Nicotine reduces discrimination between threat and safety in the hippocampus, nucleus accumbens and amygdala.

Nicotine intake is linked to the maintenance and development of anxiety disorders and impairs adaptive discrimination of threat and safety in rodents and humans. Yet, it is unclear if nicotine exerts a causal pharmacological effect on the affective and neural mechanisms that underlie aversive learning. We conducted a pre-registered, pseudo-randomly and double-blinded pharmacological fMRI study to investigate the effect of acute nicotine on Fear Acquisition and Extinction in non-smokers (n = 88). Our results show that nicotine administration led to decreased discrimination between threat and safety in subjective fear. Nicotine furthermore decreased differential (threat vs. safety) activation in the hippocampus, which was functionally coupled with Nucleus Accumbens and amygdala, compared to placebo controls. Additionally, nicotine led to enhanced physiological arousal to learned threats and overactivation of the ventral tegmental area. This study provides mechanistic evidence that single doses of nicotine impair neural substrates of adaptive aversive learning in line with the risk for the development of pathological anxiety.

Pulsed nicotine infusions as a model for smoking: validating a tool to explore nicotine thresholds in humans.

RATIONALE: No previous studies examined the discriminative stimulus effects of intravenous (IV) nicotine in humans. OBJECTIVES: To evaluate a pulsed IV nicotine infusion procedure designed to mimic inhaled nicotine delivery and to identify a range of nicotine doses that may capture the threshold doses for the subjective and discriminative stimulus effects of nicotine. By determining these thresholds, we can gain valuable insights into the addictive threshold of nicotine. METHODS: Eleven participants had 2 Test Sessions following overnight abstinence from smoking. Test Session 1 examined participants' ability to discriminate 0.1 mg nicotine/pulse nicotine from saline. Test Session 2 examined if participants can discriminate 0.05, 0.025, and 0.0125 mg nicotine/pulse of nicotine from saline. These nicotine doses were delivered as a cluster of 4 pulsed-nicotine infusions of 2-second duration with a 28-second interval between each pulse. RESULTS: The lowest doses of nicotine that produced greater responses than saline for discrimination, subjective effects, and heart rate ranged from 0.05 to 0.1 mg nicotine/pulse. CONCLUSIONS: These findings support the validity of our pulsed-infusion procedure as a model for nicotine delivery by smoking and its utility in examining factors that may impact the addictive threshold of nicotine.

Adrenalectomy exacerbates stress-induced impairment in fear discrimination: A causal role for kynurenic acid?

Impaired activity of the hypothalamic-pituitary axis and reduced blood levels of glucocorticoids (GCs) are signature features of stress-related maladies. Recent evidence suggests a possible role of the tryptophan metabolite kynurenic acid (KYNA) in this context. Here we investigated possible causal relationships in adult male rats, using stress-induced fear discrimination as a translationally relevant behavioral outcome measure. One week following adrenalectomy (ADX) or sham surgery, animals were for 2 h either physically restrained or exposed to a predator odor, which caused a much milder stress response. Extracellular KYNA levels were determined before, during and after stress by in vivo microdialysis in the prefrontal cortex. Separate cohorts underwent a fear discrimination procedure starting immediately after stress termination. Different auditory conditioned stimuli (CS) were either paired with a foot shock (CS+) or non-reinforced (CS-). One week later, fear was assessed by re-exposing the animals to each CS. Separate groups of rats were treated with the KYNA synthesis inhibitor BFF-816 prior to stress initiation to test a causal role of KYNA in fear discrimination. Restraint stress raised extracellular KYNA levels by ∼85 % in ADX rats for several hours, and these animals were unable to discriminate between CS+ and CS-. Both effects were prevented by BFF-816 and were not observed after exposure to predator odor or in sham-operated rats. These findings suggest that a causal connection exists between adrenal function, stress-induced KYNA increases, and behavioral deficits. Pharmacological inhibition of KYNA synthesis may therefore be an attractive, novel option for the treatment of stress-related disorders.

Sex differences in extinction and reinstatement of nicotine discrimination in rats: The effects of reinforcer devaluation.

Nicotine functions effectively as an interoceptive operant discriminative stimulus (SD) that sets the occasion for voluntarily emitted behavior to be reinforced by biologically relevant outcomes (e.g., food). This has been demonstrated primarily with male rats. Far less is known about nicotine's operant SD functions in female rats. There are no reports of sex differences in extinction and recovery of the SD functions of nicotine, which may elucidate smoking cessation and relapse. In view of this, eight male and eight female rats were trained to nose poke differentially among quasirandomly intermixed sessions of food reinforcement variable interval (VI-30 s) and nonreinforcement in a go/no-go across session one-manipulanda operant drug discrimination procedure. For half the rats, presession administration of nicotine (0.30 mg/kg, subcutaneous) occasioned reinforcement sessions of nose pokes (i.e., SD); for the remaining rats, it occasioned nonreinforcement (SΔ). Saline sessions occasioned the opposite contingencies. Training was conducted first under feeding restriction and then under free feeding, which was then followed by extinction sessions that were also conducted with free feeding. During discrimination training, response rates for females did not differ from males when conducted under restricted feeding but did so during training and later extinction conducted under free feeding. Females also exhibited greater reinstatement of responding under the nicotine SD but not the SΔ. These data provide additional evidence for sex differences in rats with the discriminative stimulus functions of nicotine under low, but not high, food-drive states-and may have implications for sex/gender differences in smoking cessation and relapse. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

AMPA and NMDA receptors in dentate gyrus mediate memory for sucrose in two port discrimination task.

Although the phenomenon of memory formation and recall associated with the use of psychotropic drugs has been extensively studied, mechanisms underlying memories for natural reward have not been clarified. Herein, we test the hypothesis that glutamatergic receptors in the dentate gyrus play a role in memories associated with sucrose. We used pellet self-administration protocol to generate memories in two-port nose-poke discrimination task using male Wistar rats. During non-rewarded probe trial, the conditioned animals readily discriminated the active port versus inactive port and showed massive increase in mRNA expression of AMPA receptor subunit genes (gria2, gria3) as well as c-Fos protein in the DG. Access to sweet pellet further enhanced c-Fos expression in the DG. However, animals pre-treated with AMPA receptor antagonist CNQX (intra-DG), on exposure to operant chamber (no pellet), showed decreased discrimination as well as c-Fos expression. We suggest that AMPA receptors in DG mediate recall and consolidation of memories associated with sucrose consumption. CNQX pre-treated animals, if presented with sweet pellet on nose poke, exhibited high discrimination index coupled with increased c-Fos expression. In these CNQX treated rats, the DI was again decreased following administration of NMDA receptor antagonist AP5. We suggest that, although AMPA receptors are blocked, the access to sweet pellet may induce surge of glutamate in the DG, which in turn may reinstate memories via activation of erstwhile silent synapses in NMDA dependant manner.

Increased sensitivity in detection of deficits following two commonly used animal models of stroke.

Stroke is a leading cause of death and disability in the United States. Most strokes are ischemic, resulting in both cognitive and motor impairments. Animal models of ischemic stroke such as the distal middle cerebral artery occlusion (dMCAO) and photothrombotic stroke (PTS) procedures have become invaluable tools, with their own advantages and disadvantages. The dMCAO model is clinically relevant as it occludes the artery most affected in humans, but yields variability in the infarct location as well as the behavioral and cognitive phenotypes disrupted. The PTS model has the advantage of allowing for targeted location of infarct, but is less clinically relevant. The present study evaluates phenotype disruption over time in mice subjected to either dMCAO, PTS, or a sham surgery. Post-surgery, animals were tested over 28 days on standard motor tasks (grid walk, cylinder, tapered beam, and rotating beam), as well as a novel odor-based operant task; the 5:1 Odor Discrimination Task (ODT). Results demonstrate a significantly greater disturbance of motor control with PTS as compared with Sham and dMCAO. Disruption of the PTS group was detected up to 28 days post-stroke on the grid walk, and up to 7 days on the rotating and tapered beam tasks. PTS also led to significant short-term disruption of ODT performance (1-day post-surgery), exclusively in males, which appeared to be driven by motoric disruption of the lick response. Together, this data provides critical insights into the selection and optimization of animal models for ischemic stroke research. Notably, the PTS procedure was best suited for producing disruptions of motor behavior that can be detected with common behavioral assays and are relatively enduring, as is observed in human stroke.

Resiliência: avaliação de pacientes queimados em um hospital de urgência e emergência / Resilience: evaluation of burned patients in an urgency and emergency hospital / Resiliencia: evaluación de pacientes quemados en un hospital de urgencias y emergencias

A recuperação de vítimas de queimaduras é longa e dolorosa e afeta diversas esferas da vida do paciente. A resiliência, que se refere à capacidade humana de enfrentar e se adaptar a eventos adversos, exerce grande importância no processo de recuperação da queimadura. Logo, este trabalho objetiva avaliar a capacidade de resiliência de pacientes queimados, no momento da admissão e da alta hospitalar, em um hospital de emergência e urgência de Goiânia. Trata-se de um estudo descritivo, quantitativo e transversal que utiliza a Escala de Resiliência de Connor-Davidson (CD-RISC) como instrumento de mensuração. Na admissão hospitalar, a média da resiliência foi de 71,35, tendo sido observada uma relação significativa entre o fator Amparo da escala CD-RISC e a presença do(a) companheiro(a). O escore de resiliência encontrado nesta pesquisa é consistente com outros achados da literatura científica internacional e nacional referente à expressão da resiliência em vítimas de queimaduras e outros adoecimentos. A relação entre o fator Amparo e a presença de um(a) companheiro(a) enfatiza a importância da rede de apoio familiar na reabilitação do paciente queimado.(AU)

The recovery of burned patients is long and painful and impacts on different areas of people's lives. Resilience, which refers to the human capacity to face and adapt to adverse events, plays a major role in the process of recovery from burns. Therefore, the present study aims to assess the resilience of burned patients, on admission and hospital discharge, in an emergency and urgency hospital in Goiânia. This is a descriptive, quantitative and cross-sectional study that uses the Connor-Davidson Resilience Scale (CD RISC) as a measuring instrument. At hospital admission, the mean resilience was 71.35, with a significant association between the Support factor on the CD RISC scale and the presence of a partner. The resilience score found in the present study is consistent with other findings in the international and national scientific literature regarding the expression of resilience in victims of burns and other illnesses. The relationship between the Support factor and the presence of a partner emphasizes the importance of the family support network in the rehabilitation of the burned patient.(AU)

La recuperación de los pacientes quemados es larga y dolorosa e impacta en diferentes esferas de la vida de las personas. La resiliencia, que se refiere a la capacidad humana para enfrentar y adaptarse a eventos adversos, juega un papel importante en el proceso de recuperación de las quemaduras. Por tanto, el presente estudio tiene como objetivo evaluar la resiliencia de los pacientes quemados, en el momento del ingreso y el alta, en un hospital de emergencia y urgencia en Goiânia. Se trata de un estudio descriptivo, cuantitativo y transversal que utiliza la Escala de Resiliencia Connor-Davidson (CD RISC) como instrumento de medida. Al ingreso hospitalario, la resiliencia media fue de 71,35, con associación significativa entre el factor Amparo de la escala CD RISC y la presencia de pareja. El puntaje de resiliencia encontrado en el presente estudio es consistente con otros hallazgos en la literatura científica nacional e internacional sobre la expresión de resiliencia en víctimas de quemaduras y otras enfermedades. La relación entre el factor Amparo y la presencia de pareja enfatiza la importancia de la red de apoyo familiar en la rehabilitación del paciente quemado.(AU)

Evidências de validade do teste informatizado para avaliação das funções executivas / Evidence of validity of the computerized test for evaluating executive functions / Evidencia de validez de la prueba computarizada para evaluación de funciones ejecutivas

Funções executivas (FE) referem-se ao conjunto de habilidades que, de forma integrada, coordenam o comportamento e a cognição. Assim, o comprometimento no desenvolvimento das FE está ligado a vários desfechos negativos ao longo da vida. Portanto, a avaliação dessas habilidades na infância é essencial para identificar e prevenir prejuízos na vida adulta. Este estudo teve como objetivo investigar evidências de validade do Teste Informatizado para Avaliação das Funções Executivas (Tafe) pelo critério de idade e pelo padrão de correlação entre medidas do TAFE e outras medidas de FE. Para isso, foi utilizada uma amostra de 51 crianças, entre 4 e 10 anos de idade, matriculadas em uma escola privada na cidade de Goiânia (GO), da pré-escola ao 4º ano do ensino fundamental. Como instrumentos, foram utilizados, além do Tafe, as tarefas de Bloco de Corsi, Teste de Trilhas A e B, Teste de Trilhas Pré-Escolares, Teste de Stroop Pré-Escolares e Subteste Dígitos da Escala Wechsler de Inteligência. Foram conduzidas análises estatísticas Kruskal Wallis para verificar a evidência de validade por relação com idade e análises de correlação não paramétrica de Spearman para avaliar as evidências de validade convergente. O instrumento investigado mostrou-se efetivo para discriminar entre as diferentes faixas etárias, assim, sensível ao desenvolvimento das FE. Os resultados obtidos no Tafe correlacionaram-se aos obtidos em outros testes que também avaliaram FE, mostrando claros padrões de convergência. Logo, as análises dos resultados fornecem evidências de validade ao Tafe, derivadas a partir de diferentes estratégias de investigação.(AU)

Executive functions (EF) refer to the set of skills that, in an integrated way, coordinate behavior and cognition. Thus, the commitment in developing EF is linked to several negative outcomes throughout life. Therefore, the assessment of these abilities in childhood is essential to identify and prevent possible harm in adult life. This study aimed to investigate evidences of validity of the Computerized Test for Evaluation of Executive Functions (TAFE) by the age criterion and by the pattern of correlation between TAFE measures and other EF measures. To this end, a sample of 51 children, between 4 and 10 years old, enrolled in a private school in the municipality of Goiânia (GO), from preschool to the 4th year of elementary school, was used. As instruments, in addition to TAFE, the tasks of Corsi Block, Trails Test A and B, Preschool Trails Test, Preschool Stroop Test and the Digits Subtest of the Wechsler Intelligence Scale were used. Kruskal Wallis statistical analyzes were conducted to verify the evidence of validity by age criteria and Spearman's nonparametric correlation analysis to assess evidence of convergent validation. The instrument investigated was effective to discriminate between different age groups, thus being sensitive to the development of EF. The results obtained in TAFE were correlated with those obtained in other tests that also assess FE, showing patterns of convergence. Therefore, the analysis of the results provides validation evidence to TAFE, derived from different investigation methods.(AU)

Las funciones ejecutivas (FE) se refieren al conjunto de habilidades que coordinan la conducta y la cognición. Así, el deterioro en el desarrollo de FE está relacionado con varios resultados negativos durante la vida. Por tanto, la valoración de estas habilidades en la infancia es fundamental para identificar y prevenir posibles daños en la vida adulta. Este estudio tuvo como objetivo investigar la evidencia de validez de la Prueba Computarizada para Evaluación de Funciones Ejecutivas (Tafe) por el criterio de edad y convergencia entre las medidas Tafe y otras medidas de FE. Para ello, se utilizó una muestra de 51 niños, de entre 4 y 10 años de edad, matriculados en un colegio privado de Goiânia (Goiás, Brasil) desde la preescolar hasta 4.º de primaria. Como instrumentos, además del Tafe, se utilizaron las tareas de Bloque de Corsi, el Test de los senderos A y B, el Test de los Senderos Preescolares, el Test de Stroop Preescolar y la Subprueba de Dígitos de la Escala Wechsler de Inteligencia. Se realizaron análisis estadísticos de Kruskal Wallis para verificar la validez por criterios de edad y análisis de correlación no-paramétrica de Spearman para evaluar la evidencia de validez convergente. Tafe demostró ser efectivo para discriminar entre diferentes grupos de edad, así es sensible al desarrollo de FE. Los resultados en Tafe se correlacionaron con los obtenidos en otras pruebas de FE, lo que muestra claros patrones de convergencia. Por tanto, el análisis aporta evidencias de validez para Tafe, derivadas de diferentes estrategias de investigación.(AU)

Olhares e produções de saberes: narrativas da psicologia acerca das relações raciais / Gaze and knowledge production: psychology narratives about racial relations / Mirada y producción de saber: narrativas de la psicología sobre las relaciones raciales

Este artigo realiza um percurso histórico das narrativas teóricas construídas pelas elites intelectuais brancas brasileiras sobre as relações raciais no campo psicológico, bem como os efeitos desse processo no desenvolvimento da psicologia enquanto ciência e profissão. Como a maioria de profissionais da área é branca em um país cuja maioria da população é negra, torna-se cada vez mais urgente e necessário revisitar tanto as bases da psicologia acerca das relações raciais quanto o modo como essas relações se dão no cotidiano, com vistas a construir caminhos para pensar teoria e prática comprometidas com a igualdade racial. Nesse sentido, tecem-se considerações sobre as narrativas teóricas acerca das relações raciais no campo científico brasileiro, destacando o lugar da psicologia nesse percurso. Em seguida, discutem-se as relações entre as perspectivas da realidade social e das produções de saberes nesse campo. Ainda mais especificamente no campo da psicologia, evidenciam-se os paradigmas que orientaram os estudos sobre as relações raciais na área e, por fim, aponta-se um caminho possível para a construção de uma ciência psicológica compromissada com a igualdade racial.(AU)

This paper presents a historical overview of the theoretical narratives constructed by white Brazilian intellectual elites about race relations within psychology and its the effects on the development of Psychology as a science and a profession. As psychology professionals are white, whereas the majority of the population is black, it is increasingly urgent and necessary to revisit the foundations of psychology on everyday life racial relations, towards a theory and practice committed to racial equality. The text presents considerations on the theoretical narratives about race relations in the Brazilian scientific field, highlighting the role played by psychology. It then discusses the relations between social reality and knowledge production in this field. Regarding psychology specifically, it highlights the paradigms that guided studies on race relations in the field and proposes a possible way to develop a psychological science committed to racial equality.(AU)

Este trabajo realiza un recorrido histórico sobre las narrativas teóricas construidas por las élites intelectuales brasileñas blancas sobre las relaciones raciales en el campo de la Psicología, y los efectos de este proceso en el desarrollo de la psicología como ciencia y profesión. Como la mayoría de los profesionales en el área son blancos en un país donde la mayoría de la población es negra, es cada vez más urgente y necesario revisar los fundamentos de la psicología sobre las relaciones raciales, y cómo son estas relaciones en la vida cotidiana, para que podamos construir teoría y práctica comprometidas con la igualdad racial. Primero, se reflexionará sobre las narrativas teóricas de las relaciones raciales en este campo científico brasileño, destacando el lugar de la psicología en este camino. Luego, se discutirán las relaciones entre las perspectivas sobre la realidad social y la producción de conocimiento en este campo. Aún más específicamente en el campo de la psicología, se resaltarán los paradigmas que guiaron los estudios sobre las relaciones raciales en el área y, finalmente, se señalará un posible camino en la construcción de una ciencia psicológica comprometida con la igualdad racial.(AU)

Loucura sob ataque: contribuições de Ignacio Martín-Baró sobre colonização, guerra e saúde mental para o Brasil contemporâneo / Madness under attack: contributions from Ignacio Martín-Baró on colonization, war and mental health for contemporary Brazil / La locura bajo ataque: contribuciones de Ignacio Martín-Baró sobre la colonización, la guerra y la salud mental para el Brasil contemporáneo

Diante da multiplicação atual dos inimigos nacionais no Brasil, que atravessam as relações de gênero, sexualidade, raça e classe, neste texto abordamos um aspecto específico dessa guerra generalizada: a guerra contra os loucos. Com o objetivo de analisar o retorno recente do fortalecimento das arquiteturas de confinamento no campo da saúde mental, demarcando relações entre racionalidade e território, este artigo parte de um questionamento a respeito do espaço político dado ao louco e ao enlouquecimento, à diferença e à dor, à guerra aos loucos e à loucura na guerra. Como disparador, nos acompanhará principalmente a obra de Ignacio Martín-Baró e suas críticas ao psicologismo colonial, assim como à naturalização e à patologização de condições e efeitos do capitalismo. Podemos traçar instigantes paralelos da nossa experiência com os escritos de Martín-Baró, elaborando um lugar de resistência possível para a psicologia nesse campo de batalha.

In view of the current multiplication of national enemies in Brazil, which cross gender, sexuality, race and class relations, in this text we approach a specific aspect of this generalized war: the war against the mad. With the objective of analyzing the recent return of strengthening confinement architectures in the field of mental health, demarcating relations between rationality and territory, this article is triggered from a questioning about the political space given to the mad and the madness, to the difference and to the pain, to the war against the mad and to the madness in war. As a trigger, it will be shared the work of Ignacio Martín-Baró and his criticisms of colonial psychologism, as well as the naturalization and pathologization of conditions and effects of capitalism. We can draw instigating parallels from our experience with Martín-Baró's writings, elaborating a possible place of resistance for psychology in this battlefield.

En vista de la actual multiplicación de enemigos nacionales en Brasil, que atraviesan las relaciones de género, sexualidad, raza y clase, en este texto abordamos un aspecto específico de esta guerra generalizada: la guerra contra los locos. Con el objetivo de analizar el reciente regreso del fortalecimiento de las arquitecturas de confinamiento en el campo de la salud mental, demarcando relaciones entre racionalidad y territorio, este artículo parte de un cuestionamiento sobre el espacio político que se le da al loco y a la locura, a la diferencia y al dolor, a la guerra contra los locos y a la locura en la guerra. Como detonante, nos acompañará la obra de Ignacio Martín-Baró y sus críticas al psicologismo colonial, así como la naturalización y patologización de las condiciones y efectos del capitalismo. Podemos trazar paralelos estimulantes de nuestra experiencia con los escritos de Martín-Baró, creando un posible lugar de resistencia para la psicología en este campo de batalla.

VIP interneurons regulate olfactory bulb output and contribute to odor detection and discrimination.

In the olfactory bulb (OB), olfactory information represented by mitral/tufted cells (M/Ts) is extensively modulated by local inhibitory interneurons before being transmitted to the olfactory cortex. While the crucial roles of cortical vasoactive-intestinal-peptide-expressing (VIP) interneurons have been extensively studied, their precise function in the OB remains elusive. Here, we identify the synaptic connectivity of VIP interneurons onto mitral cells (MCs) and demonstrate their important role in olfactory behaviors. Optogenetic activation of VIP interneurons reduced both spontaneous and odor-evoked activity of M/Ts in awake mice. Whole-cell recordings revealed that VIP interneurons decrease MC firing through direct inhibitory synaptic connections with MCs. Furthermore, inactivation of VIP interneurons leads to increased MC firing and impaired olfactory detection and odor discrimination. Therefore, our results demonstrate that VIP interneurons control OB output and play critical roles in odor processing and olfactory behaviors.

Discrimination, psychological functioning, and substance use among U.S. young adults aged 18-28, 2017.

This study aimed to test whether (a) discrimination is associated with past 30-day/current alcohol, cigarette, e-cigarette, alcohol, marijuana, and other illicit drug use among Black and White U.S. adults aged 18-28, (b) psychological distress (PD) and positive well-being (PW) are mediators of the discrimination-substance use relationships, and (c) the associations are moderated by race and sex. Using data from a 2017 U.S. nationally representative survey we conducted multiple-group moderated mediation analyses among 2,192 young adults aged 18-28 (508 Black males, 594 Black females, 533 White males, 557 White females). Black males had higher discrimination, Whites had higher PW, and females had higher PD scores. Discrimination was positively associated with PD and negatively associated with PW. Among all groups, discrimination was positively associated with other illicit drug (direct and indirect), and marijuana use through PD. Indirect effects were stronger among White males for other illicit drugs and Black males for marijuana. The indirect effect of discrimination and alcohol use through PW was positive for Black females and negative for all other groups examined. Among Black males only, discrimination was positively associated with cigarette and alcohol use through PD (positive) and cigarette smoking through PW (negative). This study highlights the negative influence of perceived discrimination on current licit and illicit substance use among Black and White young adults. Our results suggest that this relationship may be partially mediated by PD and PW, especially among Black male young adults. Future discrimination and substance use studies should consider potential mediation effects of poor mental health and differences by race and sex. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Ability of dog owners to identify their dogs by smell.

Several studies report that olfactory cues play an important role in human life; humans are essentially able to recognize other family members and friends by their odors. Moreover, recent studies report that humans are also able to identify odors of non-conspecifics. The aim of this study was to determine whether dog owners are able to identify their dogs by smell and distinguish the odor of their own dogs from those of other dogs. A total of 53 dog owners (40 females and 13 males of different ages) volunteered to take part in this study. A number of the participants (17) owned 2 dogs; these owners took part in the study twice (i.e., working with only one dog at a time). Sterile gauze pads were used to collect odor samples from the dogs. Each pad was placed in its own sterile glass jar (750 ml) with a twist off lid until the experiment commenced. Participants were asked to identify their own dog´s odor from a line-up of 6 glass containers. This experiment demonstrated that dog owners are capable of identifying their dogs by smell on a significant level. Results of this study additionally suggested that male owners outperformed their female counterparts in the identification process. Moreover, dog owners whose dogs were housed outside had a higher success rate in identification than did participants who kept their dogs indoors with them. The dog owners found it easier to identify dogs that had been neutered, fed dry dog food and bathed less frequently. In general, younger dog owners tended to have more success when attempting to identify their dogs than did their older counterparts.

Task-dependent effects of nicotine treatment on auditory performance in young-adult and elderly human nonsmokers.

Electrophysiological studies show that nicotine enhances neural responses to characteristic frequency stimuli. Previous behavioral studies partially corroborate these findings in young adults, showing that nicotine selectively enhances auditory processing in difficult listening conditions. The present work extended previous work to include both young and older adults and assessed the nicotine effect on sound frequency and intensity discrimination. Hypotheses were that nicotine improves auditory performance and that the degree of improvement is inversely proportional to baseline performance. Young (19-23 years old) normal-hearing nonsmokers and elderly (61-80) nonsmokers with normal hearing between 500 and 2000 Hz received nicotine gum (6 mg) or placebo gum in a single-blind, randomized crossover design. Participants performed three experiments (frequency discrimination, frequency modulation identification, and intensity discrimination) before and after treatment. The perceptual differences were analyzed between pre- and post-treatment, as well as between post-treatment nicotine and placebo conditions as a function of pre-treatment baseline performance. Compared to pre-treatment performance, nicotine significantly improved frequency discrimination. Compared to placebo, nicotine significantly improved performance for intensity discrimination, and the improvement was more pronounced in the elderly with lower baseline performance. Nicotine had no effect on frequency modulation identification. Nicotine effects are task-dependent, reflecting possible interplays of subjects, tasks and neural mechanisms.

Multi-Odor Discrimination by Rat Sniffing for Potential Monitoring of Lung Cancer and Diabetes.

The discrimination learning of multiple odors, in which multi-odor can be associated with different responses, is important for responding quickly and accurately to changes in the external environment. However, very few studies have been done on multi-odor discrimination by animal sniffing. Herein, we report a novel multi-odor discrimination system by detection rats based on the combination of 2-Choice and Go/No-Go (GNG) tasks into a single paradigm, in which the Go response of GNG was replaced by 2-Choice, for detection of toluene and acetone, which are odor indicators of lung cancer and diabetes, respectively. Three of six trained rats reached performance criterion, in 12 consecutive successful tests within a given set or over 12 sets with a success rate of over 90%. Through a total of 1300 tests, the trained animals (N = 3) showed multi-odor sensing performance with 88% accuracy, 87% sensitivity and 90% specificity. In addition, a dependence of behavior response time on odor concentrations under given concentration conditions was observed, suggesting that the system could be used for quantitative measurements. Furthermore, the animals' multi-odor sensing performance has lasted for 45 days, indicating long-term stability of the learned multi-odor discrimination. These findings demonstrate that multi-odor discrimination can be achieved by rat sniffing, potentially providing insight into the rapid, accurate and cost-effective multi-odor monitoring in the lung cancer and diabetes.

Transplantation of rat dental pulp stem cells facilities post-lesion recovery in the somatosensory whisker cortex of male Wistar rats.

Damage to somatosensory "barrel" cortex reduces the rats' behavioral sensitivity in discrimination of tactile stimuli. Here, we examined how transplantation of stem cells into the lesioned barrel cortex can help in recovery of sensory capacities. We induced mechanical lesions in the right barrel cortex area of male rats. Three days after lesioning, rats received one of three transplantation types: un-differentiated dental pulp stem cells (U-DPSCs) or differentiated dental pulp stem cells (D-DPSCs), or cell medium (vehicle). A fourth group of rats were control without any Surgery. For 4 consecutive weeks, starting one week after transplantation, we evaluated the rats' preference to explore novel textures as a measure of sensory discrimination ability, also measured the expression of glial fibrillary acidic protein (GFAP), Olig 2, nestin, neuronal nuclei (NeuN), brain-derived neurotrophic factor (BDNF) and neuroligin1 by immunohistochemistry and western blotting. Unilateral mechanical lesion decreased the rats' preferential exploration of novel textures compared to the control group across the 4-week behavioral tests. Following stem cell therapy, the rats' performance significantly improved at week 2-4 compared to the vehicle group. Compared to the control group, there was a significant decrease in the expression of nestin, NeuN, Olig 2, BDNF, neuroligin1 and a significant increase in the expression of GFAP in the vehicle group. The expression of the neural markers was significantly higher in DPSCs compared with the vehicle group whereas GFAP level was lower in DPSCs compared to vehicle. We found that DPSCs therapy affected a range of neuronal markers in the barrel cortex post lesion, and improved the rats' recovery for sensory discrimination.

Engram Size Varies with Learning and Reflects Memory Content and Precision.

Memories are rarely acquired under ideal conditions, rendering them vulnerable to profound omissions, errors, and ambiguities. Consistent with this, recent work using context fear conditioning has shown that memories formed after inadequate learning time display a variety of maladaptive properties, including overgeneralization to similar contexts. However, the neuronal basis of such poor learning and memory imprecision remains unknown. Using c-fos to track neuronal activity in male mice, we examined how these learning-dependent changes in context fear memory precision are encoded in hippocampal ensembles. We found that the total number of c-fos-encoding cells did not correspond with learning history but instead more closely reflected the length of the session immediately preceding c-fos measurement. However, using a c-fos-driven tagging method (TRAP2 mouse line), we found that the degree of learning and memory specificity corresponded with neuronal activity in a subset of dentate gyrus cells that were active during both learning and recall. Comprehensive memories acquired after longer learning intervals were associated with more double-labeled cells. These were preferentially reactivated in the conditioning context compared with a similar context, paralleling behavioral discrimination. Conversely, impoverished memories acquired after shorter learning intervals were associated with fewer double-labeled cells. These were reactivated equally in both contexts, corresponding with overgeneralization. Together, these findings provide two surprising conclusions. First, engram size varies with learning. Second, larger engrams support better neuronal and behavioral discrimination. These findings are incorporated into a model that describes how neuronal activity is influenced by previous learning and present experience, thus driving behavior.SIGNIFICANCE STATEMENT Memories are not always formed under ideal circumstances. This is especially true in traumatic situations, such as car accidents, where individuals have insufficient time to process what happened around them. Such memories have the potential to overgeneralize to irrelevant situations, producing inappropriate fear and contributing to disorders, such as post-traumatic stress disorder. However, it is unknown how such poorly formed fear memories are encoded within the brain. We find that restricting learning time results in fear memories that are encoded by fewer hippocampal cells. Moreover, these fewer cells are inappropriately reactivated in both dangerous and safe contexts. These findings suggest that fear memories formed at brief periods overgeneralize because they lack the detail-rich information necessary to support neuronal discrimination.

Pharmacological fMRI provides evidence for opioidergic modulation of discrimination of facial pain expressions.

The endogenous opioid system is strongly involved in the modulation of pain. However, the potential role of this system in perceiving painful facial expressions from others has not been sufficiently explored as of yet. To elucidate the contribution of the opioid system to the perception of painful facial expressions, we conducted a double-blind, within-subjects pharmacological functional magnetic resonance imaging (fMRI) study, in which 42 participants engaged in an emotion discrimination task (pain vs. disgust expressions) in two experimental sessions, receiving either the opioid receptor antagonist naltrexone or an inert substance (placebo). On the behavioral level, participants less frequently judged an expression as pain under naltrexone as compared to placebo. On the neural level, parametric modulation of activation in the (putative) right fusiform face area (FFA), which was correlated with increased pain intensity, was higher under naltrexone than placebo. Regression analyses revealed that brain activity in the right FFA significantly predicted behavioral performance in disambiguating pain from disgust, both under naltrexone and placebo. These findings suggest that reducing opioid system activity decreased participants' sensitivity for facial expressions of pain, and that this was linked to possibly compensatory engagement of processes related to visual perception, rather than to higher level affective processes, and pain regulation.

Perception of internal medicine residents regarding psychiatric patients' care / Percepções de médicos residentes em clínica médica em relação ao atendimento de pacientes psiquiátricos

Abstract: Introduction: Mental disorders are accountable for the segregation of patients in many diverse cultures and historical moments worldwide. The evolution of neuroscience, technologies and advances in the psychosocial sphere have not been enough to change this paradigm. Many people still fear having social relations with someone with a psychiatric disorder, despite scientific progress and efforts to reduce prejudice in recent decades. Objective: The aim of this study was to assess the training in mental health during the undergraduate course offered to residents in Internal Medicine and analyze the feelings, perceptions, and stigmas of these physicians regarding the care offered to patients with mental disorders. Method: This study has a qualitative, quantitative approach and descriptive, cross-sectional design. Thirty-two residents in Internal Medicine participated and, for comparison, the questionnaires were also answered by 8 residents in Psychiatry. Two instruments were applied: one for the characterization of the participants' sociodemographic profile and the attribution questionnaire (AQ-26B). Qualitative data were obtained through a focus group with 14 residents and the content analysis was used for categorization. The most frequent categories were illustrated with Pareto charts. Results: The results demonstrated that residents in internal medicine showed higher indexes of stigma regarding aspects such as fear and intolerance. It was also possible to infer gaps related to training in mental health, low perception of care responsibility, in addition to the difficulty in legitimizing complaints and showing negative feelings. Conclusion: One can conclude the need for educational interventions that promote the decrease of the stigma and the search for training regarding comprehensive and empathic care for patients with mental disorders.

Resumo: Introdução: Os transtornos mentais são responsáveis pela segregação de pacientes em diversas culturas e momentos históricos globalmente. A evolução das neurociências, tecnologias e avanços na esfera psicossocial não têm sido suficientes para mudar este paradigma. Muitas pessoas ainda temem ter relações sociais com alguém com transtorno psiquiátrico, apesar dos avanços científicos e dos esforços para reduzir o preconceito nas últimas décadas. Objetivo: Este estudo teve como objetivos avaliar a formação em saúde mental na graduação oferecida a médicos residentes de clínica médica e analisar os sentimentos, as percepções e os estigmas deles ante a assistência a pacientes com transtornos mentais. Método: Trata-se de um estudo com abordagens qualitativas e quantitativas, de natureza descritiva e transversal. Participaram 32 residentes de clínica médica, e, para comparação, os questionários foram respondidos por oito residentes de psiquiatria. Aplicaram-se dois instrumentos: um para a caracterização do perfil sociodemográfico dos participantes e o questionário de atribuição (AQ-26B). Os dados qualitativos foram obtidos por meio de grupo focal com 14 residentes, e empregou-se a análise de conteúdo para categorização. As categorias de maior frequência foram ilustradas com diagramas de Pareto. Resultado: Como os residentes de clínica demonstraram maiores índices de estigma em aspectos como medo e intolerância, intuiu-se que há lacunas na formação em saúde mental, baixa percepção de responsabilidade do cuidado, além de dificuldade em legitimar as queixas e exibir sentimentos negativos. Conclusão: Concluiu-se pela necessidade de intervenções educacionais que fomentem a diminuição do estigma e a busca de capacitação para o cuidado integral e empático de pessoas com transtornos mentais.