Faculty Bibliography

High-throughput electron microscopy has started to reveal synaptic connectivity maps of single circuits and whole brain regions, for example, in the Drosophila olfactory system. However, efficacy, timing, and frequency tuning of synaptic vesicle release are also highly diversified across brain synapses. These features critically depend on the nanometer-scale coupling distance between voltage-gated Ca²⁺ channels (VGCCs) and the synaptic vesicle release machinery. Combining light super resolution microscopy with in vivo electrophysiology, we show here that two orthogonal scaffold proteins (ELKS family Bruchpilot, BRP, and Syd-1) cluster-specific (M)Unc13 release factor isoforms either close (BRP/Unc13A) or further away (Syd-1/Unc13B) from VGCCs across synapses of the Drosophila olfactory system, resulting in different synapse-characteristic forms of short-term plasticity. Moreover, BRP/Unc13A versus Syd-1/Unc13B ratios were different between synapse types. Thus, variation in tightly versus loosely coupled scaffold protein/(M)Unc13 modules can tune synapse-type-specific release features, and "nanoscopic molecular fingerprints" might identify synapses with specific temporal features.

OBJECTIVE Since the first clinical application of the incisionless magnetic resonance-guided focused ultrasound (MRgFUS) technology only small series of patients have been reported, and thus only extrapolations of the procedure-related risks could be offered. In this study, the authors analyze side-effects and targeting accuracy in 180 consecutive treatments with MRgFUS for chronic therapy-resistant idiopathic Parkinson's disease (PD), essential tremor (ET), cerebellar tremor (CT), and neuropathic pain (NP), all performed in their dedicated center. METHODS A total of 180 treatments with MRgFUS for chronic therapy-resistant idiopathic PD, ET, CT, and NP were prospectively assessed for side-effects and targeting accuracy. Monitoring for later side-effects was continued for at least 3 months after the procedure in all but 1 case (0.6%); in that single case, the patient was lost to follow-up after an uneventful early postoperative course. The surgical targets were the pallidothalamic tract (pallidothalamic tractotomy, n = 105), the cerebellothalamic tract (cerebellothalamic tractotomy, n = 50), the central lateral nucleus (central lateral thalamotomy, n = 84), the centrum medianum (centrum medianum thalamotomy, n = 12), and the globus pallidus (pallidotomy, n = 2). Cognitive testing was performed before, 1-2 days after, and 1 year after the procedure. The Mini-Mental State Examination (MMSE) was used for the first 29 cases and was then replaced by the Montreal Cognitive Assessment (MoCA). Lesion reconstruction and measurement of targeting accuracy were done on 2-day posttreatment MR images for each performed target. To determine targeting accuracy measurement, 234 out of the 253 lesions depicted in the 2-day postoperative MR examination could be 3D-reconstructed. RESULTS The mean MoCA score was slightly improved 2 days postoperatively (p = 0.002) and remained stable at 1-year follow-up (p = 0.03). The mean MMSE score was also slightly improved 2 days postoperatively and at 1-year follow-up, but the improvement was not statistically significant (p = 0.06 and p = 0.2, respectively). The mean (± SD) accuracy was 0.32 ± 0.29 mm, 0.29 ± 0.28 mm, and 0.44 ± 0.39 mm for the mediolateral, anteroposterior, and dorsoventral dimensions, respectively. The mean 3D accuracy was 0.73 ± 0.39 mm. As to side-effects, 14 events over 180 treatments were documented. They were classified into procedure-related (n = 4, 2.2%), effect on neighboring structures (n = 3, 1.7%), and disease-related (n = 7, 3.9%). There was no bleeding. CONCLUSIONS The incisionless transcranial MRgFUS technology demonstrates a higher targeting accuracy and a lower side-effect profile than techniques requiring cerebral penetration. In the absence of penetration brain shift, this technique avoids the placement of a thermolesion away from the chosen target, thus suppressing the need for reversible therapeutic energy application. With the use of proper physiopathology-based targets, definitive therapeutic effects can be coupled with sparing of sensory, motor, and paralimbic/multimodal thalamocortical functions. Clinical efficacy, not analyzed in this investigation, will ultimately rest in proper target selection and optimized thermolesional coverage of the target.

Acute pain evokes protective neural and behavioral responses. Chronic pain, however, disrupts normal nociceptive processing. The prefrontal cortex (PFC) is known to exert top-down regulation of sensory inputs; unfortunately, how individual PFC neurons respond to an acute pain signal is not well characterized. We found that neurons in the prelimbic region of the PFC increased firing rates of the neurons after noxious stimulations in free-moving rats. Chronic pain, however, suppressed both basal spontaneous and pain-evoked firing rates. Furthermore, we identified a linear correlation between basal and evoked firing rates of PFC neurons, whereby a decrease in basal firing leads to a nearly 2-fold reduction in pain-evoked response in chronic pain states. In contrast, enhancing basal PFC activity with low-frequency optogenetic stimulation scaled up prefrontal outputs to inhibit pain. These results demonstrate a cortical gain control system for nociceptive regulation and establish scaling up prefrontal outputs as an effective neuromodulation strategy to inhibit pain.

BACKGROUND:The choice for drugs over alternative reinforcers is a translational hallmark feature of drug addiction. The neural basis of such drug-biased choice is not well understood, particularly in individuals with protracted drug abstinence who cannot ethically participate in studies that offer drug-using opportunities. METHODS:We developed a functional magnetic resonance imaging drug-choice task to examine the choice for viewing drug-related images, rather than for actually consuming a drug. Actively using (n = 18) and abstaining (n = 19) individuals with a history of cocaine use disorder (CUD: dependence or abuse) and matched healthy control subjects (n = 26) participated. RESULTS:Individuals with CUD, especially those actively using cocaine outside the laboratory, made more choices than control subjects to view images depicting cocaine (especially when directly compared against images depicting an alternative appetitive reinforcer [food]). Functional magnetic resonance imaging data revealed that in individuals with CUD, the act of making drug-related choices engaged brain regions implicated in choice difficulty or ambivalence (i.e., dorsal anterior cingulate cortex, which was higher in all individuals with CUD than control subjects). Drug-related choices in CUD also engaged brain regions implicated in reward (e.g., midbrain/ventral tegmental area, which was most activated in active users, although this region was not hypothesized a priori). CONCLUSIONS:These results help clarify the neural mechanisms underlying drug-biased choice in human addiction, which, beyond mechanisms involved in value assignment or reward, may critically involve mechanisms that contribute to resolving difficult decisions. Future studies are needed to validate these behavioral and neural abnormalities as markers of drug seeking and relapse in treatment contexts.

OBJECTIVE:Familial dysautonomia (FD) is an autosomal recessive disorder characterized by impaired development of sensory and afferent autonomic nerves. Untreated sleep-disordered breathing (SDB) has been reported to increase the risk of sudden unexpected death in FD. We aimed to describe the prevalence and characteristics of SDB in FD. PATIENTS/METHODS/METHODS:measurements during different sleep stages. RESULTS:Overall, 85% of adults and 91% of pediatric patients had some degree of SDB. Obstructive sleep apneas were more severe in adults (8.5 events/h in adults vs. 3.5 events/h in children, p = 0.04), whereas central apneas were more severe (10.8 vs. 2.8 events/h, p = 0.04) and frequent (61.8% vs. 45%, p = 0.017) in children. Overall, a higher apnea-hypopnea index was associated with increased severity of hypoxia and hypoventilation, although in a significant fraction of patients (67% and 46%), hypoxemia and hypoventilation occurred independent of apneas. CONCLUSION/CONCLUSIONS:monitoring during polysomnography in all patients with FD to detect SDB.

Background: KAT P channels couple cellular metabolism and electrophysiology. Their molecular composition varies in different tissues and species. Rodent atrial KAT P channels have the SUR1 regulatory subunit, are activated by diazoxide and have been implicated in arrhythmogenesis in hypertension and excess beta-adrenergic tone. In contrast, human atrial KATP channels are insensitive to diazoxide and modulate APD only during extreme metabolic stress, where the SUR2A regulatory subunit is thought to be predominant. Objective: We hypothesized that changes in the human atrial action potential associated with beta-agonism are mediated by recruitment of SUR1-containing KATP channels. Methods: We used human induced pluripotent stem cell (hiPSC)-derived atrial cardiomyocytes where expression of a fuorescent reporter is driven by the atrial-specifc gene sarcolipin. Atrial specifcation was induced with retinoic acid. Di-4-ANBDQBS was used to perform optical action potential measurements on days 65-80 of differentiation. Excised patch clamping was used to evaluate KAT P channel density. Heterozygous ABCC8 (SUR1+/-) cells were generated using CRISPR/CAS9. Results: Optical mapping data are for APD90 with stimulation at 1.25 Hz The combination of isoproterenol (ISO, 10mu M) and rolipram (ROL, 10mu M) abbreviated APD compared to control (247.4+/-12.5ms, n=16 vs 344.2+/-22.9ms, n=22; p=0.002). This was ameliorated by 10mu M glibenclamide (312.0+/-18.9ms, n=23 vs 247.4+/-12.5ms, n=16; p=0.01). More patches from cells exposed to ISO and ROL had functional KATP channels (4/22 vs 0/24, p=0.045). Diazoxide shortened APD (267.3+/-21.7ms, n=20 vs 344.2+/-22.9ms, n=22; p=0.02). This was potentiated by prior beta-agonism (179.7+/-14.3ms, n=18 vs 267.3+/-21.7ms, n=20; p=0.002). Deletion of one ABCC8 allele ameliorated APD shortening with exposure to ISO, ROL, and diazoxide (240.9+/-18.2ms, n=14 vs 179.7+/-14.3ms, n=18; p=0.012). Functional KATP channel density after exposure to beta-agonists was reduced in SUR1+/-cells (1/40 vs 4/22, p=0.049). Conclusion: SUR1-containing KATP channels partially mediate beta-adrenergic APD shortening in human atrial cells and may represent a therapeutic target for atrial arrhythmia prevention

Severe temper outbursts (STO) in children are associated with impaired school and family functioning and may contribute to negative outcomes. These outbursts can be conceptualized as excessive frustration responses reflecting reduced emotion regulation capacity. The anterior cingulate cortex (ACC) has been implicated in negative affect as well as emotional control, and exhibits disrupted function in children with elevated irritability and outbursts. This study examined the intrinsic functional connectivity (iFC) of a region of the ACC, the anterior midcingulate cortex (aMCC), in 5- to 9-year-old children with STO (n = 20), comparing them to children with attention-deficit/hyperactivity disorder (ADHD) without outbursts (ADHD; n = 18). Additional analyses compared results to a sample of healthy children (HC; n = 18) and examined specific associations with behavioral and emotional dysregulation. Compared to the ADHD group, STO children exhibited reduced iFC between the aMCC and surrounding regions of the ACC, and increased iFC between the aMCC and precuneus. These differences were also seen between the STO and HC groups; ADHD and HC groups did not differ. Specificity analyses found associations between aMCC-ACC connectivity and hyperactivity, and between aMCC-precuneus iFC and emotion dysregulation. Disruption in aMCC networks may underlie the behavioral and emotional dysregulation characteristic of children with STO.