C57BL/6J offspring mice reared by a single-mother exhibit, compared to mice reared in a biparental parenting structure, distinct neural activation patterns and heightened ethanol-induced anxiolysis.

RATIONALE: Parenting experiences with caregivers play a key role in neurodevelopment. We recently reported that adolescents reared by a single-mother (SM) display an anxiety-prone phenotype and drink more alcohol, compared to peers derived from a biparental (BP) rearing condition. OBJECTIVES: To investigate if SM and BP offspring infant mice exhibit differential sensitivity to ethanol-induced locomotor activity and differential activity patterns in brain areas related to anxiety response. We also analyzed anxiety response and ethanol-induced anxiolysis in SM and BP adolescents. METHODS: Mice reared in SM or BP conditions were assessed for (a) ethanol-induced locomotor activity at infancy, (b) central expression of Fos-like proteins (likely represented mostly by FosB, a transcription factor that accumulates after chronic stimuli exposure and serves as a molecular marker of neural plasticity) and cathecolaminergic activity, and (c) anxiety-like behavior and ethanol-induced anxiolysis in adolescence. RESULTS: Infant mice were sensitive to the stimulating effects of 2.0 g/kg alcohol, regardless parenting structure. SM mice exhibited, relative to BP mice, a significantly greater number of Fos-like positive cells in the central amygdala and basolateral amygdala nuclei. Ethanol treatment, but not parenting condition, induced greater activation of dopaminergic neurons in ventral tegmental area. SM, but not BP, adolescent mice were sensitive to ethanol-induced anxiolysis. CONCLUSIONS: These results highlight the complex relationship between parenting experiences and neurodevelopment. The SM parenting may result in greater neural activation patterns in brain areas associated with anxiety response, potentially contributing to increased basal anxiety and alcohol sensitivity.

Event-related potentials during the ultimatum game in people with symptoms of depression and/or social anxiety.

Depression and social anxiety are common disorders that have a profound impact on social functioning. The need for studying the neural substrates of social interactions in mental disorders using interactive tasks has been emphasized. The field of neuroeconomics, which combines neuroscience techniques and behavioral economics multiplayer tasks such as the Ultimatum Game (UG), can contribute in this direction. We assessed emotions, behavior, and Event-Related Potentials in participants with depression and/or social anxiety symptoms (MD/SA, n = 63, 57 females) and healthy controls (n = 72, 67 females), while they played the UG. In this task, participants received fair, mid-value, and unfair offers from other players. Mixed linear models were implemented to assess trial level changes in neural activity. The MD/SA group reported higher levels of sadness in response to mid-value and unfair offers compared to controls. In controls, the Medial Frontal Negativity associated with fair offers increased over time, while this dynamic was not observed in the MD/SA group. The MD/SA group showed a decreased P3/LPP in all offers, compared to controls. These results indicate an enhanced negative emotional response to unfairness in the MD/SA group. Neural results reveal a blunted response over time to positive social stimuli in the MD/SA group. Moreover, between-group differences in P3/LPP may relate to a reduced saliency of offers and/or to a reduced availability of resources for processing incoming stimuli in the MD/SA group. Findings may shed light into the neural substrates of social difficulties in these disorders.

Influence of Time-of-Day on Maximal Exercise Capacity Is Related to Daily Thermal Balance but Not to Induced Neuronal Activity in Rats.

In the present study, we investigated whether the daily fluctuations of internal body temperature (Tb) and spontaneous locomotor activity (SLA) interact with the thermal and neuronal adjustments induced by high-intensity aerobic exercise until fatigue. The body temperature and SLA of adult Wistar rats (n = 23) were continuously recorded by telemetry for 48 h. Then, the rats were subjected to a protocol of graded exercise until fatigue or rest on the treadmill during light and dark-phases. Tb, tail skin temperature and ambient temperature during each experimental session were recorded. At the end of the last experimental session, the animals were anaesthetized; the brains were perfused and removed for immunohistochemical analysis of c-fos neuronal activation. The daily rhythms of SLA and Tb were strongly correlated (r = 0.88 and p < 0.001), and this was followed by a daily oscillation in both the ratio and the correlation index between these variables (p < 0.001). Exercise capacity was associated with a lower resting Tb (p < 0.01) and was higher in the light-phase (p < 0.001), resulting in an increased capacity to accumulate heat during exercise (p < 0.01). Independent of time-of-day, high intensity exercise strongly activated the hypothalamic paraventricular nucleus (PVN), the supra-optic nucleus (SON) and the locus coeruleus (LC) (p < 0.001) but not the suprachiasmatic nucleus (SCN). Taken together, our results points toward a role of the circadian system in a basal activity control of the thermoregulatory system as an important component for the onset of physical activities. In fact, rather than directly limiting the adjustments induced by exercise the present study brings new evidence that the effect of time-of-day on exercise performance occurs at the threshold level for each thermoregulatory system effector activity. This assumption is based on the observed resilience of the central clock to high-intensity exercise and the similarities in exercise-induced neuronal activation in the PVN, SON, and LC.

The state of art of biological processes in paternal care / Processos biológicos na paternidade: estado de arte

This review of the state of art aimed to present the most recent data on neuronal, neurochemical, hormonal and genetic bases of paternal care using MEDLINE and PsycInfo databases (1970-2013). An integrated model of biological substrates that assist men in the transition to fatherhood is presented. Guided by a genetic background, hypothalamic-midbrain-limbic-paralimbic-cortical circuits were found to be activated in fathers when infant stimuli are presented. A set of specific neuropeptides and steroid hormones are produced and seem to be related to brain activation, potentiating the paternal phenotype. Together, genetic, brain and hormonal processes suggest the existence of biological bases of paternal care in humans, activated and enhanced by infant stimuli and responsive to variations in the father-infant relationship. (AU)

A presente revisão teve por objectivo apresentar o estado de arte dos dados mais recentes sobre as bases neuronais, neuroquímicas, hormonais e genéticas da paternidade, com recurso às bases de dados MEDLINE e PsycInfo (1970-2013). É apresentado um modelo de integração conceptual dos substratos biológicos que assistem os homens na transição para a parentalidade. Guiado por um background genético, circuitos neuronais hipotalámicos-mesencefálicos-límbicos-paralímbicos-corticais surgem ativados em pais quando lhes são apresentados estímulos infantís. Um conjunto de neuropéptidos e hormonas esteróides são também produzidos e relacionam-se com a activação neuronal, potenciando o fenótipo paternal. No seu conjunto, processos genéticos, neuronais e hormonais sugerem a existência de uma base biológica do comportamento paternal em humanos, activada e potenciada por estímulos infantís e responsiva a variações na relação pai-filho. (AU)