Enhanced Post-Learning Memory Consolidation is Influenced by Arousal Predisposition and Emotion Regulation but Not By Stimulus Valence or Arousal

Emotionally arousing stimuli are more memorable than neutral ones and arousal induced after learning enhances later retrieval. However, there is as yet little study of how stimulus qualities might interact with induced arousal and how individual differences might influence the modulation of memory. Thus, the present study examined the effect of arousal induced after learning on memory for words that varied in both arousal and valence quality, as well as the influence of three individual differences factors that are known to influence arousal response: emotional suppression, emotional reappraisal, and arousal predisposition. Seventy-six adults (57 female) viewed and rated 60 words that normatively ranged from high to low in arousal and valence. Ten minutes later, they viewed a 3-min comedic or neutral video clip. Arousal induced after learning enhanced 1-week delayed memory, spanning the lengthy task without preference for word type or serial position, contrasting with reports of arousal effects interacting with stimulus qualities. Importantly, being predisposed to arousal led to greater enhancement of long-term memory modulation, while the use of emotional reappraisal, which reduces arousal responding, inhibited the ability of arousal to induce memory enhancement. Thus, individual differences that influence arousal responding can contribute to or interfere with memory modulation

Modulation of Long-Term Memory by Arousal in Alexithymia: The Role of Interpretation

Moderate physiological or emotional arousal induced after learning modulates memory consolidation, helping to distinguish important memories from trivial ones. Yet, the contribution of subjective awareness or interpretation of arousal to this effect is uncertain. Alexithymia, which is an inability to describe or identify one’s emotional and arousal states even though physiological responses to arousal are intact, provides a tool to evaluate the role of arousal interpretation. Participants scoring high and low on alexithymia (N = 30 each) learned a list of 30 words, followed by immediate recall. Participants then saw either an arousing (oral surgery) or neutral video (tooth brushing). Memory was tested 24-h later. Physiological response to arousal was comparable between groups, but subjective response to arousal was impaired in high alexithymia. Yet, delayed word recognition was enhanced by arousal regardless of alexithymia status. Thus, subjective response to arousal, i.e., cognitive appraisal, was not necessary for memory modulation to occur

Memory Enhancement by a Semantically Unrelated Emotional Arousal Source Induced After Learning

It has been well established that moderate physiological or emotional arousal modulates memory. However, there is some controversy about whether the source of arousal must be semantically related to the information to be remembered. To test this idea, 35 healthy young adult participants learned a list of common nouns and afterward viewed a semantically unrelated, neutral or emotionally arousing videotape. The tape was shown after learning to prevent arousal effects on encoding or attention, instead influencing memory consolidation. Heart rate increase was significantly greater in the arousal group, and negative affect was significantly less reported in the non-arousal group after the video. The arousal group remembered significantly more words than the non-arousal group at both 30 min and 24 h delays, despite comparable group memory performance prior to the arousal manipulation. These results demonstrate that emotional arousal, even from an unrelated source, is capable of modulating memory consolidation. Potential reasons for contradictory findings in some previous studies, such as the timing of “delayed” memory tests, are discussed

Prevention of drowsy driving by means of warning sound

Traffic accidents occur due to inattentive driving such as drowsy driving. A variety of support systems that make an attempt to prevent inattentive driving are under development. The development of a system to prevent drowsy driving using auditory or tactile alarm system is undertaken. It is essential to detect the low arousal state and warn drivers of such a state so that drowsy can be prevented. EEG (Electroencephalography) was used to evaluate how an arousal level degraded with time for eight participants under a low arousal level. Mean power frequency (MPF) was calculated to evaluate an arousal level. The value of MPF was compared between high and low arousal levels. The difference of arousal effect among four warning sounds was examined. As a result, there was no significant difference of arousal effect among four alarm sounds. The alarm sound was found to temporarily heighten participants' arousal level

Arousal regulates frequency tuning in primary auditory cortex.

Changes in arousal influence cortical sensory representations, but the synaptic mechanisms underlying arousal-dependent modulation of cortical processing are unclear. Here, we use 2-photon Ca2+ imaging in the auditory cortex of awake mice to show that heightened arousal, as indexed by pupil diameter, broadens frequency-tuned activity of layer 2/3 (L2/3) pyramidal cells. Sensory representations are less sparse, and the tuning of nearby cells more similar when arousal increases. Despite the reduction in selectivity, frequency discrimination by cell ensembles improves due to a decrease in shared trial-to-trial variability. In vivo whole-cell recordings reveal that mechanisms contributing to the effects of arousal on sensory representations include state-dependent modulation of membrane potential dynamics, spontaneous firing, and tone-evoked synaptic potentials. Surprisingly, changes in short-latency tone-evoked excitatory input cannot explain the effects of arousal on the broadness of frequency-tuned output. However, we show that arousal strongly modulates a slow tone-evoked suppression of recurrent excitation underlying lateral inhibition [H. K. Kato, S. K. Asinof, J. S. Isaacson, Neuron, 95, 412-423, (2017)]. This arousal-dependent "network suppression" gates the duration of tone-evoked responses and regulates the broadness of frequency tuning. Thus, arousal can shape tuning via modulation of indirect changes in recurrent network activity

Reduced level of arousal and increased mortality in adult acute medical admissions: a systematic review and meta-analysis

Abstract Background Reduced level of arousal is commonly observed in medical admissions and may predict in-hospital mortality. Delirium and reduced level of arousal are closely related. We systematically reviewed and conducted a meta-analysis of studies in adult acute medical patients of the relationship between reduced level of arousal on admission and in-hospital mortality. Methods We conducted a systematic review (PROSPERO: CRD42016022048), searching MEDLINE and EMBASE. We included studies of adult patients admitted with acute medical illness with level of arousal assessed on admission and mortality rates reported. We performed meta-analysis using a random effects model. Results From 23,941 studies we included 21 with 14 included in the meta-analysis. Mean age range was 33.4 - 83.8 years. Studies considered unselected general medical admissions (8 studies, n=13,039) or specific medical conditions (13 studies, n=38,882). Methods of evaluating level of arousal varied. The prevalence of reduced level of arousal was 3.1%-76.9% (median 13.5%). Mortality rates were 1.7%-58% (median 15.9%). Reduced level of arousal was associated with higher in-hospital mortality (pooled OR 5.71; 95% CI 4.21-7.74; low quality evidence: high risk of bias, clinical heterogeneity and possible publication bias). Conclusions Reduced level of arousal on hospital admission may be a strong predictor of in-hospital mortality. Most evidence was of low quality. Reduced level of arousal is highly specific to delirium, better formal detection of hypoactive delirium and implementation of care pathways may improve outcomes. Future studies to assess the impact of interventions on in-hospital mortality should use validated assessments of both level of arousal and delirium

The influence of affective factors on time perception

Several studies have suggested that both affective valence and arousal affect the perception of time. How-ever, in previous experiments these two affective dimensions were not systematically controlled. In the present study, a set of emotional slides rated for valence and arousal (International Affective Picture System) were projected to two groups of subjects for 2, 4 and 6 sec. One group estimated the duration on an analog scale and a second group reproduced the interval by pushing a button. Heart rate and skin conductance responses were also recorded. A highly significant valence by arousal interaction affected duration judg-ments. For low arousal stimuli, the duration of negative slides was judged relatively shorter than the duration of positive slides. For high arousal stimuli, the duration of negative slides was judged longer than the dura-tion of positive slides. These results are interpreted within a model of action tendency, in which the level of arousal controls two different motivational mechanisms, one emotional and the other attentional

AMPLITUDE OF HEART RATE MODULATION WITH THE PERIOD OF\ud 3 CARDIOCYCLES DEPENDS ON THE PHYSIOLOGICAL AROUSAL OF THE BRAIN

Amplitude of the 3-cardiocycle modulation of heart rate in records of 300 cardiointervals depends of the physiological arousal of brain. As arousal is a physiological component of stress, the amplitude of this heart rate modulation may be used as a diagnostic parameter on the arousal in stress related studies.\u