Event-related activation in the human amygdala associates with later memory for individual emotional experience.
The role of the amygdala in enhancing declarative memory for emotional experiences has been investigated in a number of animal, patient, and brain imaging studies. Brain imaging studies, in particular, have found a correlation between amygdala activation during encoding and subsequent memory. Because of the design of these studies, it is unknown whether this correlation is based on individual differences between participants or within-subject variations in moment-to-moment amygdala activation related to individual stimuli. In this study, participants saw neutral and negative scenes and indicated how emotionally intense they found each scene. Separate functional magnetic resonance imaging responses in the amygdala for each scene were related to the participants' report of their experience at study and to performance in an unexpected memory test 3 weeks after scanning. The amygdala had the greatest response to scenes rated as most emotionally intense. The degree of activity in the left amygdala during encoding was predictive of subsequent memory only for scenes rated as most emotionally intense. These findings support the view that amygdala activation reflects moment-to-moment subjective emotional experience and that this activation enhances memory in relation to the emotional intensity of an experience. (+info)
Neural correlates of conscious self-regulation of emotion.
A fundamental question about the relationship between cognition and emotion concerns the neural substrate underlying emotional self-regulation. To address this issue, brain activation was measured in normal male subjects while they either responded in a normal manner to erotic film excerpts or voluntarily attempted to inhibit the sexual arousal induced by viewing erotic stimuli. Results demonstrated that the sexual arousal experienced, in response to the erotic film excerpts, was associated with activation in "limbic" and paralimbic structures, such as the right amygdala, right anterior temporal pole, and hypothalamus. In addition, the attempted inhibition of the sexual arousal generated by viewing the erotic stimuli was associated with activation of the right superior frontal gyrus and right anterior cingulate gyrus. No activation was found in limbic areas. These findings reinforce the view that emotional self-regulation is normally implemented by a neural circuit comprising various prefrontal regions and subcortical limbic structures. They also suggest that humans have the capacity to influence the electrochemical dynamics of their brains, by voluntarily changing the nature of the mind processes unfolding in the psychological space. (+info)
Misattribution, false recognition and the sins of memory.
Memory is sometimes a troublemaker. Schacter has classified memory's transgressions into seven fundamental 'sins': transience, absent-mindedness, blocking, misattribution, suggestibility, bias and persistence. This paper focuses on one memory sin, misattribution, that is implicated in false or illusory recognition of episodes that never occurred. We present data from cognitive, neuropsychological and neuroimaging studies that illuminate aspects of misattribution and false recognition. We first discuss cognitive research examining possible mechanisms of misattribution associated with false recognition. We also consider ways in which false recognition can be reduced or avoided, focusing in particular on the role of distinctive information. We next turn to neuropsychological research concerning patients with amnesia and Alzheimer's disease that reveals conditions under which such patients are less susceptible to false recognition than are healthy controls, thus providing clues about the brain mechanisms that drive false recognition. We then consider neuroimaging studies concerned with the neural correlates of true and false recognition, examining when the two forms of recognition can and cannot be distinguished on the basis of brain activity. Finally, we argue that even though misattribution and other memory sins are annoying and even dangerous, they can also be viewed as by-products of adaptive features of memory. (+info)
Episodic memory and common sense: how far apart?
Research has revealed facts about human memory in general and episodic memory in particular that deviate from both common sense and previously accepted ideas. This paper discusses some of these deviations in light of the proceedings of The Royal Society's Discussion Meeting on episodic memory. Retrieval processes play a more critical role in memory than commonly assumed; people can remember events that never happened; and conscious thoughts about one's personal past can take two distinct forms-'autonoetic' remembering and 'noetic' knowing. The serial-dependent-independent (SPI) model of the relations among episodic, semantic and perceptual memory systems accounts for a number of puzzling phenomena, such as some amnesic patients' preserved recognition memory and their ability to learn new semantic facts, and holds that episodic remembering of perceptual information can occur only by virtue of its mediation through semantic memory. Although common sense endows many animals with the ability to remember their past experiences, as yet there is no evidence that humanlike episodic memory-defined in terms of subjective time, self, and autonoetic awareness-is present in any other species. (+info)
Anxiety, depression and anger suppression in infertile couples: a controlled study.
BACKGROUND: Although several authors have suggested an important pathogenic role for psychosocial factors in 'functional' infertility, the extent to which depression, anxiety and expressed emotional patterns correlate to infertility is not yet clear. METHODS: This study included 156 infertile couples (recruited at intake) and 80 fertile couples, whose personal characteristics were recorded. They were examined using scales for the evaluation of the degree of psychopathology [Hamilton Anxiety Rating Scale (HAM-A), Hamilton Depression Rating Scale (HAM-D)], and anger expression [State-Trait Anger Expression Inventory (STAXI)]. The 156 infertile couples were then subdivided into groups based on the cause of infertility ('organic', 'functional' or 'undetermined'). The psychometric evaluation was double-blind with respect to the causes of infertility. RESULTS: Differences emerged in the degree of psychopathology between 'organic' and 'functional' infertile subjects and fertile controls. In women, logistic regression identified three variables able to predict the diagnosis subtype; these variables are HAM-A, HAM-D, and tendency toward anger suppression. In men, anger did not emerge as a predictor for diagnosis, whereas HAM-A and HAM-D did. CONCLUSIONS: The 'functional' infertile subjects of this sample showed particular psychopathological and psychological features, independent from the stress reaction following the identification of the cause of infertility. (+info)
Neural systems underlying the suppression of unwanted memories.
Over a century ago, Freud proposed that unwanted memories can be excluded from awareness, a process called repression. It is unknown, however, how repression occurs in the brain. We used functional magnetic resonance imaging to identify the neural systems involved in keeping unwanted memories out of awareness. Controlling unwanted memories was associated with increased dorsolateral prefrontal activation, reduced hippocampal activation, and impaired retention of those memories. Both prefrontal cortical and right hippocampal activations predicted the magnitude of forgetting. These results confirm the existence of an active forgetting process and establish a neurobiological model for guiding inquiry into motivated forgetting. (+info)
The accumulative effect of trauma exposure on short-term and delayed verbal memory in a treatment-seeking sample of female rape victims.
The accumulative effect of prior high-magnitude trauma exposure on memory was examined in 73 rape victims, 92% of whom had current posttraumatic stress disorder (PTSD). Participants were administered the Logical Memory component of the Wechsler Memory Scale, the Quick Test to obtain an estimate of intelligence, and were assessed for prior traumatic experiences. Prior exposure to high-magnitude stressors (e.g., child rape, being kidnapped) was significantly correlated with poorer performance on the memory tasks. Regression analyses controlling for estimated IQ and psychopathology severity demonstrated that magnitude of prior trauma exposure predicted performance on the memory task, suggesting that in the current sample, deficits in verbal memory may be related (in part) to the degree of accumulative stress experienced over the lifetime. (+info)
Plasticity in the entorhinal cortex suppresses memory for contextual fear.
Several studies have delineated a role for the hippocampus in fear conditioning. However, in this task, the role of the entorhinal cortex (EC), the main input-output structure for the hippocampus, is uncertain. The extracellular signal-regulated kinase (ERK) cascade has been shown to be a molecular correlate for long-term memory, and its activity is required for various types of memory storage, including fear memory. In this study, we show that ERK activity in the EC increased 90 min after fear conditioning. Post-training intra-EC infusion of ERK cascade inhibitors (PD098059, UO126) at 40 min, but not at 10 min, resulted in increased freezing to the context, but not to the tone, during a 48 hr retention test. Interestingly, both PD098059- and UO126-infused animals also demonstrated anticipatory freezing in the context, freezing maximally at the time the shock was given during training. This anticipatory behavior was also seen in naive animals receiving additional training. Together, these results suggest that ERK-mediated plasticity in the EC normally suppresses context-specific fear memory, especially the temporal nature of the freezing response, and that blocking this plasticity mimics the effects of additional training. (+info)