Assessing posttraumatic cognitive processes: the Event Related Rumination Inventory

Cognitive processes in the aftermath of experiencing a major life stressor play an important role in the impact of the event on the person. Intrusive thoughts about the event are likely to be associated with continued distress, while deliberate rumination, aimed at understanding and problem-solving, should be predictive of posttraumatic growth (PTG). The Event Related Rumination Inventory (ERRI), designed to measure these two styles of rumination, is described and validation information is provided. Using a college student sample screened for having experienced highly stressful life events, data were obtained (N=323) to conduct an exploratory factor analysis that supported the two factors of the ERRI. Separate confirmatory factor analyses (CFA) on two additional samples (Ns=186 and 400) supported a two-factor model. The two ERRI factors were validated by comparison with related variables and by assessing their contributions to predicting distress and PTG in two samples (Ns=198 and 202) that had been combined to conduct the second CFA. Data indicate the ERRI has solid psychometric properties, captures variance not measured by stable differences in cognitive styles, and the separate factors are related to posttraumatic distress and growth as predicted by existing models of PTG.     

A behavior-based circuit model of how outcome expectations organize learned behavior in larval Drosophila

Drosophila larvae combine a numerically simple brain, a correspondingly moderate behavioral complexity, and the availability of a rich toolbox for transgenic manipulation. This makes them attractive as a study case when trying to achieve a circuit-level understanding of behavior organization. From a series of behavioral experiments, we suggest a circuitry of chemosensory processing, odor-tastant memory trace formation, and the "decision" process to behaviorally express these memory traces--or not. The model incorporates statements about the neuronal organization of innate vs. conditioned chemosensory behavior, and the types of interaction between olfactory and gustatory pathways during the establishment as well as the behavioral expression of odor-tastant memory traces. It in particular suggests that innate olfactory behavior is responsive in nature, whereas conditioned olfactory behavior is captured better when seen as an action in pursuit of its outcome. It incorporates the available neuroanatomical and behavioral data and thus should be useful as scaffold for the ongoing investigations of the chemo-behavioral system in larval Drosophila.     

The role of the nucleus accumbens in knowing when to respond

While knowing what to expect is important, it is equally important to know when to expect it and to respond accordingly. This is apparent even in simple Pavlovian training situations in which animals learn to respond more strongly closer to reward delivery. Here we report that the nucleus accumbens core, an area well-positioned to represent information about the timing of impending rewards, plays a critical role in this timing function.     

Hippocampal tauopathy in tau transgenic mice coincides with impaired hippocampus-dependent learning and memory, and attenuated late-phase long-term depression of synaptic transmission

We evaluated various forms of hippocampus-dependent learning and memory, and hippocampal synaptic plasticity in THY-Tau22 transgenic mice, a murine tauopathy model that expresses double-mutated 4-repeat human tau, and shows neuropathological tau hyperphosphorylation and aggregation throughout the brain. Focussing on hippocampus, immunohistochemical studies in aged THY-Tau22 mice revealed prominent hyper- and abnormal phosphorylation of tau in CA1 region, and an increase in glial fibrillary acidic protein (GFAP) in hippocampus, but without signs of neuronal loss. These mice displayed spatial, social, and contextual learning and memory defects that could not be reduced to subtle neuromotor disability. The behavioral defects coincided with changes in hippocampal synaptic functioning and plasticity as measured in paired-pulse and novel long-term depression protocols. These results indicate that hippocampal tauopathy without neuronal cell loss can impair neural and behavioral plasticity, and further show that transgenic mice, such as the THY-Tau22 strain, might be useful for preclinical research on tauopathy pathogenesis and possible treatment.     

A comparative study of aggression amongst Nigerian university students in Niger Delta region

There is genuine concern over social violence and aggression among youths in many countries. Despite considerable efforts directed toward molding the pattern of model behavior, frequent disturbances and various antisocial vices among youths in our environment may be due to failure to acknowledge the risk factors associated with aggression. The objective of this study was to assess the level of aggressive traits among students in higher institutions, as well as identifying the possible predictive factors. Using a two-stage random sampling method, 515 fifteen students, comprising 306 from arts and 209 from medicine faculties, University of Uyo were screened for aggressive traits; using Buss-Perry Aggression (BPAQ) Questionnaire. A total of 306 arts students and 209 medical students fully completed the questionnaire. Among the arts students, 127 (41.5%) were males and 179 (58.5%) females. Similarly, of the 209 medical students, 143 (68.4%) were males and 66 (31.6%) females. The mean age for arts students was 28.7 years (SD = 7.9); while that of medical students was 23.6 years (SD = 4.9). The difference in the mean was statistically significant (t = 8.15, P = 0.001). A total of 139 (45 .4%) of arts students showed abnormal overall score for aggression as against 74 (35.4%) of medical students. This difference was statistically significant (χ(2) = 5.139, P = 0.01). There was also significant difference in the physical and verbal aggression subscales as 123 (40.2%) of arts against 53 (25.4%) medical students showed physical aggression (χ(2) = 12.15, P = 0.001), while 82 (26.8%) against 109 (52.2%) showed verbal aggression (χ(2) = 34.218, P = 0.001). Verbal aggression was positively correlated with female students; males have 2.98 odds ratio of being aggressive (P = 0.001). There is a high level of aggressive traits among students in higher institutions of learning. This can manifest in behaviors and vices capable of disturbing public peace and academic activities in schools. Therefore, there is need to curb aggression in order to create conducive learning environment and maintain societal norms.     

Mind the gap: bridging economic and naturalistic risk-taking with cognitive neuroscience

Economists define risk in terms of the variability of possible outcomes, whereas clinicians and laypeople generally view risk as exposure to possible loss or harm. Neuroeconomic studies using relatively simple behavioral tasks have identified a network of brain regions that respond to economic risk, but these studies have had limited success predicting naturalistic risk-taking. By contrast, more complex behavioral tasks developed by clinicians (e.g. Balloon Analogue Risk Task and Iowa Gambling Task) correlate with naturalistic risk-taking but resist decomposition into distinct cognitive constructs. We propose here that to bridge this gap and better understand neural substrates of naturalistic risk-taking, new tasks are needed that: are decomposable into basic cognitive and/or economic constructs; predict naturalistic risk-taking; and engender dynamic, affective engagement.     

Reciprocal relations between cognitive neuroscience and formal cognitive models: opposites attract?

Cognitive neuroscientists study how the brain implements particular cognitive processes such as perception, learning, and decision-making. Traditional approaches in which experiments are designed to target a specific cognitive process have been supplemented by two recent innovations. First, formal cognitive models can decompose observed behavioral data into multiple latent cognitive processes, allowing brain measurements to be associated with a particular cognitive process more precisely and more confidently. Second, cognitive neuroscience can provide additional data to inform the development of formal cognitive models, providing greater constraint than behavioral data alone. We argue that these fields are mutually dependent; not only can models guide neuroscientific endeavors, but understanding neural mechanisms can provide key insights into formal models of cognition.     

The relevance of Nash equilibrium to psychiatric disorders

In game theory, the word ‘game’ is used to describe any interdependence between interacting parties, and the Nash equilibrium is a prominent tool for analysing such interactions. I argue that the concept of the Nash equilibrium may also be used in non-gaming contexts. An individual is in a Nash equilibrium if his or her beliefs are consistent with his or her actions. Given that discordance between beliefs and behaviour is a typical cause of psychiatric disorders, individuals who are not in a Nash equilibrium are likely to be affected by such disorders. In this regard, the concept of the Nash equilibrium could aptly be introduced into the medical practitioner’s vocabulary for describing a patient’s mental health status.     

Chimpanzees’ use of conspecific cues in matching-to-sample tasks: public information use in a fully automated testing environment

Social animals have much to gain from observing and responding appropriately to the actions of their conspecific group members. This can in turn lead to the learning of novel behavior patterns (social learning) or to foraging, ranging, or social behavioral choices copied from fellow group members, which do not necessarily result in long-term learning, but at the time represent adaptive responses to environmental cues (public information use). In the current study, we developed a novel system for the study of public information use under fully automated conditions. We modified a classic single-subject laboratory paradigm—matching-to-sample (MTS)—and examined chimpanzees’ ability to interpret and utilize cues provided by the behavior of a conspecific to solve the task. In Experiment 1, two subjects took turns on an identity MTS task, with one subject (the model) performing the first half of the trial and the other subject (the observer) completing the trial using the model’s actions as discriminative cues. Both subjects performed above chance from the first session onwards. In Experiment 2, the subjects were tested on a symbolic version of the same MTS task, with one subject showing spontaneous transfer. Our study establishes a novel method for examining public information use within a highly controlled and automated setting.