Effect of emotion on hippocampal-dependent associative binding through the lens of the weather prediction task.

Progressive imbalance in the interaction between spatial and procedural memory systems in the R6/2 mouse model of Huntington’s disease

In general, emotion is known to enhance memory processes. However, the effect of emotion on associative memory and the underling neural mechanisms remains largely unexplored. In this study, we explored brain activation during an associative memory task that involved the encoding and retrieval of word and face pairs. The word and face pairs consisted of either negative or positive words with neutral faces. Significant hippocampal activation was observed during both encoding and retrieval, regardless of whether the word was negative or positive. Negative and positive emotionality differentially affected the hemodynamic responses to encoding and retrieval in the amygdala, with increased responses during encoding negative word and face pairs. Furthermore, activation of the amygdala during encoding of negative word and neutral face pairs was inversely correlated with subsequent memory retrieval. These findings suggest that activation of the amygdala induced by negative emotion during encoding may disrupt associative memory performance.

The hippocampal and striatal memory systems are thought to operate independently and in parallel in supporting cognitive memory and habits, respectively. Much of the evidence for this principle comes from double dissociation data, in which damage to brain structure A causes deficits in Task 1 but not Task 2, whereas damage to structure B produces the reverse pattern of effects. Typically, animals are explicitly trained in one task. Here, we investigated whether this principle continues to hold when animals concurrently learn two types of tasks. Rats were trained on a plus maze in either a spatial navigation or a cue-response task (sequential training), whereas a third set of rats acquired both (concurrent training). Subsequently, the rats underwent either sham surgery or neurotoxic lesions of the hippocampus (HPC), medial dorsal striatum (DSM), or lateral dorsal striatum (DSL), followed by retention testing. Finally, rats in the sequential training condition also acquired the novel "other" task. When rats learned one task, HPC and DSL selectively supported spatial navigation and cue response, respectively. However, when rats learned both tasks, HPC and DSL additionally supported the behavior incongruent with the processing style of the corresponding memory system. Thus, in certain conditions, the hippocampal and striatal memory systems can operate cooperatively and in synergism. DSM significantly contributed to performance regardless of task or training procedure. Experience with the cue-response task facilitated subsequent spatial learning, whereas experience with spatial navigation delayed both concurrent and subsequent response learning. These findings suggest that there are multiple operational principles that govern memory networks. Currently, we distinguish among several types of memories, each supported by a distinct neural circuit. The memory systems are thought to operate independently and in parallel. Here, we demonstrate that the hippocampus and the dorsal striatum memory systems operate independently and in parallel when rats learn one type of task at a time, but interact cooperatively and in synergism when rats concurrently learn two types of tasks. Furthermore, new learning is modulated by past experiences. These results can be explained by a model in which independent and parallel information processing that occurs in the separate memory-related neural circuits is supplemented by information transfer between the memory systems at the level of the cortex.

Time course of effects of emotion on item memory and source memory for Chinese words

A key question is how new semantic representations are formed in the human brain and how this may benefit from the hippocampal episodic memory system. Here, we describe the major effective connectivity between the hippocampal memory system and the anterior temporal lobe (ATL) semantic memory system in humans. Then, we present and model a theory of how semantic representations may be formed in the human ATL using slow associative learning in semantic attractor networks that receive inputs from the hippocampal episodic memory system. The hypothesis is that if one category of semantic representations is being processed for several seconds, then a slow short-term memory trace associative biologically plausible learning rule will enable all the components during that time to be associated together in a semantic attractor network. This benefits from the binding of components provided by the hippocampal episodic memory system. The theory is modeled in a four-layer network for view-invariant visual object recognition, followed by a semantic attractor network layer that utilizes a temporal trace associative learning rule to form semantic categories based on the inputs that occur close together in time, using inputs from the hippocampal system or from the world.

Threat-induced modulation of hippocampal and striatal memory systems during navigation of a virtual environment

Gender differences in the effects of post-learning emotion on consolidation of item memory and source memory

Emotions are a constant companion in people’s life, and most of the emotions have been characterized into either positive or negative emotions. While people are experiencing different types of emotions, their memory system and brain mechanisms will be impacted differently. As memory is a brain function that people need in daily life, it is paramount to investigate and understand the mechanism of the influence that emotions have on human brain. This paper analyzed 8 experiments on the difference between positive and negative emotions influence on memory system (4 for positive emotions and 4 for negative emotions). On the one hand, positive emotions have been shown to improve working memory, which can increase learning efficiency, but their effect on short-term memory is still unclear. On the other hand, negative emotions can impair working memory and disrupt short-term memory for positive or neutral information, while improving memory retention for negative events.

Regular exercise has numerous benefits for brain health, including the structure and function of the hippocampus. The hippocampus plays a critical role in memory function, and is altered in a number of psychiatric disorders associated with memory impairments (e.g., depression and schizophrenia), as well as healthy aging. While many studies have focused on how regular exercise may improve hippocampal integrity in older individuals, less is known about these effects in young to middle-aged adults. Therefore, we assessed the associations of regular exercise and cardiorespiratory fitness with hippocampal structure and function in these age groups. We recruited 40 healthy young to middle-aged adults, comprised of two groups (n=20) who self-reported either high or low levels of exercise, according to World Health Organization guidelines. We assessed cardiorespiratory fitness using a graded exercise test (VO2 max) and hippocampal structure via manual tracing of T1-weighted magnetic resonance images. We also assessed hippocampal function using magnetic resonance spectroscopy to derive estimates of N-acetyl-aspartate concentration and hippocampal-dependent associative memory and pattern separation tasks. We observed evidence of increased N-acetyl-aspartate concentration and associative memory performance in individuals engaging in high levels of exercise. However, no differences in hippocampal volume or pattern separation capacity were observed between groups. Cardiorespiratory fitness was positively associated with left and right hippocampal volume and N-acetyl-aspartate concentration. However, no associations were observed between cardiorespiratory fitness and associative memory or pattern separation. Therefore, we provide evidence that higher levels of exercise and cardiorespiratory fitness are associated with improved hippocampal structure and function. Exercise may provide a low-risk, effective method of improving hippocampal integrity in an early-to-mid-life stage.

The formation of associations between items and their context has been proposed to rely on mechanisms distinct from those supporting memory for a single item. Although emotional experiences can profoundly affect memory, our understanding of how it interacts with different aspects of memory remains unclear. We performed three experiments to examine the effects of emotion on memory for items and their associations. By presenting neutral and negative items with background contexts, Experiment 1 demonstrated that item memory was facilitated by emotional affect, whereas memory for an associated context was reduced. In Experiment 2, arousal was manipulated independently of the memoranda, by a threat of shock, whereby encoding trials occurred under conditions of threat or safety. Memory for context was equally impaired by the presence of negative affect, whether induced by threat of shock or a negative item, relative to retrieval of the context of a neutral item in safety. In Experiment 3, participants were presented with neutral and negative items as paired associates, including all combinations of neutral and negative items. The results showed both above effects: compared to a neutral item, memory for the associate of a negative item (a second item here, context in Experiments 1 and 2) is impaired, whereas retrieval of the item itself is enhanced. Our findings suggest that negative affect impairs associative memory while recognition of a negative item is enhanced. They support dual-processing models in which negative affect or stress impairs hippocampal-dependent associative memory while the storage of negative sensory/perceptual representations is spared or even strengthened.

ObjectivesStudies have found that empathy is important in moral development and violence suppression, and emotion also affects empathy. However, the combinatorial effect of emotion and empathy on the processing of conflicts is not known.Materials and methodsA total of 44 undergraduate students (23 in low-empathy group and 21 in high-empathy group) were enrolled in this study. They were subjected to positive, negative, and neutral emotion evoking, as well as conflicting or nonconflicting proposals. Event-related potential technology was used to study the combinatorial effects of empathy and emotion on the processing of conflict of interest.ResultsWe found that under the influence of a positive emotion, both low- and high-empathy groups exhibited lower rejection rates. In the context of conflict, individuals in the high-empathy group showed fewer refusals under positive emotion. In the low-empathy group, there was no significant difference between responses to different emotions, but conflicting proposals induced more negative medial frontal negativity than nonconflicting proposals. Individuals in the low-empathy group showed different late positive potentials when responding to different types of proposals under both neutral and negative emotions, whereas those in the high-empathy group only showed different late positive potentials responding to different types of proposals under negative emotion.ConclusionOur results indicate that under positive emotion, individuals with low empathy show less difference in processing either conflicting or nonconflicting proposals, whereas under negative emotion, individuals with high empathy show enhanced motivation toward nonconflicting proposals.

Mineralocorticoid Receptor Blockade Prevents Stress-Induced Modulation of Multiple Memory Systems in the Human Brain

The main purpose of this research is to identify the mediator function performed by perceived stress level in the relationship between positive and negative emotions and mental toughness. 383 athletes voluntarily participated in the research, 252 (65.7%) male and 131 (34.2%) female. The athletes’ ages are between 15 and 55 (19.41±5.57). As part of the convenience sampling approach, data were collected from 40 of Turkey’s 81 provinces online (using a web-based Google form). The questionnaire consists of two parts. In the first part, there are questions about the demographic characteristics of the athletes. In the second part, some questions measure perceived stress, positive/ negative emotions, and mental toughness information in sports. Confirmatory factor analysis was used to understand whether the scales were suitable for the sample group and to increase the reliability of the mediator model. In the study, the effect of negative and positive emotions on mental toughness was tested with Simple Linear Regression Analysis. The mediating function of perceived stress in the relationship between positive and negative emotions and mental toughness was evaluated using the SPSS PROCESS macro (Model 4; Hayes, 2018). The direct effect of negative emotions on mental toughness was statistically significant (β=-0.2629; p<0.05). In addition, the direct effect of positive emotions on mental toughness was statistically significant (β=0.3720; p<0.05). Increased negative emotions in athletes were associated with increased perceived stress, predicting lower mental toughness. Once again, increased positive emotions in athletes were associated with a partial effect with reduced perceived stress, predicting relatively higher mental toughness.

The antecedents of counterproductive work behaviour (CWB) in the higher education sector have remained unexamined in available literature. Moreover, the impact of job insecurity, job stress, and negative emotions on the occurrence of CWB within the academic context have hardly been interrogated. This study therefore, aimed at investigating the impact of job insecurity, job stress and negative emotions on CWB and further examining the mediating role of job stress and negative emotions in the occurrences of CWB among academics. Data was collected from 716 academics in Technical Universities in Ghana using self-reported questionnaires with close-ended questions and a convenient sampling technique. Confirmatory Factor Analysis was conducted to verify the measurement structure of the constructs. Structural Equation Model was employed to test the hypotheses in the conceptual model. The result showed a statistically significant direct effect of job insecurity, job stress and negative emotions on the occurrence of counterproductive work behaviour among academics. It was further revealed that there is a positive relationship between job insecurity and job stress, with job stress partially mediating the relationship between job insecurity and counterproductive work behaviour. Furthermore, negative emotions acted as a partial mediator in the relationship between job stress and counterproductive work behaviour. The findings have implications for higher education institutions in taking steps to address job insecurity, job stress, and negative emotional experiences of academics to mitigate counterproductive work behaviour among academics.

This study is the first to investigate how negative and positive emotional states influence children's arithmetic performance and age-related differences therein. Children aged 8-14 (n = 149) were asked to verify true/false, one-digit addition problems (i.e., 8 + 2 = 10. True? False?) which were superimposed on emotionally negative, positive, or neutral pictures. The main results showed that (a) both positive and negative emotions impaired children's arithmetic performance, (b) deleterious effects of negative emotions were larger than those of positive emotions, (c) effects of emotions were modulated by the type of (true/false) problems, (d) effects of emotions on current trials were influenced by emotions on immediately preceding trials, and (e) effects of emotions as well as their trial-to-trial modulations changed with children's age. These findings have important implications for further our understanding of effects of emotions in children's arithmetic and how these effects change as children grow older.