Digital Commons Network^™

Altered Gating Of KV1.4 In The Nucleus Accumbens Suppresses Motivation For Reward, Bernadette O'Donovan, Adewale Adeluyi, Erin L Anderson, Robert D. Cole, Jill R. Turner, Pavel I. Ortinski

Neuroscience Faculty Publications

Deficient motivation contributes to numerous psychiatric disorders, including withdrawal from drug use, depression, schizophrenia, and others. Nucleus accumbens (NAc) has been implicated in motivated behavior, but it remains unclear whether motivational drive is linked to discrete neurobiological mechanisms within the NAc. To examine this, we profiled cohorts of Sprague-Dawley rats in a test of motivation to consume sucrose. We found that substantial variability in willingness to exert effort for reward was not associated with operant responding under low-effort conditions or stress levels. Instead, effort-based motivation was mirrored by a divergent NAc shell transcriptome with differential regulation at potassium and dopamine …

Distinct Patterns Of Default Mode And Executive Control Network Circuitry Contribute To Present And Future Executive Function In Older Adults, Christopher A. Brown, Frederick A. Schmitt, Charles D. Smith, Brian T. Gold

Neuroscience Faculty Publications

Executive function (EF) performance in older adults has been linked with functional and structural profiles within the executive control network (ECN) and default mode network (DMN), white matter hyperintensities (WMH) burden and levels of Alzheimer's disease (AD) pathology. Here, we simultaneously explored the unique contributions of these factors to baseline and longitudinal EF performance in older adults. Thirty-two cognitively normal (CN) older adults underwent neuropsychological testing at baseline and annually for three years. Neuroimaging and AD pathology measures were collected at baseline. Separate linear regression models were used to determine which of these variables predicted composite EF scores at baseline …

Rediscovery Of The Endangered Carchi Andean Toad, Rhaebo Colomai (Hoogmoed, 1985), In Ecuador, With Comments On Its Conservation Status And Extinction Risk, Carolina Reyes-Puig, Gabriela B. Bittencourt-Silva, María Torres-Sánchez, Mark Wilkinson, Jeffrey W. Streicher, Simon T. Maddock, Ramachandran Kotharambath, Hendrik Müller, Francesca Nicole Angiolani Larrera, Diego Amieda-Reinoso, Santiago R. Ron, Diego Francisco Cisneros-Heredia

Neuroscience Faculty Publications

Since 1984 there have been no records of Rhaebo colomai (Hoogmoed, 1985) within the territory of Ecuador. This species was known from 2 localities in the province of Carchi, northwestern Ecuador, and the department of Nariño, southwestern Colombia, which were reported in 1979 and 2015, respectively. We report the recent sightings of R. colomai at 3 new localities in Ecuador and discuss and evaluate this species’ extinction risk and conservation status.

What Lies Beneath? Molecular Evolution During The Radiation Of Caecilian Amphibians, María Torres-Sánchez, David J. Gower, David Alvarez-Ponce, Christopher J. Creevey, Mark Wilkinson, Diego San Mauro

Neuroscience Faculty Publications

Background: Evolution leaves an imprint in species through genetic change. At the molecular level, evolutionary changes can be explored by studying ratios of nucleotide substitutions. The interplay among molecular evolution, derived phenotypes, and ecological ranges can provide insights into adaptive radiations. Caecilians (order Gymnophiona), probably the least known of the major lineages of vertebrates, are limbless tropical amphibians, with adults of most species burrowing in soils (fossoriality). This enigmatic order of amphibians are very distinct phenotypically from other extant amphibians and likely from the ancestor of Lissamphibia, but little to nothing is known about the molecular changes underpinning their radiation. …

Hdac Regulates Transcription At The Outset Of Axolotl Tail Regeneration, S. Randal Voss, Larissa V. Ponomareva, Varun B. Dwaraka, Kaitlin E. Pardue, Nour W. Al Haj Baddar, A. Katherine Rodgers, M. Ryan Woodcock, Qingchao Qiu, Anne Crowner, Dana Blichmann, Shivam Khatri, Jon S. Thorson

Neuroscience Faculty Publications

Tissue regeneration is associated with complex changes in gene expression and post-translational modifications of proteins, including transcription factors and histones that comprise chromatin. We tested 172 compounds designed to target epigenetic mechanisms in an axolotl (Ambystoma mexicanum) embryo tail regeneration assay. A relatively large number of compounds (N = 55) inhibited tail regeneration, including 18 histone deacetylase inhibitors (HDACi). In particular, romidepsin, an FDA-approved anticancer drug, potently inhibited tail regeneration when embryos were treated continuously for 7 days. Additional experiments revealed that romidepsin acted within a very narrow, post-injury window. Romidepsin treatment for only 1-minute post amputation inhibited …

Rediscovering The Axolotl As A Model For Thyroid Hormone Dependent Development, Anne Crowner, Shivam Khatri, Dana Blichmann, S. Randal Voss

Neuroscience Faculty Publications

The Mexican axolotl (Ambystoma mexicanum) is an important model organism in biomedical research. Much current attention is focused on the axolotl's amazing ability to regenerate tissues and whole organs after injury. However, not forgotten is the axolotl's equally amazing ability to thwart aspects of tissue maturation and retain juvenile morphology into the adult phase of life. Unlike close tiger salamander relatives that undergo a thyroid hormone regulated metamorphosis, the axolotl does not typically undergo a metamorphosis. Instead, the axolotl exhibits a paedomorphic mode of development that enables a completely aquatic life cycle. The evolution of paedomorphosis allowed axolotls …

The Effects Of Huntingtin-Lowering: What Do We Know So Far?, William F. Kaemmerer, Richard C. Grondin

Neuroscience Faculty Publications

Therapies targeting mutant huntingtin DNA, mRNA, and protein have a chance at becoming the first disease-modifying treatments for Huntington’s disease, a fatal inherited neurodegenerative disorder for which only symptom management treatments are available today. This review focuses on evidence addressing several key questions pertinent to huntingtin-lowering, ranging from the functions of wild-type huntingtin (wtHTT) that may be disrupted by huntingtin-lowering treatments through the various ways huntingtin can be lowered, the tolerability of wtHTT-lowering in mice and primates, what has been found in the Ionis Pharmaceutical safety trial of a huntingtin-lowering therapy, and to the question of how much mutant huntingtin …

Multi-Tissue Transcriptomes Of Caecilian Amphibians Highlight Incomplete Knowledge Of Vertebrate Gene Families, María Torres-Sánchez, Christopher J. Creevey, Etienne Kornobis, David J. Gower, Mark Wilkinson, Diego San Mauro

Neuroscience Faculty Publications

RNA sequencing (RNA-seq) has become one of the most powerful tools to unravel the genomic basis of biological adaptation and diversity. Although challenging, RNA-seq is particularly promising for research on non-model, secretive species that cannot be observed in nature easily and therefore remain comparatively understudied. Among such animals, the caecilians (order Gymnophiona) likely constitute the least known group of vertebrates, despite being an old and remarkably distinct lineage of amphibians. Here, we characterize multi-tissue transcriptomes for five species of caecilians that represent a broad level of diversity across the order. We identified vertebrate homologous elements of caecilian functional genes of …

Validations Of Apomorphine-Induced Bold Activation Correlations In Hemiparkinsonian Rhesus Macaques, Jorge E. Quintero, Yi Ai, Anders H. Andersen, Peter A. Hardy, Richard Grondin, Zain Guduru, Don M. Gash, Greg A. Gerhardt, Zhiming Zhang

Neuroscience Faculty Publications

Identification of Parkinson's disease at the earliest possible stage of the disease may provide the best opportunity for the use of disease modifying treatments. However, diagnosing the disease during the pre-symptomatic period remains an unmet goal. To that end, we used pharmacological MRI (phMRI) to assess the function of the cortico-basal ganglia circuit in a non-human primate model of dopamine deficiency to determine the possible relationships between phMRI signals with behavioral, neurochemical, and histological measurements. Animals with unilateral treatments with the neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), that expressed stable, long-term hemiparkinsonism were challenged with the dopaminergic receptor agonist, apomorphine, and structure-specific phMRI …

Effects Of The Dual Orexin Receptor Antagonist Dora-22 On Sleep In 5xfad Mice, Marilyn J. Duncan, Hannah Farlow, Chairtra Tirumalaraju, Do-Hyun Yun, Chanung Wang, James A. Howard, Madison N. Sanden, Bruce F. O'Hara, Kristen J. Mcquerry, Adam D. Bachstetter

Neuroscience Faculty Publications

Introduction: Sleep disruption is a characteristic of Alzheimer's disease (AD) that may exacerbate disease progression. This study tested whether a dual orexin receptor antagonist (DORA) would enhance sleep and attenuate neuropathology, neuroinflammation, and cognitive deficits in an AD-relevant mouse model, 5XFAD.

Methods: Wild-type (C57Bl6/SJL) and 5XFAD mice received chronic treatment with vehicle or DORA-22. Piezoelectric recordings monitored sleep and spatial memory was assessed via spontaneous Y-maze alternations. Aβ plaques, Aβ levels, and neuroinflammatory markers were measured by immunohistochemistry, enzyme-linked immunosorbent assay, and real-time polymerase chain reaction, respectively.

Results: In 5XFAD mice, DORA-22 significantly increased light-phase sleep without reducing Aβ levels, …