Delay-dependent working memory impairment in young-adult and aged 5-HT1BKO mice as assessed in a radial-arm water maze

Serotonin (5-HT) plays a modulatory role in mnemonic functions, especially by interacting with the cholinergic system. The 5-HT1B receptor is a key target of this interaction. The 5-HT1B receptor knockout mice were found previously to exhibit a facilitation in hippocampal-dependent spatial reference memory learning. In the present study, we submitted mice to a delayed spatial working memory task, allowing the introduction of various delays between an exposure trial and a test trial. The 5-HT1BKO and wild-type mice learned the task in a radial-arm water maze (returning to the most recent presented arm containing the escape platform), and exhibited a high level of performance at delays of 0 and 5 min. However, at the delay of 60 min, only 5-HT1BKO mice exhibited an impairment. At a delay of 90 min, all mice were impaired. Treatment by scopolamine (0.8 mg/kg) induced the same pattern of performance in wild type as did the mutation for short (5 min, no impairment) and long (60 min, impairment) delays. The 22-month-old wild-type and knockout mice exhibited an impairment at short delays (5 and 15 min). The effect of the mutation affected both young-adult and aged mice at delays of 15, 30, and 60 min. Neurobiological data show that stimulation of the 5-HT1B receptor inhibits the release of acetylcholine in the hippocampus, but stimulates this in the frontal cortex. This dual function might, at least in part, explain the opposite effect of the mutation on reference memory (facilitation) and delay-dependent working memory (impairment). These results support the idea that cholinergic-serotonergic interactions play an important role in memory processes.     

Performance implications of leader briefings and team-interaction training for team adaptation to novel environments

The authors examined how leader briefings and team-interaction training influence team members' knowledge structures concerning processes related to effective performance in both routine and novel environments. Two-hundred thirty-seven undergraduates from a large mid-Atlantic university formed 79 three-member tank platoon teams and participated in a low-fidelity tank simulation. Team-interaction training, leader briefings, and novelty of performance environment were manipulated. Findings indicated that both leader briefings and team-interaction training affected the development of mental models, which in turn positively influenced team communication processes and team performance. Mental models and communication processes predicted performance more strongly in novel than in routine environments. Implications for the role of team-interaction training, leader briefings, and mental models as mechanisms for team adaptation are discussed.     

Blinded by trust in close others: Examining the effect of social closeness on cooperative behaviors during the COVID-19 pandemic

In the context of public health crises such as the COVID-19 pandemic, it is essential that individuals cooperate by complying with preventive measures (e.g., wearing a mask). The current research examines how high trust in close others is linked to less cooperation—that is, less compliance with measures—and thus, undermines collective interests. Specifically, we test whether individuals are less willing to comply with preventive measures when interacting with close others they trust. We conducted two experiments in which participants read a vignette depicting a social interaction with either close others (e.g., family) or strangers. Participants had to report the extent to which they would (1) trust the other people in the situation and (2) comply with the mask wearing and physical distancing measures during this interaction. In both experiments, we find that when individuals are considering an interaction with close others, they report experiencing higher trust which is then linked to lower compliance with preventive measures. In Experiment 2, we further demonstrate that participants report less compliance with preventive measures around close others, even when they perceive non-compliance with the measures as morally “wrong”. Our findings shed light on the challenges that compliance with preventive measures poses during social interactions in a context of high trust.     

Defensive pessimism and precautionary action during the COVID pandemic

The purpose of this research was to test, in the context of the COVID-19 pandemic, the hypothesis that individuals who use defensive pessimism as a strategy to manage anxiety are likely to act to prevent or mitigate negative outcomes. Across three crowd-sourced samples (Total N = 1416), defensive pessimism was correlated with self-reports of more precautionary behavior (Studies 1, 2, & 3) and fewer COVID-positive results (Study 3).     

Language Development in Children with Simple-Partial Left-Hemisphere Epilepsy

The nature of cerebral involvement in the acquisition of language was addressed in this longitudinal study of children with an early diagnosis of epilepsy with simple-partial seizures (SPE) and with epileptogenic foci localized in the left frontal (LF) lobe. Yearly evaluations of six SPE-LF children on tests of linguistic comprehension (pointing, understanding of narrative, and understanding of prepositions) and production (repetition, lexical diversity, and grammatical production) were carried out between the ages of 3 and 8 years and compared to those of large samples of control children on the same tasks and at each age level. Linguistic production of all children were transcribed, coded, and analyzed using the Child Language Data Exchange System (MacWhinney & Snow, 1991). Individual evolution trajectories revealed that SPE-LF children showed a clear dissociation in linguistic performance between comprehension and production. Linguistic comprehension gradually improved to reach normal performance levels by age 7 while linguistic production, even at later stages, remained quite poor. This dissociation in the development of linguistic performance in SPE-LF children suggests a complex interplay between brain maturation dynamics and dysfunction modulating the succession of stages in language development. The observed persistent deficits in specific aspects of linguistic performance argue for an early involvement of the anterior areas of the left cerebral hemisphere in the production of language.     

Impaired word naming in right-brain-damaged right-handers: error types and time-course analyses

The purpose of this study is to search for cues that could account for the fact that right-hemisphere lesions affect word naming when the criterion for naming is semantic. The authors analyzed the errors as well as the time course of productions of 35 vascular right-brain-damaged subjects (RBD) and 20 control subjects (C) in a semantic-based word-naming task. Results show that there are no differences between groups in terms of (a) the number of errors produced and, (b) the patterns of error types. However, results also show a reduction of verbal fluency for semantic criteria in RBD-subjects present only after the first 30 seconds of production. These results indicate that reduction of word production in RBD-subjects is not the consequence of nonspecific factors such as perseveration or spontaneity, but reflects problems with the less automatized processes permitting exploration of semantic organization, either because scanning process are affected, or because the presence of a discreet semantic impairment prevents scanning from being as efficient. Given that efficient exploration of semantic knowledge is important for lexico-semantic functioning, the present results suggest that the right hemisphere contributes to some aspects of lexico-semantic processing necessary for language production.     

Centering on figurative features during the comprehension of sentences describing scenes

Summary Subjects were asked to read sentences which described scenes containing objects. In the scene described in each sentence, a specific part of a particular object was necessarily implied as having an important role. The object was named but none of its parts were. The assumption was that the subjects, while processing the sentence and immediately afterward, would cognitively center on the important part, as a function of the context created by the sentence. Immediately after reading the sentence, the subjects were probed with a picture of either the important part, or of an unimportant part of the object. Judgments of the compatibility of this picture probe with the sentence were faster for pictures of important parts than for pictures of other parts. This was taken as supporting the hypothesis of cognitive centration. In a second experiment, in which words were used as probes instead of pictures, a purely verbal process to account for the results was ruled out. In a third experiment, subjects were given instructions to intentionally form visual images of the scenes described by the sentences. In this case, overall response times to the picture probes were shorter than in the absence of such instructions, but this decrease was greater for pictures of unimportant parts. This finding was interpreted as showing that imagery instructions increase the rate of activation of features to varying degrees as a function of the previous level of activation.     

Colour and emotion: children also associate red with negative valence

The association of colour with emotion constitutes a growing field of research, as it can affect how humans process their environment. Although there has been increasing interest in the association of red with negative valence in adults, little is known about how it develops. We therefore tested the red–negative association in children for the first time. Children aged 5–10 years performed a face categorization task in the form of a card‐sorting task. They had to judge whether ambiguous faces shown against three different colour backgrounds (red, grey, green) seemed to ‘feel good’ or ‘feel bad’. Results of logistic mixed models showed that – as previously demonstrated in adults – children across the age range provided significantly more ‘feel bad’ responses when the faces were given a red background. This finding is discussed in relation to colour–emotion association theories.