Evidence suggests several causes for depression, including traumatic life events, disease, poison, and nutritional deficiencies. Many of these causes are associated with elevated levels of inflammatory biomarkers in the blood, which may in turn lead to inflammatory changes in the brain. Our authors examine what the latest research reveals about the link between inflammation in the brain and depression, and how a better understanding of that link can play a critical first step in the personalization of care.
In contrast to a wealth of human studies, little is known about the ontogeny and consistency of empathy-related capacities in other species. Consolation—post-conflict affiliation from uninvolved bystanders to distressed others—is a suggested marker of empathetic concern in non-human animals. Using longitudinal data comprising nearly a decade of observations on over 3000 conflict interactions in 44 chimpanzees (Pan troglodytes), we provide evidence for relatively stable individual differences in consolation behaviour. Across development, individuals consistently differ from one another in this trait, with higher consolatory tendencies predicting better social integration, a sign of social competence. Further, similar to recent results in other ape species, but in contrast to many human self-reported findings, older chimpanzees are less likely to console than are younger individuals. Overall, given the link between consolation and empathy, these findings help elucidate the development of individual socio-cognitive and -emotional abilities in one of our closest relatives.
by
Amy L. Panczakiewicz;
Leila Glass;
Claire Coles;
Julie Kable;
Elizabeth R. Sowell;
Jeffrey R. Wozniak;
Kenneth L. Jones;
Edward P. Riley;
Sarah N. Mattson
Background: Neurobehavioral consequences of heavy prenatal alcohol exposure are well documented; however, the role of age or sex in these effects has not been studied. The current study examined the effects of prenatal alcohol exposure, sex, and age on neurobehavioral functioning in children. Methods: Subjects were 407 youth with prenatal alcohol exposure (n = 192) and controls (n = 215). Two age groups (child [5 to 7 years] or adolescent [10 to 16 years] ) and both sexes were included. All subjects completed standardized neuropsychological testing, and caregivers completed parent-report measures of psychopathology and adaptive behavior. Neuropsychological functioning, psychopathology, and adaptive behavior were analyzed with separate 2 (exposure history) × 2 (sex) × 2 (age) multivariate analyses of variance (MANOVAs). Significant effects were followed by univariate analyses. Results: No 3-way or 2-way interactions were significant. The main effect of group was significant in all 3 MANOVAs, with the control group performing better than the alcohol-exposed group on all measures. The main effect of age was significant for neuropsychological performance and adaptive functioning across exposure groups with younger children performing better than older children on 3 measures (language, communication, socialization). Older children performed better than younger children on a different language measure. The main effect of sex was significant for neuropsychological performance and psychopathology; across exposure groups, males had stronger language and visual spatial scores and fewer somatic complaints than females.
Conclusions: Prenatal alcohol exposure resulted in impaired neuropsychological and behavioral functioning. Although adolescents with prenatal alcohol exposure may perform more poorly than younger exposed children, the same was true for nonexposed children. Thus, these cross-sectional data indicate that the developmental trajectory for neuropsychological and behavioral performance is not altered by prenatal alcohol exposure, but rather, deficits are consistent across the 2 age groups tested. Similarly, observed sex differences on specific measures were consistent across the groups and do not support sexually dimorphic effects in these domains.
Background: The incidence of depression and anxiety disorders is twice as high in women than men; however, females exhibit less neuronal damage following an equivalent ischemic event. Microembolic stroke increases anxiety- and depressive-like behaviors in male rats but the behavioral repercussions in females are unknown.
Findings: Given the relative neuronal protection from stroke in ovary-intact females, female rats exposed to microembolic stroke may be behaviorally protected as compared to males. The data presented demonstrate that anxiety-like behavior is increased in males despite a comparable increase in microglial activation following microembolic stroke in both males and females.
Conclusions: These data suggest that males may be more behaviorally susceptible to the effects of microembolic stroke and further illustrate a dissociation between neuroinflammation and behavior in females.
Stress and hypothalamic–pituitary–adrenal (HPA) axis dysregulation have been associated with externalizing behavior in adolescence, but few studies have examined these factors in a treatment context. This study investigated the relationship between stress, cortisol, and externalizing behavior among 120 adolescent males (mean age=15) receiving Multisystemic Therapy (MST). To examine the differential relationship of cortisol with various types of stressors, self-report measures assessed lifetime stress, current episodic stress, and daily hassles. Morning and afternoon cortisol samples were collected to examine whether the relationship between stress and treatment outcome depended on the youth’s biological stress levels. Regression analyses indicated that awakening cortisol levels moderated the relationship between daily hassles and externalizing behaviors at post-treatment. More specifically, higher levels of daily hassles predicted worse outcomes only among adolescents with high levels of morning cortisol. In addition, lifetime stressors and afternoon measures of cortisol interacted to predict changes in caretaker reports of externalizing problems and youth arrests following treatment; lifetime stressors were positively associated with externalizing behavior when adolescents had low levels of afternoon cortisol. Implications for theory and future directions for evidence-based treatment are discussed.
High frequency (>1 Hz) repetitive transcranial magnetic stimulation (rTMS) applied to the left prefrontal cortex and low frequency (≤1 Hz) rTMS applied to the right prefrontal cortex have shown antidepressant effects. However, the clinical significance of these effects has often been modest. It was hypothesized that a combination of these two techniques might act synergistically and result in more clinically relevant antidepressant effects. Sixty-two subjects with treatment-resistant major depression (an average of 8 failed medication trials) were randomized to receive combination right low frequency (1 Hz)/left high frequency (10 Hz) rTMS over the dorsolateral prefrontal cortex at 110% of the motor threshold vs sham rTMS. Subjects were treated for 2 weeks (10 weekday sessions) and received 1600 stimulations during each treatment session. Subjects receiving combination treatment were further randomized to receive different orders of treatment: right low frequency first (Slow Right) vs left high frequency first (Fast Left). There were no statistical differences in the active vs sham treatment arms in the primary outcome variable, the Hamilton Depression Rating Scale (HDRS). However compared with subjects in the Sham and Slow Right arms, there was a trend for subjects in the Fast Left arm to show improvement in the HDRS, the Beck Depression Inventory, and the Brief Psychotic Rating Scale with increased number of treatments. The Fast Left arm also showed significant improvement in both blinded clinician and self-ratings of global improvement. These differences were hypothesized to be due to the decreased number of failed medication trials for subjects in Fast Left arm. Neuropsychological performance was not significantly different between the sham and active rTMS arms. Future studies should increase the number of treatment sessions and focus on subjects with moderate treatment resistance.
Strong reciprocity is considered here as the propensity to sacrifice resources to be kind or to punish in response to prior acts, a behavior not simply reducible to self-interest and a likely force behind human cooperation and sociality. The aim was to capture emerging signs of strong reciprocity in human ontogeny and across highly contrasted cultures. Three- and 5-year-old middle class American children (N = 162) were tested in a simple, multiple round, three-way sharing game involving the child, a generous puppet, and a stingy puppet. At the end of the game, the child was offered an opportunity to sacrifice some of her personal gains to punish one of the puppets. By 3 years, American children demonstrate a willingness to engage in costly punishment. However, only 5-year-olds show some evidence of strong reciprocity by orienting their punishment systematically toward the stingy puppet. Further analyses and three additional control conditions demonstrate that such propensity is not simply reducible to (a) straight imitation, or (b) inequity aversion. To assess the relative universality of such development, a group of 5- to 6-year-old children from rural Samoa (N = 14) were tested and compared to age and gender-matched American children. Samoan children did not manifest the same propensity toward strong reciprocity. The results are interpreted as pointing to (1) the developmental emergence of an ethical stance between 3 and 5 years of age, and (2) that the expression of such stance by young children could depend on culture.
Depression and psychostimulant addiction are co-morbid conditions; depression is a significant risk factor for psychostimulant abuse, and the rate of depression in drug addicts is higher than in the general population. Despite the prevalence of this comorbidity, there are few animal models examining psychostimulant abuse behaviors in depression. We have shown previously that while rats selectively bred for depression-like phenotypes (SwLo) have blunted mesolimbic dopamine (DA) signaling and locomotor responses to dopaminergic drugs, they voluntarily administer excessive amounts of psychostimulants compared to normal or depression-resistant (SwHi) rats in oral consumption paradigms. To determine whether this increased drug intake by depression-sensitive rats extends to operant self-administration, we assessed fixed ratio-1, progressive ratio, extinction, and reinstatement responding for cocaine and amphetamine in SwLo and SwHi rats. Contrary to the oral consumption results, we found that the SwHi rats generally responded more for both cocaine and amphetamine than the SwLo rats in several instances, most notably in the progressive ratio and reinstatement tests. Food-primed reinstatement of food seeking was also elevated in SwHi rats. These results provide further insight into the neurobiology of depression and addiction comorbidity and caution that oral and operant psychostimulant self-administration paradigms can yield different, and this case, opposite results.
Rachlin's teleological behaviorism eliminates the first-person ontology of conscious experience by identifying mental states with extended patterns of behavior, and thereby maintains the materialist ontology of science. An alternate view, informed by brain-based and externalist philosophies of mind, is shown also to maintain the materialist ontology of science, but without eliminating the phenomenology of consciousness. This view implies that to be judged human, machines not only must exhibit complicated temporally structured patterns of behavior, but also must have first-person conscious experience. Although confirming machine sentience is likely to be problematic, extended contact with a machine that results in a person interacting with it as if it were conscious could reasonably lead to the conclusion that for all intents and purposes it is.
Our two closest living primate relatives, chimpanzees (Pan troglodytes) and bonobos (Pan paniscus), exhibit significant behavioral differences despite belonging to the same genus and sharing a very recent common ancestor. Differences have been reported in multiple aspects of social behavior, including aggression, sex, play and cooperation. However, the neurobiological basis of these differences has only been minimally investigated and remains uncertain. Here, we present the first ever comparison of chimpanzee and bonobo brains using diffusion tensor imaging, supplemented with a voxel-wise analysis of T1-weighted images to specifically compare neural circuitry implicated in social cognition. We find that bonobos have more gray matter in brain regions involved in perceiving distress in both oneself and others, including the right dorsal amygdala and right anterior insula. Bonobos also have a larger pathway linking the amygdala with the ventral anterior cingulate cortex, a pathway implicated in both top–down control of aggressive impulses as well as bottom–up biases against harming others. We suggest that this neural system not only supports increased empathic sensitivity in bonobos, but also behaviors like sex and play that serve to dissipate tension, thereby limiting distress and anxiety to levels conducive with prosocial behavior.