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1.
Learn Mem ; 29(11): 390-400, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36253006

RESUMEN

Social anxiety disorder (SAD) is a common anxiety disorder characterized by a marked fear of social situations. Treatments for SAD, including exposure therapy and medication, are not satisfactory for all patients. This has led to the development of several paradigms to study social fear in rodents. However, there are still some social impairments observed in SAD patients that have never been examined in rodent models. Indeed, social situations avoided by SAD patients include not only social interactions but also public performances and being observed by others. Nevertheless, tests used to assess sociability in rodents evaluate mostly social interaction in pairs. Thus, we developed a new test-a socially enriched environment test-that evaluates sociability within a group of three unfamiliar conspecifics in an enriched environment. In this study, we induced a SAD-like behavior (i.e., social fear) in male mice using social fear conditioning (SFC) and then tested social fear using the socially enriched environment test and the three-chamber test. Finally, we tested the effects of fear extinction and acute diazepam treatment in reversing social fear. Results revealed, in conditioned mice, decreased object exploration in proximity to conspecifics, social interaction, and mouse-like object exploration. Extinction training, but not acute diazepam treatment, reversed SFC-induced behavioral changes. These findings demonstrate that the socially enriched environment test provides an appropriate behavioral approach to better understand the etiology of SAD. This test may also have important implications in the exploration of new treatments.


Asunto(s)
Fobia Social , Animales , Ansiedad , Diazepam/farmacología , Diazepam/uso terapéutico , Modelos Animales de Enfermedad , Extinción Psicológica , Miedo , Masculino , Ratones , Conducta Social
2.
Eur J Neurosci ; 54(10): 7710-7732, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34670326

RESUMEN

Treatment of post-traumatic stress disorder is complicated by the presence of alcohol use disorder comorbidity. Little is known about the underlying brain mechanisms. We have recently shown, in mice, that the post-traumatic stress disorder-like phenotype is characterised by the increase and decrease in total dendritic number and length in the prelimbic and infralimbic areas of the medial prefrontal cortex, respectively. Here, we examined whether repeated ethanol exposure would exacerbate these changes and whether this would be associated with difficulty to extinguish passive avoidance behaviour, as an indicator of treatment resistance. We also analysed whether other known trauma-associated changes, like increased or decreased corticosterone and decreased brain-derived neurotrophic factor levels, would also be exacerbated. Male mice underwent trauma exposure (1.5-mA footshock), followed, 8 days later, by a conditioned place preference training with ethanol. Tests for fear sensitization, passive avoidance, anxiety-like behaviour, extinction acquisition and relapse susceptibility were used to assess behaviour changes. Plasma corticosterone and brain-derived neurotrophic factor levels and prefrontal dendritic changes were subsequently measured. Trauma-susceptible mice exposed to ethanol acquired a strong place preference and behaved differently from those not exposed to ethanol, with delayed avoidance extinction and higher avoidance relapse vulnerability. Ethanol potentiated trauma-associated dendritic changes in the prelimbic area and suppressed trauma-associated dendritic changes in the infralimbic area. However, ethanol had no effect on trauma-induced increased corticosterone and decreased brain-derived neurotrophic factor levels. These data suggest that the modification of prefrontal trauma-related changes, due to alcohol use, can characterise, and probably support, treatment-resistant post-traumatic stress disorder.


Asunto(s)
Trastornos por Estrés Postraumático , Animales , Condicionamiento Clásico , Etanol/toxicidad , Extinción Psicológica , Miedo , Masculino , Ratones , Corteza Prefrontal
3.
Aust N Z J Psychiatry ; 54(8): 818-831, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32271126

RESUMEN

INTRODUCTION: The inability to extinguish a conditioned fear is thought to be at the core of post-traumatic stress disorder. Eye movement desensitization and reprocessing therapy has been efficacious for post-traumatic stress disorder, but the brain mechanisms underlying the effect are still unknown. The core effect of eye movement desensitization and reprocessing therapy seems to rely on the simultaneous association of bilateral alternating stimulation and the recall of the traumatic memory. To shed light on how eye movement desensitization and reprocessing therapy functions, we aimed to highlight the structures activated by bilateral alternating stimulation during fear extinction and its recall. METHODS: We included 38 healthy participants in this study. Participants were examined twice in functional magnetic resonance imaging, over 2 consecutive days. On the first day, they performed two fear conditioning and extinction procedures, one with and one without the bilateral alternating stimulation during the fear extinction learning phase in a counter-balanced order across the participants. On the second day, participants completed the fear extinction recall procedure, in the same order as the previous day. Statistical significance of maps was set at p < 0.05 after correction for family-wise error at the cluster level. RESULTS: The analysis revealed significant activation with versus without bilateral alternating stimulation at the early extinction in the bilateral auditory areas, the right precuneus, and the left medial frontal gyrus. The same pattern was found in the early recall on the second day. The connectivity analysis found a significant increase in connectivity during bilateral alternating stimulation versus without bilateral alternating stimulation in the early extinction and recall between the two superior temporal gyri, the precuneus, the middle frontal gyrus and a set of structures involved in multisensory integration, executive control, emotional processing, salience and memory. CONCLUSION: We show for the first time that in the eye movement desensitization and reprocessing therapy the bilateral alternating stimulation is not a simple sensory signal and can activate large emotional neural networks.


Asunto(s)
Extinción Psicológica , Desensibilización y Reprocesamiento del Movimiento Ocular , Miedo , Recuerdo Mental , Trastornos por Estrés Postraumático/psicología , Trastornos por Estrés Postraumático/terapia , Estimulación Acústica , Adulto , Femenino , Humanos , Masculino
4.
Learn Mem ; 24(9): 462-471, 2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-28814472

RESUMEN

Fear, which can be expressed innately or after conditioning, is triggered when a danger or a stimulus predicting immediate danger is perceived. Its role is to prepare the body to face this danger. However, dysfunction in fear processing can lead to psychiatric disorders in which fear outweighs the danger or possibility of harm. Although recognized as highly debilitating, pathological fear remains insufficiently treated, indicating the importance of research on fear processing. The neurobiological basis of normal and pathological fear reactions is reviewed in this article. Innate and learned fear mechanisms, particularly those involving the amygdala, are considered. These fear mechanisms are also distinguished in specific phobias, which can indeed be nonexperiential (implicating innate, learning-independent mechanisms) or experiential (implicating learning-dependent mechanisms). Poor habituation and poor extinction are presented as dysfunctional mechanisms contributing to persistence of nonexperiential and experiential phobias, respectively.


Asunto(s)
Miedo , Neurobiología , Trastornos Fóbicos , Animales , Encéfalo/fisiopatología , Miedo/psicología , Humanos , Instinto , Trastornos Fóbicos/patología , Trastornos Fóbicos/psicología
5.
Neurobiol Learn Mem ; 113: 62-8, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24333383

RESUMEN

We have recently shown that post-extinction retraining of rats, with a shock intensity that is too weak to induce by itself significant fear acquisition, impairs the recall of fear extinction memory. Tetanic stimulation (TS) of the medial prefrontal cortex (mPFC), applied before or following this retraining, facilitates extinction recall. Here we investigated whether mPFC TS can also facilitate expression of fear extinction when rats are retrained with the same shock intensity as during the initial fear acquisition. Rats were implanted with stimulating electrodes in the mPFC and were trained to acquire freezing to a conditioning chamber, in which they had to enter freely. In Experiment 1, extinction of this response was followed by reconditioning and then another extinction training. Acquired freezing was extinguished successfully, while reacquired freezing, which was associated with increased chamber entry latencies, was resistant to subsequent extinction. Both reacquired freezing and increased chamber entry latencies were absent in rats that received post-reconditioning mPFC TS. In Experiment 2, post-conditioning mPFC TS had no effect on initially acquired freezing. In Experiment 3, rats were submitted to reconditioning without experiencing extinction training. In this condition, both reacquired freezing and increased chamber entry latencies were still present in rats that received post-reconditioning mPFC TS. These findings provide additional evidence for the fundamental role of the mPFC in maintaining expression of fear extinction.


Asunto(s)
Condicionamiento Psicológico/fisiología , Estimulación Eléctrica/métodos , Extinción Psicológica/fisiología , Miedo/fisiología , Corteza Prefrontal/fisiología , Animales , Reacción Cataléptica de Congelación/fisiología , Masculino , Ratas , Ratas Sprague-Dawley
6.
Neurobiol Learn Mem ; 101: 33-8, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23313613

RESUMEN

We have recently shown that post-extinction exposure of rats to a sub-conditioning procedure (SCP, i.e., retraining with a shock intensity that is too weak to induce by itself significant fear conditioning) or to acute stress provokes reemergence of extinguished fear. Furthermore, this SCP effect can be abolished by high-frequency stimulation (HFS) of the medial prefrontal cortex (mPFC), when applied following the SCP. The aim of the present study was to test whether HFS of the mPFC is effective in preventing both SCP-induced and acute stress-provoked fear reemergence. Rats implanted with stimulating electrodes in the mPFC were trained to acquire high levels of freezing to conditioned auditory cue. This fear response was then extinguished. Three weeks later, no spontaneous recovery was observed, but rats exposed to either the SCP or acute stress again exhibited high levels of freezing. HFS of the mPFC, applied before provoking fear reemergence, prevented the effects of SCP, but not acute stress. These data suggest that acute stress may have more impact on functions of the mPFC and/or associated structures than a situational reminder of fear conditioning.


Asunto(s)
Condicionamiento Clásico/fisiología , Miedo/fisiología , Corteza Prefrontal/fisiología , Estrés Psicológico/fisiopatología , Animales , Estimulación Eléctrica , Extinción Psicológica/fisiología , Reacción Cataléptica de Congelación/fisiología , Masculino , Ratas , Ratas Wistar
7.
Neurobiol Learn Mem ; 101: 39-45, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23298787

RESUMEN

Difficulties to treat fear-associated disorders, including posttraumatic stress disorder, are thought to result from dysfunction in fear extinction learning and/or memory. Animal studies on extinction modulation are therefore promising for the development of new treatments. Recent rat studies, including ones using low-frequency stimulation (LFS), have demonstrated that the ventral hippocampus (VH) modulates extinction memory. The present study explores whether the VH also modulates extinction learning. For this, rats were implanted with stimulating electrodes in the VH and experienced contextual fear conditioning, followed 6 or 24 h later by VH LFS and three sessions of extinction training. We found that, whatever the delay used (6 or 24 h), animals that received VH LFS displayed persistent low levels of freezing from the second extinction session, whereas control rats showed low levels of freezing only during the third session. In animals submitted to a stress condition (provoked by a single inescapable foot-shock followed by three sessions of situational reminders) prior to fear conditioning, VH LFS also reduced freezing levels, which, in contrast, remained high in control rats during the course of extinction training. These data suggest that LFS, targeting the VH, may be useful in reducing fear responses during extinction learning.


Asunto(s)
Condicionamiento Clásico/fisiología , Extinción Psicológica/fisiología , Miedo/fisiología , Hipocampo/fisiología , Animales , Estimulación Eléctrica , Reacción Cataléptica de Congelación/fisiología , Masculino , Ratas , Ratas Wistar , Estrés Psicológico/fisiopatología
8.
Am J Geriatr Psychiatry ; 21(4): 391-7, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23498386

RESUMEN

OBJECTIVES: To determine if there is a specific pattern of gross motor activity associated with apathy in individuals with Alzheimer disease (AD). DESIGN: Examination of ad libitum 24-hour ambulatory gross motor activity patterns. SETTING: Community-dwelling, outpatient. PARTICIPANTS: Ninety-two individuals with AD, 35 of whom had apathy. MEASUREMENTS: Wrist actigraphy data were collected and examined using functional principal component analysis (fPCA). RESULTS: Individuals with apathy have a different pattern of gross motor activity than those without apathy (first fPCA component, p <0.0001, t = 5.73, df = 90, t test) such that there is a pronounced decline in early afternoon activity in those with apathy. This change in activity is independent of depression (p = 0.68, F[1, 89] = 0.05, analysis of variance). The decline in activity is consistent with an increase in napping. Those with apathy also have an early wake and bedtime (second fPCA component, t = 2.53, df = 90, p <0.05, t test). CONCLUSIONS: There is a signature activity pattern in individuals with apathy and AD that is distinct from those without apathy and those with depression. Actigraphy may be a useful adjunctive measurement in the clinical diagnosis of apathy in the context of AD.


Asunto(s)
Enfermedad de Alzheimer/fisiopatología , Enfermedad de Alzheimer/psicología , Apatía , Análisis de Componente Principal , Actigrafía , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/complicaciones , Ritmo Circadiano/fisiología , Depresión/complicaciones , Depresión/fisiopatología , Depresión/psicología , Femenino , Humanos , Masculino , Actividad Motora/fisiología , Sueño
9.
Am J Geriatr Psychiatry ; 20(9): 806-14, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21997602

RESUMEN

OBJECTIVE: Across all stages of Alzheimer disease (AD), apathy is the most common neuropsychiatric symptom. Studies using the Neuropsychiatric Inventory (NPI) have found that apathy is present in up to 70% of individuals with Alzheimer disease. One of the main difficulties in assessing apathy and other neuropsychiatric symptoms is the absence of reliable, objective measures. Motor activity assessment using ambulatory actigraphy could provide an indirect, objective evaluation of apathy. The aim of our study was to assess the relationship between apathy and daytime motor activity in AD, using ambulatory actigraphy. METHODS: One hundred seven AD outpatients wore a wrist actigraph (Motionlogger) during seven consecutive 24-hour periods to evaluate motor activity. Participants were divided into two subgroups according to their apathy subscores on the NPI: individuals with apathy (NPI-apathy subscores >4) and those without. Daytime mean motor activity scores were compared between the two subgroups. RESULTS: Individuals with AD who had symptoms of apathy (n = 43; age = 79 ± 4.7 years; Mini-Mental State Examination = 20.9 ± 4.8) had significantly lower daytime mean motor activity than AD patients without apathy (n = 64; age = 76.3 ± 7.7; Mini-Mental State Examination = 21.5 ± 4.7), while nighttime mean motor activity did not significantly differ between the two subgroups. CONCLUSIONS: Ambulatory actigraphy could be added to currently used questionnaires as a simple, objective technique for assessing apathy in the routine assessment of AD patients.


Asunto(s)
Actigrafía/psicología , Enfermedad de Alzheimer/fisiopatología , Enfermedad de Alzheimer/psicología , Apatía/fisiología , Actividad Motora/fisiología , Fotoperiodo , Actigrafía/métodos , Anciano , Enfermedad de Alzheimer/complicaciones , Femenino , Humanos , Masculino , Pruebas Neuropsicológicas
10.
Vet Res Commun ; 46(1): 189-201, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34791575

RESUMEN

A cross-sectional study was conducted in Colombia to recover Brucella spp. DNA from bovine whole-blood samples through probe-based real-time PCR (qPCR). By an SNP-based assay, vaccine strains were differentiated from field strains. The associated factors were evaluated using logistical regression models. A total of 656 random cows from 40 herds were selected and analyzed using serology and PCR. The qPCR assay detected 9.5% (n = 62/656; 95% CI: 7.3, 12.0) of the animals with Brucella-DNA presence, while the serological test detected a 6.6% (n = 43/656; CI: 4.8, 8.7). 62.5% (n = 25/40; 95% CI: 45.8, 77.3) of positive cases were detected at the herd-level by the qPCR, while only 27.5% (n = 11/40; 95% CI: 14.6, 43.9) were detected by the serological test. All positive samples were identified as field Brucella strains employing the SNP-based assay. In the final regression model at the animal-level, five variables were associated with Brucella-DNA presence: the use of bulls for mating recorded history of reproductive problems, pregnant cows, parlor milking, and cows belonging to farms ≤200 m from the main road. At the herd-level, two variables were associated with Brucella-DNA presence: recorded history of reproductive problems and the use of bulls for mating. Given the fluctuant brucellosis prevalence in endemic areas, updated epidemiological studies are necessary to evaluate the disease dynamic and if established prevention and control measures have been effective or need to be adjusted. The increase in the prevalence of brucellosis in animal reservoirs creates an important risk of transmission in humans.


Asunto(s)
Brucella , Brucelosis Bovina , Animales , Anticuerpos Antibacterianos , Brucella/genética , Brucelosis Bovina/diagnóstico , Brucelosis Bovina/epidemiología , Bovinos , Colombia/epidemiología , Estudios Transversales , Femenino , Masculino , Embarazo , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Factores de Riesgo
11.
Neurobiol Learn Mem ; 95(4): 510-8, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21397708

RESUMEN

Post-extinction exposure of rats to a sub-conditioning procedure can evoke conditioned fear, which may correspond to fear return and/or fear learning potentiation. The aim of the present study was to clarify this issue and examine the effects of tetanic stimulation of the hippocampus (HPC) and medial prefrontal cortex (mPFC), two brain regions implicated in post-extinction modulation of conditioned fear. Rats were initially submitted to five tone-shock pairings with either a 0.7-mA or 0.1-mA shock. Tone-evoked freezing was observed only with the higher shock intensity, indicating that the 0.1-mA shock corresponded to a sub-conditioning procedure. All conditioned rats underwent fear extinction with 20 tone-alone trials. When retrained with the sub-conditioning procedure, they displayed again tone-evoked freezing, except when the initial tone was unpaired or a new tone was paired with the 0.1-mA shock, demonstrating fear return rather than fear learning potentiation. We also found that HPC and mPFC tetanic stimulations, applied 24h after the sub-conditioning procedure, similarly reduced this fear return. However, mPFC inactivation abolished temporary HPC tetanus effect, whereas HPC inactivation did not interfere with mPFC tetanus effect. These data confirm our previous findings and reveal the nature of HPC-mPFC interactions in post-extinction modulation of conditioned fear.


Asunto(s)
Aprendizaje por Asociación/fisiología , Condicionamiento Clásico/fisiología , Extinción Psicológica/fisiología , Hipocampo/fisiología , Corteza Prefrontal/fisiología , Estimulación Acústica , Animales , Estimulación Eléctrica , Miedo , Masculino , Memoria a Largo Plazo/fisiología , Vías Nerviosas/fisiología , Ratas , Ratas Wistar , Reconocimiento en Psicología/fisiología
12.
Brain Struct Funct ; 226(7): 2219-2241, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34195855

RESUMEN

Pre- and post-trauma drug use can interfere with recovery from post-traumatic stress disorder (PTSD). However, the biological underpinnings of this interference are poorly understood. Here we examined the effect of pre-fear conditioning cocaine self-administration on PTSD-like symptoms in male rats, and defined impairment of fear extinction as difficulty to recover from PTSD. We also examined cell density changes in brain regions suspected of being involved in resistance to PTSD recovery. Before footshock stress testing, rats were trained to self-administer cocaine during 20 consecutive days, after which they were exposed to footshocks, while other rats continued to self-administer cocaine until the end of the experiment. Upon assessment of three PTSD-like symptoms (fear during situational reminders, anxiety-like behavior, and impairment of recognition memory) and fear extinction learning and memory, changes in cell density were measured in the medial prefrontal cortex, hippocampus, and amygdala. Results show that pre-footshock cocaine exposure did not affect fear during situational reminders. Fear conditioning did not lead to an increase in cocaine consumption. However, in footshock stressed rats, cocaine induced a reduction of anxiety-like behavior, an aggravation of recognition memory decline, and an impairment of extinction memory. These behavioral alterations were associated with increased cell density in the hippocampal CA1, CA2, and CA3 regions and basolateral amygdala, but not in the medial prefrontal cortex. Our findings suggest that enhancement of cell density in the hippocampus and amygdala may be changes associated with drug use, interfering with PTSD recovery.


Asunto(s)
Trastornos por Estrés Postraumático , Amígdala del Cerebelo , Animales , Recuento de Células , Cocaína/toxicidad , Extinción Psicológica , Miedo , Hipocampo , Masculino , Preparaciones Farmacéuticas , Ratas
13.
Biomedica ; 41(2): 208-217, 2021 06 29.
Artículo en Inglés, Español | MEDLINE | ID: mdl-34214261

RESUMEN

This is the case of a 50-year-old male from the region of Urabá, Colombia, with a mixed infection by Rickettsia rickettsii and Leptospira interrogans serovar Copenhageni ST78 and negative test for malaria and dengue fever. The patient presented with febrile syndrome and was unresponsive to systemic antibiotic treatment, who finally died in the intensive care unit. We established the postmortem diagnosis through molecular typification of the two etiological agents. In the inspection at the patient's home, we found a Rattus rattus specimen infected with L. interrogans of the same serovar found in him. We found no ticks parasitizing the domestic animals cohabitating with the patient. This case of a mixed infection with progressive and fatal symptoms in a patient with occupational risk in a tropical disease endemic zone highlights the importance of considering the potential presentation of simultaneous etiologies in patients with multiple medical visits for unresolved febrile syndromes associated with risky exposure during agricultural activities.


Se presenta el caso de un hombre de 50 años de edad proveniente de la región de Urabá, Colombia, con una infección mixta por Rickettsia rickettsii y Leptospira interrogans serovar Copenhageni ST78, y pruebas negativas para malaria y dengue. El paciente presentó un síndrome febril que no mejoró con el tratamiento antibiótico sistémico y, finalmente, falleció en la unidad de cuidados intensivos. El diagnóstico post mortem se hizo mediante tipificación molecular de los dos agentes etiológicos. En la inspección del domicilio del paciente, se encontró un ejemplar de Rattus rattus infectado con L. interrogans del mismo serovar detectado en él. No se encontraron garrapatas en los animales domésticos que habitaban con el paciente. Se reporta una infección mixta con síntomas clínicos progresivos y fatales en un paciente con antecedentes laborales de riesgo en una zona endémica para enfermedades tropicales, lo que obliga a tener presente la posibilidad de infecciones simultáneas en personas procedentes de áreas endémicas que consulten reiteradamente por síndrome febril sin resolución y tengan riesgo laboral relacionado con actividades agrícolas.


Asunto(s)
Coinfección , Leptospirosis , Infecciones por Rickettsia , Animales , Anticuerpos Antibacterianos , Humanos , Leptospirosis/complicaciones , Leptospirosis/diagnóstico , Masculino , Persona de Mediana Edad , Ratas , Rickettsia rickettsii
14.
Neuroscience ; 418: 166-176, 2019 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-31487540

RESUMEN

Post-traumatic stress disorder (PTSD) is triggered by exposure to traumatic events, but not everyone who experiences trauma develops this disorder. Like humans, PTSD-like symptoms develop in some laboratory rodents (susceptible individuals), while others express less or no symptoms (resilient individuals). Here, considering (i) the putative causal role of fear conditioning in PTSD development and (ii) the involvement of the medial prefrontal cortex (mPFC) in the regulation of conditioned fear response, we tested whether trauma-associated changes in the mPFC may discriminate stress-resilient from stress-susceptible mice. From data on avoidance behavior (as a major symptom), we found that trauma-exposed mice displayed a bimodal distribution in their step-through latency, with low avoider (stress-resilient) individuals and high avoider (stress-susceptible) individuals. Dendrites of Golgi-Cox-stained neurons were analyzed in two parts of the mPFC: the prelimbic (PrL) and infralimbic (IL) areas. In the resilient phenotype, the total number of dendrites decreased in the PrL and increased in the IL; however, it decreased only in the IL in the susceptible phenotype compared to controls. These findings demonstrate that the type of post-trauma morphological changes in the mPFC is associated with susceptibility or resilience to trauma-related symptoms.


Asunto(s)
Dendritas/patología , Resiliencia Psicológica , Trastornos por Estrés Postraumático/patología , Animales , Reacción de Prevención , Escala de Evaluación de la Conducta , Miedo/psicología , Masculino , Ratones , Neuronas , Corteza Prefrontal/patología , Estrés Psicológico
15.
Ticks Tick Borne Dis ; 10(5): 995-996, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31151921

RESUMEN

This report describes a new lethal case of Rickettsia rickettsii infection in a child from Northwestern Colombia, after ten years of the last outbreaks in the same region. Colombian public-health authorities should consider to include this severe rickettsiosis in the compulsory-reporting diseases, with the aim of knowing its burden in the country.


Asunto(s)
Rickettsia rickettsii/aislamiento & purificación , Fiebre Maculosa de las Montañas Rocosas/microbiología , Preescolar , Colombia , Resultado Fatal , Humanos , Masculino
16.
Neurobiol Learn Mem ; 89(4): 560-6, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18039585

RESUMEN

Disruptions of fear extinction-related potentiation of synaptic efficacy in the connection between the hippocampus (HPC) and the medial prefrontal cortex (mPFC) have been shown to impair the recall of extinction memory. This study was undertaken to examine if chronic mild stress (CMS), which is known to alter induction of HPC-mPFC long-term potentiation, would also interfere with both extinction-related HPC-mPFC potentiation and extinction memory. Following fear conditioning (5 tone-shock pairings), rats were submitted to fear extinction (20 tone-alone presentations), which produced an increase in the amplitude of HPC-mPFC field potentials. HPC low-frequency stimulation (LFS), applied immediately after training, suppressed these changes and induced fear return during the retention test (5 tone-alone presentations). CMS, delivered before fear conditioning, did not interfere with fear extinction but blocked the development of extinction-related potentiation in the HPC-mPFC pathway and impaired the recall of extinction. These findings suggest that HPC LFS may provoke metaplastic changes in HPC outputs that may mimic alterations associated with a history of chronic stress.


Asunto(s)
Estimulación Eléctrica , Extinción Psicológica/fisiología , Miedo/fisiología , Hipocampo/fisiología , Memoria/fisiología , Estrés Psicológico/fisiopatología , Animales , Enfermedad Crónica , Privación de Alimentos , Iluminación , Potenciación a Largo Plazo/fisiología , Masculino , Plasticidad Neuronal/fisiología , Corteza Prefrontal/fisiología , Ratas , Ratas Wistar , Restricción Física , Recompensa , Privación de Agua
17.
Psychopharmacology (Berl) ; 196(4): 583-9, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17992518

RESUMEN

RATIONALE: Contextual fear conditioning can produce both changes in hippocampal synaptic efficacy and potentiation of subsequent fear learning. OBJECTIVES: In this study, we tested whether fluoxetine reverses these effects. MATERIALS AND METHODS: In the first experiment, we examined alterations of baseline synaptic efficacy and induction of synaptic plasticity in the CA3 region of the hippocampus during re-exposure of rats, treated with fluoxetine (7 mg/kg) or vehicle, in a context where they previously received 15 eyelid shocks or no shock (controls). In the second experiment, fear learning potentiation was examined in rats that were initially submitted to conditioning (15 eyelid shocks) and extinction training and then re-exposed to a less intense stressor (three eyelid shocks). RESULTS: Conditioned fear stress decreased synaptic efficacy and blocked the induction of synaptic potentiation in the fimbria-CA3 pathway. Conditioned rats treated with fluoxetine were protected against these electrophysiological changes and did not differ from controls (i.e., no depression and normal induction of potentiation of synaptic efficacy). However, fluoxetine treatment did not suppress conditioned freezing. After fear extinction, exposure of rats to a subconditioning stressor provoked conditioning (fear learning potentiation) in rats treated with vehicle but not in those treated with fluoxetine. CONCLUSIONS: These findings indicate that fluoxetine treatment, which is ineffective on conditioned fear stress-induced freezing, may have beneficial effects on conditioned fear stress-induced disturbance of hippocampal plasticity. These data also suggest that restoration of hippocampal functioning may contribute to protection against exaggerated reactions to mild stressors reported in patients with post-traumatic stress disorder.


Asunto(s)
Miedo/efectos de los fármacos , Fluoxetina/farmacología , Hipocampo/efectos de los fármacos , Plasticidad Neuronal/efectos de los fármacos , Inhibidores Selectivos de la Recaptación de Serotonina/farmacología , Animales , Condicionamiento Psicológico/efectos de los fármacos , Condicionamiento Psicológico/fisiología , Electrochoque , Párpados , Miedo/fisiología , Fluoxetina/administración & dosificación , Hipocampo/fisiopatología , Aprendizaje/efectos de los fármacos , Masculino , Ratas , Ratas Wistar , Inhibidores Selectivos de la Recaptación de Serotonina/administración & dosificación , Estrés Psicológico/fisiopatología
18.
Prog Neuropsychopharmacol Biol Psychiatry ; 32(5): 1312-9, 2008 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-18514376

RESUMEN

We reported recently that ketamine can increase the power of high-frequency oscillations (HFO) in the rodent nucleus accumbens (NAc), a region implicated in the pathophysiology of schizophrenia. Lamotrigine is known to reduce several of the abnormal behaviors induced by NMDA receptor antagonists in humans and rodents. This prompted us to examine whether lamotrigine would disrupt ketamine-enhanced HFO. Local field potentials (LFPs) and locomotor activity were recorded from male Wistar rats chronically implanted with electrodes in the NAc. Rats were pretreated with either saline or lamotrigine for 60min followed by injection of ketamine (25mg/kg). A separate group received a unilateral intra-NAc infusion of lamotrigine immediately followed by systemic injection of ketamine. We found systemic injection of a high dose of lamotrigine (20.1mg/kg) reduced the power and frequency of ketamine-enhanced HFO. This dose of lamotrigine was also associated with a decrease in both spontaneous HFO and locomotor activity, but did not significantly reduce locomotor activity induced by ketamine. In contrast, a low dose of lamotrigine (2.0mg/kg) produced a small, but significant increase of both ketamine-enhanced HFO and locomotor activity. Local infusion of lamotrigine into the NAc did not significantly affect ketamine-induced HFO, suggesting lamotrigine produces its effect on structures afferent to the NAc, and effects on HFO most likely result from modulating excitatory transmission to the NAc.


Asunto(s)
Antagonistas de Aminoácidos Excitadores/farmacología , Ventilación de Alta Frecuencia , Potenciales de la Membrana/efectos de los fármacos , Núcleo Accumbens/efectos de los fármacos , Triazinas/farmacología , Algoritmos , Análisis de Varianza , Animales , Relación Dosis-Respuesta a Droga , Electroencefalografía , Ketamina/farmacología , Lamotrigina , Masculino , Microinyecciones , Actividad Motora/efectos de los fármacos , Núcleo Accumbens/fisiología , Ratas , Ratas Wistar , Análisis Espectral , Factores de Tiempo
19.
Clin Neurol Neurosurg ; 110(1): 19-24, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17900799

RESUMEN

OBJECTIVES: The aim of the present study was to stress the relationship between neuropsychiatric symptoms and most particularly apathy and striatal dopamine uptake in patients with Alzheimer's disease (AD) or dementia with Lewy body (DLB). PATIENTS AND METHODS: Twenty-two patients (AD n=14; DLB n=8) were included. All patients had neuropsychological and behavioral examination including Mini Mental Test Examination (MMSE), Neuropsychiatric Inventory (NPI), and UPDRS for the motor activity assessment. Apathy dimensions, emotional blunting, lack of initiative and lack of interest were assessed using the Apathy Inventory (AI). Dopamine transporter (DAT) striatal uptake was assessed using (123)I-FP-CIT (DaTSCAN) SPECT. Quantitative measurements were obtained in 3D using a method which compensates for physical detection biases including partial volume effect. RESULTS: We observed a correlation between DAT uptake and NPI's domains only for apathy. More specifically using the AI, lack of initiative significantly correlated with bilateral putamen DAT uptake. Using partial correlation coefficients controlling for the UPDRS score, the correlation remained significant between lack of initiative and right and left putamen DAT uptake. CONCLUSION: These results demonstrate a relationship between apathy and DAT levels independent from motor activity. They suggest that the patients with neurodegenerative diseases presenting with apathy are characterized by some degree of dopaminergic neuronal loss.


Asunto(s)
Enfermedad de Alzheimer/metabolismo , Corteza Cerebral/metabolismo , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/metabolismo , Enfermedad por Cuerpos de Lewy/metabolismo , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/diagnóstico por imagen , Enfermedad de Alzheimer/psicología , Corteza Cerebral/diagnóstico por imagen , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Enfermedad por Cuerpos de Lewy/diagnóstico por imagen , Enfermedad por Cuerpos de Lewy/psicología , Masculino , Pruebas Neuropsicológicas , Tomografía Computarizada de Emisión de Fotón Único
20.
Health Policy ; 85(1): 94-104, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17707542

RESUMEN

OBJECTIVES: To rationalise the use of hospital emergency units, the Cuban health system developed from 1996 onwards an extra muros first line emergency system (FLES). We analyse the use of the FLES and its determinants, in order to develop proposals to channel inappropriate users to their family doctor. METHODS: In the FLES of an urban (Cerro) and a rural (Baracoa) municipality we collected, from July 1999 to June 2001, data on the moment of consultation, age and sex of the patient, referral status, motive of consultation, emergency classification, diagnosis and medical conduct. A variable "inappropriate use" was constructed. We used multivariate logistic regression to quantify the strength of the associations between patient characteristics, the night-time use, medical procedures, referral, and inappropriate use of the FLES. RESULTS: Over the 2 years observation period, 24879 and 59795 patient contacts were registered with the principal emergency policlinic in Baracoa and Cerro, respectively. In both municipalities the overall "inappropriate" use was almost 60%. There was no correlation with age and gender but inappropriate use was 50% more frequent during the day. Referred patients in both localities were up to 12 times more frequently hospitalized. CONCLUSION: Cuba's FLES attract patients that would be better attended by their family doctor. To strengthen his central position in the health system, one should strengthen the family doctor's technical platform, increase his permanence at the cabinet, and improve communication with the community on the rationale of the family doctor--FLES set up.


Asunto(s)
Instituciones de Atención Ambulatoria/estadística & datos numéricos , Servicios Médicos de Urgencia/estadística & datos numéricos , Aceptación de la Atención de Salud/estadística & datos numéricos , Adolescente , Adulto , Anciano , Niño , Preescolar , Cuba , Servicio de Urgencia en Hospital/estadística & datos numéricos , Femenino , Mal Uso de los Servicios de Salud/estadística & datos numéricos , Humanos , Lactante , Modelos Logísticos , Masculino , Persona de Mediana Edad , Derivación y Consulta/estadística & datos numéricos , Servicios de Salud Rural , Servicios Urbanos de Salud
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