Medicine and Health Sciences Commons^™

Loss Of Katnal2 Leads To Ependymal Ciliary Hyperfunction And Autism-Related Phenotypes In Mice, Ryeonghwa Kang, Zachary Papadopoulos, Jonathan Kipnis, Et Al.

2020-Current year OA Pubs

Autism spectrum disorders (ASD) frequently accompany macrocephaly, which often involves hydrocephalic enlargement of brain ventricles. Katnal2 is a microtubule-regulatory protein strongly linked to ASD, but it remains unclear whether Katnal2 knockout (KO) in mice leads to microtubule- and ASD-related molecular, synaptic, brain, and behavioral phenotypes. We found that Katnal2-KO mice display ASD-like social communication deficits and age-dependent progressive ventricular enlargements. The latter involves increased length and beating frequency of motile cilia on ependymal cells lining ventricles. Katnal2-KO hippocampal neurons surrounded by enlarged lateral ventricles show progressive synaptic deficits that correlate with ASD-like transcriptomic changes involving synaptic gene down-regulation. Importantly, early …

Effects Of Complete And Partial Loss Of The 24s-Hydroxycholesterol-Generating Enzyme, Hong-Jin Shu, Luke H Ziolkowski, Sofia V Salvatore, Ann M Benz, David F Wozniak, Carla M Yuede, Steven M Paul, Charles F Zorumski, Steven Mennerick

2020-Current year OA Pubs

Brain cholesterol metabolic products include neurosteroids and oxysterols, which play important roles in cellular physiology. In neurons, the cholesterol oxidation product, 24S-hydroxycholesterol (24S-HC), is a regulator of signaling and transcription. Here, we examined the behavioral effects of 24S-HC loss, using global and cell-selective genetic deletion of the synthetic enzyme CYP46A1. Mice that are globally deficient in CYP46A1 exhibited hypoactivity at young ages and unexpected increases in conditioned fear memory. Despite strong reductions in hippocampal 24S-HC in mice with selective loss of CYP46A1 in VGLUT1-positive cells, behavioral effects were not recapitulated in these conditional knockout mice. Global knockout produced strong, developmentally …

Spatial And Amplitude Dynamics Of Neurostimulation: Insights From The Acute Intrahippocampal Kainate Seizure Mouse Model, Thomas J Foutz, Nicholas Rensing, Lirong Han, Dominique M Durand, Michael Wong

2020-Current year OA Pubs

OBJECTIVE: Neurostimulation is an emerging treatment for patients with drug-resistant epilepsy, which is used to suppress, prevent, and terminate seizure activity. Unfortunately, after implantation and despite best clinical practice, most patients continue to have persistent seizures even after years of empirical optimization. The objective of this study is to determine optimal spatial and amplitude properties of neurostimulation in inhibiting epileptiform activity in an acute hippocampal seizure model.

METHODS: We performed high-throughput testing of high-frequency focal brain stimulation in the acute intrahippocampal kainic acid mouse model of status epilepticus. We evaluated combinations of six anatomic targets and three stimulus amplitudes.

RESULTS: …

Dorsal Hippocampus To Nucleus Accumbens Projections Drive Reinforcement Via Activation Of Accumbal Dynorphin Neurons, Khairunisa Mohamad Ibrahim, Nicolas Massaly, Hye-Jean Yoon, Rossana Sandoval, Allie J Widman, Robert J Heuermann, Sidney Williams, William Post, Sulan Pathiranage, Tania Lintz, Azra Zec, Ashley Park, Robert W Gereau 4th, Jose A Morón, Et Al.

2020-Current year OA Pubs

The hippocampus is pivotal in integrating emotional processing, learning, memory, and reward-related behaviors. The dorsal hippocampus (dHPC) is particularly crucial for episodic, spatial, and associative memory, and has been shown to be necessary for context- and cue-associated reward behaviors. The nucleus accumbens (NAc), a central structure in the mesolimbic reward pathway, integrates the salience of aversive and rewarding stimuli. Despite extensive research on dHPC→NAc direct projections, their sufficiency in driving reinforcement and reward-related behavior remains to be determined. Our study establishes that activating excitatory neurons in the dHPC is sufficient to induce reinforcing behaviors through its direct projections to the …

Shared And Unique Heritability Of Hippocampal Subregion Volumes In Children And Adults, Jacob G Pine, Arpana Agrawal, Ryan Bogdan, Sridhar Kandala, Shelly Cooper, Deanna M Barch

2020-Current year OA Pubs

Behavioral genetic analyses have not demonstrated robust, unique, genetic correlates of hippocampal subregion volume. Genetic differentiation of hippocampal longitudinal axis subregion volume has not yet been investigated in population-based samples, although this has been demonstrated in rodent and post-mortem human tissue work. The following study is the first population-based investigation of genetic factors that contribute to gray matter volume along the hippocampal longitudinal axis. Twin-based biometric analyses demonstrated that longitudinal axis subregions are associated with significant, unique, genetic variance, and that longitudinal axis subregions are also associated with significant shared, hippocampus-general, genetic factors. Our study's findings suggest that genetic differences …

The Herbicide Glyphosate Inhibits Hippocampal Long-Term Potentiation And Learning Through Activation Of Pro-Inflammatory Signaling, Yukitoshi Izumi, Kazuko A O'Dell, Charles F Zorumski

2020-Current year OA Pubs

Glyphosate, a herbicide marketed as Roundup, is widely used but there are concerns this exposure could impair cognitive function. In the CA1 region of rat hippocampal slices, we investigated whether glyphosate alters synaptic transmission and long-term potentiation (LTP), a cellular model of learning and memory. Our hypothesis is that glyphosate alters neuronal function and impairs LTP induction via activation of pro-inflammatory processes. Roundup depressed excitatory synaptic potentials(EPSPs) in a dose-dependent manner with complete suppression at 2000 mg/L. At concentrations ≤ 20 mg/L Roundup did not affect basal transmission, but 4 mg/L Roundup administered for 30 min inhibited LTP induction. Acute …

Allopregnanolone Effects On Inhibition In Hippocampal Parvalbumin Interneurons, Xinguo Lu, Peter Lambert, Ann Benz, Charles F. Zorumski, Steven J. Mennerick

2020-Current year OA Pubs

Allopregnanolone (AlloP) is a neurosteroid that potentiates ionotropic GABAergic (GABA

Cnih3 Deletion Dysregulates Dorsal Hippocampal Transcription Across The Estrous Cycle, Bernard Mulvey, Hannah E. Frye, Tania Lintz, Stuart Fass, Eric Tycksen, Elliot C. Nelson, Jose A. Morón, Joseph D. Dougherty

2020-Current year OA Pubs

In females, the hippocampus, a critical brain region for coordination of learning, memory, and behavior, displays altered physiology and behavioral output across the estrous or menstrual cycle. However, the molecular effectors and cell types underlying these observed cyclic changes have only been partially characterized to date. Recently, profiling of mice null for the AMPA receptor trafficking gene

Ssris Differentially Modulate The Effects Of Pro-Inflammatory Stimulation On Hippocampal Plasticity And Memory Via Sigma 1 Receptors And Neurosteroids, Yukitoshi Izumi, Angela M Reiersen, Eric J Lenze, Steven J Mennerick, Charles F Zorumski

2020-Current year OA Pubs

Certain selective serotonin reuptake inhibitors (SSRIs) have anti-inflammatory effects in preclinical models, and recent clinical studies suggest that fluvoxamine can prevent deterioration in patients with COVID-19, possibly through activating sigma 1 receptors (S1Rs). Here we examined potential mechanisms contributing to these effects of fluvoxamine and other SSRIs using a well-characterized model of pro-inflammatory stress in rat hippocampal slices. When hippocampal slices are exposed acutely to lipopolysaccharide (LPS), a strong pro-inflammatory stimulus, basal synaptic transmission in the CA1 region remains intact, but induction of long-term potentiation (LTP), a form of synaptic plasticity thought to contribute to learning and memory, is completely …

Regulation Of The Volume-Regulated Anion Channel Pore-Forming Subunit Lrrc8a In The Intrahippocampal Kainic Acid Model Of Mesial Temporal Lobe Epilepsy, Manolia R. Ghouli, Carrie R. Jonak, Rajan Sah, Todd A. Fiacco, Devin K. Binder

2020-Current year OA Pubs

Volume-regulated anion channels (VRACs) are a group of ubiquitously expressed outwardly-rectifying anion channels that sense increases in cell volume and act to return cells to baseline volume through an efflux of anions and organic osmolytes, including glutamate. Because cell swelling, increased extracellular glutamate levels, and reduction of the brain extracellular space (ECS) all occur during seizure generation, we set out to determine whether VRACs are dysregulated throughout mesial temporal lobe epilepsy (MTLE), the most common form of adult epilepsy. To accomplish this, we employed the IHKA experimental model of MTLE, and probed for the expression of LRRC8A, the essential pore-forming …

Covid-19 Induces Cns Cytokine Expression And Loss Of Hippocampal Neurogenesis, Allison L Soung, Abigail Vanderheiden, Xiaoping Jiang, Traci Bricker, Adrianus C M Boon, Robyn S Klein, Et Al.

2020-Current year OA Pubs

Infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with acute and postacute cognitive and neuropsychiatric symptoms including impaired memory, concentration, attention, sleep and affect. Mechanisms underlying these brain symptoms remain understudied. Here we report that SARS-CoV-2-infected hamsters exhibit a lack of viral neuroinvasion despite aberrant blood-brain barrier permeability. Hamsters and patients deceased from coronavirus disease 2019 (COVID-19) also exhibit microglial activation and expression of interleukin (IL)-1β and IL-6, especially within the hippocampus and the medulla oblongata, when compared with non-COVID control hamsters and humans who died from other infections, cardiovascular disease, uraemia or trauma. In the …

Rapid Astrocyte-Dependent Facilitation Amplifies Multi-Vesicular Release In Hippocampal Synapse, Jongyun Myeong, Vitaly A Klyachko

2020-Current year OA Pubs

Synaptic facilitation is a major form of short-term plasticity typically driven by an increase in residual presynaptic calcium. Using near-total internal reflection fluorescence (near-TIRF) imaging of single vesicle release in cultured hippocampal synapses, we demonstrate a distinctive, release-dependent form of facilitation in which probability of vesicle release is higher following a successful glutamate release event than following a failure. This phenomenon has an onset of ≤500 ms and lasts several seconds, resulting in clusters of successful release events. The release-dependent facilitation requires neuronal contact with astrocytes and astrocytic glutamate uptake by EAAT1. It is not observed in neurons grown alone …

Rapidplan Hippocampal Sparing Whole Brain Model Version 2-How Far Can We Reduce The Dose?, Hefei Liu, Ryan Clark, Anthony Magliari, Robert Foster, Francisco Reynoso, Matthew Schmidt, Vinai Gondi, Christopher Abraham, Heather Curry, Patrick Kupelian, Deepak Khuntia, Sushil Beriwal

2020-Current year OA Pubs

Whole-brain radiotherapy has been the standard palliative treatment for patients with brain metastases due to its effectiveness, availability, and ease of administration. Recent clinical trials have shown that limiting radiation dose to the hippocampus is associated with decreased cognitive toxicity. In this study, we updated an existing Knowledge Based Planning model to further reduce dose to the hippocampus and improve other dosimetric plan quality characteristics. Forty-two clinical cases were contoured according to guidelines. A new dosimetric scorecard was created as an objective measure for plan quality. The new Hippocampal Sparing Whole Brain Version 2 (HSWBv2) model adopted a complex recursive …

Acrylamide Inhibits Long-Term Potentiation And Learning Involving Microglia And Pro-Inflammatory Signaling, Yukitoshi Izumi, Chika Fujii, Kazuko A O'Dell, Charles F Zorumski

2020-Current year OA Pubs

Acrylamide is a chemical used in various industries and a product following high-temperature cooking of vegetables containing asparagine. Environmental or dietary exposure to acrylamide could impair cognitive function because of its neurotoxicity. Using rat hippocampal slices, we tested whether acrylamide alters induction of long-term potentiation (LTP), a cellular model of learning and memory. We hypothesized that acrylamide impairs cognitive function via activation of pro-inflammatory cytokines because robust upregulation of NLRP3 inflammasome has been reported. Although acrylamide up to 3 mM did not alter basal synaptic transmission, incubation with 10 μM or acute administration of 100 μM acrylamide inhibited induction of …

Slitrk2 Variants Associated With Neurodevelopmental Disorders Impair Excitatory Synaptic Function And Cognition In Mice, Salima El Chehadeh, Dorothy K Grange, Et Al

2020-Current year OA Pubs

SLITRK2 is a single-pass transmembrane protein expressed at postsynaptic neurons that regulates neurite outgrowth and excitatory synapse maintenance. In the present study, we report on rare variants (one nonsense and six missense variants) in SLITRK2 on the X chromosome identified by exome sequencing in individuals with neurodevelopmental disorders. Functional studies showed that some variants displayed impaired membrane transport and impaired excitatory synapse-promoting effects. Strikingly, these variations abolished the ability of SLITRK2 wild-type to reduce the levels of the receptor tyrosine kinase TrkB in neurons. Moreover, Slitrk2 conditional knockout mice exhibited impaired long-term memory and abnormal gait, recapitulating a subset of …

A Human Single-Neuron Dataset For Face Perception, Runnan Cao, Chujun Lin, Nicholas J Brandmeir, Shuo Wang

2020-Current year OA Pubs

The human amygdala and hippocampus have long been associated with face perception. Here, we present a dataset of single-neuron activity in the human amygdala and hippocampus during face perception. We recorded 2082 neurons from the human amygdala and hippocampus when neurosurgical patients with intractable epilepsy performed a one-back task using natural face stimuli, which mimics natural face perception. Specifically, our data include (1) single-neuron activity from the amygdala (996 neurons) and hippocampus (1086 neurons), (2) eye movements (gaze position and pupil), (3) psychological assessment of the patients, and (4) social trait judgment ratings from a subset of patients and a …

Fmrp Regulates Gabaa Receptor Channel Activity To Control Signal Integration In Hippocampal Granule Cells, Pan-Yue Deng, Ajeet Kumar, Valeria Cavalli, Vitaly A Klyachko

2020-Current year OA Pubs

Fragile X syndrome, the most common inherited form of intellectual disability, is caused by loss of fragile X mental retardation protein (FMRP). GABAergic system dysfunction is one of the hallmarks of FXS, yet the underlying mechanisms remain poorly understood. Here, we report that FMRP interacts with GABA

Identifying The Neurophysiological Effects Of Memory-Enhancing Amygdala Stimulation Using Interpretable Machine Learning, Mohammad S E Sendi, Cory S Inman, Kelly R Bijanki, Lou Blanpain, James K Park, Stephan Hamann, Robert E Gross, Jon T Willie, Babak Mahmoudi

2020-Current year OA Pubs

BACKGROUND: Direct electrical stimulation of the amygdala can enhance declarative memory for specific events. An unanswered question is what underlying neurophysiological changes are induced by amygdala stimulation.

OBJECTIVE: To leverage interpretable machine learning to identify the neurophysiological processes underlying amygdala-mediated memory, and to develop more efficient neuromodulation technologies.

METHOD: Patients with treatment-resistant epilepsy and depth electrodes placed in the hippocampus and amygdala performed a recognition memory task for neutral images of objects. During the encoding phase, 160 images were shown to patients. Half of the images were followed by brief low-amplitude amygdala stimulation. For local field potentials (LFPs) recorded from …

Bacterial Sepsis Increases Hippocampal Fibrillar Amyloid Plaque Load And Neuroinflammation In A Mouse Model Of Alzheimer's Disease, Jacob M Basak, Aura Ferreiro, Lucy S Cohen, Patrick W Sheehan, Collin J Nadarajah, Michael F Kanan, Kimberley V Sukhum, Gautam Dantas, Erik S Musiek

2020-Current year OA Pubs

BACKGROUND: Sepsis, a leading cause for intensive care unit admissions, causes both an acute encephalopathy and chronic brain dysfunction in survivors. A history of sepsis is also a risk factor for future development of dementia symptoms. Similar neuropathologic changes are associated with the cognitive decline of sepsis and Alzheimer's disease (AD), including neuroinflammation, neuronal death, and synaptic loss. Amyloid plaque pathology is the earliest pathological hallmark of AD, appearing 10 to 20 years prior to cognitive decline, and is present in 30% of people over 65. As sepsis is also more common in older adults, we hypothesized that sepsis might …