Role of environmental enrichment on social interaction, anxiety, locomotion, and memory in Wistar rats under chronic methylphenidate intake.

Introduction: Chronic use of various compounds can have long-lasting effects on animal behavior, and some of these effects can be influenced by the environment. Many environmental enrichment protocols have the potential to induce behavioral changes. Aim: The aim of the present study was to investigate how environmental enrichment can mitigate the effects of chronic methylphenidate consumption on the behavior of Wistar rats. Methods: The animals were housed for 20 days under either an environmental enrichment protocol (which included tubes of different shapes) or standard housing conditions. After seven days, half of the rats received 13 days of oral administration of methylphenidate (2 mg/kg). After seven days, the rats underwent behavioral tests, including the elevated plus maze (anxiety), open field (locomotion), object-in-place recognition test (spatial memory), and a test for social interaction (social behavior). Results: The results showed that the enriched environmental condition reversed the enhanced time in the open arms of the elevated plus maze induced by methylphenidate (F[1,43] = 4.275, p = 0.045). Methylphenidate also enhanced exploratory rearing in the open field (F[1,43] = 4.663, p = 0.036) and the time spent in the open area of the open field (H[3] = 8.786, p = 0.032). The enriched environment mitigated the inhibition of social interaction with peers induced by methylphenidate (H[3] = 16.755, p < 0.001) as well as the preference for single exploratory behavior (H[3] = 9.041, p = 0.029). Discussion: These findings suggest that environmental enrichment can counteract some of the effects of methylphenidate. These results are relevant for the clinical treatment of the long-lasting secondary effects associated with methylphenidate pharmacological treatment.

Providing Environmental Enrichment without Altering Behavior in Male and Female Wistar Rats (Rattus norvegicus).

In research using animal models, subjects are commonly maintained under standard housing conditions, mainly because of the idea that enhancing welfare conditions could alter experimental data. Another common practice in many laboratories relates to the preponderant use of males. Several reasons justifying this practice include the rapid hormonal and endocrine change in females, which may require a higher number of female animals to achieve more homogenous groups, thereby creating a dilemma with the reduction principle in animal research. In past decades, a relationship between enriched environments and enhanced cognitive functions has been reported in rats, but many of those enriched environmental protocols were not systematically or rigorously studied, leading to unexpected effects on behavior. Here we report the effects of 4 types of housing conditions (standard, structural changes, exercise, and foraging) in Wistar rats on anxiety (elevated plus maze), exploratory (open field), and stress vulnerability (forced swim test) responses. Sex was used as a blocking factor. Data show no effect of housing conditions on anxiety and exploratory behaviors, but do show an effect on stress responses. These results suggest the possibility of using a protocol for environmental enrichment without concern about altering experimental data. From this stand, new ways to enhance animal welfare in research laboratories could be designed and implemented.

Post-recurrence survival in patients with cervical cancer.

BACKGROUND: Up to 26% of patients with early-stage cervical cancer experience relapse after primary surgery. However, little is known about which factors influence prognosis following disease recurrence. Therefore, our aims were to determine post-recurrence disease-specific survival (PR-DSS) and to identify respective prognostic factors for PR-DSS. METHODS: Data from 528 patients with early-stage cervical cancer who relapsed after primary surgery performed between 2007 and 2016 were obtained from the SCANN study (Surveillance in Cervical CANcer). Factors related to the primary disease and recurrence were combined in a multivariable Cox proportional hazards model to predict PR-DSS. RESULTS: The 5-year PR-DSS was 39.1% (95% confidence interval [CI] 22.7%-44.5%), median disease-free interval between primary surgery and recurrence (DFI1) was 1.5 years, and median survival after recurrence was 2.5 years. Six significant variables were identified in the multivariable analysis and were used to construct the prognostic model. Two were related to primary treatment (largest tumour size and lymphovascular space invasion) and four to recurrence (DFI1, age at recurrence, presence of symptoms, and recurrence type). The C-statistic after 10-fold cross-validation of prognostic model reached 0.701 (95% CI 0.675-0.727). Three risk-groups with significantly differing prognoses were identified, with 5-year PR-DSS rates of 81.8%, 44.6%, and 12.7%. CONCLUSIONS: We developed the robust model of PR-DSS to stratify patients with relapsed cervical cancer according to risk profiles using six routinely recorded prognostic markers. The model can be utilised in clinical practice to aid decision-making on the strategy of recurrence management, and to better inform the patients.

Cathodal transcranial direct current stimulation on the prefrontal cortex applied after reactivation attenuates fear memories and prevent reinstatement after extinction.

BACKGROUND: In the last decade, pharmacological strategies targeting reconsolidation after memory retrieval have shown promising efforts to attenuate persistent memories and overcome fear recovery. However, most reconsolidation inhibiting agents have not been approved for human testing. While non-invasive neuromodulation can be considered an alternative approach to pharmacological treatments, there is a lack of evidence about the efficacy of these technologies when modifying memory traces via reactivation/reconsolidation mechanism. OBJECTIVE: In this study, we evaluate the effect of cathodal (c-tDCS) and anodal (a-DCS) transcranial direct current stimulation applied after memory reactivation and extinction in rats. METHODS: Male Wistar rats were randomly assigned into three groups: one sham group, one anodal tDCS group, and one cathodal tDCS group (500 µA, 20 min). Reconsolidation and extinction of fear memories were evaluated using a contextual fear conditioning. RESULTS: Our results showed that c-tDCS and a-tDCS after memory reactivation can attenuate mild fear memories. However, only c-tDCS stimulation prevented both fear expression under strong fear learning and fear recovery after a reinstatement protocol without modification of learning rate or extinction retrieval. Nevertheless, the remote memories were resistant to modification through this type of neuromodulation. Our results are discussed considering the interaction between intrinsic excitability promoted by learning and memory retrieval and the electric field applied during tDCS. CONCLUSION: These results point out some of the boundary conditions influencing the efficacy of tDCS in fear attenuation and open new ways for the development of noninvasive interventions aimed to control fear-related disorders via reconsolidation.

Fear Incubation Using an Extended Fear-Conditioning Protocol for Rats.

Emotional memory has been primarily studied with fear-conditioning paradigms. Fear conditioning is a form of learning through which individuals learn the relationships between aversive events and otherwise neutral stimuli. The most-widely utilized procedures for studying emotional memories entail fear conditioning in rats. In these tasks, the unconditioned stimulus (US) is a footshock presented once or several times across single or several sessions, and the conditioned response (CR) is freezing. In a version of these procedures, called cued fear conditioning, a tone (conditioned stimulus, CS) is paired with footshocks (US) during the training phase. During the first test, animals are exposed to the same context in which training took place, and freezing responses are tested in the absence of footshocks and tones (i.e., a context test). During the second test, freezing is measured when the context is changed (e.g., by manipulating the smell and walls of the experimental chamber) and the tone is presented in the absence of footshocks (i.e., a cue test). Most cued fear conditioning procedures entail few tone-shock pairings (e.g., 1-3 trials in a single session). There is a growing interest in less common versions involving an extensive number of pairings (i.e., overtraining) related to the long-lasting effect called fear incubation (i.e., fear responses increase over time without further exposure to aversive events or conditioned stimuli). Extended fear-conditioning tasks have been key to the understanding of fear incubation's behavioral and neurobiological aspects, including its relationship with other psychological phenomena (e.g., post-traumatic stress disorder). Here, we describe an extended fear-conditioning protocol that produces overtraining and fear incubation in rats. This protocol entails a single training session with 25 tone-shock pairings (i.e., overtraining) and a comparison of conditioned freezing responses during context and cue tests 48 h (short-term) and 6 weeks (long-term) after training.

Distinct patterns of brain Fos expression in Carioca High- and Low-conditioned Freezing Rats.

BACKGROUND: The bidirectional selection of high and low anxiety-like behavior is a valuable tool for understanding the neurocircuits that are responsible for anxiety disorders. Our group developed two breeding lines of rats, known as Carioca High- and Low-conditioned Freezing (CHF and CLF), based on defensive freezing in the contextual fear conditioning paradigm. A random selected line was employed as a control (CTL) comparison group for both CHF and CLF lines of animals. The present study performed Fos immunochemistry to investigate changes in neural activity in different brain structures among CHF and CLF rats when they were exposed to contextual cues that were previously associated with footshock. RESULTS: The study indicated that CHF rats expressed high Fos expression in the locus coeruleus, periventricular nucleus of the hypothalamus (PVN), and lateral portion of the septal area and low Fos expression in the medial portion of the septal area, dentate gyrus, and prelimbic cortex (PL) compared to CTL animals. CLF rats exhibited a decrease in Fos expression in the PVN, PL, and basolateral nucleus of the amygdala and increase in the cingulate and perirhinal cortices compared to CTL animals. CONCLUSIONS: Both CHF and CLF rats displayed Fos expression changes key regions of the anxiety brain circuitry. The two bidirectional lines exhibit different pattern of neural activation and inhibition with opposing influences on the PVN, the main structure involved in regulating the hypothalamic-pituitary-adrenal neuroendocrine responses observed in anxiety disorders.

Synaptic plasticity in Alzheimer's disease and healthy aging.

The strength and efficiency of synaptic connections are affected by the environment or the experience of the individual. This property, called synaptic plasticity, is directly related to memory and learning processes and has been modeled at the cellular level. These types of cellular memory and learning models include specific stimulation protocols that generate a long-term strengthening of the synapses, called long-term potentiation, or a weakening of the said long-term synapses, called long-term depression. Although, for decades, researchers have believed that the main cause of the cognitive deficit that characterizes Alzheimer's disease (AD) and aging was the loss of neurons, the hypothesis of an imbalance in the cellular and molecular mechanisms of synaptic plasticity underlying this deficit is currently widely accepted. An understanding of the molecular and cellular changes underlying the process of synaptic plasticity during the development of AD and aging will direct future studies to specific targets, resulting in the development of much more efficient and specific therapeutic strategies. In this review, we classify, discuss, and describe the main findings related to changes in the neurophysiological mechanisms of synaptic plasticity in excitatory synapses underlying AD and aging. In addition, we suggest possible mechanisms in which aging can become a high-risk factor for the development of AD and how its development could be prevented or slowed.

A systematic review of brain functional connectivity patterns involved in episodic and semantic memory.

The study of functional connectivity and declarative memory has lately been focused on finding biomarkers of neuropsychological diseases. However, little is known about its patterns in healthy brains. Thus, in this systematic review we analyze and integrate the findings of 81 publications regarding functional connectivity (measured by fMRI during both task and resting-state) and semantic and episodic memory in healthy adults. Moreover, we discriminate and analyze the main areas and links found in specific memory phases (encoding, storage or retrieval) based on several criteria, such as time length, depth of processing, rewarding value of the information, vividness and amount or kind of details retrieved. There is a certain degree of overlap between the networks of episodic and semantic memory and between the encoding and retrieval stages. Although several differences are pointed out during the article, this calls to attention the need for further empirical studies that actively compare both types of memory, particularly using other baseline conditions apart from the traditional resting state. Indeed, the active involvement of the default mode network in both declarative memory and resting condition suggests the possibility that during rest there is an on-going memory processing. We find support for the 'attention to memory' hypothesis, the memory differentiation model and the appropriate transfer hypothesis, but some evidence is inconsistent with the traditional hub-and-spoke model.

Efectos de la estimulación eléctrica habenular en la modulación de respuestas emocionales en ratas Wistar / Efeitos da estimulação elétrica habenular na modulação de respostas emocionais em ratos Wistar / Effects of electrical stimulation of the habenula on the modulation of emotional responses in Wistar rats

Resumen A pesar del amplio uso de la estimulación cerebral profunda para controlar patologías neurológicas y neuropsiquiátricas, su mecanismo de acción aún no es claramente conocido, y existen pocos estudios sistemáticos que relacionen la variación de parámetros de estimulación eléctrica (frecuencia, intensidad, duración del pulso) y la ejecución comportamental. La habénula es una estructura reguladora de respuestas emocionales diana en tratamientos para dolor crónico y depresión, pero la relación entre su estimulación crónica y el desempeño animal en pruebas conductuales no se ha establecido con claridad. Con el objetivo de evaluar el efecto emocional de la estimulación habenular crónica, en este estudio se utilizaron ratas Wistar que recibieron estimulación habenular a intensidad baja (10-80 pA) o alta (120-260 pA) y frecuencia baja (80-150 Hz) o alta (240380 Hz): BIBF-AIBF-BIAF-AIAF, durante 15 minutos a lo largo de tres días consecutivos. Al cuarto día, se hizo la evaluación en un laberinto elevado en cruz y en campo abierto. Los resultados indican un efecto de tipo ansiolítico en el tratamiento BIAF, en comparación con BIBF y AIBF (aumento del número de entradas, porcentaje de tiempo en brazos abiertos y de la distancia recorrida en ellos), efecto que no se explica por cambios en la locomotricidad (distancia recorrida en los brazos cerrados y la exploración en el campo abierto). Se concluye que el parámetro frecuencia posee mayor impacto sobre el efecto comportamental que la intensidad -lo que puede explicar algunos hallazgos paradójicos previos-, que los parámetros utilizados no poseen efecto ansiogénico, y que los efectos potencialmente ansiogénicos de la estimulación a baja frecuencia y el papel de los sistemas dopaminérgicos y serotoninérgicos encontrados deben ser estudiados en futuras investigaciones.

Resumo Apesar do amplo uso da estimulação cerebral profunda para controlar patologias neurológicas e neuropsiquiátricas, seu mecanismo de ação ainda não é claramente conhecido e existem poucos estudos sistemáticos que relacionem a variação de parâmetros de estimulação elétrica (frequência, intensidade, duração do pulso) e a execução comportamental. A habênula é uma estrutura reguladora de respostas emocionais específicas em tratamentos para dor crònica e depressão, mas a relação entre sua estimulação crònica e o desempenho animal em testes comportamentais não foi claramente estabelecida. Com o objetivo de avaliar o efeito emocional da estimulação habenular crònica, neste estudo foram utilizados ratos Wistar que receberam estimulação habenular de intensidade baixa (10-80 pA) ou alta (120-260 pA) e frequência baixa (80-150 Hz) ou alta (240-380 Hz): BIBF-AIBF-BIAF-AIAF, durante 15 minutos ao longo de três dias consecutivos. No quarto dia, foi feita a avaliação em um labirinto em cruz elevado e em campo aberto. Os resultados indicam um efeito de tipo ansiolítico no tratamento BIAF, em comparação com BIBF e AIBF (aumento do número de entradas, porcentagem de tempo em braços abertos e da distância percorrida neles), efeito que não se explica por mudanças na locomotividade (distância percorrida nos braços fechados e a exploração no campo aberto). Conclui-se que o parâmetro "frequência" tem mais impacto sobre o efeito comportamental do que a "intensidade" - o que pode explicar algumas descobertas paradoxais prévias -, que os parâmetros utilizados não tenham efeito ansiogênico, e que os efeitos potencialmente ansiogênicos da estimulação de baixa frequência e o papel dos sistemas dopaminérgicos e serotoninérgicos encontrados devem ser estudados em pesquisas futuras.

Abstract Deep brain stimulation is a widely-used approach to the treatment of neurologic and neuropsychiatric diseases. However, its mechanisms remain unclear. There are few systematic studies relating variations on electrical stimulation parameters (frequency, intensity, pulse duration) and behavioral outcome. The habenula relates to emotional behavior and is a main target for chronic pain and depression stimulation treatment. The relation between habenular electrical stimulation and performance in behavioral tests has not been clearly defined. In order to assess the emotional effects of chronic habenular electrical stimulation, Wistar male rats were unilaterally implanted with electrodes aimed to the lateral habenula and assigned to low (10-80 pA) or high (120-260 pA) intensity and low (80-150 Hz) or high (240-380 Hz) frequency conditions: BIBF-AIBF-BIAF-AIAF. They received electrical stimulation 15 minutes/day for three consecutive days and on the fourth day were tested in the elevated plus maze and the open field. The results of these study show that BIAF stimulation has a possible anxiolytic-like effect when compared to BIBF and AIBF (increase in the percentage of open-arms time, entries into the open-arms and total-distance-run in the open-arms). This is not due to any changes in locomotion (total-distance-run and open field exploration). It is concluded that frequency is more important than intensity for behavioral modification. This could explain some previous inconsistent results. The data also suggest that these parameters of stimulation have no anxiogenic effects. The role for dopaminergic and serotonergic systems must be subsequently evaluated as well as potential anxiogenic-like effects of low frequency stimulation.

Coarse Graining, Nonmaximal Entropy, and Power Laws.

We show that coarse graining produces significant and predictable effects on the entropy of states of equilibrium when the scale of coarse graining becomes comparable to that of density fluctuations. We demonstrate that a coarse-grained entropy typically evolves toward a state of effective equilibrium with a lower value than that of the state of maximum entropy theoretically possible. The finer the coarse graining, the greater the drop in effective entropy, and the more relevant the fluctuations around that. Fundamental considerations allow us to derive a remarkable power law that relates coarse graining to the effective entropy gap. Another power law is found that precisely relates the noise range of effective entropy fluctuations to coarse graining. We test both power laws with numerical simulations based on a well-studied two-dimensional lattice gas model. As expected, the effects of these power laws diminish as our description approaches a macroscopic level, eventually disappearing in the thermodynamic limit, where the maximum entropy principle is reasserted.

Neuro-«lo que sea¼: inicio y auge de una pseudociencia para el siglo XXI / Neuro-"whatever": Beginnings of a new pseudoscience for the XXI century

El paso del estado sésil al movimiento activo, requirió del desarrollo de un sistema nervioso capaz de coordinar el movimiento hacia fuentes de alimentación y el escape de posibles amenazas. En respuesta a los cambios en los ambientes macro- y micro-, los sistemas nerviosos fueron integrando habilidades cada vez mejores culminando en el «ensayo mental¼ (León & Cárdenas, 2011): el animal podía «imaginar¼ las consecuencias de algunas de sus acciones (causas y efectos), sin requerir ejecutarlas: la diferencia entre la vida y la muerte. Ya en los albores de la humanidad, esa necesidad imperiosa de buscar causas -ahora en una esfera plenamente mental- se plasmó en la creación de conceptualizaciones animistas de la naturaleza y por ello las primeras manifestaciones culturales fueron las explicaciones del universo en términos de mitos, leyendas, cuentos e historias transmitidas generacionalmente. El desarrollo de las tecnologías que fortalecían la unión cultural y las alianzas entre clanes, impulsó el desarrollo del conocimiento científico que mejoraba la tecnología y satisfacía más profundamente la sed de explicación del mundo. Fue la primera gran escisión entre ciencia y tecnología. Para el común, el impacto de la tecnología sobre la vida diaria es mucho más evidente que el de la ciencia, visión inmediatista que aún hoy rige, lastimosamente, a muchos organismos de gestión de la ciencia y la tecnología en muchos países. La separación ciencia (comprensible por pocos) / tecnología (usable por todos) hizo que paulatinamente se fuera desconociendo el real valor de la ciencia y permitió que muchas formas de conocimiento no científico, mucho más fácil de comprender y de transmitir -las «pseudociencias¼ (pseudo = que quiere ser, pero no es)- fueran instaurándose. Este conocimiento es «comprobado¼ por casos únicos que alguna vez sucedieron o que alguien reporto que vio o escucho (sin importar la veracidad del reporte). Ritos, mitos, magia, leyendas, alquimia y otras muchas ideas surgieron de esa forma.

Behavioral Effects of Systemic, Infralimbic and Prelimbic Injections of a Serotonin 5-HT2A Antagonist in Carioca High- and Low-Conditioned Freezing Rats.

The role of serotonin (5-hydroxytryptamine [5-HT]) and 5-HT2A receptors in anxiety has been extensively studied, mostly without considering individual differences in trait anxiety. Our laboratory developed two lines of animals that are bred for high and low freezing responses to contextual cues that are previously associated with footshock (Carioca High-conditioned Freezing [CHF] and Carioca Low-conditioned Freezing [CLF]). The present study investigated whether ketanserin, a preferential 5-HT2A receptor blocker, exerts distinct anxiety-like profiles in these two lines of animals. In the first experiment, the animals received a systemic injection of ketanserin and were exposed to the elevated plus maze (EPM). In the second experiment, these two lines of animals received microinjections of ketanserin in the infralimbic (IL) and prelimbic (PL) cortices and were exposed to either the EPM or a contextual fear conditioning paradigm. The two rat lines exhibited bidirectional effects on anxiety-like behavior in the EPM and opposite responses to ketanserin. Both systemic and intra-IL cortex injections of ketanserin exerted anxiolytic-like effects in CHF rats but anxiogenic-like effects in CLF rats. Microinjections of ketanserin in the PL cortex also exerted anxiolytic-like effects in CHF rats but had no effect in CLF rats. These results suggest that the behavioral effects of 5-HT2A receptor antagonism might depend on genetic variability associated with baseline reactions to threatening situations and 5-HT2A receptor expression in the IL and PL cortices. Highlights -CHF and CLF rats are two bidirectional lines that are based on contextual fear conditioning.-CHF rats have a more "anxious" phenotype than CLF rats in the EPM.-The 5-HT2A receptor antagonist ketanserin had opposite behavioral effects in CHF and CLF rats.-Systemic and IL injections either decreased (CHF) or increased (CLF) anxiety-like behavior.-PL injections either decreased (CHF) anxiety-like behavior or had no effect (CLF).

Running wheel training does not change neurogenesis levels or alter working memory tasks in adult rats.

BACKGROUND: Exercise can change cellular structure and connectivity (neurogenesis or synaptogenesis), causing alterations in both behavior and working memory. The aim of this study was to evaluate the effect of exercise on working memory and hippocampal neurogenesis in adult male Wistar rats using a T-maze test. METHODS: An experimental design with two groups was developed: the experimental group (n = 12) was subject to a forced exercise program for five days, whereas the control group (n = 9) stayed in the home cage. Six to eight weeks after training, the rats' working memory was evaluated in a T-maze test and four choice days were analyzed, taking into account alternation as a working memory indicator. Hippocampal neurogenesis was evaluated by means of immunohistochemistry of BrdU positive cells. RESULTS: No differences between groups were found in the behavioral variables (alternation, preference index, time of response, time of trial or feeding), or in the levels of BrdU positive cells. DISCUSSION: Results suggest that although exercise may have effects on brain structure, a construct such as working memory may require more complex changes in networks or connections to demonstrate a change at behavioral level.

Effect of Overcrowding on Hair Corticosterone Concentrations in Juvenile Male Wistar Rats.

In many species, chronic stress due to overcrowding during the juvenile period triggers several metabolic and behavioral pathologies in adulthood. The aim of this study was to determine whether a chronic stress condition (overcrowding) induces changes in plasma and hair corticosterone concentrations, overall growth, and organ weights in young Wistar rats. The experimental subjects were divided into 2 groups (control and overcrowded); the overcrowded subjects were exposed to overcrowding during days 38 through 65 after birth. Plasma and hair corticosterone concentrations were higher in overcrowded rats compared with control subjects. In addition, overcrowding reduced body and organ weight gains. These results demonstrate that measuring the concentration of corticosterone in hair samples is an effective, noninvasive method for monitoring chronic stress in rats.

Aproximación Neurodinámica a la Cognición Social / Neurodimanic Approach to Social Cognition

En las últimas décadas ha crecido el estudio los mecanismos involucrados en el comportamiento social, gran parte de estas indagaciones se han realizado desde una aproximación de la neurociencia social cognitiva, la cual se basa en un modelo representacional del procesamiento de información. No obstante, esta aproximación ha sido ampliamente criticada por desconocer la participación del cuerpo, la dinámica afectiva, el contexto social, el cambio durante el desarrollo y suponer un procesamiento modular endógeno. En este sentido, este artículo presenta un modelo neurodinámico de la cognición social (CS), comprendiéndola desde una aproximación enactiva, situada, relacional y sistémica. Desde este modelo se describen los principales cambios en esperados la actividad cerebral durante las interacciones sociales en tiempo real y durante la ontogenia. Se concluye resaltando los desafíos y oportunidades que este tipo de aproximaciones puede proporcionar a la neurociencia y psicología social del futuro.

In recent decades it has seen a growing interest to study the mechanisms involved in social behavior, much of these inquiries fall within social cognitive neuroscience approach, which is based on a representational model of information processing. However, this approach has been widely criticized for ignoring the body participation, emotional dynamics, social context, developmental changes and assuming an endogenous modular processing. In this regard, this article presents a neurodynamic model of social cognition, which understand social process from an enactive, embodied, situated, relational and systemic perspective. This model let us described the main expected changes in brain activity during ongoing social interactions and ontogeny. The conclusion highlights the challenges and opportunities that this kind of approach can provide for a coming neuroscience and social psychology.

La Enfermedad de Parkinson: Etiología, Tratamientos y Factores Preventivos / Parkinson Disease: Etiology, Treatments and Preventive Factors

La enfermedad de Parkinson (EP) es la patología neurodegenerativa motora con mayor incidencia a nivel mundial, cuyas causas aún no son claras. Actualmente no existe cura, pero es posible contar con diferentes tratamientos que permiten aliviar algunos de sus síntomas y enlentecer su curso. Debido a la gran cantidad de informaciones, en ocasiones contradictorias sobre los llamados "factores de riesgo" (entendidos éstos como situaciones que pueden exacerbar la posibilidad de aparición de la enfermedad, incluyendo desde la predisposición familiar hasta la exposición prolongada a substancias exógenas), en esta revisión se pretende ofrecer una panorámica actual sobre factores asociados a la aparición de EP Se revisan también algunos tratamientos que buscan contrarrestar la pérdida de la función dopaminérgica de la substancia nigra (SN) y algunas de las aproximaciones terapéuticas tanto farmacológicas, como por estimulación cerebral profunda (ECP) o por implante celular. Se revisan también investigaciones sobre el potencial terapéutico de compuestos con alta especificidad a receptores colinérgicos (nAChRs) y antagonistas de receptores de adenosina, específicamente del subtipo A2A. Posiblemente durante las próximas décadas, nuestro conocimiento en epigenética pueda arrojar nuevas luces sobre esta interacción, así como sobre las relaciones entre ciertas líneas de microbios intestinales y aparición de EP. En este momento, la alternativa terapéutica que ofrece mayor eficacia es la ECP, sin embargo, a futuro se espera que el desarrollo de nuevas estrategias de implante cerebral pueda ofrecer una cura real de la EP.

Parkinson's disease (PD) is the most prevalent neurodegenerative motor pathology worldwide, the causes of which are still unclear. Currently there is no cure, but it is possible to have different treatments that allow to alleviate some of its symptoms and slow its course. Due to the large amount of information, sometimes contradictory, about the so-called "risk factors" (understood as situations that may exacerbate the possibility of the onset of the disease, from family predisposition to prolonged exposure to exogenous substances), in this review aims to provide a current overview of factors associated with the occurrence of PD. We also review some treatments that seek to counteract the loss of the dopaminergic function of the substance nigra (SN) and some of the therapeutic approaches both pharmacologically, by deep brain stimulation (DBS) or by cellular implantation. Also reviewed investigations on the therapeutic potential of compounds with high specificity to cholinergic receptors (nAChRs) and adenosine receptor antagonists, specifically the A2A subtype. Possibly, during the next decades, our knowledge in epigenetics may shed new light on this interaction, as well as on the relationships between certain lines of intestinal microbes and onset of PD. At this time, the most effective therapeutic alternative is DBS; however, in the future it is expected that the development of new brain implant strategies may offer a real cure for PD.

Medial orbitofrontal cortex lesion prevents facilitatory effects of d-cycloserine during fear extinction.

Animal models of fear extinction have an important clinical relevance to pharmacological and exposure-based therapies for anxiety disorders. Lesions of prefrontal structures impair fear extinction. On the other hand, d-cycloserine is able to enhance this process. We hypothesize that the integrity of cortical structures involved in inhibitory control of emotional responses is crucial for the facilitatory effects of d-cycloserine. Here, we showed that medial orbitofrontal cortex lesion prevents d-cycloserine enhancement of fear extinction. These preliminary results suggest that effects of pharmacological treatments could be dependent on cortical activity state to promote fear memory reduction.

Contribution of the parafascicular nucleus in the spontaneous object recognition task.

The parafascicular (PF) nucleus, a posterior component of the intralaminar nuclei of the thalamus, is considered to be an essential structure in the feedback systems of basal ganglia-thalamo-cortical circuits critically involved in cognitive processes. The specific role played by multimodal information encoded in PF neurons in learning and memory processes is still unclear. We conducted two experiments to investigate the role of the PF in the spontaneous object recognition (SOR) task. The behavioral effects of pretraining rats with bilateral lesions of PF with N-methyl-D-aspartate (NMDA) were compared to vehicle controls. In the first experiment, rats were tested on their ability to remember the association immediately after training trials and in the second experiment after a 24h delay. Our findings provide evidence that PF lesions critically affect both SOR tests and support its role in that non-spatial form of relational memory.