Spatial learning in the rat: impairment induced by the thiol-proteinase inhibitor, leupeptin, and an analysis of [3H]glutamate receptor binding in relation to learning

Rats were given continuous intraventricular infusion of saline or the thiol-proteinase inhibitor leupeptin, via subcutaneously implanted osmotic minipumps, while being trained on a spatial learning water task using spaced trials. Leupeptin caused overnight forgetting during training, but performance eventually reached asymptote in both groups. A retention test conducted 48 h later to assess spatial memory revealed no significant group differences, but did cause, in saline-treated rats only, a disruption of subsequent retraining back to the correct spatial location. The groups showed no differences in Cl-dependent [3H]glutamate receptor binding to hippocampal or entorhinal cortex membranes subsequent to training. In a second experiment, normal rats trained on the same task also showed no differences in Cl-dependent [3H]glutamate binding relative to rats exposed to the water task but given random spatial position training and handled controls. The results are discussed in relation to the hypothesis of Lynch and Baudry (Science (1984) 224, 1057-1063) that a calcium-dependent thiol proteinase is involved in memory formation through its ability to modify glutamate receptor distribution and dendritic spine shape.     

The effects of naloxone and cage size on social play and activity in isolated young rats

The effects of large and small housing environments as well as naloxone on social play (as defined by pinning behavior) in isolated postweanling male rats were investigated. Animals housed in small cages played significantly more than those housed in larger cages. This effect was not observed when cage size was reversed. Administration of 0.5, 1.0, and 5.0 mg/kg of naloxone resulted in significant decreases in play behavior as compared to saline controls, both before housing environments were switched, and after. Animals in both isolation conditions were also compared to animals that were socially housed. Isolation was found to increase social play as well as the time spent in active social interaction, but had no effect on locomotor activity. While housing in a small cage increases play behavior, it had no effect on the amount of time spent in active social interaction or on activity. While administration of 0.5, 1.0, and 5.0 mg/kg naloxone to habituated animals differentially housed did not result in an overall decrease in activity, when compared with saline controls, only those animals housed in small cages and injected with the high dose of naloxone differed significantly from controls. In animals having no prior play experience, the activity of animals housed in the large and small cages differed significantly from each other only in the saline and 5.0 mg/kg naloxone conditions. Since naloxone's effect on play behavior was strong, but its effect on activity was not profound, our data suggest that naloxone primarily affects the affective component of play rather than altering activity levels.     

The Application of Behavior Change Theory to Family-Based Services: Improving Parent Empowerment in Children’s Mental Health

We describe the development of a parent empowerment program (PEP) using a community-based participatory research approach. In collaboration with a group of dedicated family advocates working with the Mental Health Association of New York City and state policy makers, academic researchers took an iterative approach to crafting and refining PEP to better prepare family advocates to help bridge the gaps in service access among children with emotional and behavioral problems. Despite the growth of family-led, family support programs nationally, research that demonstrates the positive benefits of such programs is scarce in the children’s mental health literature. The PEP model is based on research data about barriers families face in mental health service utilization (e.g., stigma, perceptions of providers, attitudes towards mental illness, service availability, etc.). PEP is premised on (a) the concept of empowerment as a process, (b) the need to engage parents in becoming active agents of change, and (c) the application of an integrated framework to empower parents, called the Parents as Agents of Change model. Our paper focuses on describing the application of a Unified Theory of Behavior Change as a theoretical framework to help activate parents as change agents in meeting their children’s mental health needs. Based on an integrated model of grassroots driven Principles of Parent Support and research-based Unified Theory of Behavior Change, PEP’s Parents as Agents of Change model provides a conceptual framework for testing the effectiveness of family support services in children’s mental health, a much-needed area for future research.     

The costs and benefits of providing feedback during learning

It seems uncontroversial that providing feedback after a test, in the form of the correct answer, enhances learning. In real-world educational situations, however, the time available for learning is often constrained— and feedback takes time. We report an experiment in which total time for learning was fixed, thereby creating a trade-off between spending time receiving feedback and spending time on other learning activities. Our results suggest that providing feedback is not universally beneficial. Indeed, under some circumstances, taking time to provide feedback can have a negative net effect on learning. We also found that learners appear to have some insight about the costs of feedback; when they were allowed to control feedback, they often skipped unnecessary feedback in favor of additional retrieval attempts, and they benefited from doing so. These results underscore the importance of considering the costs and benefits of interventions designed to enhance learning.     

Memory-enhancing corticosterone treatment increases amygdala norepinephrine and Arc protein expression in hippocampal synaptic fractions

Considerable evidence indicates that glucocorticoid hormones enhance the consolidation of memory for emotionally arousing events through interactions with the noradrenergic system of the basolateral complex of the amygdala (BLA). We previously reported that intra-BLA administration of a β-adrenoceptor agonist immediately after inhibitory avoidance training enhanced memory consolidation and increased hippocampal expression of the protein product of the immediate early gene activity-regulated cytoskeletal-associated protein (Arc). In the present experiments corticosterone (3 mg/kg, i.p.) was administered to male Sprague-Dawley rats immediately after inhibitory avoidance training to examine effects on long-term memory, amygdala norepinephrine levels, and hippocampal Arc expression. Corticosterone increased amygdala norepinephrine levels 15 min after inhibitory avoidance training, as assessed by in vivo microdialysis, and enhanced memory tested at 48 h. Corticosterone treatment also increased expression of Arc protein in hippocampal synaptic tissue. The elevation in BLA norepinephrine appears to participate in corticosterone-influenced modulation of hippocampal Arc expression as intra-BLA blockade of β-adrenoceptors with propranolol (0.5 μg/0.2 μL) attenuated the corticosterone-induced synaptic Arc expression in the hippocampus. These findings indicate that noradrenergic activity at BLA β-adrenoceptors is involved in corticosterone-induced enhancement of memory consolidation and expression of the synaptic-plasticity-related protein Arc in the hippocampus.     

Climate Change is Unjust War: Geoengineering and the Rising Tides of War

Climate change is undeniably a global problem, but the situation is especially dire for countries whose territory is comprised entirely or primarily of low‐lying land. While geoengineering might offer an opportunity to protect these states, international consensus on the particulars of any geoengineering proposal seems unlikely. To consider the moral complexities created by unilateral deployment of geoengineering technologies, we turn to a moral convention with a rich history of assessing interference in the sovereign affairs of foreign states: the just war tradition. We argue that the just war framework demonstrates that, for these nations, geoengineering offers a justified form of self‐defense from an unwarranted, albeit unintentional, aggression. This startling result places our own carbon‐emitting activities in a stark new light: in perpetrating climate change, we are, in fact, waging war on the most vulnerable.     

Unconceived alternatives and conservatism in science: the impact of professionalization,peer-review,and Big Science

Synthese - Scientific realists have suggested that changes in our scientific communities over the course of their history have rendered those communities progressively less vulnerable to the...     

Comparison of blocking strategies informed by precursor assessment to decrease pica

Pica is dangerous behavior and often maintained by automatic reinforcement. We conducted a latency functional analysis (FA) using safe consumption items to verify that pica was maintained in part by automatic reinforcement and exclude participants for whom pica was likely maintained solely by attention. Next, we identified precursors to pica through a probability analysis and conducted a brief blocking assessment for participants' whose pica occurred in the alone and attention conditions of the FA. Finally, we compared blocking precursors with pica, touching an inedible item and the pica itself. Results showed that five of the six participants' pica was likely maintained by automatic reinforcement, and pica decreased during the brief blocking assessment for three of four participants. Results of the blocking comparison showed that blocking behaviors earlier in the response hierarchy was as effective as only blocking pica attempts for two participants and more effective for one participant.     

The impact of bilingual environments on selective attention in infancy

Bilingualism has been observed to influence cognitive processing across the lifespan but whether bilingual environments have an effect on selective attention and attention strategies in infancy remains an unresolved question. In Study 1, infants exposed to monolingual or bilingual environments participated in an eye‐tracking cueing task in which they saw centrally presented stimuli followed by a target appearing on either the left or right side of the screen. Halfway through the trials, the central stimuli reliably predicted targets' locations. In Study 2, the first half of the trials consisted of centrally presented cues that predicted targets' locations; in the second half, the cue–target location relation switched. All infants performed similarly in Study 1, but in Study 2 infants raised in bilingual, but not monolingual, environments were able to successfully update their expectations by making more correct anticipatory eye movements to the target and expressing faster reactive eye latencies toward the target in the post‐switch condition. The experience of attending to a complex environment in which infants simultaneously process and contrast two languages may account for why infants raised in bilingual environments have greater attentional control than those raised in monolingual environments.     

The relationship between biological and psychosocial risk factors and resting‐state functional connectivity in 2‐month‐old Bangladeshi infants: A feasibility and pilot study

Childhood poverty has been associated with structural and functional alterations in the developing brain. However, poverty does not alter brain development directly, but acts through associated biological or psychosocial risk factors (e.g. malnutrition, family conflict). Yet few studies have investigated risk factors in the context of infant neurodevelopment, and none have done so in low‐resource settings such as Bangladesh, where children are exposed to multiple, severe biological and psychosocial hazards. In this feasibility and pilot study, usable resting‐state fMRI data were acquired in infants from extremely poor (n = 16) and (relatively) more affluent (n = 16) families in Dhaka, Bangladesh. Whole‐brain intrinsic functional connectivity (iFC) was estimated using bilateral seeds in the amygdala, where iFC has shown susceptibility to early life stress, and in sensory areas, which have exhibited less susceptibility to early life hazards. Biological and psychosocial risk factors were examined for associations with iFC. Three resting‐state networks were identified in within‐group brain maps: medial temporal/striatal, visual, and auditory networks. Infants from extremely poor families compared with those from more affluent families exhibited greater (i.e. less negative) iFC in precuneus for amygdala seeds; however, no group differences in iFC were observed for sensory area seeds. Height‐for‐age, a proxy for malnutrition/infection, was not associated with amygdala/precuneus iFC, whereas prenatal family conflict was positively correlated. Findings suggest that it is feasible to conduct infant fMRI studies in low‐resource settings. Challenges and practical steps for successful implementations are discussed.