Emotional intensity predicts autobiographical memory experience

College students generated autobiographical memories from distinct emotional categories that varied in valence (positive vs. negative) and intensity (high vs. low). They then rated various perceptual, cognitive, and emotional properties for each memory. The distribution of these emotional memories favored a vector model over a circumplex model. For memories of all specific emotions, intensity accounted for significantly more variance in autobiographical memory characteristics than did valence or age of the memory. In two additional experiments, we examined multiple memories of emotions of high intensity and positive or negative valence and of positive valence and high or low intensity. Intensity was a more consistent predictor of autobiographical memory properties than was valence or the age of the memory in these experiments as well. The general effects of emotion on autobiographical memory properties are due primarily to intensity differences in emotional experience, not to benefits or detriments associated with a specific valence.     

Dissociation of event-related potentials indexing arousal and semantic cohesion during emotional word encoding

Event-related potential (ERP) studies have shown that emotional stimuli elicit greater amplitude late positive-polarity potentials (LPPs) than neutral stimuli. This effect has been attributed to arousal, but emotional stimuli are also more semantically coherent than uncategorized neutral stimuli. ERPs were recorded during encoding of positive, negative, uncategorized neutral, and categorized neutral words. Differences in LPP amplitude elicited by emotional versus uncategorized neutral stimuli were evident from 450 to 1000 ms. From 450 to 700 ms, LPP effects at midline and right hemisphere frontal electrodes indexed arousal, whereas LPP effects at left hemisphere centro-parietal electrodes indexed semantic cohesion. This dissociation helps specify the processes underlying emotional stimulus encoding, and suggests the need to control for semantic cohesion in emotional information processing studies.     

Conceptual similarity promotes generalization of higher order fear learning

We tested the hypothesis that conceptual similarity promotes generalization of conditioned fear. Using a sensory preconditioning procedure, three groups of subjects learned an association between two cues that were conceptually similar, unrelated, or mismatched. Next, one of the cues was paired with a shock. The other cue was then reintroduced to test for fear generalization, as measured by the skin conductance response. Results showed enhanced fear generalization that correlated with trait anxiety levels in the group that learned an association between conceptually similar stimuli. These findings suggest that conceptual representations of conditional stimuli influence human fear learning processes.     

Arousal-Mediated Memory Consolidation: Role of the Medial TemporalLobe in Humans

Although the influence of emotional arousal on declarative memory has been documented behaviorally, the mechanisms underlying arousal-memory interactions and their representation in the human brain remain uncertain. One route through which arousal achieves its effects on memory performance is by regulating consolidation processes. Animal research has revealed that the amygdala strengthens hippocampal-dependent memory consolidation in a limited time window following participation in an arousing task. To examine whether this integrative function of amygdalo-hippocampal structures extends to the human brain, we tested unilateral-temporal-lobectomy patients on an adaptation of a classic paradigm in which levels of physiological arousal at encoding modulate retention over time. Subjects rated emotionally arousing (taboo) and neutral words on an arousal scale while their skin conductance responses (SCRs) were monitored. Recall for the words was assessed immediately and after a 1-hr delay. Both temporal-lobectomy patients and control subjects generated enhanced SCRs and arousal ratings for the arousing words at the time of encoding. However, only control subjects exhibited an increase in memory for the arousing words over time. This group difference in the effect of arousal on the rate of forgetting suggests that the role of medial temporal lobe structures in memory consolidation for arousing events is conserved across species.     

Dissociable effects of conscious emotion regulation strategies on explicit and implicit memory

The authors manipulated emotion regulation strategies at encoding and administered explicit and implicit memory tests. In Experiment 1, participants used reappraisal to enhance and decrease the personal relevance of unpleasant and neutral pictures. In Experiment 2, decrease cues were replaced with suppress cues that directed participants to inhibit emotion-expressive behavior. Across experiments, using reappraisal to enhance the personal relevance of pictures improved free recall. By contrast, attempting to suppress emotional displays tended to impair recall, especially compared to the enhance condition. Using reappraisal to decrease the personal relevance of pictures had different effects depending on picture type. Paired with unpleasant pictures, the decrease cue tended to improve recall. Paired with neutral stimuli, the decrease cue tended to impair recall. Emotion regulation did not affect perceptual priming. Results highlight dissociable effects of emotion regulation on explicit and implicit memory, as well as dissociations between regulation strategies with respect to explicit memory.     

Brain activity associated with omission of an aversive event reveals the effects of fear learning and generalization

During fear learning, anticipation of an impending aversive stimulus increases defensive behaviors. Interestingly, omission of the aversive stimulus often produces another response around the time the event was expected. This omission response suggests that the subject detected a mismatch between what was predicted and what actually occurred, thereby providing an indirect measure of cognitive expectancy. Here, we used functional magnetic resonance imaging to investigate whether omission-related brain activity reflects fear expectancy during learning and generalization of conditioned fear. During conditioning, a face expressing a moderate amount of fear (conditioned stimulus, CS+) signaled delivery of an aversive shock unconditioned stimulus (US), whereas the same face with a neutral expression was unreinforced. In a subsequent generalization test, subjects were presented with faces expressing more or less fear intensity than the CS+. Psychophysiological results revealed an increase in the skin conductance response (SCR) during learning when the US was omitted. Omission-related SCRs were also observed during the generalization test following the offset of high- but not low-intensity face expressions. Neuroimaging results revealed omission-related neural activity during learning in the anterior cingulate cortex, parietal cortex, insula, and striatum. These same regions also showed omission-related responses during the generalization test following highly expressive fearful faces. Finally, regression analysis on omission responses during the generalization test revealed correlations in offset-related SCRs and neural activity in the dorsomedial prefrontal cortex and posterior parietal cortex. Thus, converging psychophysiological and neural activity upon omission of aversive stimulation provides a novel metric of US expectancy, even to generalized cues that had no prior history of reinforcement.     

Effects of stress and sex on acquisition and consolidation of human fear conditioning

We examined the relationship between stress hormone (cortisol) release and acquisition and consolidation of conditioned fear learning in healthy adults. Participants underwent acquisition of differential fear conditioning, and consolidation was assessed in a 24-h delayed extinction test. The acquisition phase was immediately followed by an 11-min psychosocial stress period (arithmetic test combined with a public speech). Salivary cortisol was sampled at various time points before and after acquisition and retention of fear conditioning. Results showed two effects of endogenous cortisol. Post-acquisition cortisol correlated with fear acquisition in male but not female participants. In addition, post-acquisition cortisol correlated with consolidation of fear but only in those participants with high cortisol levels. We conclude that in the short term, a robust and sexually dimorphic relationship exists between fear learning and stress hormone levels. For those participants whose fear learning is accompanied by high stress hormone levels, a long-term relationship exists between cortisol release and memory consolidation. These short-term and long-term effects may relate to the differential involvement of mineralocorticoid and glucocorticoid receptor subtypes, respectively. The findings have implications for understanding the role of stress, sex, and hormones in different stages of fear learning and memory.     

Modulation of reflexive orienting to gaze direction by facial expressions

Facial expression and gaze perception are thought to share brain mechanisms but behavioural interactions, especially from gaze-cueing paradigms, are inconsistent. We conducted a series of gaze-cueing studies using dynamic facial cues to examine orienting across different emotional expression and task conditions, including face inversion. Across experiments, at a short stimulus–onset asynchrony (SOA) we observed both an expression effect (i.e., faster responses when the face was emotional versus neutral) and a cue validity effect (i.e., faster responses when the target was gazed-at), but no interaction between validity and emotion. Results from face inversion suggest that the emotion effect may have been due to both facial expression and stimulus motion. At longer SOAs, validity and emotion interacted such that cueing by emotional faces, fearful faces in particular, was enhanced relative to neutral faces. These results converge with a growing body of evidence that suggests that gaze and expression are initially processed independently and interact at later stages to direct attentional orienting.     

Adolescent development of insula‐dependent interoceptive regulation

Adolescence is hypothesized to be a critical period for the maturation of self‐regulatory capacities, including those that depend on interoceptive sensitivity, but the neural basis of interoceptive regulation in adolescence is unknown. We used functional magnetic resonance imaging and psychophysiology to study interoceptive regulation in healthy adolescent females. Participants regulated their gut activities in response to a virtual roller coaster by deep breathing aided by visually monitoring their online electrogastrogram (EGG) activity through a virtual thermometer (i.e. gut biofeedback), or without biofeedback. Analyses focused on the insula, given its putative role in interoception. The bilateral posterior insula showed increased activation in the no‐biofeedback compared to biofeedback condition, suggesting that the participants relied more on interoceptive input when exteroceptive feedback was unavailable. The bilateral dorsal anterior insula showed activation linearly associated with age during both induction and regulation, and its activation during regulation correlated positively with change of EGG in the tachygastria frequency band from induction to regulation. Induction‐related activation in the bilateral ventral anterior insula was nonlinearly associated with age and peaked at mid‐adolescence. These results implicate different developmental trajectories of distinct sub‐regions of the insula in interoceptive processes, with implications for competing neurobiological theories of female adolescent development.     

Is all motivation good for learning? Dissociable influences of approach and avoidance motivation in declarative memory

The present study investigated the effects of approach versus avoidance motivation on declarative learning. Human participants navigated a virtual reality version of the Morris water task, a classic spatial memory paradigm, adapted to permit the experimental manipulation of motivation during learning. During this task, participants were instructed to navigate to correct platforms while avoiding incorrect platforms. To manipulate motivational states participants were either rewarded for navigating to correct locations (approach) or punished for navigating to incorrect platforms (avoidance). Participants' skin conductance levels (SCLs) were recorded during navigation to investigate the role of physiological arousal in motivated learning. Behavioral results revealed that, overall, approach motivation enhanced and avoidance motivation impaired memory performance compared to nonmotivated spatial learning. This advantage was evident across several performance indices, including accuracy, learning rate, path length, and proximity to platform locations during probe trials. SCL analysis revealed three key findings. First, within subjects, arousal interacted with approach motivation, such that high arousal on a given trial was associated with performance deficits. In addition, across subjects, high arousal negated or reversed the benefits of approach motivation. Finally, low-performing, highly aroused participants showed SCL responses similar to those of avoidance-motivation participants, suggesting that for these individuals, opportunities for reward may evoke states of learning similar to those typically evoked by threats of punishment. These results provide a novel characterization of how approach and avoidance motivation influence declarative memory and indicate a critical and selective role for arousal in determining how reinforcement influences goal-oriented learning.