Incentive motivation and ultrasonic vocalizations in rats

After experiencing a reward, the positive affective reactions it induces can become associated with its sensory properties and related cues. However, the manner in which such affective reward representations are expressed in animals remains unclear. Juvenile and adult rats communicate through ultrasonic vocalizations (USVs), which also serve as situation-dependent affective signals. Since rats emit high frequency (i.e., 50-kHz) USVs in socially and non-socially rewarding situations, 50-kHz calls might prove to be a way incentive motivational state is signaled when training rats to anticipate food rewards under some predictable cues. In general, the results show that reward-cues become effective to elicit 50-kHz calls. Under certain conditions, however, the utterance of 50-kHz calls can be either suppressed during a highly motivational state, or more strikingly, can be elicited when food rewards were devalued by satiation. For rats, both a state of hunger and waiting for access to a daily meal can be negatively perceived if the food reward offered turns out to be less satisfying than expected. Learning to anticipate such a negative state seemed to suppress the otherwise positive affective reactions evoked by having access to a highly expected food. Such a frustration-like effect occurred only at the USVs level without being indicated behaviourally through changes in rats’ learning and motivation to approach and consume the reward. In contrast, providing continued access to the reward prevented the suppression of USVs. Surprisingly, in spite of being sated and no longer interested in seeking and consuming the reward, rats nevertheless continued to emit appetitive USVs in the presence of cues predicting a previously desired food. Rats as a whole, just as with humans, seem to represent rewards affectively beyond basal appetite requirements. However, the ability to attribute incentive salience to reward cues has been shown to strongly differ among individuals. The second study, therefore, focused on the analysis of individual differences in conditioned anticipatory activity elicited by reward-related cues as indicative of the predisposition of animals to attribute incentive salience to otherwise neutral stimuli. Across several experiments, individual rats prone to attribute incentive salience to reward cues –as indicated by high levels of either rearing activity, or sign-tracking behavior– showed heightened reward-induced affective responses, namely in the form of 50-kHz calls. When re-exposing rats to reward cues after a non-testing period, USVs were elicited even at higher rates than previously, especially in subjects prone to attributing incentive salience to reward cues. USVs appeared reliably expressed over time and persisted despite physiological needs have already been fulfilled. Interestingly, USVs were still elicited by reward cues even though reward-oriented behaviors and exploratory activity were drastically weakened by reward devaluation. Additionally, prone subjects seemed to undergo particular adaptations in their dopaminergic system related to incentive learning, as indicated by the attenuated response to the catecholamine agonist amphetamine and to the dopamine receptor antagonist flupenthixol. The investigation of the psychological and neurobiological factors underlying affective states as related to incentive motivation is of remarkable relevance in preclinical- and clinical-oriented research. The current findings may have translational potential, since for some individuals, excessive attribution of incentive salience to reward cues may lead to compulsive behavior disorders, such as overeating, pathological gambling, and drug addiction. Certain aspects of these disabling human conditions can be further investigated with the same animal models as implemented in the present studies

The environmental enrichment model revisited: A translatable paradigm to study the stress of our modern lifestyle

Mounting evidence shows that physical activity, social interaction and sensorimotor stimulation provided by environmental enrichment (EE) exert several neurobehavioural effects traditionally interpreted as enhancements relative to standard housing (SH) conditions. However, this evidence rather indicates that SH induces many deficits, which could be ameliorated by exposing animals to an environment vaguely mimicking some features of their wild habitat. Rearing rodents in social isolation (SI) can aggravate such deficits, which can be restored by SH or EE. It is not surprising, therefore, that most preclinical stress models have included severe and unnatural stressors to produce a stress response prominent enough to be distinguishable from SH or SI—frequently used as control groups. Although current stress models induce a stress-related phenotype, they may fail to represent the stress of our urban lifestyle characterized by SI, poor housing and working environments, sedentarism, obesity and limited access to recreational activities and exercise. In the following review, we discuss the stress of living in urban areas and how exposures to and performing activities in green environments are stress relievers. Based on the commonalities between human and animal EE, we discuss how models of housing conditions (e.g., SI–SH– EE) could be adapted to study the stress of our modern lifestyle. The housing conditions model might be easy to implement and replicate leading to more translational results. It may also contribute to accomplishing some ethical commitments by promoting the refinement of procedures to model stress, diminishing animal suffering, enhancing animal welfare and eventually reducing the number of experimental animals needed.Universidad de Costa Rica/[723-B9-197]/UCR/Costa RicaUniversidad de Costa Rica/[837-B8-123]/UCR/Costa RicaUniversidad de Costa Rica/[837-B7-603]/UCR/Costa RicaUniversidad de Costa Rica/[837-C0-606]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Psicológicas (IIP)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Neurociencias (CIN)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Environmental Enrichment and Physical Exercise Attenuate the Depressive-Like Effects Induced by Social Isolation Stress in Rats

We assessed the antidepressant-like effects of environmental enrichment (EE) and physical exercise (PE) compared with the selective serotonin reuptake inhibitor fluoxetine against the depression-related neurobehavioral alterations induced by postweaning social isolation (SI) in rats. After 1 month of SI, rats were submitted to PE (treadmill), EE, or fluoxetine (10 mg/kg), which were compared with naïve SI and grouphoused rats. After 1 month, behavior was analyzed in the open field (OFT), the sucrose preference (SPT), and the forced swimming (FST) tests. Afterward, the hippocampal serotonin contents, its metabolite, and turnover were measured. SI induced a depressionrelated phenotype characterized by a marginal bodyweight gain, anxiety, anhedonia, behavioral despair, and alterations of serotonin metabolism. EE produced the widest and largest antidepressive-like effect, followed by PE and fluoxetine, which were almost equivalent. The treatments, however, affected differentially the neurobehavioral domains investigated. EE exerted its largest effect on anhedonia and was the only treatment inducing anxiolytic-like effects. Fluoxetine, in contrast, produced its largest effect on serotonin metabolism, followed by its anti-behavioral despair action. PE was a middleground treatment with broader behavioral outcomes than fluoxetine, but ineffective to reverse the serotonergic alterations induced by SI. The most responsive test to the treatments was the FST, followed closely by the SPT. Although OFT locomotion and body weight varied considerably between groups, they were barely responsive to PE and fluoxetine. From a translational standpoint, our data suggest that exercise and recreational activities may have broader health benefits than antidepressants to overcome confinement and the consequences of chronic stress.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Psicológicas (IIP)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Neurociencias (CIN)UCR::Vicerrectoría de Docencia::Salud::Facultad de Medicina::Escuela de Medicin

Neurobehavioral Effects of Restricted and Unpredictable Environmental Enrichment in Rats

To study how motivational factors modulate experience-dependent neurobehavioral plasticity, we modify a protocol of environmental enrichment (EE) in rats. We assumed that the benefits derived from EE might vary according to the level of incentive salience attributed to it. To enhance the rewarding properties of EE, access to the EE cage varied randomly from 2 to 48 h for 30 days (REE). The REE group was enriched only 50% of the time and was compared to standard housing and continuous EE (CEE) groups. As behavioral readout, we analyzed the spontaneous activity and the ultrasonic vocalizations (USVs) within the EE cage weekly, and in the open field test at the end of the experiment. In the cage, REE increased the utilization of materials, physical activity, and the rate of appetitive USVs. In the OF, the CEE-induced enhancements in novelty habituation and social signaling were equaled by the REE. At the neural level, we measured the expression of genes related to neural plasticity and epigenetic regulations in different brain regions. In the dorsal striatum and hippocampus, REE upregulated the expression of the brain-derived neurotrophic factor, its tropomyosin kinase B receptor, and the DNA methyltransferase 3A. Altogether, our results suggest that the higher activity within the cage and the augmented incentive motivation provoked by the REE boosted its neurobehavioral effects equaling or surpassing those observed in the CEE condition. As constant exposures to treatments or stimulating environments are virtually impossible for humans, restricted EE protocols would have greater translational value than traditional ones.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Neurociencias (CIN)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Psicológicas (IIP

Psychometric characteristics of the scale for treatment adherence in type 2 diabetes mellitus - version III (EATDM-III©) in a sample of diabetics patients of Costa Rica

Se probó la Escala de Adherencia al Tratamiento de la Diabetes Mellitus tipo II-versión III (EATDM-III©), la cual estaba compuesta por los factores Apoyo Familiar, la Organización y Apoyo Comunal, el Ejercicio Físico, el Control Médico, el Higiene y Autocuidado, la Dieta y la Valoración de la Condición Física. La investigación se realizó en el Hospital Dr. Rafael Ángel Calderón Guardia, Costa Rica, n=104 personas de ambos sexos, durante los meses de febrero-marzo de 2006. El instrumento demostró una confiabilidad alta (á=0,88). Se obtuvieron correlaciones significativas entre cada factor y en la relación factores-Escala total. La EATDM-III© es un instrumento valioso para medir la adherencia al tratamiento en personas con Diabetes Mellitus tipo II.The Scale for Treatment Adherence in Type 2 Diabetes Mellitus - version III (EATDM-III©) was tested. It was compounded by the following factors: Family Support, Organization and Community Support, Physical Exercise, Medical Control, Hygiene and Self-Care, Diet and Assessment of Physical Condition. The research was developed at Dr. Rafael Ángel Calderón Guardia Hospital, Costa Rica, n=104 subjects, both genders, during the months of February-March 2006. The instrument showed a high reliability (á=0,879) and several signifi cant correlations inter factors and between factors and the total scale. The EATDM-III© is a valuable instrument to measure the treatment adherence in people with Type 2 Diabetes Mellitus.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Psicológicas (IIP

Behavioral changes across novelty habituation: Contextual modulation of self-grooming after a stress event

Grooming is a widespread behavior in the animal kingdom primarily geared towards the care of the body surface; nonetheless, other behavioral functions have been investigated and postulated. For example, rodents display high levels of grooming in contexts of potential threat, a fact usually interpreted as a sign of stress and anxiety. Conversely, new evidence suggests that during the process of habituation to novel and threatening contexts, particular sequences of grooming would act as a behavioral feedback facilitating emotional de-arousal. To test those opposing hypotheses about grooming interpretation, we assessed how testing contexts with different gradients of familiarity would affect exploratory activity and risk-assessment behaviors, and grooming subtypes of stressed and non-stressed rats. For that purpose, different groups of male Wistar rats were tested in one of the follow conditions: (1) in an unfamiliar open-field arena, (2) in a familiar open-field arena, (3) and in a home cage. Prior to the 20-minutes testing session, half of the animals within each testing condition were stressed by receiving three foot shocks of 1 mA 5 seconds apart. If grooming indicates stress and anxiety, it should increase at the beginning of tests, with stressed rats displaying even higher levels of grooming as compared with their non-stressed counterparts. However, if grooming facilitates emotional de-arousal, it should increase as exploration and risk-assessment decrease. In such scenario, unstressed animals tested in the familiar contexts should display the greater levels of grooming, in contrast to pre-stressed animals tested in unfamiliar contexts. Evidence will be presented about how the degree of novelty and threat associated with the testing context, may modulate defensive behaviors after an acute stress. Furthermore, the detailed analysis of the kinetic changes in grooming sequences will provide new insights into the understanding of grooming and its informative value in preclinical research. We propose that the richness of grooming interpretation lies in the careful analysis of its sub-components over time. Here, we will bring new evidence that support the hypothesis that long and complex sequences of grooming would facilitate emotional de-arousal, whereas short and head-directed sequences would be more related with ongoing stress states.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Neurociencias (CIN)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Psicológicas (IIP)UCR::Vicerrectoría de Docencia::Salud::Facultad de Medicina::Escuela de MedicinaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Muscarinic and glutamatergic regulation of self-grooming behavior and ultrasonic vocalizations in the context of open-field habituation in rats

We tested whether pharmacological impairment of OF-habituation after the administration (i.p.) of scopolamine (SCP; muscarinic antagonist) or MK-801 (MK; NMDA antagonist) was able to disrupt or alter grooming syntaxes. Amnesic drugs were daily administered during four consecutive days 20-min prior to a 15-min OF. On the fifth day, rats were given vehicle and tested as previously mentioned. We found that neither SCP nor MK altered the behavioral kinetics of locomotion. However, SCP and MK strongly inhibited the emission of rearing behavior. In despite of such inhibition, the emission of rearing leveled off in all groups on the last testing day. Further, MK but specially SCP, strongly disrupts grooming syntax. Overall, MK and SCP decreased the time spent on grooming behavior, causing only a mild reduction on its frequency of emission of this behavior. Further, both drugs increased the emission of the short, head-directed sequences of grooming, called here as cephalic grooming, but dramatically abolished the emission of the most complex forms of this behavior. In despite of such strong modulation on grooming syntax, neither MK not SCP altered grooming emission on the last testing day. The evidence provided here suggest that, in despite of the inhibition of exploratory and self-compensating behaviors along the OF exposures, back-ground mechanisms of information processing allows habituation to occur.Universidad de Costa Rica/[837-B8-123]/UCR/Costa RicaUniversidad de Costa Rica/[723-B9-197]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Psicológicas (IIP)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Neurociencias (CIN

Development of a psychometric scale for assess stress, depression and type a behavior pattern

Se probó la Escala de Estrés, Depresión, y Patrón de Conducta tipo A © (EEDPA-I©), la cual estaba compuesta por tres secciones Parte II (presencia de eventos estresores), Parte III (alteraciones fisiológicas) y Parte IV (depresión y patrón de conducta tipo A). La investigación se realizó en área central de la provincia de San José, n=400 personas de ambos sexos, durante los meses de mayo-junio de 2004. El instrumento demostró una confiabilidad alta (α=0,92). Se obtuvieron correlaciones significativas entre cada factor y en la relación factores-Escala total. La EEDPA-I© es un instrumento valioso para medir los factores que la componen.The Scale for Stress, Depression and Type A Behavior Pattern © (EEDPA-I©) was tested. It was composed of three sections: Part II (presence of stressor events), Part III (physiological disfunctions) and Part IV (depression and Type A Behavior Pattern). The research was developed in the central area of San José province, n=400 subjects, both sexes, during the months of May-June 2004. The instrument showed a high reliability (α=0,92) and several significant correlations among factors and between factors and Total Scale. The EEDPA-I© is a valuable instrument to measure the factors that compose it.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Psicológicas (IIP

Calidad y diversidad de la dieta en la población urbana de Argentina

Una dieta variada se asocia a una mayor probabilidad de incorporar micronutrientes esenciales. El índice de diversidad de dieta (IDD) es el indicador que mide esta variedad, mientras que el índice de calidad de dieta (ICD) determina cuánto de esa diversidad refleja la inclusión de alimentos saludables. El objetivo del estudio fue evaluar la calidad y diversidad de la dieta de la población argentina identificando las diferencias por sexo, edad, nivel socioeconómico, estado nutricional y región. La muestra fue de 1266 sujetos de población urbana, de ambos sexos, entre 15 y 65 años y de todos los NSE. Se realizó una evaluación antropométrica y de la ingesta, a través de 2 recordatorios de 24 horas. El IDD se evaluó siguiendo las guías propuestas en el año 2016 por la Organización de las Naciones Unidas para la Alimentación y la Agricultura y el desarrollo del ICD se realizó siguiendo la metodología de Imamura y col. El ICD fue relativamente bajo, con un puntaje de 63.9%. El IDD fue de 4.48 de un máximo de 10, lo que refleja una dieta poca variada; adicionalmente, solo el 50% de la población informó una dieta variada. Estos indicadores fueron significativamente menores en las personas con bajo NSE. El IDD y el porcentaje de personas con dieta diversa fue mayor en los habitantes del área metropolitana de Buenos Aires. Este estudio evidenció que la calidad de la dieta en la población argentina es baja y con un consumo limitado de los grupos de alimentos que más aportan micronutrientesUCR::Vicerrectoría de Docencia::Salud::Facultad de Medicina::Escuela de MedicinaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Psicológicas (IIP)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Neurociencias (CIN

Socioeconomic status impact on diet quality and body mass index in eight Latin American countries: ELANS study results

Poor health and diet quality are associated with living within a low socioeconomic status (SES). This study aimed to investigate the impact of SES on diet quality and body mass index in Latin America. Data from the “Latin American Health and Nutrition Study (ELANS)”, a multi-country, population-based study of 9218 participants, were used. Dietary intake was collected through two 24 h recalls from participants of Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Peru and Venezuela. Diet quality was assessed using the dietary quality score (DQS), the dietary diversity score (DDS) and the nutrients adequacy ratio (NAR). Chi-squared and multivariate-variance analyses were used to estimate possible associations. We found that participants from the low SES consumed less fruits, vegetables, whole grains, fiber and fish and seafood and more legumes than those in the high SES. Also, the diet quality level, assessed by DQS, DDS and NAR mean, increased with SES. Women in the low SES also showed a larger prevalence of abdominal obesity and excess weight than those in the middle and high SES. Health policies and behavioral-change strategies should be addressed to reduce the impact of socioeconomic factors on diet quality and body weight, with gender as an additional level of vulnerability.UCR::Vicerrectoría de Docencia::Salud::Facultad de Medicina::Escuela de MedicinaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Neurociencias (CIN)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Psicológicas (IIP