A Playroom Observation Procedure to Assess Children with Mental Retardation and ADHD

Forty-two children (ages 6 to 12 years old) with moderate mental retardation to borderline intellectual functioning were studied in a laboratory playroom setting to determine whether children identified as ADHD (attention deficit hyperactivity disorder) or controls differed on activity and attentional measures. Children with ADHD were further divided into ADHD + conduct problems (ADHD + CD) and ADHD-only subgroups (with an ADHD-combined group comprising children of both subgroups). An interval recording system was used to code observations of independent play and a restricted academic task. Results indicated that the ADHD-combined group was significantly more vocal and engaged in a significantly greater number of toy changes than controls during independent play. Significant group differences were also noted during the restricted academic task, with the ADHD-combined and ADHD + CD groups more off-task and engaging in a greater number of toy touches than controls. Discriminant analyses found independent play measures to predict group membership in 70 percent of cases (ADHD-combined vs. controls), but in only 64 percent of cases using measures from the restricted academic task. No significant findings resulted when the ADHD subjects were further divided into two subgroups. Despite some inconsistent findings, such laboratory-based observations may be of value in the diagnosis of ADHD in children with moderate mental retardation to borderline intellectual functioning.     

Sex differences in behavioral consequences of defeat in the rat are not organized by testosterone during early development

Male and female rats react differently to losing an aggressive encounter, the presence of testosterone (at the time of confrontation) being a critical factor in the manifestation of this sex difference. Female rats were androgenized by 250 μg testosterone propionate sc on days 1 and 5 after birth. When adult they received a sc testosterone proprionate (TP) implant and were subjected to repeated defeats by being placed in the cage of an aggressive resident female. In contrast to males, which freeze and become permanently submissive, androgenized females showed no freezing or other signs of submission. The sex difference in response to defeat is therefore not dependent on the presence of testosterone during the period of post-natal sexual differentiation.     

Inward- and Outward-Directed Violence in the Lives of Urban Minority Adults Followed from Middle School into Their Thirties

This study explores connections between inward-directed violence and outward-directed violence using data from the Reach for Health sample, which was originally recruited in the 1990s from three middle schools in economically distressed, predominantly African American neighborhoods of New York City. Now in their thirties, participants (N = 595) completed surveys assessing current suicidal thoughts and behaviors as well as other violence involvements, including intimate partner violence victimization and perpetration. About 10% of males and females reported any suicidal ideation or attempt in the past 12 months. In logistic regression analyses adjusting for sociodemographics, prior reports of feeling blue in middle school (OR: 1.12, CI: 1.02–4.39) and young adult suicidality (OR: 2.54, CI: 1.30–4.95) are significantly related to later suicidality. So are concurrent aggressive behaviors, including reports of physical fighting outside the home (OR: 2.70, CI: 1.29–5.67) and IPV perpetration (OR: 2.09, CI: 1.11–3.94). Neither IPV victimization nor witnessing neighborhood violence is correlated. Findings shed light on the persistence of suicidality in the lives of those who come of age, and often remain, in communities with high levels of poverty, and confirm linkages of suicidality with externally directed aggression. Life-stage interventions are needed to counter the interwoven causes and consequences of multiple forms of violence.     

The neural pathways mediating quiet-biting attack behavior from the hypothalamus in the cat: A functional autoradiographic study

Electrical stimulation of the region of the lateral hypothalamus produced a consistent form of quiet-biting attack behavior in cats. In one series of experiments, cats, implanted with electrodes from which attack had been elicited, were anesthetized and then were injected with a bolus of ¹⁴C-2-deoxyglucose at the same time as electrical stimulation was delivered through the attack electrodes. Brains prepared for X-ray autoradiography revealed that lateral hypothalamic stimulation activated the classical medial forebrain bundle pathway supplying the septal region, diagonal band, lateral preoptic area, and ventral tegmental region. Stimulation of quiet-attack sites in perifornical hypothalamus resulted in the activation of a much more extensive projection system which included the central and lateral tegmental fields of the midbrain and pons, and central gray region, as well as the structures described above. In a second series of experiments, ³H-leucine was placed into the region of the electrode tip from which attack was elicited in order to identify more precisely the pathways arising from that site. In general, tritiated amino acid radioautography replicated the ¹⁴C-2-deoxyglucose findings. In addition, the amino acid radioautographic data revealed the presence of extensive projections from perifornical hypothalamus to such pontine structures as the nucleus locus coeruleus, motor nucleus of NV , and the lateral pontine tegmental field. The functional connections between the lateral hypothalamic “attack region” and lateral preoptic zone were also confirmed by electrophysiological methods.     

Cooperative social coordination and aggression: Sex and strain differences in the effects of housing on gonadectomized rats with hormone replacement

Laboratory rats were used to investigate sex and strain differences in the effects of aggression on a cooperative behavior in which pairs learned to coordinate shuttling in a rectangular chamber. The level of aggression was manipulated by comparing males and females of the aggressive S3 strain and a less aggressive Sprague-Dawley-derived strain and housing same-sex partners either together or individually (8 groups, n = 7 pairs per group). Hormone levels were stabilized by gonadectomy and daily injections of the appropriate sex hormone. The only serious coordination deficits were in individually housed males, associated with violent fighting and an extreme dominance/subordinance relationship that was not observed in females. All other groups readily learned and performed the coordination with evidence that low and moderate levels of aggression could facilitate coordination by evoking species-typical behaviors that increased proximity, synchrony, and differentiation within pairs. The discussion focused on models of affiliative behavior in the study of aggression and the compatibility between moderate levels of aggression and cooperation.     

Cooperative social coordination and aggression: Sex and strain differences in the effects of housing on gonadectomized rats with hormone replacement

Laboratory rats were used to investigate sex and strain differences in the effects of aggression on a cooperative behavior in which pairs learn to coordinate shuttling in a rectangular chamber. The level of aggression was manipulated by comparing males and females of the aggressive S3 strain and a less aggressive Sprague-Dawley-derived strain and by housing same-sex partners either together or individually (eight groups, n = 7 pairs per group). Hormone levels were stabilized by gonadectomy and daily injections of the appropriate sex hormone. The only serious coordination deficits were in individually housed males, associated with violent fighting and an extreme dominance/subordinance relationship that was not observed in females. All other groups readily learned and performed the coordination, with evidence that low and moderate levels of aggression could facilitate coordination by evoking species-typical behaviors that increased proximity, synchrony, and differentiation within pairs. The discussion focused on models of affiliative behavior in the study of aggression and the compatibility between moderate levels of aggression and cooperation.