Spindle Activity Research Articles

Nature and Nurture: Brain Region-Specific Inheritance of Sleep Neurophysiology in Adolescence.

Sleep-specific oscillations of spindles and slow waves are generated through thalamocortical and corticocortical loops, respectively, and provide a unique opportunity to measure the integrity of these neuronal systems. Understanding the relative contribution of genetic factors to sleep oscillations is important for determining whether they constitute useful endophenotypes that mark vulnerability to psychiatric illness. Using high-density sleep EEG recordings in human adolescent twin pairs (n = 60; 28 females), we find that over posterior regions 80-90% of the variance in slow oscillations, slow wave, and spindle activity is due to genes. Surprisingly, slow (10-12 Hz) and fast (12-16 Hz) anterior spindle amplitude and σ power are largely driven by environmental factors shared among the twins. To our knowledge this is the first example of a neural phenotype that exhibits a strong influence of nature in one brain region, and nurture in another. Overall, our findings highlight the utility of the sleep EEG as a reliable and easy to measure endophenotype during adolescence. This measure may be used to measure disease risk in development before the onset of a psychiatric disorder; the location within the brain of deficits in sleep neurophysiology may suggest whether the ultimate cause is genetic or environmental.SIGNIFICANCE STATEMENT Two cardinal oscillations of sleep, slow waves and sleep spindles, play an important role in the core functions of sleep including memory consolidation, synaptic plasticity, and the recuperative function of sleep. In this study, we use a behavioral genetics approach to examine the heritability of sleep neurophysiology using high-density EEG in a sample of early adolescent twins. Our findings reveal a strong influence of both environmental and genetic factors in shaping these oscillations, dependent on brain region. Thus, during a developmental period when brain structure and function is in flux, we find that the sleep EEG is among the most heritable of human traits over circumscribed brain regions.

Insights on auditory closed-loop stimulation targeting sleep spindles in slow oscillation up-states

BackgroundThe consolidation of sleep-dependent memories is mediated by an interplay of cortical slow oscillations (SOs) and thalamo-cortical sleep spindles. Whereas an enhancement of SOs with auditory closed-loop stimulation has been proven highly successful, the feasibility to induce and boost sleep spindles with auditory stimulation remains unknown thus far. New methodHere we tested the possibility to enhance spindle activity during endogenous SOs and thereby to promote memory consolidation. Performing a sleep study in healthy humans, we applied an auditory Spindle stimulation and compared it with an Arrhythmic stimulation and a control condition comprising no stimulation (Sham). ResultsWith Spindle stimulation we were not able to directly entrain endogenous spindle activity during SO up-states. Instead, both Spindle and Arrhythmic stimulation evoked a resonant SO response accompanied by an increase in spindle power phase-locked to the SO up-state. Assessment of overnight retention of declarative word-pairs revealed no difference between all conditions. Comparison with existing methodsOur Spindle stimulation produced oscillatory evoked responses (i.e., increases in SOs and spindle activity during SO up-states) quite similar to those observed after the auditory closed-loop stimulation of SOs in previous studies, lacking however the beneficial effects on memory retention. ConclusionOur findings put the endeavour for a selective enhancement of spindle activity via auditory pathways into perspective and reveal central questions with regard to the stimulation efficacy on both an electrophysiological and a neurobehavioral level.

Large-scale structure and individual fingerprints of locally coupled sleep oscillations

Slow oscillations and sleep spindles, the canonical electrophysiological oscillations of nonrapid eye movement sleep, are thought to gate incoming sensory information, underlie processes of sleep-dependent memory consolidation, and are altered in various neuropsychiatric disorders. Accumulating evidence of the predominantly local expression of these individual oscillatory rhythms suggests that their cross-frequency interactions may have a similar local component. However, it is unclear whether locally coordinated sleep oscillations exist across the cortex, and whether and how these dynamics differ between fast and slow spindles, and sleep stages. Moreover, substantial individual variability in the expression of both spindles and slow oscillations raises the possibility that their temporal organization shows similar individual differences. Using two nights of multichannel electroencephalography recordings from 24 healthy individuals, we characterized the topography of slow oscillation-spindle coupling. We found that while slow oscillations are highly restricted in spatial extent, the phase of the local slow oscillation modulates local spindle activity at virtually every cortical site. However, coupling dynamics varied with spindle class, sleep stage, and cortical region. Moreover, the slow oscillation phase at which spindles were maximally expressed differed markedly across individuals while remaining stable across nights. These findings both add an important spatial aspect to our understanding of the temporal coupling of sleep oscillations and demonstrate the heterogeneity of coupling dynamics, which must be taken into account when formulating mechanistic accounts of sleep-related memory processing.

Menstrual Cycle Effects on Sleep.

Subjective and objective sleep changes occur during the menstrual cycle. Poorer sleep quality in the premenstrual phase and menstruation is common in women with premenstrual symptoms or painful menstrual cramps. There is increased sleep spindle activity from follicular to luteal phase, potentially progesterone related. Luteal phase changes also include blunted temperature rhythm amplitude and reduced rapid eye movement sleep. Women with polycystic ovary syndrome should be screened for sleep disordered breathing. Short sleep duration is associated with irregular menstrual cycles, which may impact reproductive health. Menstrual cycle phase and menstrual-related disorders should be considered when assessing women's sleep complaints.

Genetic risk factors for schizophrenia associate with sleep spindle activity in healthy adolescents.

Schizophrenia has been associated with disturbed sleep, even before the onset of the disorder, and also in non-schizophrenic first-order relatives. This may point to an underlying genetic influence. Here we examine whether weighted polygenic risk scores (PRS) for schizophrenia are associated with sleep spindle activity in healthy adolescents. Our sample comes from a community-based cohort of 157 non-schizophrenic adolescents (57% girls) having both genetic data and an overnight sleep EEG measurement available. Based on a recent genome-wide association study, we calculated PRS for schizophrenia across the whole genome. We also calculated PRS for the CACNA1l gene region, which has been associated with both schizophrenia and sleep spindle formation. We performed an overnight sleep EEG at the homes of the participants. Stage two sleep spindles were detected using an automated algorithm. Sleep spindle amplitude, duration, intensity and density were measured separately for central and frontal derivations and for fast (13-16Hz) and slow (10-13Hz) spindles. PRS for schizophrenia was associated with higher fast spindle amplitude (p=0.04), density (p=0.006) and intensity (p=0.04) at the central derivation, and PRS in the CACNA1l region associated with higher slow spindle amplitude (p=0.01), duration (p=0.03) and intensity (p=0.002) at the central derivation. A positive association between genetic variants for schizophrenia and sleep spindle activity among healthy adolescents supports a view that sleep spindles and schizophrenia share similar genetic pathways. This study suggests that altered sleep spindle activity might serve as an endophenotype of schizophrenia.

No effect of vocabulary reactivation in older adults

Quality of memory and sleep declines with age. However, the mechanistic interactions underlying the memory function of sleep in older adults are still unknown. It is widely assumed that the beneficial effect of sleep on memory relies on reactivation during Non-rapid eye movement (NREM) sleep. Targeting these reactivations by cue re-exposure reliably improves memory in younger participants. Here we tested whether the memory reactivation mechanism during sleep is still functional in old age. For this purpose we applied targeted memory reactivation (TMR) during NREM sleep in healthy adults over 60 years and directly compared the results to a group of younger participants. In contrast to young participants, older adults’ memories did not generally benefit from TMR during NREM sleep. On the oscillatory level, successful reactivation of Dutch words during sleep did not reveal the characteristic increases in early theta activity and frontal spindle activity previously reported in young participants. Only in a later time window, theta oscillations were similarly increased during successful cueing for both young and older participants. Our results suggest that reactivating memories during sleep might be possible also in older adults. However at the same time this reactivation by TMR does not necessarily lead to a strengthening of memories across sleep as in younger participants. Further studies are needed to examine a potential loss of functionality of memory reactivation for consolidation during sleep in older adults.

Antitumor effects of anlotinib in thyroid cancer

There is no effective treatment for patients with poorly differentiated papillary thyroid cancer or anaplastic thyroid cancer (ATC). Anlotinib, a multi-kinase inhibitor, has already shown antitumor effects in various types of carcinoma in a phase I clinical trial. In this study, we aimed to better understand the effect and efficacy of anlotinib against thyroid carcinoma cells in vitro and in vivo. We found that anlotinib inhibits the cell viability of papillary thyroid cancer and ATC cell lines, likely due to abnormal spindle assembly, G2/M arrest, and activation of TP53 upon anlotinib treatment. Moreover, anlotinib suppresses the migration of thyroid cancer cells in vitro and the growth of xenograft thyroid tumors in mice. Our data demonstrate that anlotinib has significant anticancer activity in thyroid cancer, and potentially offers an effective therapeutic strategy for patients of advanced thyroid cancer type.

Absent sleep EEG spindle activity in GluA1 (Gria1) knockout mice: relevance to neuropsychiatric disorders

Sleep EEG spindles have been implicated in attention, sensory processing, synaptic plasticity and memory consolidation. In humans, deficits in sleep spindles have been reported in a wide range of neurological and psychiatric disorders, including schizophrenia. Genome-wide association studies have suggested a link between schizophrenia and genes associated with synaptic plasticity, including the Gria1 gene which codes for the GluA1 subunit of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor. Gria1−/− mice exhibit a phenotype relevant for neuropsychiatric disorders, including reduced synaptic plasticity and, at the behavioural level, attentional deficits leading to aberrant salience. In this study we report a striking reduction of EEG power density including the spindle-frequency range (10–15 Hz) during sleep in Gria1−/− mice. The reduction of spindle-activity in Gria1−/− mice was accompanied by longer REM sleep episodes, increased EEG slow-wave activity in the occipital derivation during baseline sleep, and a reduced rate of decline of EEG slow wave activity (0.5–4 Hz) during NREM sleep after sleep deprivation. These data provide a novel link between glutamatergic dysfunction and sleep abnormalities in a schizophrenia-relevant mouse model.

Mélatonine : aspects physiologiques et pharmacologiques en relation avec le sommeil, intérêt d’une forme galénique à libération prolongée (Circadin®) dans l’insomnie

Melatonin is a hormone secreted by the pineal gland. It displays a very marked nycthohemeral rhythm, which is entrained to the light dark cycle. The secretion spreads over 8–10 hours, with a maximum around 3–4 a.m. Melatonin plays the role of an endogenous synchronizer which regulates circadian rhythms, especially the sleep/wake and temperature rhythms. Acute melatonin administration reduces sleep latency, increases theta/alpha power and spindle activity (soporific activity). Fast-release melatonin preparations showed inconstant effects in insomnia. Melatonin displays a short blood half-life, a fast turn over and undergoes a high first-pass hepatic metabolism. More than 80% is excreted exclusively in the urine as 6-sulfatoxymelatonin. The individual's capacity to produce the endogenous hormone, the decline in circadian clock output and the increase in complaints of poor sleep quality at older age led to develop a prolonged-release melatonin preparation to mimic the endogenous secretion in patients. This reviews provides data on physiological and pharmacological melatonin effects related to sleep and summarizes trials published about Circadin® efficacy and tolerance in insomnia. Preliminary therapeutic data on other indications are given. The main clinically relevant benefits are improvements in sleep quality and latency, next-day morning alertness and quality of life. The response develops over several days. An oral 2-mg dose once daily, for 3 months, is generally well tolerated with no rebound, withdrawal or ‘hangover’ effects and no safety concerns on concomitant therapy with antihypertensive, antidiabetic, lipid-lowering or anti-inflammatory drugs. Untoward effects of hypnotics on cognition, memory, postural stability and sleep structure are not seen with Circadin®. Given as a first-line prescription, with 13 weeks’ posology and the lack of rebound effects, Circadin® has the potential to improve quality of life in insomnia patients aged 55 years and older and avoid long-term use of hypnotics.

Using optimal combined moderators to define heterogeneity in neural responses to randomized conditions: Application to the effect of sleep loss on fear learning

Comparing the neural outcomes of two randomized experimental groups is a primary aim of many functional neuroimaging studies. However, between-group effects can be obscured by heterogeneity in neural responses. Optimal Combined Moderator (OCM) approaches have previously been used to clarify heterogeneity in clinical outcomes following treatment randomization. We show that OCMs can also be used to clarify heterogeneity in the effect of a randomized experimental condition on neural responses. In 78 healthy adults aged 18–30 from the Effects of Dose-Dependent Sleep Disruption on Fear and Reward (SFeRe) study, we used demographic, clinical, genetic, and polysomnographic characteristics to develop OCMs for the effect of a randomized sleep restriction (SR) versus normal sleep (NS) condition on blood-oxygen-level dependent responses in the right amygdala (RAmyg) and subgenual anterior cingulate cortex (sgACC) during fear conditioning (FC) and extinction (FE) paradigms. The OCM for the RAmyg during FE was strongest [r (95% CI) = 0.52 (0.42, 0.68)], withstood cross-validation, and divided the sample into two subgroups with opposing experimental effects. Among N = 48 participants (“SR < NS”), those with SR exhibited less RAmyg activation during FE than those with NS [d (95%CI) = −1.10 (−1.86, −0.77)]. Among the remaining N = 30 participants (“SR > NS”), those with SR exhibited greater RAmyg activation during FE following SR than those with NS [d (95%CI) = 0.87 (0.37,1.78)]. SR > NS participants were more likely to be female, white, l/l genotype carriers, and have a psychiatric history. They had less sleep (overall and in REM), lower REM density, and lower spindle activity (12–16 Hz). Applying OCMs to randomized studies with neural outcomes can clarify neural heterogeneity and jumpstart mechanistic research; with further validation they also offer promise for personalized brain-based treatments and interventions.

Effect of surgical correction of equinus foot deformity on triceps surae spasticity in stroke patients

Equinus foot deformity (EFD) in stroke can be due to triceps surae (TS) spasticity. Aim of this work is to study the short-term effects of EFD surgical correction on TS spasticity in a sample of hemiplegic patients. A sample of 48 chronic stroke patients, 53(14) years, 19/29 R/L, 6(5) years after lesion, median FAC = 4, walking speed 0.51(0.28) m/s who underwent surgical TS lengthening was included in the study. TS spasticity was assessed through the Modified Tardieu Scale (MTS) before and 1 month after surgery both with the knee extended and flexed at 90 degrees (MTS_KE, MTS_KF). Before/after surgery MTS values were compared using the Wilcoxon test. Percentages of patients with worsened, unchanged and improved MTS scores were also computed and reported. Both MTS_KE and MTS_KF scores significantly decreased one month after surgery ( P = 0.002 and P < 0.001, respectively). MTS_KE score (see Fig. 1 ) worsened in 4 subjects (8%), was stable in 23 (48%) and improved in 21 subjects (44%). MTS_KF score worsened in 2 subjects (3%), was stable in 18 subjects (38%) and improved in 28 subjects (58%). Eight subjects were completely relieved from spasticity. Along with restoring ankle joint range of motion, surgical TS lengthening can also decrease muscle reflex overactivity. This is reasonably due to the reduction in spindle activation during the stretching maneuver consequent to the decrease in muscle shortening, passive tension and stiffness. This should reduce the reflex inputs to the spinal pathways involved in muscle tone control. In conclusion, FS can produce positive changes on TS spasticity in adult stroke survivors. A study on long-term effects is ongoing.

The effect of neuro-orthopedic surgery on spasticity in patients with Stiff knee gait (SKG)

Quadriceps femoris (QF) spasticity is frequent in patients with upper motor neuron lesion (UMNL) and SKG. Aim of this work is to study the effect of QF lengthening by functional surgery (FS) on spasticity in adults with UMNL following stroke or traumatic brain injury (TBI). A sample of 25 chronic patients with UMNL, 53 (13) years, 16/19 L/R, 6 (5) years after lesion, who underwent surgical QF lengthening was included in the study. The same surgeon always performed the surgeries. QF spasticity was assessed through the Modified Tardieu Scale (MTS) before and 1 month after surgery. MTS was used in this study as is not affected by passive muscle characteristics. Paired MTS values were compared using the non-parametric Wilcoxon test. Percentages of patients with worsened, unchanged and improved MTS scores were also computed and reported. MTS distribution is presented in Fig. 1 . Spasticity significantly decreased at 1 month after surgery ( P < 0.001). MTS score, was stable in 9 subjects (36%), improved in 16 subjects (64%) and never worsened. Noteworthy, 12 subjects (48%) were completely relieved from QF spasticity at the 1-month mark, with MTS decreasing from 3 to 0 and from 2 to 0. Along with restoring passive muscle length, FS can also be effective in reducing QF spasticity in adult stroke and TBI survivors. This is reasonably due to the reduction in spindle activation during the stretching maneuver consequent to the decrease in muscle shortening, passive tension and stiffness. Data collection is ongoing to obtain long-term results on a wider sample.

The Neurophysiological Effect of Acoustic Stimulation with Real-time Sleep Spindle Detection.

Sleep spindle is a salient brain activity found in the sigma frequency range (11-16 Hz) during sleep stage 2. It has been demonstrated that sleep spindle is related to memory consolidation, neurodegenerative disease, and mental disorders. Slow wave activity (0.5-4 Hz) is the most prominent EEG activity during sleep and appears as a large, spontaneous synchronization of cortical neurons. The role of slow wave activity has been proposed to regulate synaptic strength and memory consolidation. Many studies have investigated the effect of acoustic stimuli during the sleep slow wave. However, there have been few studies which investigated an effect of acoustic stimulation during sleep spindle activity. In this study, we examined the neurophysiological effect of acoustic stimulation during sleep spindle activity. We delivered pink noise after the detection of sleep spindle, and surmised that acoustic stimulation after sleep spindle detection may preserve delta activity during ongoing sleep. Further, we observed suppression of the sleep spindle activity around the times of acoustic stimulation and evoked slow wave activity and theta band activity immediately after tone onset.

First record of chromosome count and cytomixis in an endemic species ofClematis ladakhianaGrey-Wilson (Ranunculaceae) from cold deserts of Jammu and Kashmir

Meiotic investigations carried out from the cold desert regions of Ladakh (India) record the first ever chromosome count (2n = 32) and cytomixis in Clematis ladakhiana. The phenomenon of cytomixis involving chromatin transfer among 2–6 adjacent pollen mother cells (PMCs) through cytoplasmic channels was observed at different meiotic stages. The chromatin transfer resulted into hypo, hyperploid and enucleated PMCs. Although the frequency of meiocytes involved in chromatin transfer was low it induces abnormalities in chromatin and spindle activity, resulting into some pollen malformation in the form of variable sized fertile and sterile pollen grains. The Majority (86.60%) of the pollen grains observed were large sized, (86.60%) while (7.79%) are relatively small sized.

Thalamocortical and intracortical laminar connectivity determines sleep spindle properties.

Sleep spindles are brief oscillatory events during non-rapid eye movement (NREM) sleep. Spindle density and synchronization properties are different in MEG versus EEG recordings in humans and also vary with learning performance, suggesting spindle involvement in memory consolidation. Here, using computational models, we identified network mechanisms that may explain differences in spindle properties across cortical structures. First, we report that differences in spindle occurrence between MEG and EEG data may arise from the contrasting properties of the core and matrix thalamocortical systems. The matrix system, projecting superficially, has wider thalamocortical fanout compared to the core system, which projects to middle layers, and requires the recruitment of a larger population of neurons to initiate a spindle. This property was sufficient to explain lower spindle density and higher spatial synchrony of spindles in the superficial cortical layers, as observed in the EEG signal. In contrast, spindles in the core system occurred more frequently but less synchronously, as observed in the MEG recordings. Furthermore, consistent with human recordings, in the model, spindles occurred independently in the core system but the matrix system spindles commonly co-occurred with core spindles. We also found that the intracortical excitatory connections from layer III/IV to layer V promote spindle propagation from the core to the matrix system, leading to widespread spindle activity. Our study predicts that plasticity of intra- and inter-cortical connectivity can potentially be a mechanism for increased spindle density as has been observed during learning.

Structural Heterozygosity and Cytomixis in &lt;i&gt;Deutzia staminea&lt;/i&gt; R. Br. ex Wall. from Parvati Valley, Himachal Pradesh, India

Male meiotic studies have been performed on plants basis in Deutzia staminea collected from three localities of Parvati valley, Kullu district, Himachal Pradesh, India. The scored accessions uniformly exhibited the diploid chromosome count of 2n=26 confirming the earlier reports from other regions of North-West Himalayas. The individuals studied from Gurthigarh showed perfectly normal meiosis, microsporogenesis and 100% pollen fertility. On the other hand, plants studied from Pulga and Malana showed the existence of multiple associations of chromosomes due to structural heterozygosity for reciprocal translocations. Analysis of 118 countable pollen mother cells (PMCs) showed that 17.8% meiocytes depicted multivalent of ring or chain type involving 2.87% of the chromosomes. Also these individuals showed the phenomenon of cytomixis (6.57% PMCs), chromatin stickiness, and abnormal spindle activity depicted in form of out of plate bivalents, chromatin bridges and laggards. The existence of some pollen sterility (15–29%) in diploid individuals seems to be the consequence of multivalents during metaphase I (MI) and cytomictically induced meiotic irregularities in the PMCs.

Local and Widespread Slow Waves in Stable NREM Sleep: Evidence for Distinct Regulation Mechanisms.

Previous work showed that two types of slow waves are temporally dissociated during the transition to sleep: widespread, large and steep slow waves predominate early in the falling asleep period (type I), while smaller, more circumscribed slow waves become more prevalent later (type II). Here, we studied the possible occurrence of these two types of slow waves in stable non-REM (NREM) sleep and explored potential differences in their regulation. A heuristic approach based on slow wave synchronization efficiency was developed and applied to high-density electroencephalographic (EEG) recordings collected during consolidated NREM sleep to identify the potential type I and type II slow waves. Slow waves with characteristics compatible with those previously described for type I and type II were identified in stable NREM sleep. Importantly, these slow waves underwent opposite changes across the night, with only type II slow waves displaying a clear homeostatic regulation. In addition, we showed that the occurrence of type I slow waves was often followed by larger type II slow waves, whereas the occurrence of type II slow waves was usually followed by smaller type I waves. Finally, type II slow waves were associated with a relative increase in spindle activity, while type I slow waves triggered periods of high-frequency activity. Our results provide evidence for the existence of two distinct slow wave synchronization processes that underlie two different types of slow waves. These slow waves may have different functional roles and mark partially distinct “micro-states” of the sleeping brain.

Do different salience cues compete for dominance in memory over a daytime nap?

Information that is the most salient and important for future use is preferentially preserved through active processing during sleep. Emotional salience is a biologically adaptive cue that influences episodic memory processing through interactions between amygdalar and hippocampal activity. However, other cues that influence the importance of information, such as the explicit direction to remember or forget, interact with the inherent salience of information to determine its fate in memory. It is unknown how sleep-based processes selectively consolidate this complex information. The current study examined the development of memory for emotional and neutral information that was either cued to-be-remembered (TBR) or to-be-forgotten (TBF) across a daytime period including either napping or wakefulness. Baseline memory revealed dominance of the TBR cue, regardless of emotional salience. As anticipated, napping was found to preserve memory overall significantly better than remaining awake. Furthermore, we observed a trending interaction indicating that napping specifically enhanced the discrimination between the most salient information (negative TBR items) over other information. We found that memory for negative items was positively associated with the percentage of SWS obtained during a nap. Furthermore, the magnitude of the difference in memory between negative TBR items and negative TBF items increased with greater sleep spindle activity. Taken together, our results suggest that although the cue to actively remember or intentionally forget initially wins out, active processes during sleep facilitate the competition between salience cues to promote the most salient information in memory.

Spindle activity in young children with autism, developmental delay, or typical development.

To determine whether spindle activity differs in young children with and without autism. We investigated differences in spindle density, duration, and oscillatory features in 135 young children with autism, developmental delay without autism (DD), or typical development (TD) and secondarily assessed the dimensional relationship between spindle density and both cognitive ability and social functioning. Compared to TD, both spindle density (Cohen d 0.93, 95% confidence interval [CI] 0.49-1.37) and duration (Cohen d 0.58, 95% CI 0.15-1.01) were significantly decreased in autism. Spindle density was also significantly reduced in autism compared to DD (Cohen d 0.61, 95% CI 0.13-1.09). Decreased spindle frequency in autism compared to both TD (Cohen d 0.47, 95% CI 0.04-0.90) and DD (Cohen d 0.58, 95% CI 0.10-1.06) did not survive correction. The DD group did not differ significantly from the TD group on any spindle parameter. These results, suggesting a relationship between spindle density and autism but not DD, were further illustrated in exploratory analyses, wherein nonverbal ratio IQ (RIQ) and the Vineland Socialization domain standard score were strongly correlated with spindle density in the full sample (r = 0.33, p ≤ 001 and r = 0.41, p ≤ 001, respectively) but not within group. After nonverbal RIQ was accounted for, the relationship between spindle density and Vineland Socialization remained statistically significant (r = 0.23, p < 0.01). However, Vineland Socialization scores accounted for the relationship between spindle density and nonverbal RIQ (r = 0.04, p = 0.67). In a large cohort of young children with autism, spindle density was reduced compared to groups of age-matched children with DD or TD. Alterations in the maturational trajectory of spindles may provide valuable insight into the neurophysiologic differences related to behavior in disorders of neurodevelopment.

0669 Thalamocortical Dysfunction In Patients With Idiopathic Restless Legs Syndrome (RLS) Suggested By Reduced Sleep Spindle Activity

0669 Thalamocortical Dysfunction In Patients With Idiopathic Restless Legs Syndrome (RLS) Suggested By Reduced Sleep Spindle Activity