Faculty Bibliography

Digital spatial profiling (DSP) facilitates RNA sequencing (RNA-seq) of small populations of cells, specifically ~20 pyramidal neurons in postmortem formalin-fixed paraffin-embedded (FFPE) human brain tissue. This approach enables precise expression profiling via RNA-seq data linked to spatially characterized samples utilizing tissue-bound probes. We present a comprehensive protocol for manual slide preparation using the GeoMx DSP system as preliminary steps to spatial characterization of lamina-specific pyramidal neurons in human postmortem Brodmann area 9 (BA9) frontal cortex brain tissue.

Aggression is an innate behavior conserved across species, serving as a critical means to compete for food, mating opportunities, and other essential resources. A central question in aggression research is the extent to which inter-individual variability in aggression is shaped by genetic factors. Here, we examine aggressive behaviors in naïve male mice across seven genetically defined strains and find large cross-strain differences. We find a tight correlation between aggressiveness and anxiety levels across strains, but not within the same strain, suggesting strong genetic control of both traits. Pharmacologically elevating anxiety in high-aggression strains reduces aggression, revealing a causal relationship between these behaviors. We further demonstrate that differences in the synaptic and cellular properties of neurons in the ventrolateral ventromedial hypothalamus (VMHvl) largely account for cross-strain variability in male aggression, and that chemogenetically increasing VMHvl excitability enhances attack behavior in a low-aggression strain. Together, these findings reveal the neuronal implementation of the genetic control of innate aggression level.

Accurate assessment of cardiac mechanics and hemodynamics is important for understanding cardiac dysfunction and disease progression. However, conventional echocardiographic metrics primarily reflect global mechanical performance and provide limited insight into intraventricular flow dynamics. Ultrafast vector Doppler imaging (VDI) enables contrast-agent-free quantification of intracardiac flow, but acquisition-related reproducibility is difficult to isolate clinically because physiological conditions, acoustic windows, and probe orientation may vary simultaneously. Murine imaging permits repeated acquisitions under standardized conditions, enabling controlled assessment of cycle-to-cycle and imaging-plane variability, and providing a platform for systematic evaluation of VDI in the heart. We established a standardized framework for intraventricular flow quantification using ultrafast VDI and evaluated its reproducibility in a cardiomyocyte-specific Tafazzin knockout (Taz-cKO) murine model of dilated cardiomyopathy (DCM). Nine male mice (n = 3 Taz-cKO and n = 6 controls), aged 12-13 months, were studied. Cycle-to-cycle variability (beat-to-beat variation) averaged ~17.5%, whereas between-acquisition variability was higher (~25.5%), reflecting differences in imaging-plane orientation. Despite this variability, VDI-derived parameters differentiated control and DCM mice, with reduced kinetic energy and vector concentration, increased flow angle difference, and reduced vorticity magnitude during systole. Correlations with conventional echocardiographic indices ranged from weak to strong and varied by parameter, region, and cardiac phase, reflecting heterogeneous associations across metrics. These findings indicate that VDI-derived parameters capture complementary aspects of intraventricular flow not fully reflected by conventional measures of cardiac function. Overall, these results establish the reproducibility and physiological relevance of ultrafast VDI and support its potential for longitudinal and translational studies of cardiac flow dynamics.

The transcription factor early B-cell factor 1 (EBF1) plays critical developmental roles in numerous organ systems, including B-cells, kidney, bone, and heart. During cardiogenesis, cardiomyocyte expression of EBF1 is reportedly undetectable and its effects on myocyte development and proliferation are thought to reflect a non-cell autonomous mechanism, acting via intercellular communication from EBF1 expressing non-myocyte cells. Here, using single-cell transcriptional profiling, we confirm the absence of Ebf1 transcripts in cardiomyocytes. Furthermore, employing computational receptor-ligand interaction analysis of dissociated cells from wildtype and EBF1-deficient hearts, we show that loss of function of this pioneer transcription factor enhances fibroblast to myocyte signaling via the collagen-integrin pathway. Finally, we generated fibroblast-specific EBF1 knockout mice using a PDGFRα-Cre transgenic driver, and found a nearly identical phenotype to that of the generalized knockout, with runting, premature death, an increase in left ventricular relative wall thickness and cardiomyocyte hyperplasia. These findings provide further mechanistic insight into the non-cell autonomous mechanism of action of EBF1 in cardiac growth and development.

BACKGROUND:Abnormalities in Autonomic Nervous System activity are well described in psychosis but their peripheral versus CNS origins remains unresolved. However, the purely peripheral component of the sudomotor sweat reflex can be quantified using the Quantitative Sudomotor Axon Reflex Test (Q-SWEAT), in which local postganglionic fibers are stimulated by applying acetylcholine to the skin. METHOD/METHODS:This study assessed Q-SWEAT, psychiatric symptoms (PANSS; HAMD) and cognition (MATRICS) in 33 participants with psychosis, 17 with nonpsychotic affective disorders, and 23 healthy controls. Statistical analyses included ANOVA, GENLIN ordinal logistic regression, and Spearman correlations. RESULTS:(2)=9.75, p = 0.008). Specifically, the psychosis group was 5.37-fold more likely to have sudomotor dysfunction compared to healthy controls (95% CI 1.86, 15.45) and this remained significant when controlling for anticholinergic burden. The NP-affective group did not differ from those with psychosis or healthy controls. Across the overall sample, sudomotor dysfunction was significantly associated with greater cognitive impairment and increased psychiatric symptom severity. DISCUSSION/CONCLUSIONS:This first of its kind study shows abnormal sudomotor sweat reflexes in psychosis are independent of CNS input and not fully explained by anticholinergic medications but are associated with symptoms and cognition. We propose that muscarinic M3 acetylcholine receptors, which occur in eccrine sweat glands and in the CNS, may be relevant, although microvascular and inflammatory pathologies can impact the PNS and CNS. Sudomotor dysfunction could also underlie the abnormal thermoregulation in psychosis. More research is needed to confirm and extend these observations implicating a novel biomarker for psychosis.

OBJECTIVES/OBJECTIVE:This study aims to validate vocoders as acoustic models of cochlear implants by determining whether they capture both perceptual sound quality and speech performance. We hypothesize that valid acoustic models of cochlear implants require listener-specific amounts of frequency mismatch between input filters and output tones or noise bands. DESIGN/METHODS:Forty-four adult single-sided deaf cochlear implant users were tested 1 to 5 times for a total of 73 sessions at different time points after initial stimulation. Participants had a cochlear implant in one ear and normal or near-normal hearing in the contralateral ear, allowing within-subject comparisons. In Experiment 1, participants used a method-of-adjustment procedure to select acoustic models most similar to their cochlear implant by adjusting three parameters: low- and high-frequency cutoffs of the acoustic output, and channel interaction (overlap among output sound carriers). In Experiment 2, participants rated the perceptual similarity of five acoustic model types using questionnaires assessing overall similarity and four acoustic dimensions (intelligibility, pleasantness, harshness, and loudness). The five model types included the self-selected model, two all-channel frequency-matched vocoders (tone and noise), and two six-channel frequency-matched vocoders (tone and noise). Frequency-matched acoustic models had output noise bands or tones that were frequency-matched to the analysis filters. In Experiment 3, speech perception was evaluated under six conditions: with the cochlear implant alone and with each of the five acoustic model types presented to the normal hearing ear. RESULTS:Nearly all participants (69 of 73 sessions) selected acoustic models with frequency ranges different from their clinical frequency allocation tables. The low-frequency edge of self-selected models was significantly higher than clinical allocations (456 Hz for Cochlear Ltd. and 266 Hz for MED-EL). Over 80% of selections used minimal channel interaction (tones, nonoverlapping noise bands, or adjacent noise bands). Self-selected models received significantly higher similarity ratings (mean of 6.11, where 6 means "somewhat similar" and 7 "very similar") compared with all frequency-matched models, which were rated around 3 ("not very similar"). Self-selected models were rated most similar to the cochlear implant across multiple acoustic dimensions and were the only models not rated significantly different from the cochlear implant on any dimension. For speech perception, all-channel frequency-matched models significantly overestimated performance compared with the cochlear implant for both words and sentences. Self-selected models provided speech scores closest to cochlear implant performance. Joint analysis of similarity ratings and speech perception scores demonstrated that self-selected models were the only acoustic models achieving both perceptual similarity to the cochlear implant (rating of 6.11 with 7 being "very similar") and comparable speech perception scores (within five percentage points). CONCLUSIONS:Frequency-matched acoustic models fail to replicate the sound of a cochlear implant and all-channel frequency-matched acoustic models also significantly overestimate speech perception. In contrast, self-selected acoustic models incorporating listener-specific perceptual frequency mismatch provide substantially better matches in both subjective sound quality and speech intelligibility. However, variability in similarity ratings across individuals may suggest that additional perceptual components remain unaccounted for in the current parameter set. These findings question the validity of frequency-matched acoustic models of cochlear implants in research applications.

Nuclear factor I (NFI) misexpressions in humans are associated with severe brain malformations, yet the underlying mechanisms remain poorly understood. Here, we show that NFIs regulate the broad lineage progression and lifespan of radial glial progenitors (RGPs), thereby bidirectionally controlling neocortical development. Human cerebral organoids carrying patient-mimicking NFI mutations exhibit expression-level-dependent bidirectional impairments in RGP temporal development, coinciding with patient phenotypes. In mouse models, selective removal of NFIs leads to a dramatic protraction of RGP lineage progression and lifespan, excessive progeny output, and cortical overgrowth and abnormal folding, whereas overexpression of NFIs accelerates RGP lineage progression, resulting in developmental-stage-dependent precocious production of diverse neural progenies. Moreover, NFIs exhibit positive autoregulation and progressive increase in expression and regulate distinct temporal-specific targets underlying RGP lineage progression. These results suggest that NFIs act as evolutionarily conserved key global temporal regulators of RGP lineage progression and neocortical development.

Somatic mutations accumulate throughout life in every cell, and this process constitutes one of the hallmarks of aging-genomic instability. Caloric restriction (CR) has been shown to extend lifespan across diverse species. Using high-fidelity duplex DNA sequencing of bulk liver, bulk kidney, hepatocytes, and cerebellar neurons, we found that CR in mice reduces genome-wide somatic mutation burdens across multiple tissues and cell types. CR reduced both substitution and insertion/deletion burdens, with the magnitude of these effects varying across sample types. CR also decreased the activity of the enigmatic single-base substitution (SBS) mutational process SBS5 that gives rise to most mutations in mammals. Surprisingly, the mutation burden reduction from CR was greatest in transcriptionally inactive regions. This work illuminates links between diet, aging, and genomic integrity and establishes genomic integrity as a modifiable axis of aging.

Flying flies can determine ambient wind direction in flight, but what neural representations might support this behavior are unclear. Ambient wind acting on a flying fly creates distinct patterns of airflow and optic flow. Here, we used two-photon imaging to characterize encoding of these two variables across columnar inputs to the fly navigation center, called PFNs. We find tuning for airflow direction and speed across many PFN types but only optic flow direction tuning in limited types. We do not observe tuning to optic flow speed. We build and validate an encoding model that enables simulation of PFN representations during real and simulated flight maneuvers. We show that these representations are sufficient to decode ambient wind direction both theoretically and using a simple feedforward ANN. Our work shows how a compact multisensory representation of self-motion could be used to infer a property of the external world that cannot be directly measured by a single sensory system.