0109 Slow Wave Sleep Time and Its Oscillatory Features Show Opposite Associations with Emotional Memory Consolidation Following Stress

Introduction

Sleep and stress can both enhance emotional memory consolidation. During slow wave sleep (SWS), oscillatory features such as slow oscillations (SO), sleep spindles (SS), and critically, their coupling, are believed to facilitate consolidation. How they relate to emotional memory consolidation is less clear, and how stress interacts with these oscillations is unknown.

Methods

In this study, participants either underwent a psychosocial stressor (the Trier Social Stress Task; n = 32) or a control task (n=32). Next, they encoded 150 neutral, negative, and positive images while undergoing fMRI. Participants then spent the night in the lab with polysomnographic recording. The next day they were given a surprise recognition test.

Results

There was better memory for emotional compared to neutral items in the stress group. Within this group, % of time spent in SWS positively correlated with emotional memory consolidation (r=.37, p=.039). However, SO-SS coupling during SWS was negatively correlated with emotional memory consolidation in the stress group (r=-.47, p=.007). This was driven by participants who showed a high cortisol response following the stressor (cortisol * coupling interaction p=.03) Results were similar when negative and positive items were analyzed separately. No correlations with neutral item memory were found.

Conclusion

Sleep stage time and sleep oscillatory activity exert different effects on emotional memory following stress, and that SO-SS coupling does not always promote episodic memory consolidation. SO-SS coupling can impair emotional memories when encoded during periods of elevated stress, and accompanying neuromodulators such as cortisol are high.

Support

National Science Foundation, Grant/Award Number: BXS-1539361

0111 Emotional Memory-Associated Voxel-Extent Reactivation During Episodic Memory Retrieval Varies as a Function of Post-Learning Sleep

Introduction

Slow wave sleep (SWS) and rapid eye-movement (REM) sleep enhance neutral and emotional memory consolidation, respectively. Emotional episodic memory retrieval is also enhanced when encoding-specific functional brain patterns are reactivated at retrieval, especially in ventral visual stream and frontal brain regions as well as amygdala. Here we investigate how sleep impacts the association between memory-dependent brain pattern reactivation and episodic memory retrieval.

Methods

Healthy adults (N = 22; 11F, 11M; age: 19–29 years) were scanned during an incidental encoding task and a surprise recognition memory task 24h later. Overnight sleep was monitored with polysomnography. During encoding, participants viewed line drawings of negative, neutral, and positive images, each followed by their full-colored photo. At recognition, participants distinguished new from encoded line drawings. Brain reactivation was measured at the single-subject level as the percentage of voxels activated at encoding that were also activated during successful recognition (reactivation%); this metric was calculated independently in whole-brain and 3 ROI-based maps (inferior temporal lobe (ITL), medial prefrontal cortex, and amygdala). Multiple linear regression was performed to predict memory performance from functional brain reactivation and sleep physiology.

Results

In whole-brain analyses, the association between negative memory performance and reactivation% decreased with greater REM sleep amount. This interaction approached significance for positive, but was not significant for neutral, memory performance. Additionally, the association between neutral, but not emotional, memory performance and reactivation% decreased with greater amounts of SWS sleep. In ROI-based analyses, positive, but not negative or neutral, memory performance was independently predicted by REM sleep amount and ITL reactivation%. No effects of SWS amount were observed in ROI-based analyses.

Conclusion

Greater amounts of sleep decreased the association between brain reactivation and memory performance. Sufficient sleep may change cortical representations of episodic memories, resulting in less reliance on encoding-related reactivation during memory retrieval.

Support

NSF Grant BCS 1539361

Relationships Among Nightly Sleep Quality, Daily Stress, and Daily Affect

Objectives.

We explored the prospective, microlevel relationship between nightly sleep quality (SQ) and the subsequent day's stress on positive (PA) and negative affect (NA) as well as the moderating relationships between nightly SQ, subsequent stress, and subsequent PA on NA. We investigated whether age moderated these relationships.

Method.

We collected 56 days of sleep, stress, and affect data using daily diary questionnaires (N = 552). We used multilevel modeling to assess relationships at the between- and within-person levels.

Results.

Daily increases in SQ and decreases in stress interacted to predict higher daily PA and lower daily NA. Better SQ in older adults enhanced the benefits of PA on the stress-NA relationship more during times of low stress, whereas better sleep in younger adults enhanced the benefits of PA more during times of high stress. Between-person effects were stronger predictors of well-being outcomes than within-person variability.

Discussion.

The combination of good SQ and higher PA buffered the impact of stress on NA. The moderating impact of age suggests that sleep and stress play different roles across adulthood. Targeting intervention and prevention strategies to improve SQ and enhance PA could disrupt the detrimental relationship between daily stress and NA.

Two-photon-induced photoluminescence imaging of tumors using near-infrared excited gold nanoshells

Gold nanoshells (dielectric silica core/gold shell) are a novel class of hybrid metal nanoparticles whose unique optical properties have spawned new applications including more sensitive molecular assays and cancer therapy. We report a new photo-physical property of nanoshells (NS) whereby these particles glow brightly when excited by near-infrared light. We characterized the luminescence brightness of NS, comparing to that of gold nanorods (NR) and fluorescent beads (FB). We find that NS are as bright as NR and 140 times brighter than FB. To demonstrate the potential application of this bright two-photon-induced photoluminescence (TPIP) signal for biological imaging, we imaged the 3D distribution of gold nanoshells targeted to murine tumors.

Are stimulants overprescribed? Treatment of ADHD in four U.S. communities

OBJECTIVE

To address rising concerns about the possible overdiagnosis of attention-deficit hyperactivity disorder (ADHD) and overtreatment with stimulants. To date, almost no studies have examined ADHD in unbiased community-based studies, ascertaining both the prevalence of the diagnosis within nonreferred populations and the extent to which various treatments (i.e., stimulant medication, mental health treatments, and educational interventions) are used.

METHOD

As a part of the Methods for the Epidemiology of Child and Adolescent Mental Disorders (MECA) Study, the authors examined epidemiological survey data obtained from 1,285 children and their parents across 4 U.S. communities. Analyses examined the frequency of children's ADHD diagnosis, the extent to which medications were prescribed, as well as the provision of other services (e.g., psychosocial treatments, school-based educational interventions).

RESULTS

Findings indicated that 5.1% of children met full DSM-III-RADHD criteria across the pooled sample. Only 12.5% of children meeting ADHD criteria had been treated with stimulants during the previous 12 months. Some children who had been prescribed stimulants did not meet full ADHD diagnostic criteria, but these children manifested high levels of ADHD symptoms, suggesting that the medication had been appropriately prescribed. Children with ADHD were generally more likely to receive mental health counseling and/or school-based interventions than medication.

CONCLUSIONS

Medication treatments are often not used in treating ADHD children identified in the community, suggesting the need for better education of parents, physicians, and mental health professionals about the effectiveness of these treatments. On the basis of these data it cannot be concluded that substantial "overtreatment" with stimulants is occurring across communities in general.