The Impact of Cognitive Behavioral Therapy on Sleep Problems in Autistic Children with Co-occurring Anxiety

PURPOSE

This study seeks to examine the relationship between anxiety-symptom severity and sleep behaviors in autistic children receiving cognitive behavioral therapy (CBT).

METHODS

We conducted a secondary-data analysis from a sample of 93 autistic youth, 4 to 14 years, participating in 24 weeks of CBT. Clinicians completed the Pediatric Anxiety Rating Scale (PARS) and parents completed the Children's Sleep Habits Questionnaire, Abbreviated/Short Form (CSHQ-SF) at baseline, mid-treatment, post-treatment and 3 months post-treatment. Mediation analysis evaluated the role of anxiety symptoms in mediating the effect of time in treatment on sleep.

RESULTS

There was a negative association between time in treatment and scores on the CSHQ-SF (b = - 3.23, SE = 0.493, t = - 6.553, p < 0.001). Increased time in treatment was associated with decreased anxiety (b = - 4.66, SE = 0.405, t = - 11.507, p < 0.001), and anxiety symptoms decreased with CSHQ-SF scores (b = 0.322, SE = 0.112, t = 2.869, p = 0.005). The indirect effect of time in treatment on CSHQ-SF scores through PARS reduction was negative, but not statistically significant.

CONCLUSION

Increased time in CBT was associated with decreased anxiety severity and improved sleep behaviors. Reductions in anxiety symptoms may mediate improvements in sleep problems, but larger sample sizes are necessary to explore this further.

Sensory experiences questionnaire unravels differences in sensory profiles between MECP2-related disorders

The methyl CpG-binding protein-2 (MECP2) gene is located on the Xq28 region. Loss of function mutations or increased copies of MECP2 result in Rett syndrome (RTT) and MECP2 duplication syndrome (MDS), respectively. Individuals with both disorders exhibit overlapping autism symptoms, yet few studies have dissected the differences between these gene dosage sensitive disorders. Further, research examining sensory processing patterns in persons with RTT and MDS is largely absent. Thus, the goal of this study was to analyze and compare sensory processing patterns in persons with RTT and MDS. Towards this goal, caregivers of 50 female individuals with RTT and 122 male individuals with MDS, between 1 and 46 years of age, completed a standardized measure of sensory processing, the Sensory Experiences Questionnaire. Patterns detected in both disorders were compared against each other and against normative values. We found sensory processing abnormalities for both hyper- and hypo-sensitivity in both groups. Interestingly, abnormalities in MDS were more pronounced compared with in RTT, particularly with items concerning hypersensitivity and sensory seeking, but not hyposensitivity. Individuals with MDS also exhibited greater sensory symptoms compared with RTT in the areas of tactile and vestibular sensory processing and for both social and nonsocial stimuli. This study provides a first description of sensory symptoms in individuals with RTT and individuals with MDS. Similar to other neurodevelopmental disorders, a variety of sensory processing abnormalities was found. These findings reveal a first insight into sensory processing abnormalities caused by a dosage sensitive gene and may ultimately help guide therapeutic approaches for these disorders.

Co-transmitting interneurons in the mouse olfactory bulb regulate olfactory detection and discrimination

Co-transmission of multiple neurotransmitters from a single neuron increases the complexity of signaling information within defined neuronal circuits. Superficial short-axon cells in the olfactory bulb release both dopamine and γ-aminobutyric acid (GABA), yet the specific targets of these neurotransmitters and their respective roles in olfaction have remained unknown. Here, we implement intersectional genetics in mice to selectively block GABA or dopamine release from superficial short-axon cells to identify their distinct cellular targets, impact on circuit function, and behavioral contribution of each neurotransmitter toward olfactory behaviors. We provide functional and anatomical evidence for divergent superficial short-axon cell signaling onto downstream neurons to shape patterns of mitral cell firing that contribute to olfactory-related behaviors.

A systematic-review of olfactory deficits in neurodevelopmental disorders: From mouse to human

Olfactory impairment is a common clinical motif across neurodevelopmental disorders, suggesting olfactory circuits are particularly vulnerable to disease processes and can provide insight into underlying disease mechanisms. The mouse olfactory bulb is an ideal model system to study mechanisms of neurodevelopmental disease due to its anatomical accessibility, behavioral relevance, ease of measuring circuit input and output, and the feature of adult neurogenesis. Despite the clinical relevance and experimental benefits, olfactory testing across animal models of neurodevelopmental disease has been inconsistent and non-standardized. Here we performed a systematic literature review of olfactory function testing in mouse models of neurodevelopmental disorders, and identified intriguing inconsistencies that include evidence for both increased and decreased acuity in odor detection in various mouse models of Autism Spectrum Disorder (ASD). Based on our identified gaps in the literature, we recommend direct comparison of different mouse models of ASD using standardized tests for odor detection and discrimination. This review provides a framework to guide future olfactory function testing in mouse models of neurodevelopmental diseases.

A 14-Year-Old Boy With Fevers, Cytopenias, and Neurocognitive Decline

A 14-year-old boy presented to our institution with a 1-month history of neurocognitive decline and intermittent fevers. His history was significant for fevers, headaches, and a 10-lb weight loss. Previous examinations by multiple medical providers were significant only for bilateral cervical lymphadenopathy. Previous laboratory workup revealed leukopenia, neutropenia, and elevated inflammatory markers. Despite improvement in his laboratory values after his initial presentation, his fevers persisted, and he developed slowed and "jerky" movements, increased sleep, slurred speech, delusions, visual hallucinations, and deterioration in his school performance. A brain MRI performed at an outside hospital before admission at our institution was concerning for patchy, increased T2 and fluid-attenuated inversion recovery signal intensity in multiple areas, including the basal ganglia. After transfer to our institution and admission to the pediatric hospital medicine team, the patient had an acute decompensation. Our subspecialists will discuss the initial evaluation, workup, differential diagnosis, definitive diagnosis, and subsequent management of this patient.

Update on Palliative Care for Pediatric Neurology

It has long been recognized that patients with neurological conditions, and particularly pediatric neurology patients, are well suited for palliative care because they frequently have a high symptom burden and variable prognoses. In 1996, the American Academy of neurology formally recognized a need for neurologists to "understand and apply the principles of palliative medicine." Subsequently, some reviews have proposed a simultaneous care model in which palliative care is integrated for all neurology patients from the time of diagnosis. This article will review the current status of palliative care in pediatric neurology and discuss barriers to its integration.

Student views on the role of self-regulated learning in a surgery clerkship

BACKGROUND

Self-regulated learning, including student-generated learning goals and flexibility in the learning structure are increasingly being used to enhance medical education. The role of these practices in surgical education of medical students has not been studied.

MATERIALS AND METHODS

We administered an 18-question electronic survey to all third-year medical students at Washington University in St. Louis School of Medicine. Of the 126 students invited, 64 responded and 56 were included in the analysis.

RESULTS

We found that third-year medical students develop learning goals at the beginning of the surgery clerkship. Although these learning goals theoretically can be a mechanism for enhanced student-faculty engagement, students are not aware of formal mechanisms for sharing these goals with faculty members. Furthermore, students report a lack of flexibility within the surgery clerkship and discomfort with requesting specific learning opportunities. Finally, students report that they believe increased flexibility could improve student engagement, learning, and the overall clerkship experience.

CONCLUSIONS

We therefore propose that a mechanism for students to share their learning goals with faculty and an infrastructure in which student learning experiences can be tailored to fit with these individualized goals would enhance student surgical learning.

Multiplexed temporal coding of electric communication signals in mormyrid fishes

The coding of stimulus information into patterns of spike times occurs widely in sensory systems. Determining how temporally coded information is decoded by central neurons is essential to understanding how brains process sensory stimuli. Mormyrid weakly electric fishes are experts at time coding, making them an exemplary organism for addressing this question. Mormyrids generate brief, stereotyped electric pulses. Pulse waveform carries information about sender identity, and it is encoded into submillisecond-to-millisecond differences in spike timing between receptors. Mormyrids vary the time between pulses to communicate behavioral state, and these intervals are encoded into the sequence of interspike intervals within receptors. Thus, the responses of peripheral electroreceptors establish a temporally multiplexed code for communication signals, one consisting of spike timing differences between receptors and a second consisting of interspike intervals within receptors. These signals are processed in a dedicated sensory pathway, and recent studies have shed light on the mechanisms by which central circuits can extract behaviorally relevant information from multiplexed temporal codes. Evolutionary change in the anatomy of this pathway is related to differences in electrosensory perception, which appears to have influenced the diversification of electric signals and species. However, it remains unknown how this evolutionary change relates to differences in sensory coding schemes, neuronal circuitry and central sensory processing. The mormyrid electric communication pathway is a powerful model for integrating mechanistic studies of temporal coding with evolutionary studies of correlated differences in brain and behavior to investigate neural mechanisms for processing temporal codes.

Detection of submillisecond spike timing differences based on delay-line anticoincidence detection

Detection of submillisecond interaural timing differences is the basis for sound localization in reptiles, birds, and mammals. Although comparative studies reveal that different neural circuits underlie this ability, they also highlight common solutions to an inherent challenge: processing information on timescales shorter than an action potential. Discrimination of small timing differences is also important for species recognition during communication among mormyrid electric fishes. These fishes generate a species-specific electric organ discharge (EOD) that is encoded into submillisecond-to-millisecond timing differences between receptors. Small, adendritic neurons (small cells) in the midbrain are thought to analyze EOD waveform by comparing these differences in spike timing, but direct recordings from small cells have been technically challenging. In the present study we use a fluorescent labeling technique to obtain visually guided extracellular recordings from individual small cell axons. We demonstrate that small cells receive 1-2 excitatory inputs from 1 or more receptive fields with latencies that vary by over 10 ms. This wide range of excitatory latencies is likely due to axonal delay lines, as suggested by a previous anatomic study. We also show that inhibition of small cells from a calyx synapse shapes stimulus responses in two ways: through tonic inhibition that reduces spontaneous activity and through precisely timed, stimulus-driven, feed-forward inhibition. Our results reveal a novel delay-line anticoincidence detection mechanism for processing submillisecond timing differences, in which excitatory delay lines and precisely timed inhibition convert a temporal code into a population code.

Retrograde fluorescent labeling allows for targeted extracellular single-unit recording from identified neurons in vivo

The overall goal of this method is to record single-unit responses from an identified population of neurons. In vivo electrophysiological recordings from individual neurons are critical for understanding how neural circuits function under natural conditions. Traditionally, these recordings have been performed 'blind', meaning the identity of the recorded cell is unknown at the start of the recording. Cellular identity can be subsequently determined via intracellular¹, juxtacellular² or loose-patch³ iontophoresis of dye, but these recordings cannot be pre-targeted to specific neurons in regions with functionally heterogeneous cell types. Fluorescent proteins can be expressed in a cell-type specific manner permitting visually-guided single-cell electrophysiology^4-6. However, there are many model systems for which these genetic tools are not available. Even in genetically accessible model systems, the desired promoter may be unknown or genetically homogenous neurons may have varying projection patterns. Similarly, viral vectors have been used to label specific subgroups of projection neurons⁷, but use of this method is limited by toxicity and lack of trans-synaptic specificity. Thus, additional techniques that offer specific pre-visualization to record from identified single neurons in vivo are needed. Pre-visualization of the target neuron is particularly useful for challenging recording conditions, for which classical single-cell recordings are often prohibitively difficult^8-11. The novel technique described in this paper uses retrograde transport of a fluorescent dye applied using tungsten needles to rapidly and selectively label a specific subset of cells within a particular brain region based on their unique axonal projections, thereby providing a visual cue to obtain targeted electrophysiological recordings from identified neurons in an intact circuit within a vertebrate CNS.

The most significant novel advancement of our method is the use of fluorescent labeling to target specific cell types in a non-genetically accessible model system. Weakly electric fish are an excellent model system for studying neural circuits in awake, behaving animals¹². We utilized this technique to study sensory processing by "small cells" in the anterior exterolateral nucleus (ELa) of weakly electric mormyrid fish. "Small cells" are hypothesized to be time comparator neurons important for detecting submillisecond differences in the arrival times of presynaptic spikes¹³. However, anatomical features such as dense myelin, engulfing synapses, and small cell bodies have made it extremely difficult to record from these cells using traditional methods^{11, 14}. Here we demonstrate that our novel method selectively labels these cells in 28% of preparations, allowing for reliable, robust recordings and characterization of responses to electrosensory stimulation.

Sensory receptor diversity establishes a peripheral population code for stimulus duration at low intensities

Peripheral filtering is a fundamental mechanism for establishing frequency tuning in sensory systems. By contrast, detection of temporal features, such as duration, is generally thought to result from temporal coding in the periphery, followed by an analysis of peripheral response times within the central nervous system. We investigated how peripheral filtering properties affect the coding of stimulus duration in the electrosensory system of mormyrid fishes using behavioral and electrophysiological measures of duration tuning. We recorded from individual knollenorgans, the electrosensory receptors that mediate communication, and found correlated variation in frequency tuning and duration tuning, as predicted by a simple circuit model. In response to relatively high intensity stimuli, knollenorgans responded reliably with fixed latency spikes, consistent with a temporal code for stimulus duration. At near-threshold intensities, however, both the reliability and the temporal precision of responses decreased. Evoked potential recordings from the midbrain, as well as behavioral responses to electrosensory stimulation, revealed changes in sensitivity across the range of durations associated with the greatest variability in receptor sensitivity. Further, this range overlapped with the natural range of variation in species-specific communication signals, suggesting that peripheral duration tuning affects the coding of behaviorally relevant stimuli. We measured knollenorgan, midbrain and behavioral responses to natural communication signals and found that each of them were duration dependent. We conclude that at relatively low intensities for which temporal coding is ineffective, diversity among sensory receptors establishes a population code, in which duration is reflected in the population of responding knollenorgans.