Dopamine D1 receptors regulate protein synthesis-dependent long-term recognition memory via extracellular signal-regulated kinase 1/2 in the prefrontal cortex

Several lines of evidence suggest that extracellular signal-regulated kinase1/2 (ERK1/2) and dopaminergic system is involved in learning and memory. However, it remains to be determined if the dopaminergic system and ERK1/2 pathway contribute to cognitive function in the prefrontal cortex (PFC). The amount of phosphorylated ERK1/2 was increased in the PFC immediately after exposure to novel objects in the training session of the novel object recognition test. An inhibitor of ERK kinase impaired long-term recognition memory 24 h after the training although short-term memory tested 1 h after the training was not affected by the treatment. The dopamine D1 receptor agonist increased ERK1/2 phosphorylation in the PFC in vivo as well as in cortical neurons in vitro. Microinjection of the dopamine D1 receptor antagonist into the PFC impaired long-term recognition memory whereas the D2 receptor antagonist had no effect. Immunohistochemistry revealed that exposure to novel objects resulted in an increase in c-Fos expression in the PFC. Microinjection of the protein synthesis inhibitor anisomycin into the PFC impaired the long-term recognition memory. These results suggest that the activation of ERK1/2 following the stimulation of dopamine D1 receptors is necessary for the protein synthesis-dependent long-term retention of recognition memory in the PFC.     

Contextual learning induces an increase in the number of hippocampal CA1 neurons expressing high levels of BDNF

We examined behaviorally induced expression of brain-derived neurotrophic factor (BDNF) in area CA1 of the hippocampus. Sprague-Dawley rats were trained in a contextual fear conditioning (CFC) task, sacrificed 4h later, and their brains were processed for immunohistochemistry. We found distinctively high levels of BDNF immunoreactivity in a small number ( approximately 1%) of CA1 neurons in untrained animals. The number of these exceptional neurons, which are identified as BDNF(++) in this study, was increased by up to approximately 3% after CFC. This increase was blocked in the presence of a memory-impairing dose of a NMDA receptor antagonist (MK801 0.3 mg/kg, i.p.) given 30 min prior to training. The BDNF signal intensity in BDNF(++) neurons correlated with that of surrounding glutamic acid decarboxylase (GAD) 65. This correlation between GAD65 and BDNF signal intensities suggests that BDNF upregulation was associated with increased signaling via inhibitory GABAergic synapses that would lessen further intervening neuronal activity. Our observation that neurons which upregulate BDNF expression following a learning experience are rich in GAD65-enriched afferent synapses suggests that these neurons may have distinct roles in memory consolidation.     

Robustness of the two-dimensional structure of recognition of facial expression: evidence under different intensities of emotionality.

Many studies have indicated that recognition of facial expression is geometrically represented in terms of two underlying bipolar dimensions, pleasure-displeasure and the intensity of arousal. A psychological space defined by these two dimensions has been found under particular conditions using prototype faces: however, the question arises whether this two-dimensional psychological space is also an accurate representation for faces with lower emotional intensity. To test this we prepared four different conditions of emotional intensity (100%, 75%, 50%, and 25% of emotionality) for six basic facial expressions using morphing. Participants (29 for the 100%, 30 for 75%, 35 for 50%, and 34 for the 25% condition) in each condition rated the facial stimuli on a 6-point scale of "not at all" and "very much so". Multidimensional scaling for each condition clearly indicated a two-dimensional representation and multiple correlations showed significant similarity across conditions (p < .001). This shows that the two-dimensional representation of recognition of facial expression is robust.     

Basic Psychological Need Satisfaction and Frustration in Japan: Controlling for the Big Five Personality Traits

Abstract : The present study investigated the function of satisfaction and frustration of the basic psychological needs – autonomy, competence, and relatedness – that contribute to subjective well‐being (life‐satisfaction, vitality, and depression) through a back‐translation procedure of the Basic Psychological Need Satisfaction and Frustration Scale (BPNSFS). A total of 564 Japanese undergraduates (356 males, 205 females, three unknown; M _age = 18.61 years, SD = 1.48) participated in a questionnaire survey. Confirmatory factor analysis showed that the BPNSFS had the same six‐factor structure as that found in the original version. Structural equation modeling showed that satisfaction of each of the three needs contributed to the prediction of subjective well‐being (life satisfaction and vitality), whereas frustration of each need uniquely contributed to the prediction of ill‐being (depressed affect). These results support previous findings found in Belgium, China, the USA, and Peru, confirming that satisfaction of basic psychological needs represents a critical element for healthy functioning across cultures. However, controlling for the effects of the Big Five personality traits indicates the possible over‐estimation for the functions of the needs while clarifying these roles.     

A small-world network model of facial emotion recognition

Various models have been proposed to increase understanding of the cognitive basis of facial emotions. Despite those efforts, interactions between facial emotions have received minimal attention. If collective behaviours relating to each facial emotion in the comprehensive cognitive system could be assumed, specific facial emotion relationship patterns might emerge. In this study, we demonstrate that the frameworks of complex networks can effectively capture those patterns. We generate 81 facial emotion images (6 prototypes and 75 morphs) and then ask participants to rate degrees of similarity in 3240 facial emotion pairs in a paired comparison task. A facial emotion network constructed on the basis of similarity clearly forms a small-world network, which features an extremely short average network distance and close connectivity. Further, even if two facial emotions have opposing valences, they are connected within only two steps. In addition, we show that intermediary morphs are crucial for maintaining full network integration, whereas prototypes are not at all important. These results suggest the existence of collective behaviours in the cognitive systems of facial emotions and also describe why people can efficiently recognize facial emotions in terms of information transmission and propagation. For comparison, we construct three simulated networks—one based on the categorical model, one based on the dimensional model, and one random network. The results reveal that small-world connectivity in facial emotion networks is apparently different from those networks, suggesting that a small-world network is the most suitable model for capturing the cognitive basis of facial emotions.     

The fractal property of internal structure of facial affect recognition: A complex system approach

Based on a circumplex model of facial affect, four inner affective circumplexes, assumed to have 100%, 75%, 50%, and 25% emotional intensities, were investigated in terms of fractal, which is a concept of complex systems. Results revealed that the perimeters of the circumplex excluding the 25% condition possessed fractal property characterised by features specific to fractals. Results also showed that fractal dimension in the 50% condition (1.58 dimension) was significantly higher than that in the 100% (1.45 dimension) and 75% (1.45 dimension) conditions, indicating that the cognitive structure of facial affect in the 50% condition was more complex than that in the 100% and 75% conditions.     

A Unique Variance in Future Motivation for Observed Active Behaviors on Positive Class Participation Beyond the Effect of Current Motivation

Based on self-determination theory, this study investigates a unique variance in the effect of aspirations (future motivation) on the observed active behaviors on positive class participation, while controlling for academic motivation (current motivation). In Study 1, 364 fifth- and sixth-grade elementary school students participated in a survey to confirm the validity of the Aspirations Index for Children. Confirmatory factor analysis on the theoretically hypothesized model showed an acceptable fit for the data. In Study 2, 297 fifth- and sixth-grade elementary school students participated in this survey, assessing their aspirations and academic motivation. Furthermore, their homeroom teachers evaluated the students’ academic behaviors on positive class participation. The results of multilevel structural equation modeling, which controls for the effect of current motivation, indicated the unique variance in aspirations (future motivation): intrinsic aspirations were positively associated with active behaviors on positive class participation, whereas extrinsic aspirations showed a negative relation. This study concludes that future motivation, specifically intrinsic aspirations, facilitates active learning behaviors beyond the effect of current motivation.