Faculty Bibliography

The value of preclinical diffusion MRI (dMRI) is substantial. While dMRI enables in vivo non-invasive characterization of tissue, ex vivo dMRI is increasingly being used to probe tissue microstructure and brain connectivity. Ex vivo dMRI has several experimental advantages including higher SNR and spatial resolution compared to in vivo studies, and enabling more advanced diffusion contrasts for improved microstructure and connectivity characterization. Another major advantage of ex vivo dMRI is the direct comparison with histological data, as a crucial methodological validation. However, there are a number of considerations that must be made when performing ex vivo experiments. The steps from tissue preparation, image acquisition and processing, and interpretation of results are complex, with many decisions that not only differ dramatically from in vivo imaging of small animals, but ultimately affect what questions can be answered using the data. This work represents "Part 2" of a three-part series of recommendations and considerations for preclinical dMRI. We describe best practices for dMRI of ex vivo tissue, with a focus on the value that ex vivo imaging adds to the field of dMRI and considerations in ex vivo image acquisition. We first give general considerations and foundational knowledge that must be considered when designing experiments. We briefly describe differences in specimens and models and discuss why some may be more or less appropriate for different studies. We then give guidelines for ex vivo protocols, including tissue fixation, sample preparation, and MR scanning. In each section, we attempt to provide guidelines and recommendations, but also highlight areas for which no guidelines exist (and why), and where future work should lie. An overarching goal herein is to enhance the rigor and reproducibility of ex vivo dMRI acquisitions and analyses, and thereby advance biomedical knowledge.

BACKGROUND AND OBJECTIVES/UNASSIGNED:"Brain-writing" is a technique in which group members write down ideas individually, before a group discussion, to improve idea generation and individual engagement in group discussions. We assessed the feasibility of studying the impact of brain-writing on diagnostic quality and educational experience among neurology residents in a small case-based learning environment. METHODS/UNASSIGNED:We conducted a repeated-measures study, conducted over 6 sessions consisting of groups of 3 to 5 neurology residents from different years of training. During each session, 3 cases were treated as control, "brainstorming," cases, and 3 were intervention, "brain-writing," cases, in which the group wrote down possible diagnoses and tests before engaging in a group discussion. Tests and diagnoses from the brain-writing exercise and group discussion as well as a post case survey on participant experience were recorded through a Qualtrics survey, and video recordings were reviewed to determine speaking order and number of tests and diagnoses verbalized by each member. Feasibility was determined by recruitment and ability to complete the study procedures in a pragmatic fashion that incorporated resident education. The primary outcome was accuracy of diagnoses, and secondary outcomes included number of tests and diagnoses generated, percent of "can't miss diagnoses mentioned," speaking order and psychological reactions of group members. RESULTS/UNASSIGNED:= 0.07). Junior residents spoke later and verbalized significantly fewer diagnoses and tests than senior residents in both brainstorming and brain-writing groups. There was no statistically significant difference in psychological outcomes of junior and senior residents in each group. DISCUSSION/UNASSIGNED:It is feasible to examine the impact of a behavioral-based intervention among medical trainees in a small case-based learning environment. This study, limited by a small sample size, did not find that brain-writing improved decision quality.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Disturbances in brain catecholamine activity may be associated with symptoms after exposure to repetitive head impacts (RHIs) or related chronic traumatic encephalopathy (CTE). In this article, we studied CSF catecholamines in former professional and college American football players and examined the relationship with football proxies of RHI exposure, CTE probability, cognitive performance, neuropsychiatric symptoms, and parkinsonism. METHODS:In this observational cross-sectional study, we examined male former American football players, professional ("PRO") or college ("COL") level, and asymptomatic unexposed male ("UE") individuals from the DIAGNOSE CTE Research Project. Catecholamines-norepinephrine (NE) and its metabolite, 3,4-dihydroxyphenylglycol (DHPG), and dopamine (DA) and its precursor, 3,4-dihydroxyphenylalanine (l-DOPA), and metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC)-were measured in CSF with high-performance liquid chromatography and compared across groups with analysis of covariance. Multivariable linear regression models tested the relationship between CSF catecholamines and proxies of RHI exposure (e.g., total years of playing American football), factor scores for cognition, and neurobehavioral dysregulation (explosivity, emotional dyscontrol, impulsivity, affective lability), as well as depressive/anxiety symptoms, measured with the Beck Depression/Anxiety Inventories. CTE probability and parkinsonism were assessed using the National Institute of Neurological Disorders and Stroke consensus diagnostic criteria for traumatic encephalopathy syndrome (TES), and biomarkers were compared among different diagnostic groups. RESULTS:The cohort consisted of 120 former American football players (85 PRO players, 35 COL players) and 35 UE participants (age 45-75). Former players had significantly lower levels of NE (mean difference = -0.114, 95% CI -0.190 to -0.038), l-DOPA (-0.121, 95% CI -0.109 to -0.027), and DOPAC (-0.116, 95% CI -0.177 to -0.054) than UE participants. For NE and DOPAC, these overall group differences were primarily due to differences between the PRO and UE cohorts. No significant differences were found across TES-CTE probability subgroups or TES-parkinsonism diagnostic groups. Within the COL cohort, tested as post hoc analyses, higher CSF NE and l-DOPA were associated with higher neurobehavioral dysregulation factor scores, BAI total score, and worse executive functioning and processing speed. CSF DHPG and DOPAC were associated with impulsivity only in this subgroup. DISCUSSION/CONCLUSIONS:We observed reduced CSF catecholamine concentrations in former elite American football players, although the relationship with degree of RHI exposure and the clinical impact needs further study.

Hyperphosphorylated tau (pTau) in Alzheimer's disease (AD) brain tissue is a complex mix of multiple tau species that are variably phosphorylated. The emerging studies suggest that phosphorylation of specific residues may alter the role of tau. The role of specific pTau species can be explored through protein interactome studies. The aim of this study was to analyse the interactome of tau phosphorylated at T217 (pT217), which biomarker studies suggest is one of the earliest accumulating tau species in AD. pT217 interactors were identified in fresh-frozen human brain tissue from 10 cases of advanced AD using affinity purification-mass spectrometry. The cases included a balanced cohort of APOE ε3/ε3 and ε4/ε4 genotypes (n = 5 each) to explore how apolipoprotein E altered phosphorylated tau interactions. The results were compared to our previous interactome dataset that profiled the interactors of PHF1-enriched tau to determine if individual pTau species have different interactomes. 23 proteins were identified as bona fide pT217 interactors, including known pTau interactor SQSTM1. pT217 enriched tau was phosphorylated at fewer residues compared to PHF1-enriched tau, suggesting an earlier stage of pathology development. Notable pT217 interactors included five subunits of the CTLH E3 ubiquitin ligase (WDR26, ARMC8, GID8, RANBP9, MAEA), which has not previously been linked to AD. In APOE ε3/ε3 cases pT217 significantly interacted with 46 proteins compared to 28 in APOE ε4/ε4 cases, but these proteins were significantly overlapped. CTLH E3 ubiquitin ligase subunits significantly interacted with phosphorylated tau in both APOE genotypes. pT217 interactions with SQSTM1, WDR26 and RANBP9 were validated using co-immunoprecipitation and immunofluorescent microscopy of post-mortem human brain tissue, which showed colocalisation of both protein interactors with tau pathology. Our results report the interactome of pT217 in human Alzheimer's disease brain tissue for the first time and highlight the CTLH E3 ubiquitin ligase complex as a significant novel interactor of pT217 tau.

The loss of maternal UBE3A causes Angelman syndrome whereas its duplication is associated with a heterogeneous neurodevelopmental disorder. Here, we describe two affected brothers who possess a novel UBE3A^L734S variant that is not present in two neurotypical siblings. The UBE3A^L734S variant was confirmed to be maternally inherited, and the affected individuals exhibited early global developmental delay, ongoing learning difficulties, and autistic features. Their phenotypes were inconsistent with Angelman syndrome. Biochemical characterization showed the UBE3A^L734S variant causes a dramatic increase in the activity of the UBE3A enzyme, suggesting that a gain in UBE3A activity is the driver of neurodevelopmental disease. Our observations document an emerging class of neurodevelopmental disorders caused by gain-of-function mutations in UBE3A.

Autoimmune encephalitis (AE), defined by clinical criteria and its frequent association with neural autoantibodies, often manifests with seizures, which usually stop with immunotherapy. However, a subset of encephalitic conditions present with recurrent seizures that are resistant to immunotherapy. Three primary neurological constellations that fall within this subset are discussed in this Perspective: temporal lobe epilepsy with antibodies against glutamic acid decarboxylase, epilepsy in the context of high-risk paraneoplastic antibodies, and epilepsy following adequately treated surface antibody-mediated AE. These entities all share a common mechanism of structural injury and potentially epileptogenic focal neural loss, often induced by cytotoxic T cells. Recently, we have proposed conceptualizing these conditions under the term autoimmune encephalitis-associated epilepsy (AEAE). Here, we discuss the new concept of AEAE as an emerging field of study. We consider the clinical characteristics of patients who should be investigated for AEAE and highlight the need for judicious use of traditional epilepsy therapeutics alongside immunotherapeutic considerations that are of uncertain and incomplete efficacy for this group of disorders. Last, we discuss future efforts needed to diagnose individuals before structural epileptogenesis has superseded inflammation and to develop improved therapeutics that target the specific immunological or functional disturbances in this entity.

This study investigated the potential of combining multiple MR parameters to enhance the characterization of myelin in the mouse brain. We collected ex vivo multiparametric MR data at 7 T from control and Gli1^-/- mice; the latter exhibit enhanced myelination at Postnatal Day 10 (P10) in the corpus callosum and cortex. The MR data included relaxivity, magnetization transfer, and diffusion measurements, each targeting distinct myelin properties. This analysis was followed by and compared to myelin basic protein (MBP) staining of the same samples. Although a majority of the MR parameters included in this study showed significant differences in the corpus callosum between the control and Gli1^-/- mice, only T₂, T₁/T₂, and radial diffusivity (RD) demonstrated a significant correlation with MBP values. Based on data from the corpus callosum, partial least square regression suggested that combining T₂, T₁/T₂, and inhomogeneous magnetization transfer ratio could explain approximately 80% of the variance in the MBP values. Myelin predictions based on these three parameters yielded stronger correlations with the MBP values in the P10 mouse brain corpus callosum than any single MR parameter. In the motor cortex, combining T₂, T₁/T₂, and radial kurtosis could explain over 90% of the variance in the MBP values at P10. This study demonstrates the utility of multiparametric MRI in improving the detection of myelin changes in the mouse brain.

Different theories explain how subjective experience arises from brain activity^1,2. These theories have independently accrued evidence, but have not been directly compared³. Here we present an open science adversarial collaboration directly juxtaposing integrated information theory (IIT)^4,5 and global neuronal workspace theory (GNWT)^6-10 via a theory-neutral consortium^11-13. The theory proponents and the consortium developed and preregistered the experimental design, divergent predictions, expected outcomes and interpretation thereof¹². Human participants (n = 256) viewed suprathreshold stimuli for variable durations while neural activity was measured with functional magnetic resonance imaging, magnetoencephalography and intracranial electroencephalography. We found information about conscious content in visual, ventrotemporal and inferior frontal cortex, with sustained responses in occipital and lateral temporal cortex reflecting stimulus duration, and content-specific synchronization between frontal and early visual areas. These results align with some predictions of IIT and GNWT, while substantially challenging key tenets of both theories. For IIT, a lack of sustained synchronization within the posterior cortex contradicts the claim that network connectivity specifies consciousness. GNWT is challenged by the general lack of ignition at stimulus offset and limited representation of certain conscious dimensions in the prefrontal cortex. These challenges extend to other theories of consciousness that share some of the predictions tested here^14-17. Beyond challenging the theories, we present an alternative approach to advance cognitive neuroscience through principled, theory-driven, collaborative research and highlight the need for a quantitative framework for systematic theory testing and building.

Documentation, coding, and billing (claims submission) are foundational to neurologic practice in the United States, enabling accurate reimbursement, effective communication, and data-driven advancements in patient care, research, and education. Neurologists navigate complex regulatory frameworks and evolving payer guidelines, requiring meticulous attention to diagnostic coding, evaluation and management (E/M) services, and procedure-specific requirements. This chapter examines critical aspects of neurologic billing and coding, including ICD-10-CM (International Classification of Diseases, Tenth Revision, Clinical Modification) for diagnostic accuracy, updated E/M guidelines emphasizing medical decision-making and time, and new telemedicine codes. It highlights the best practices for procedure coding and the use of digital health technologies. The challenges posed by prior authorization are explored, alongside potential solutions like artificial intelligence-driven tools and policy reform. By prioritizing precision, compliance, and technological adaptation, neurologists can enhance patient outcomes, support practice sustainability, and contribute to the broader goals of equitable, efficient, and innovative neurologic care.

OBJECTIVE:This study was undertaken to investigate diagnostic delay in adolescent onset focal epilepsy, including reasons for longer delays and associated morbidities. METHODS:Secondary analysis was done using enrollment data from the Human Epilepsy Project, a multi-institutional cohort including 34 sites in the USA, Canada, Finland, Austria, and Australia (2012-2017). Participants were aged 11-64 years at enrollment and within 4 months of treatment initiation for newly diagnosed focal epilepsy. Participants with seizure onset at age ≤ 21 years were evaluated. Data included seizure diaries documenting onset, frequency, and characteristics of seizures, reasons for diagnostic delays, and prediagnosis morbidities, including injuries, suicidal ideation, and self-injurious behaviors. RESULTS: = 7.04, p = .008). SIGNIFICANCE/CONCLUSIONS:This study highlights significant delays in diagnosing adolescent onset focal epilepsy, especially in cases with nonmotor seizures. These delays, often due to lack of recognition by patients and health care providers, are linked to more frequent seizures, higher injury rates, and increased suicidal ideation and self-injury. Early recognition and diagnosis may mitigate adverse outcomes and improve quality of life for adolescents with epilepsy.