Extensive lesions of cholinergic basal forebrain neurons do not impair spatial working memory

A recent studysuggests that lesions to all major areas of the cholinergic basal forebrain in the rat (medial septum, horizontal limb of the diagonal band of Broca, and nucleus basalis magnocellularis) impair a spatial working memory task. However, this experiment used a surgical technique that mayhave damaged cerebellar Purkinje cells. The present studytested rats with highlyselective lesions of cholinergic neurons in all major areas of the basal forebrain on a spatial working memorytask in the radial arm maze. In postoperative testing, there were no significant differences between lesion and control groups in working memory, even with a delayperiod of 8 h, with the exception of a transient impairment during the first 2 d of postoperative testing at shorter delays (0 or 2 h). This finding corroborates other results that indicate that the cholinergic basal forebrain does not playa significant role in spatial working memory. Furthermore, it underscores the presence of intact memoryfunctions after cholinergic basal forebrain damage, despite attentional impairments that follow these lesions, demonstrated in other task paradigms.     

Depression After Traumatic Brain Injury: A Review of Evidence for Clinical Heterogeneity

Depression represents a major source of disability among individuals who have suffered a traumatic brain injury (TBI), with estimates of prevalence in this population ranging over 50%. In comparison with other sequelae of TBI, depression is often poorly conceptualized and treated among acute care and rehabilitation professionals. One reason for this is the lack of clear etiological models for the development of depression following TBI. This paper argues that post-TBI depression actually represents a heterogeneous category, with multiple etiologic pathways and clinical implications. The literature in this area is reviewed, with an emphasis on an appreciation of the diversity within this clinical population. Conclusions focus on suggestions for differential diagnosis and treatment options.     

The research misconception

Recently, several researchers and philosophers argued that clinical research trials are not therapy. Their position is based on foundational research ethics documents, such as the Belmont Report, on conceptual analysis, and on the general way clinical trials are conducted. After examining and rejecting these arguments, we claim that good research is consistent with good therapy; that often trials are good therapy; and that a blanket attack on clinical trials as non-therapeutic creates a research misconception. This misconception is potentially harmful because it could weaken trial recruitment, could adversely affect funding for trials, and could overturn needed moral safeguards on therapeutic trials. Our more careful and accurate analysis of the nature of clinical trials can avoid such problems.     

Family predictors of disease management over one year in Latino and European American patients with type 2 diabetes

Family context is thought to influence chronic disease management but few studies have longitudinally examined these relationships. Research on families and chronic illness has focused almost exclusively on European American families. In this prospective study we tested a multidimensional model of family influence on disease management in type 2 diabetes in a bi-ethnic sample of European Americans and Latinos. Specifically, we tested how baseline family characteristics (structure, world view, and emotion management) predicted change in disease management over one year in 104 European American and 57 Latino patients with type 2 diabetes. We found that emotion management predicted change in disease management in both groups of patients as hypothesized, while family world view predicted change in both ethnic groups but in the predicted direction only for European Americans. Examining family context within ethnic groups is required to elucidate unique cultural patterns. Attending to culturally unique interpretations of constructs and measures is warranted. The import of family emotion management, specifically conflict resolution, in disease management deserves further study to support clinical intervention development. Examining multiple domains of family life and multidimensional health outcomes strengthens our capacity to develop theory about family contexts and individual health.     

Cooperation,Knowledge, and Time: Alternating-time Temporal Epistemic Logic and its Applications

Branching-time temporal logics have proved to be an extraordinarily successful tool in the formal specification and verification of distributed systems. Much of their success stems from the tractability of the model checking problem for the branching time logic CTL, which has made it possible to implement tools that allow designers to automatically verify that systems satisfy requirements expressed in CTL. Recently, CTL was generalised by Alur, Henzinger, and Kupferman in a logic known as Alternating-time Temporal Logic (ATL). The key insight in ATL is that the path quantifiers of CTL could be replaced by cooperation modalities, of the form , where is a set of agents. The intended interpretation of an ATL formula is that the agents can cooperate to ensure that holds (equivalently, that have a winning strategy for ). In this paper, we extend ATL with knowledge modalities, of the kind made popular in the work of Fagin, Halpern, Moses, Vardi and colleagues. Combining these knowledge modalities with ATL, it becomes possible to express such properties as group can cooperate to bring about iff it is common knowledge in that . The resulting logic — Alternating-time Temporal Epistemic Logic (ATEL) — shares the tractability of model checking with its ATL parent, and is a succinct and expressive language for reasoning about game-like multiagent systems.     

Histidine-decarboxylase knockout mice show deficient nonreinforced episodic object memory, improved negatively reinforced water-maze performance, and increased neo- and ventro-striatal dopamine turnover

The brain's histaminergic system has been implicated in hippocampal synaptic plasticity, learning, and memory, as well as brain reward and reinforcement. Our past pharmacological and lesion studies indicated that the brain's histamine system exerts inhibitory effects on the brain's reinforcement respective reward system reciprocal to mesolimbic dopamine systems, thereby modulating learning and memory performance. Given the close functional relationship between brain reinforcement and memory processes, the total disruption of brain histamine synthesis via genetic disruption of its synthesizing enzyme, histidine decarboxylase (HDC), in the mouse might have differential effects on learning dependent on the task-inherent reinforcement contingencies. Here, we investigated the effects of an HDC gene disruption in the mouse in a nonreinforced object exploration task and a negatively reinforced water-maze task as well as on neo- and ventro-striatal dopamine systems known to be involved in brain reward and reinforcement. Histidine decarboxylase knockout (HDC-KO) mice had higher dihydrophenylacetic acid concentrations and a higher dihydrophenylacetic acid/dopamine ratio in the neostriatum. In the ventral striatum, dihydrophenylacetic acid/dopamine and 3-methoxytyramine/dopamine ratios were higher in HDC-KO mice. Furthermore, the HDC-KO mice showed improved water-maze performance during both hidden and cued platform tasks, but deficient object discrimination based on temporal relationships. Our data imply that disruption of brain histamine synthesis can have both memory promoting and suppressive effects via distinct and independent mechanisms and further indicate that these opposed effects are related to the task-inherent reinforcement contingencies.     

Judging confidence influences decision processing in comparative judgments

Current theories of confidence in human judgment assume that confidence and the decision it is based on are inextricably tied to the same process (decisional locus theories) or that confidence processing begins only once the primary decision has been completed (postdecisional locus theories). In the absence of auxiliary assumptions, however, neither class of theory permits the judgment of confidence to affect primary decision processing. In the present study, we examined the effect of rendering confidence judgments on the properties of the decision process in a sensory discrimination task. An examination of the properties of the time taken to determine confidence (i.e., the time taken to render the judgment of confidence) revealed clear evidence of postdecisional confidence processing. Concomitantly, the requirement of confidence judgments was found to substantially increase decisional response times, suggesting that some confidence processing occurs during the primary decision process. We discuss the implications of these findings for contemporary models of confidence in human judgment.     

People with Williams syndrome process faces holistically

This study compared the performance of 47 adolescents and adults with Williams syndrome to 39 age-matched controls on a face recognition task. Using the whole-part paradigm developed by Tanaka and his colleagues, we found that although performance overall was lower in the participants with Williams syndrome, both groups showed similar patterns of performance across the different conditions. Both groups performed significantly better in the whole-face than in the isolated-part test condition for upright faces, but not for inverted faces. The whole-face advantage only in the upright condition provides strong evidence that people with Williams syndrome encode and recognize faces holistically in the same way as normal controls, suggesting the use of similar underlying neurocognitive mechanisms. These findings contradict earlier reports in the literature that people with Williams syndrome process faces abnormally.     

Test modality affects source monitoring and event-related potentials

Two experiments investigated the effect of test modality (visual or auditory) on source memory and event-related potentials (ERPs). Test modality influenced source monitoring such that source memory was better when the source and test modalities were congruent. Test modality had less of an influence when alternative information (i.e., cognitive operations) could be used to inform source judgments in Experiment 2. Test modality also affected ERP activity. Variation in parietal ERPs suggested that this activity reflects activation of sensory information, which can be attenuated when the sensory information is misleading. Changes in frontal ERPs support the hypothesis that frontal systems are used to evaluate source-specifying information present in the memory trace.     

Investigating the encoding and retrieval of intentions with event-related potentials

Strong evidence exists in the literature that remembering to complete intentions involves executive processing subserved by the frontal lobes. Event-related potentials were measured during the encoding of actions with the intention to perform versus more neutral material about which there was no such intentionality. Event-related potentials were also measured in a two-alternative discrimination task requiring identification of the to-be-performed actions and to-be-memorized actions. The results suggest that formation and retrieval of intentions differs from encoding and retrieval of similar material committed to memory. Additionally, the results suggest that right frontal areas may play an important role in the formation of prospective actions and that intentions are kept active in memory by processing mediated by the left frontal pole.