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Exposure to alcohol during adolescence impacts cortical and limbic brain regions undergoing maturation. In rodent models, long-term effects on behavior and neurophysiology have been described after adolescent intermittent ethanol (AIE), especially in males. We hypothesized that AIE in female rats increases conditional approach to a reward-predictive cue and corresponding neuronal activity in the orbitofrontal cortex (OFC) and nucleus accumbens (NAc). We evaluated behavior and neuronal firing after AIE (5 g/kg intragastric) or water (CON) in adult female rats. Both AIE and CON groups expressed a ST phenotype, and AIE marginally increased sign-tracking (ST) and decreased goal-tracking (GT) metrics. NAc neurons exhibited phasic firing patterns to the conditional stimulus (CS), with no differences between groups. In contrast, neuronal firing in the OFC of AIE animals was greater at CS onset and offset than in CON animals. During reward omission, OFC responses to CS offset normalized to CON levels, but enhanced OFC firing to CS onset persisted in AIE. We suggest that the enhanced OFC neural activity observed in AIE rats to the CS could contribute to behavioral inflexibility. Ultimately, AIE persistently impacts the neurocircuitry of reward-motivated behavior in female rats.

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Resumen Introducción Los cambios en la práctica profesional han transformado la intención de los estudiantes de medicina de optar por una carrera en cirugía. Objetivo Evaluar los factores asociados con esta intención en un contexto de acelerada dinámica educativa y sanitaria. Materiales y Método Evaluamos la intención de los estudiantes de diez facultades de medicina en Colombia, y los factores asociados, mediante un cuestionario (escala de Likert) desarrollado a partir de la revisión de la literatura. Identificamos la asociación entre los factores y la intención mediante un análisis de regresión lineal. Los resultados de la regresión se presentan mediante coeficientes β (p < 0,05). Resultados Un total de 252 estudiantes (65,87% mujeres) fueron incluidos en el análisis. El promedio de la intención fue 3,15 ± 1,34 (1-5). Los factores significativamente asociados fueron: identificación con el estilo de vida quirúrgico (β = 0,25); identificación con modelos (β = 0,18); atributos personales (β = 0,25) e identificación con la práctica profesional del cirujano (β = 0,16). No encontramos asociación significativa con el género (mujeres en la especialidad), prestigio, dinámica del posgrado ni recompensa futura. Conclusión Existe una intención moderada de elegir una carrera de cirugía entre estudiantes de medicina colombianos. Optar por esta carrera requiere atributos personales, modelos e identificación con el estilo de vida y práctica profesional del cirujano. Se requieren estudios cualitativos que exploren en profundidad estos resultados e intervenciones focalizadas a estimular esta intención entre los estudiantes.

Introduction The changes in the professional practice have transformed the intention of medical students to choose a surgical career. Aim Evaluate the factors associated with this intention in a context of accelerated educational and health dynamics. Materials and Method We evaluated the intention of the students of ten medical schools in Colombia, and the associated factors, through a questionnaire (Likert scale) settled from a literature review. We identify the association between the factors and the intention by using linear regression analysis. The results of the regression are presented by β coefficients (p < 0.05). Results A total of 252 students (65.87% women) were included in the analysis. The average of the intention was 3.15 ± 1.34 (1-5). The factors significantly associated were: identification with the surgical lifestyle (β = 0.25); identification with models (β = 0.18); personal attributes (β = 0.25) and identification with the professional practice of the surgeon (β = 0.16). We did not find significant associations with gender (women in the specialty), prestige, postgraduate dynamics and future rewards. Conclusion There is a moderate intention to choose a career in surgery among Colombian medical undergraduates. Choosing this career requires personal attributes, models and identification with the lifestyle and professional practice of the surgeon. Further qualitative studies are necessary to explore these results in depth, as well as interventions to stimulate this intention among students.

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BACKGROUND: Conditioned stimuli (CS) that predict reward delivery acquire the ability to induce phasic dopamine release in the nucleus accumbens (NAc). This dopamine release may facilitate conditioned approach behavior, which often manifests as approach to the site of reward delivery (called "goal-tracking") or to the CS itself (called "sign-tracking"). Previous research has linked sign-tracking in particular to impulsivity and drug self-administration, and addictive drugs may promote the expression of sign-tracking. Ethanol (EtOH) acutely promotes phasic release of dopamine in the accumbens, but it is unknown whether an alcoholic reward alters dopamine release to a CS. We hypothesized that Pavlovian conditioning with an alcoholic reward would increase dopamine release triggered by the CS and subsequent sign-tracking behavior. Moreover, we predicted that chronic intermittent EtOH (CIE) exposure would promote sign-tracking while acute administration of naltrexone (NTX) would reduce it. METHODS: Rats received 14 doses of EtOH (3 to 5 g/kg, intragastric) or water followed by 6 days of Pavlovian conditioning training. Rewards were a chocolate solution with or without 10% (w/v) alcohol. We used fast-scan cyclic voltammetry to measure phasic dopamine release in the NAc core in response to the CS and the rewards. We also determined the effect of NTX (1 mg/kg, subcutaneous) on conditioned approach. RESULTS: Both CIE and alcoholic reward, individually but not together, associated with greater dopamine to the CS than control conditions. However, this increase in dopamine release was not linked to greater sign-tracking, as both CIE and alcoholic reward shifted conditioned approach from sign-tracking behavior to goal-tracking behavior. However, they both also increased sensitivity to NTX, which reduced goal-tracking behavior. CONCLUSIONS: While a history of EtOH exposure or alcoholic reward enhanced dopamine release to a CS, they did not promote sign-tracking under the current conditions. These findings are consistent with the interpretation that EtOH can stimulate conditioned approach, but indicate that the conditioned response may manifest as goal-tracking.

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Midbrain dopamine neurons play critical roles in reward- and aversion-driven associative learning. However, it is not clear whether they do this by a common mechanism or by separate mechanisms that can be dissociated. In the present study we addressed this question by testing whether a partial lesion of the dopamine neurons of the rat SNc has comparable effects on conditioned place preference (CPP) learning and conditioned place aversion (CPA) learning. Partial lesions of dopamine neurons in the rat substantia nigra pars compacta (SNc) induced by bilateral intranigral infusion of 6-hydroxydopamine (6-OHDA, 3µg/side) or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 200µg/side) impaired learning of conditioned place aversion (CPA) without affecting conditioned place preference (CPP) learning. Control experiments demonstrated that these lesions did not impair motor performance and did not alter the hedonic value of the sucrose and quinine. The number of dopamine neurons in the caudal part of the SNc positively correlated with the CPP scores of the 6-OHDA rats and negatively correlated with CPA scores of the SHAM rats. In addition, the CPA scores of the 6-OHDA rats positively correlated with the tissue content of striatal dopamine. Insomuch as reward-driven learning depends on an increase in dopamine release by nigral neurons, these findings show that this mechanism is functional even in rats with a partial lesion of the SNc. On the other hand, if aversion-driven learning depends on a reduction of extracellular dopamine in the striatum, the present study suggests that this mechanism is no longer functional after the partial SNc lesion.

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Diazepam is a benzodiazepine receptor agonist with anxiolytic and addictive properties. Although most drugs of abuse increase the level of release of dopamine in the nucleus accumbens, here we show that diazepam not only causes the opposite effect but also prevents amphetamine from enhancing dopamine release. We used 20 min sampling in vivo microdialysis and subsecond fast-scan cyclic voltammetry recordings at carbon-fiber microelectrodes to show that diazepam caused a dose-dependent decrease in the level of tonic and electrically evoked dopamine release in the nucleus accumbens of urethane-anesthetized adult male Swiss mice. In fast-scan cyclic voltammetry assays, dopamine release was evoked by electrical stimulation of the ventral tegmental area. We observed that 2 and 3 mg of diazepam/kg reduced the level of electrically evoked dopamine release, and this effect was reversed by administration of the benzodiazepine receptor antagonist flumazenil in doses of 2.5 and 5 mg/kg, respectively. No significant effects on measures of dopamine re-uptake were observed. Cyclic voltammetry experiments further showed that amphetamine (5 mg/kg, intraperitoneally) caused a significant increase in the level of dopamine release and in the half-life for dopamine re-uptake. Diazepam (2 mg/kg) significantly weakened the effect of amphetamine on dopamine release without affecting dopamine re-uptake. These results suggest that the pharmacological effects of benzodiazepines have a dopaminergic component. In addition, our findings challenge the classic view that all drugs of abuse cause dopamine release in the nucleus accumbens and suggest that benzodiazepines could be useful in the treatment of addiction to other drugs that increase the level of dopamine release, such as cocaine, amphetamines, and nicotine.

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En este estudio, se evaluó a un grupo de niños y niñas de primero a tercer grado de educación básica primaria con problemas en la adquisición de la escritura en comparación con un grupo control. Los resultados obtenidos en la Evaluación neuropsicológica infantil "Puebla-Sevilla", muestran diferencias significativas en los factores Cinético, Cinestésico y Percepción Espacial Global entre los dos grupos. Resultados similares fueron observados en las tareas de escritura contenidas en la Evaluación Neuropsicológica Infantil (ENI). Asimismo, se tipificaron cualitativamente los tipos de errores cometidos en las tareas de escritura. Análisis posteriores mostraron una correlación en la ejecución de los sujetos, mostraron además que el factor Cinestésico puede considerarse predictor de una adecuada adquisición de la escritura y que la tarea de dictado de la ENI es sensible para el reconocimiento de dificultades en dicho factor.

In this study, we evaluated a group of boys and girls, from first to third grade of primary school, with difficulties in writing acquisition in comparison with a control group. The results obtained by using the "Evaluación Neuropsicológica infantil 'Puebla-Sevilla'" show significant differences between the experimental and the control group in the Kinetic, Kinesthesic and the Global Spatial Perception neuropsychological factors. Similar results were also obtained in the writing tasks that are part of the "Evaluación Neuropsicológica Infantil (ENI)". We also qualitatively typified the errors in the writing tasks. Correlational statistical analysis of the experimental and control groups show that the Kinesthesic factor can predict possible difficulties in the correct acquisition of the writing, and also, that the dictation task of the ENI can be valid for the recognition of difficulties in that factor.

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This review presents state-of-the-art knowledge about the roles of the basal ganglia (BG) in action-selection, cognition, and motivation, and how this knowledge has been used to improve deep brain stimulation (DBS) treatment of neurological and psychiatric disorders. Such pathological conditions include Parkinson's disease, Huntington's disease, Tourette syndrome, depression, and obsessive-compulsive disorder. The first section presents evidence supporting current hypotheses of how the cortico-BG circuitry works to select motor and emotional actions, and how defects in this circuitry can cause symptoms of the BG diseases. Emphasis is given to the role of striatal dopamine on motor performance, motivated behaviors and learning of procedural memories. Next, the use of cutting-edge electrochemical techniques in animal and human studies of BG functioning under normal and disease conditions is discussed. Finally, functional neuroimaging studies are reviewed; these works have shown the relationship between cortico-BG structures activated during DBS and improvement of disease symptoms.

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The present paper reviews foundational and contemporary theories of motivated behaviors and the growing body of evidence that they require specific functional interactions within the basal ganglia. Such evidence suggests that unconditioned responses (UR), conditioned responses (CR), goal-directed actions and stimulus-response (S-R) habits are selected in the basal ganglia. Such selection depends on activation of striatal neurons by cortical and subcortical neurons encoding unconditioned stimuli (US), conditioned stimuli (CS), goals and neutral stimuli (S). These neurons project respectively to the medial nucleus accumbens (NAc) shell/olfactory tubercle, NAc core/lateral olfactory tubercle, dorsolateral striatum and dorsomedial striatum. The strength of these synapses is altered when the levels of extracellular dopamine in the basal ganglia undergo phasic increases or decreases, which signal outcomes that are, respectively, better or worse than expected. In addition, dopamine release in response to salient USs and to CSs with incentive salience increases the signal-to-noise ratio of corticostriatal neurotransmission, thus 'energizing' the performance of selected actions. Different actions can be selected in the striatum because the striatal neurons of the so-called direct and indirect pathways can respectively initiate and end actions through pallidum/nigral-thalamic projections to premotor and motor areas of the cortex. According to this view, the basal ganglia is thought to play a role in the action-selection processes needed for the expression of both declarative and procedural memories, but the memories of the contexts, predictive stimuli or neutral stimuli associated with free rewards or with an action's outcomes are stored elsewhere.

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