Publications by authors named "Alessandro Graziano"

17 Publications

  • Page 1 of 1

Life-Saving Procedures Performed While Wearing CBRNe Personal Protective Equipment: A Mannequin Randomized Trial.

Simul Healthc 2021 Jan 8;Publish Ahead of Print. Epub 2021 Jan 8.

From the Department of Medicine (DIMED) (G.M., M.P., C.A., S.S., F.F.), University of Padova, Padova; Venice Emergency Medical Service Operations Center (N.B., D.P.), Venezia; and Istituto di Anestesia e Rianimazione-Azienda Ospedaliera Universitaria di Padova (A.G., P.N.), Padova, Italy.

Introduction: Chemical-biological-radiological-nuclear-explosive (CBRNe) are complex events. Decontamination is mandatory to avoid harm and contain hazardous materials, but can delay care. Therefore, the stabilization of patients in the warm zone seems reasonable, but research is limited. Moreover, subjects involved in biological events are considered infectious even after decontamination and need to be managed while wearing personal protective equipment (PPE), as seen with Ebola and COVID-19 pandemic. With this simulation mannequin trial, we assessed the impact of CBRNe PPE on cardiopulmonary resuscitation and combat casualty care procedures.

Methods: We compared procedures performed by emergency medicine and anesthesiology senior residents, randomized in 2 groups (CBRNe PPE vs. no PPE). Chest compression (CC) depth was defined as the primary outcome. Time to completion was calculated for the following: tourniquet application; tension pneumothorax needle decompression; peripheral venous access (PVA) and intraosseous access positioning; and drug preparation and administration. A questionnaire was delivered to evaluate participants' perception.

Results: Thirty-six residents participated. No significant difference between the groups in CC depth (mean difference = 0.26 cm [95% confidence interval = -0.26 to 0.77 cm, P = 0.318]), as well as for CC rate, CC complete release, and time for drugs preparation and administration was detected. The PPE contributed to significantly higher times for tourniquet application, tension pneumothorax decompression, peripheral venous access, and intraosseous access positioning. The residents found simulation relevant to the residencies' core curriculum.

Conclusions: This study suggests that cardiopulmonary resuscitation can be performed while wearing PPE without impacting quality, whereas other tasks requiring higher dexterity can be significantly impaired by PPE.Trial Registration Number: NCT04367454, April 29, 2020 (retrospectively registered).
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http://dx.doi.org/10.1097/SIH.0000000000000540DOI Listing
January 2021

Use of critical care resources during the first 2 weeks (February 24-March 8, 2020) of the Covid-19 outbreak in Italy.

Ann Intensive Care 2020 Oct 12;10(1):133. Epub 2020 Oct 12.

Department of Clinical, Integrated, and Experimental Medicine (DIMES), Respiratory and Critical Care, Sant'Orsola Malpighi Hospital, Bologna, Italy.

Background: A Covid-19 outbreak developed in Lombardy, Veneto and Emilia-Romagna (Italy) at the end of February 2020. Fear of an imminent saturation of available ICU beds generated the notion that rationing of intensive care resources could have been necessary.

Results: In order to evaluate the impact of Covid-19 on the ICU capacity to manage critically ill patients, we performed a retrospective analysis of the first 2 weeks of the outbreak (February 24-March 8). Data were collected from regional registries and from a case report form sent to participating sites. ICU beds increased from 1545 to 1989 (28.7%), and patients receiving respiratory support outside the ICU increased from 4 (0.6%) to 260 (37.0%). Patients receiving respiratory support outside the ICU were significantly older [65 vs. 77 years], had more cerebrovascular (5.8 vs. 13.1%) and renal (5.3 vs. 10.0%) comorbidities and less obesity (31.4 vs. 15.5%) than patients admitted to the ICU. PaO/FiO ratio, respiratory rate and arterial pH were higher [165 vs. 244; 20 vs. 24 breath/min; 7.40 vs. 7.46] and PaCO and base excess were lower [34 vs. 42 mmHg; 0.60 vs. 1.30] in patients receiving respiratory support outside the ICU than in patients admitted to the ICU, respectively.

Conclusions: Increase in ICU beds and use of out-of-ICU respiratory support allowed effective management of the first 14 days of the Covid-19 outbreak, avoiding resource rationing.
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http://dx.doi.org/10.1186/s13613-020-00750-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7549086PMC
October 2020

Hepatotoxicity after desflurane anesthesia in a morbidly obese patient.

J Clin Anesth 2018 12 7;51:55-56. Epub 2018 Aug 7.

Department of Medicine - DIMED, Section of Anesthesiology and Intensive Care, University of Padova, Padova, Italy. Electronic address:

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http://dx.doi.org/10.1016/j.jclinane.2018.08.010DOI Listing
December 2018

Induction of Interleukin-1β by Human Immunodeficiency Virus-1 Viral Proteins Leads to Increased Levels of Neuronal Ferritin Heavy Chain, Synaptic Injury, and Deficits in Flexible Attention.

J Neurosci 2015 Jul;35(29):10550-61

Departments of Pharmacology and Physiology, Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102

Synaptodendritic pruning and alterations in neurotransmission are the main underlying causes of HIV-associated neurocognitive disorders (HAND). Our studies in humans and nonhuman primates indicated that the protein ferritin heavy chain (FHC) is a critical player in neuronal changes and ensuing cognitive deficit observed in these patients. Here we focus on the effect of HIV proteins and inflammatory cytokines implicated in HAND on neuronal FHC levels, dendritic changes, and neurocognitive behavior. In two well characterized models of HAND (HIV transgenic and gp120-treated rats), we report reductions in spine density and dendritic branches in prefrontal cortex pyramidal neurons compared with age-matched controls. FHC brain levels are elevated in these animals, which also show deficits in reversal learning. Moreover, IL-1β, TNF-α, and HIV gp120 upregulate FHC in rat cortical neurons. However, although the inflammatory cytokines directly altered neuronal FHC, gp120 only caused significant FHC upregulation in neuronal/glial cocultures, suggesting that glia are necessary for sustained elevation of neuronal FHC by the viral protein. Although the envelope protein induced secretion of IL-1β and TNF-α in cocultures, TNF-α blockade did not affect gp120-mediated induction of FHC. Conversely, studies with an IL-1β neutralizing antibody or specific IL-1 receptor antagonist revealed the primary involvement of IL-1β in gp120-induced FHC changes. Furthermore, silencing of neuronal FHC abrogates the effect of gp120 on spines, and spine density correlates negatively with FHC levels or cognitive deficit. These results demonstrate that viral and host components of HIV infection increase brain expression of FHC, leading to cellular and functional changes, and point to IL-1β-targeted strategies for prevention of these alterations. Significance statement: This work demonstrates the key role of the cytokine IL-1β in the regulation of a novel intracellular mediator [i.e., the protein ferritin heavy chain (FHC)] of HIV-induced dendritic damage and the resulting neurocognitive impairment. This is also the first study that systematically investigates dendritic damage in layer II/III prefrontal cortex neurons of two different non-infectious models of HIV-associated neurocognitive disorders (HAND) and reveals a precise correlation of these structural changes with specific biochemical and functional alterations also reported in HIV patients. Overall, these data suggest that targeting the IL-1β-dependent FHC increase may represent a valid strategy for neuroprotective adjuvant therapies in HAND.
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http://dx.doi.org/10.1523/JNEUROSCI.4403-14.2015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4510293PMC
July 2015

Neuronal ferritin heavy chain and drug abuse affect HIV-associated cognitive dysfunction.

J Clin Invest 2014 Feb 9;124(2):656-69. Epub 2014 Jan 9.

Interaction of the chemokine CXCL12 with its receptor CXCR4 promotes neuronal function and survival during embryonic development and throughout adulthood. Previous studies indicated that μ-opioid agonists specifically elevate neuronal levels of the protein ferritin heavy chain (FHC), which negatively regulates CXCR4 signaling and affects the neuroprotective function of the CXCL12/CXCR4 axis. Here, we determined that CXCL12/CXCR4 activity increased dendritic spine density, and also examined FHC expression and CXCR4 status in opiate abusers and patients with HIV-associated neurocognitive disorders (HAND), which is typically exacerbated by illicit drug use. Drug abusers and HIV patients with HAND had increased levels of FHC, which correlated with reduced CXCR4 activation, within cortical neurons. We confirmed these findings in a nonhuman primate model of SIV infection with morphine administration. Transfection of a CXCR4-expressing human cell line with an iron-deficient FHC mutant confirmed that increased FHC expression deregulated CXCR4 signaling and that this function of FHC was independent of iron binding. Furthermore, examination of morphine-treated rodents and isolated neurons expressing FHC shRNA revealed that FHC contributed to morphine-induced dendritic spine loss. Together, these data implicate FHC-dependent deregulation of CXCL12/CXCR4 as a contributing factor to cognitive dysfunction in neuroAIDS.
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http://dx.doi.org/10.1172/JCI70090DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3904611PMC
February 2014

Cortical metabolic deficits in a rat model of cholinergic basal forebrain degeneration.

Neurochem Res 2013 Oct 8;38(10):2114-23. Epub 2013 Aug 8.

IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano, 64, 00143, Rome, Italy,

Evidence indicates that the degeneration of basal forebrain cholinergic neurons may represent an important factor underlying the progressive cognitive decline characterizing Alzheimer's disease (AD). However, the nature of the relationship between cholinergic depletion and AD is not fully elucidated. This study aimed at clarifying some aspects of the relation existing between deficits in cerebral energy metabolism and degeneration of cholinergic system in AD, by investigating the neuronal metabolic activity of several cortical areas after depletion of basal forebrain cholinergic neurons. In cholinergically depleted rats, we evaluated the neuronal metabolic activity by assaying cytochrome oxidase (CO) activity in frontal, parietal and posterior parietal cortices at four different time-points after unilateral injection of 192 IgG-saporin in the nucleus basalis magnocellularis. Unilateral depletion of cholinergic cells in the basal forebrain induced a bilateral decrease of metabolic activity in all the analyzed areas. Frontal and parietal cortices showed decreased metabolic activity even 3 days after the lesion, when the cholinergic degeneration was still incomplete. In posterior parietal cortex metabolic activity decreased only 7 days after the lesion. The possible molecular mechanisms underlying these findings were also investigated. Real-time PCR showed an increase of CO mRNA levels at 3, 7 and 15 days after the lesion both in frontal and parietal cortices, followed by normalization at 30 days. Western Blot analysis did not show any change in CO protein levels at any time-point after the lesion. Our findings support a link between metabolic deficit and cholinergic hypofunctionality characterizing AD pathology. The present model of cholinergic hypofunctionality provides a useful means to study the complex mechanisms linking two fundamental and interrelated phenomena characterizing AD from the early stages.
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http://dx.doi.org/10.1007/s11064-013-1120-2DOI Listing
October 2013

Road safety issues for bus transport management.

Accid Anal Prev 2013 Nov 20;60:324-33. Epub 2013 Jun 20.

Department of Civil and Environmental Engineering, School of Engineering, University of Catania, Viale Andrea Doria 6, I-95125 Catania, Italy. Electronic address:

Because of the low percentage of crashes involving buses and the assumption that public transport improves road safety by reducing vehicular traffic, public interest in bus safety is not as great as that in the safety of other types of vehicles. It is possible that less attention is paid to the significance of crashes involving buses because the safety level of bus systems is considered to be adequate. The purpose of this study was to evaluate the knowledge and perceptions of bus managers with respect to safety issues and the potential effectiveness of various technologies in achieving higher safety standards. Bus managers were asked to give their opinions on safety issues related to drivers (training, skills, performance evaluation and behaviour), vehicles (maintenance and advanced devices) and roads (road and traffic safety issues) in response to a research survey. Kendall's algorithm was used to evaluate the level of concordance. The results showed that the majority of the proposed items were considered to have great potential for improving bus safety. The data indicated that in the experience of the participants, passenger unloading and pedestrians crossing near bus stops are the most dangerous actions with respect to vulnerable users. The final results of the investigation showed that start inhibition, automatic door opening, and the materials and internal architecture of buses were considered the items most strongly related to bus passenger safety. Brake assistance and vehicle monitoring systems were also considered to be very effective. With the exception of driver assistance systems for passenger and pedestrian safety, the perceptions of the importance of other driver assistance systems for vehicle monitoring and bus safety were not unanimous among the bus company managers who participated in this survey. The study results showed that the introduction of new technologies is perceived as an important factor in improving bus safety, but a better understanding of their actual effectiveness and related risk factor avoidance must be developed to permit their useful implementation in bus fleets.
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http://dx.doi.org/10.1016/j.aap.2013.06.010DOI Listing
November 2013

Passive exercise of the hind limbs after complete thoracic transection of the spinal cord promotes cortical reorganization.

PLoS One 2013 22;8(1):e54350. Epub 2013 Jan 22.

Department of Physiology and Pharmacology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA.

Physical exercise promotes neural plasticity in the brain of healthy subjects and modulates pathophysiological neural plasticity after sensorimotor loss, but the mechanisms of this action are not fully understood. After spinal cord injury, cortical reorganization can be maximized by exercising the non-affected body or the residual functions of the affected body. However, exercise per se also produces systemic changes - such as increased cardiovascular fitness, improved circulation and neuroendocrine changes - that have a great impact on brain function and plasticity. It is therefore possible that passive exercise therapies typically applied below the level of the lesion in patients with spinal cord injury could put the brain in a more plastic state and promote cortical reorganization. To directly test this hypothesis, we applied passive hindlimb bike exercise after complete thoracic transection of the spinal cord in adult rats. Using western blot analysis, we found that the level of proteins associated with plasticity - specifically ADCY1 and BDNF - increased in the somatosensory cortex of transected animals that received passive bike exercise compared to transected animals that received sham exercise. Using electrophysiological techniques, we then verified that neurons in the deafferented hindlimb cortex increased their responsiveness to tactile stimuli delivered to the forelimb in transected animals that received passive bike exercise compared to transected animals that received sham exercise. Passive exercise below the level of the lesion, therefore, promotes cortical reorganization after spinal cord injury, uncovering a brain-body interaction that does not rely on intact sensorimotor pathways connecting the exercised body parts and the brain.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0054350PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3551921PMC
July 2013

MicroRNA modulation in complex regional pain syndrome.

J Transl Med 2011 Nov 10;9:195. Epub 2011 Nov 10.

Pharmacology & Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, USA.

Background: Aberrant expression of small noncoding RNAs called microRNAs (miRNAs) is a common feature of several human diseases. The objective of the study was to identify miRNA modulation in patients with complex regional pain syndrome (CRPS) a chronic pain condition resulting from dysfunction in the central and/or peripheral nervous systems. Due to a multitude of inciting pathologies, symptoms and treatment conditions, the CRPS patient population is very heterogeneous. Our goal was to identify differentially expressed miRNAs in blood and explore their utility in patient stratification.

Methods: We profiled miRNAs in whole blood from 41 patients with CRPS and 20 controls using TaqMan low density array cards. Since neurogenic inflammation is known to play a significant role in CRPS we measured inflammatory markers including chemokines, cytokines, and their soluble receptors in blood from the same individuals. Correlation analyses were performed for miRNAs, inflammatory markers and other parameters including disease symptoms, medication, and comorbid conditions.

Results: Three different groups emerged from miRNA profiling. One group was comprised of 60% of CRPS patients and contained no control subjects. miRNA profiles from the remaining patients were interspersed among control samples in the other two groups. We identified differential expression of 18 miRNAs in CRPS patients. Analysis of inflammatory markers showed that vascular endothelial growth factor (VEGF), interleukin1 receptor antagonist (IL1Ra) and monocyte chemotactic protein-1 (MCP1) were significantly elevated in CRPS patients. VEGF and IL1Ra showed significant correlation with the patients reported pain levels. Analysis of the patients who were clustered according to their miRNA profile revealed correlations that were not significant in the total patient population. Correlation analysis of miRNAs detected in blood with additional parameters identified miRNAs associated with comorbidities such as headache, thyroid disorder and use of narcotics and antiepileptic drugs.

Conclusions: miRNA profiles can be useful in patient stratification and have utility as potential biomarkers for pain. Differentially expressed miRNAs can provide molecular insights into gene regulation and could lead to new therapeutic intervention strategies for CRPS.
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http://dx.doi.org/10.1186/1479-5876-9-195DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3228853PMC
November 2011

Development of comprehensive accident models for two-lane rural highways using exposure, geometry, consistency and context variables.

Accid Anal Prev 2010 Jul 13;42(4):1072-9. Epub 2010 Jan 13.

Department of Civil and Environmental Engineering, University of Catania, Catania, Italy.

In Europe, approximately 60% of road accident fatalities occur on two-lane rural roads. Thus, research to develop and enhance explanatory and predictive models for this road type continues to be of interest in mitigating these accidents. To this end, this paper describes a novel and extensive data collection and modeling effort to define accident models for two-lane road sections based on a unique combination of exposure, geometry, consistency and context variables directly related to the safety performance. The first part of the paper documents how these were identified for the segmentation of highways into homogeneous sections. Next, is a description of the extensive data collection effort that utilized differential cinematic GPS surveys to define the horizontal alignment variables, and road safety inspections (RSIs) to quantify the other road characteristics related to safety. The final part of the paper focuses on the calibration of models for estimating the expected number of accidents on homogeneous sections that can be characterized by constant values of the explanatory variables. Several candidate models were considered for calibration using the Generalized Linear Modeling (GLM) approach. After considering the statistical significance of the parameters related to exposure, geometry, consistency and context factors, and goodness of fit statistics, 19 models were ranked and three were selected as the recommended models. The first of the three is a base model, with length and traffic as the only predictor variables; since these variables are the only ones likely to be available network-wide, this base model can be used in an empirical Bayesian calculation to conduct network screening for ranking "sites with promise" of safety improvement. The other two models represent the best statistical fits with different combinations of significant variables related to exposure, geometry, consistency and context factors. These multiple variable models can be used, with caution, and in conjunction with results from other studies, to derive accident modification factors for these variables for design applications, and in safety assessment for smaller samples of sites for which these variables can be assembled with relative ease.
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http://dx.doi.org/10.1016/j.aap.2009.12.015DOI Listing
July 2010

Early withdrawal of axons from higher centers in response to peripheral somatosensory denervation.

J Neurosci 2009 Mar;29(12):3738-48

Center for Neuroscience, University of California, Davis, Davis, California 95618, USA.

The mechanisms responsible for long-term, massive reorganization of representational maps in primate somatosensory cortex after deafferentation are poorly understood. Sprouting of cortical axons cannot account for the extent of reorganization, and withdrawal of axons of deafferented brainstem and thalamic neurons, permitting expression of previously silent synapses, has not been directly demonstrated. This study is focused on the second of these. In monkeys, deafferented for two years by section of the cuneate fasciculus at the C1 level, there was extensive withdrawal of axon terminals from thalamus and cortex, detectable a decade before visible atrophy of their parent neuronal somata in the cuneate nucleus or thalamus. Slow, inexorable progression of lemniscal and thalamocortical axonal withdrawal is a neurodegenerative phenomenon likely to be a powerful inducement to compensatory long-term plasticity, a mechanism that can explain the long-term evolution of cortical reorganization and, with it, phantom sensations in spinal patients and amputees.
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http://dx.doi.org/10.1523/JNEUROSCI.5388-08.2009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2977941PMC
March 2009

Vesicular glutamate transporters define two sets of glutamatergic afferents to the somatosensory thalamus and two thalamocortical projections in the mouse.

J Comp Neurol 2008 Mar;507(2):1258-76

Center for Neuroscience, University of California Davis, Davis, California 95616-8798, USA.

The ventral posterior nucleus of the thalamus (VP) receives two major sets of excitatory inputs, one from the ascending somatosensory pathways originating in the dorsal horn, dorsal column nuclei, and trigeminal nuclei, and the other originating from the cerebral cortex. Both systems use glutamate as neurotransmitter, as do the thalamocortical axons relaying somatosensory information from the VP to the primary somatosensory cortex (SI). The synapses formed by these projection systems differ anatomically, physiologically, and in their capacity for short-term synaptic plasticity. Glutamate uptake into synaptic vesicles and its release at central synapses depend on two isoforms of vesicular glutamate transporters, VGluT1 and VGluT2. Despite ample evidence of their complementary distribution, some instances exist of co-localization in the same brain areas or at the same synapses. In the thalamus, the two transcripts coexist in cells of the VP and other nuclei but not in the posterior or intralaminar nuclei. We show that the two isoforms are completely segregated at VP synapses, despite their widespread expression throughout the dorsal and ventral thalamus. We present immunocytochemical, ultrastructural, gene expression, and connectional evidence that VGluT1 in the VP is only found at corticothalamic synapses, whereas VGluT2 is only found at terminals made by axons originating in the spinal cord and brainstem. By contrast, the two VGluT isoforms are co-localized in thalamocortical axon terminals targeting layer IV, but not in those targeting layer I, suggesting the presence of two distinct projection systems related to the core/matrix pattern of organization of thalamocortical connectivity described in other mammals.
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http://dx.doi.org/10.1002/cne.21592DOI Listing
March 2008

NMDA receptor activity in learning spatial procedural strategies I. The influence of hippocampal lesions.

Brain Res Bull 2006 Oct 5;70(4-6):347-55. Epub 2006 Jul 5.

IRCCS S. Lucia, Rome, Italy.

To acquire knowledge about the environment two types of learning are necessary: declarative localizatory learning about where environmental cues and the subject are, and procedural learning about how to explore and move around the environment. Experimental data indicate that hippocampal regions are involved in spatial learning, playing a key role in building spatial cognitive maps. The contribution of hippocampal NMDA receptors to spatial functions is indicated by the disruption of place learning when NMDA long-term potentiation is blocked. Conversely, the hippocampal contribution to the acquisition of procedural strategies is still controversial. Inactivation of the hippocampus by antagonizing the activity of AMPA/kainate receptors results in impaired spatial procedural learning. However, in the presence of a blockade of NMDA long-term potentiation in hippocampal areas it is still possible to learn explorative strategies. To investigate the involvement of the hippocampal NMDA receptors in spatial procedural learning, an NMDA receptor antagonist (CGS 19755) was administered i.p. to unlesioned animals or to animals with total ablation of hippocampal structures that had been tested in the Morris water maze. The CGS administration induced peripheral circling in both unlesioned control animals and in rats with bilateral hippocampal ablation. Conversely, circling was not observed if the drug-treated animals (either unlesioned or lesioned) had been spatially trained before drug administration. These findings indicate that even in the absence of the hippocampal formation the NMDA receptor antagonist found a site of action to influence the acquisition of spatial procedures to search for the platform.
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http://dx.doi.org/10.1016/j.brainresbull.2006.06.006DOI Listing
October 2006

Widespread thalamic terminations of fibers arising in the superficial medullary dorsal horn of monkeys and their relation to calbindin immunoreactivity.

J Neurosci 2004 Jan;24(1):248-56

Center for Neuroscience, University of California Davis, Davis, California 95616, USA.

The relay of pain fibers from the spinal and medullary dorsal horn in the thalamus has become a controversial issue. This study analyzed the relationship of fibers arising in lamina I to nuclei in and around the caudal pole of the ventral posterior nuclear complex and especially to a zone of calbindin-dense immunoreactivity (VMpo) identified by some authors as the sole thalamic relay for these fibers. We show that the densest zone of calbindin immunoreactivity is part of a more extensive, calbindin-immunoreactive region that lies well within the medial tip of the ventral posterior medial nucleus (VPM), as delineated by other staining methods, and prove that the use of different anti-calbindin antibodies cannot account for differences in interpretations of the organization of the posterior thalamic region. By combining immunocytochemical staining with anterograde tracing from injections involving lamina I, we demonstrate widespread fiber terminations that are not restricted to the calbindin-rich medial tip of VPM and show that the lamina I arising fibers are not themselves calbindin immunoreactive. This study disproves the existence of VMpo as an independent thalamic pain nucleus or as a specific relay in the ascending pain system.
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http://dx.doi.org/10.1523/JNEUROSCI.4122-03.2004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6729588PMC
January 2004

A new paradigm to analyze observational learning in rats.

Brain Res Brain Res Protoc 2003 Oct;12(2):83-90

Department of Psychology, University of Rome "La Sapienza", Via dei Marsi 78, 00185, Rome, Italy.

A new paradigm of learning was developed through observational training in which rats repeatedly observed companion rats performing different spatial tasks. Observer animals were separately housed in small cages suspended over a water maze tank. They repeatedly observed companion actor rats performing spatial tasks differing according to the experimental requirements. After the observational training, observer animals were or not surgically hemicerebellectomized. This surgical ablation was performed to block any further acquisition of new behavioral strategies during actual performance of swimming task. When cerebellar symptomatology stabilized, observer animals were actually tested in the Morris Water Maze (MWM) task they had previously only observed. The observer rats displayed exploration abilities that closely matched the previously observed behaviors. The results obtained indicate that it is possible to learn complex behavioral strategies by observation using this new protocol. Furthermore, acquisition of the single facets that form the behavioral repertoire can be separately studied.
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http://dx.doi.org/10.1016/j.brainresprot.2003.08.001DOI Listing
October 2003

Automatic recognition of explorative strategies in the Morris water maze.

J Neurosci Methods 2003 Nov;130(1):33-44

Department of Psychology, University of Rome La Sapienza, Via dei Marsi 78, 00185 Rome, Italy.

Notwithstanding the development of reliable tracking systems, the quantification methodology of the Morris water maze (MWM) has witnessed an operational mismatch between the indexes used to quantify MWM performance and the cognitive concepts derived from these indexes. Indeed, escape latency is the main, and often unique, performance measure used for the quantification of behavior. Aim of the present work was to overcome this limitation by presenting a methodology that allows for automatic categorical pattern recognition of the behavioral strategies performed in the MWM. By selecting few a priori and user-defined behavioral categories, many quantitative variables and regions of interest (ROIs), we used discriminant analysis (DA) to obtain 97.9% of correct automatic recognition of categories. The developed discriminant model (DM) also allowed to predict category membership of newly recorded swim paths with the same statistical efficacy (96%), and to identify the variables that better discriminate between adjacent categories. The combination of DA with a tracking system, a selection of many variables, different ROIs and qualitative categorization, reduces the gap between the measurement process and the categories used to describe a given behavior, and offers a methodology to computationally reproduce the human categorization of behaviors in the MWM.
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http://dx.doi.org/10.1016/s0165-0270(03)00187-0DOI Listing
November 2003

Watch how to do it! New advances in learning by observation.

Brain Res Brain Res Rev 2003 Jun;42(3):252-64

Department of Psychology, University of Rome 'La Sapienza', Via dei Marsi 78, 00185, Rome, Italy.

Recent data demonstrate that the cerebellum contributes to the internal representation of action. This representation is used not only to generate motor actions, but also to understand and learn the actions and skills of others by imitation. The cerebellar networks appear to be indispensable for acquiring complex behaviors and procedures. The cerebellar role in the acquisition of procedural competencies is particularly evident in spatial information processing. The cerebellum allows acquiring by observation competencies in exploration behaviors as efficient as the competencies acquired by actually performing the same task. The specificity of the cerebellar role in the acquisition phases of learning by observation is demonstrated by the complete absence of spatial learning when the observational training is performed in presence of a cerebellar lesion. This datum is further corroborated by the evidence that, once acquired, spatial procedures can be efficiently performed even in the presence of cerebellar damage, in agreement with the neuroimaging findings of low cerebellar activation after prolonged practice. The finding that the cerebellum is involved in procedural acquisition and in observational learning allowed us to dissect a complex behavior into single behavioral units forming a complete procedural sequence, demonstrating that such behavioral units do exist and can be independently acquired.
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http://dx.doi.org/10.1016/s0165-0173(03)00176-0DOI Listing
June 2003
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