐benthic dinoflagellates (Ostreopsis siamensis) were found to have strong negative effects on urchins and indirect positive effects on macroalgae. Based on these opposing effects, blooms were expected to counteract the cascading effects of fishing. However, a large bloom of Ostreopsis led to greater divergence in macroalgae abundance between reserve and fished sites, as urchins declined at reserve sites but remained stable at fished sites. This resulted from enhanced predation rates on bloom‐affected urchins at reserve sites rather than direct lethal effects of Ostreopsis on urchins. We argue that interacting stressors can facilitate or attenuate trophic cascades depending on stressor intensity and complex non‐lethal interactions.
Controversial aspects of rectal cancer surgery following preoperative chemoradiation
Authors: Artioukh D. Y. 
Published: July 2010

AbstractThe role of surgery in the loco‐regional control of adenocarcinoma of the rectum is being increasingly challenged by the good response rates of neoadjuvant oncological treatment. This review represents an opinion paper outlining well‐established choices and new trends in surgical intervention, unresolved difficulties of local and regional staging of rectal malignancy and accurate assessment of tumour response to preoperative downstaging chemoradiation. The influence of preoperative chemoradiation on subsequent surgical strategy is discussed highlighting several controversial aspects of surgical management both when the tumour fails to respond and appears to be irresectable and when complete clinical response is observed.
Cardiopulmonary bypass and renal cell carcinoma with level IV tumour thrombus: can deep hypothermic circulatory arrest limit perioperative mortality?
Authors: Shuch Brian , Crispen Paul L. , Leibovich Bradley C. , LaRochelle Jeff C. , Pouliot Frederic , Pantuck Allan J. , Liu Weiqing , Crepel Maxime , Schuckman Anne , Rigaud Jerome , Bouchot Oliver , Patard Jean‐Jacques , Skinner Donald , Belldegrun Arie S. , Blute Michael L. 
Published: July 2010

Study Type – Therapy (case series)Level of Evidence 4 What’s known on the subject? and What does the study add? Removal of a renal cell carcinoma with a level IV tumour thrombus is a challenging surgery and generally is performed in a tertiary care centre. Performing these cases generally requires a multi‐disciplinary approach consisting of urological and vascular/cardiovascular surgeons.This study sheds light on the high surgical morbidity and mortality of these cases even at experienced centres. For patients requiring cardiopulmonary bypass, approximately 20% may not survive. In these challenging surgeries, deep hypothermic circulatory arrest may limit mortality and further studies should investigate the protective effect of this modality.OBJECTIVE• To review experience with nephrectomy/thrombectomy for a renal cell carcimoma (RCC) with a level IV tumour thrombus and to evaluate the benefit of deep hypothermic circulatory arrest (DHCA) with cardiopulmonary bypass (CPBP).PATIENTS AND METHODS• A multi‐institutional retrospective database was created to assess the outcomes of surgery for RCC and associated level IV tumour thrombus from 1983 to 2007. Patients were identified based on radiographic records/operative findings.• Only cases using CPBP were analysed. Clinicopathological and operative characteristics including use of DHCA were recorded.• Overall survival (OS) for all patients and by use of DHCA was assessed. Comparisons of clinical and operative characteristics by use of DHCA were performed.• A Cox regression model determined predictors of perioperative/in‐hospital mortality.RESULTS• In all, 63 patients underwent resection with CPBP; overall perioperative mortality was 22.2%.• There were no significant differences in clinicopathological characteristics, operative duration, estimated blood loss, transfusions, and hospital stay by use of DHCA.• Perioperative mortality rate was lower in patients undergoing DHCA (8.3% vs 37.5%, P= 0.006).• The median OS was longer for the patients undergoing DHCA (15.8 vs 7.7 months); however, this failed to reach statistical significance (P= 0.357).• On multivariate analysis, age of >60 years (hazard ratio [HR] 6.7, 95% confidence interval [CI] 1.5–31.1, P= 0.015) and the use of DHCA (HR 0.13, 95% CI 0.036–0.51, P= 0.003) were independent predictors of perioperative mortality.CONCLUSIONS• Radical nephrectomy and level IV tumour thrombectomy is associated with significant mortality.• The use of DHCA does not appear to adversely affect operative characteristics and may limit perioperative mortality.• Further prospective studies should be performed to confirm the benefit of DHCA.
Fear of hypoglycaemia in adults with Type 1 diabetes
Authors: Anderbro T. , Amsberg S. , Adamson U. , Bolinder J. , Lins P.‐E. , Wredling R. , Moberg E. , Lisspers J. , Johansson U.‐B. 
Published: July 2010

Diabet. Med. 27, 1151–1158 (2010)AbstractAims  The aim of this study was to examine the fear of hypoglycaemia and its association with demographic and disease‐specific variables in a large and unselective population of adult patients with Type 1 diabetes.Methods  Questionnaires were sent by post to all patients with Type 1 diabetes who were identified in the local diabetes registries of two hospitals in Stockholm, Sweden (n = 1387). Fear of hypoglycaemia was measured using the Swedish Hypoglycaemia Fear Survey, the Worry subscale and the Aloneness subscale. Demographic variables and disease‐specific factors were collected from patients’ self reports and medical records. Univariate analysis and multiple stepwise linear regression analysis were used in the statistical analyses of the data.Results  Seven hundred and sixty‐four (55%) patients participated in the study (mean age 43.3 years and mean HbA1c 7.0%, normal < 5.0%). The Hypoglycaemia Fear Survey ‐ Worry subscale was significantly associated with frequency of severe hypoglycaemia, number of symptoms during mild hypoglycaemia, gender, hypoglycaemic symptoms during hyperglycaemia and hypoglycaemic unawareness. The Hypoglycaemia Fear Survey ‐ Aloneness subscale was significantly associated with frequency of severe hypoglycaemia, number of symptoms during mild hypoglycaemia, gender, frequency of mild hypoglycaemia, HbA1c, hypoglycaemic unawareness and visits to the emergency room because of severe hypoglycaemia. Fear of hypoglycaemia proved to be more prevalent in females and indicated a different pattern between genders in relation to factors associated with fear of hypoglycaemia.Conclusions  This study identifies the frequency of severe hypoglycaemia as the most important factor associated with fear of hypoglycaemia. Moreover, for the first time, we document gender differences in fear of hypoglycaemia, suggesting that females are more affected by fear of hypoglycaemia than men.