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Mashup Score: 6Beyond the Paper: A Conversation with Dr. Hugo Calligaro - 8 day(s) ago
Interviewed by Dr. Paige N. McKeon, October 4, 2023 In their recent eNeuro publication, Calligaro and colleagues investigated the connectivity of the central pacemaker of the brain: the hypothalamic suprachiasmatic nucleus (SCN). This hub for entraining circadian rhythm is known to be cellularly heterogeneous, but there is little research characterizing SCN neuron connectivity. The authors used a Cre-dependent reporter targeting the mitochondria of melanopsin-expressing retinal ganglion cells (mRGCs),
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Mashup Score: 2Locus Ceruleus Dynamics Are Suppressed during Licking and Enhanced Postlicking Independent of Taste Novelty - 8 day(s) ago
Attending to salient sensory attributes of food, such as tastes that are new, displeasing, or unexpected, allows the procurement of nutrients without food poisoning. Exposure to new tastes is known to increase norepinephrine (NE) release in taste processing forebrain areas, yet the central source for this release is unknown. Locus ceruleus norepinephrine neurons (LC-NE) emerge as a candidate in signaling salient information about taste, as other salient sensory stimuli (e.g., visual, auditory, somatosensation) are known to activate LC neurons. To determine if LC neurons are sensitive to features of taste novelty, we used fiber photometry to record LC-NE activity in water-restricted mice that voluntarily licked either novel or familiar substances of differential palatability (saccharine, citric acid). We observed that LC-NE activity was suppressed during lick bursts and transiently activated upon the termination of licking and that these dynamics were independent of the familiarity of t
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Mashup Score: 6
In many real-life scenarios, our decisions could lead to multiple outcomes that conflict with value. Hence, an appropriate neural representation of the net experienced value of conflicting outcomes, which play a crucial role in guiding future decisions, is critical for adaptive behavior. As some recent functional neuroimaging work has primarily focused on the concurrent processing of monetary gains and aversive information, very little is known regarding the integration of conflicting value signals involving monetary losses and appetitive information in the human brain. To address this critical gap, we conducted a functional MRI study involving healthy human male participants to examine the nature of integrating positive emotion and monetary losses. We employed a novel experimental design where the valence (positive or neutral) of an emotional stimulus indicated the type of outcome (loss or no loss) in a choice task. Specifically, we probed two plausible integration patterns while proc
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Mashup Score: 1Monitoring Changes in TMS-Evoked EEG and EMG Activity During 1 Hz rTMS of the Healthy Motor Cortex - 12 day(s) ago
Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation technique capable of inducing neuroplasticity as measured by changes in peripheral muscle electromyography (EMG) or electroencephalography (EEG) from pre-to-post stimulation. However, temporal courses of neuromodulation during ongoing rTMS are unclear. Monitoring cortical dynamics via TMS-evoked responses using EMG (motor-evoked potentials; MEPs) and EEG (transcranial-evoked potentials; TEPs) during rTMS might provide further essential insights into its mode of action – temporal course of potential modulations. The objective of this study was to first evaluate the validity of online rTMS-EEG and rTMS-EMG analyses, and second to scrutinize the temporal changes of TEPs and MEPs during rTMS. As rTMS is subject to high inter-individual effect variability, we aimed for single-subject analyses of EEG changes during rTMS. Ten healthy human participants were stimulated with 1,000 pulses of 1 Hz rTMS over th
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Mashup Score: 15Differential effects of aging on regional corpus callosum microstructure and the modifying influence of pulse pressure - 13 day(s) ago
The corpus callosum is composed of several subregions, distinct in cellular and functional organization. This organization scheme may render these subregions differentially vulnerable to the aging process. Callosal integrity may be further compromised by cardiovascular risk factors, which negatively influence white matter health. Here, we test for heterochronicity of aging, hypothesizing an anterior-to-posterior gradient of vulnerability to aging that may be altered by effects of cardiovascular health. In 174 healthy adults across the adult lifespan (mean age=53.56 ± 18.90, range=20-94 years old, 58.62% women), pulse pressure (calculated as participant’s systolic minus diastolic blood pressure) was assessed to determine cardiovascular risk. A deterministic tractography approach via diffusion weighted imaging was utilized to extract fractional anisotropy (FA), radial diffusivity (RD) and axial diffusivity (AD) from each of five callosal subregions, serving as estimates of microstructura
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Mashup Score: 0The Mouse Inferior Colliculus Responds Preferentially to Non-Ultrasonic Vocalizations - 13 day(s) ago
The inferior colliculus (IC), the midbrain auditory integration center, analyzes information about social vocalizations and provides substrates for higher level processing of vocal signals. We used multichannel recordings to characterize and localize responses to social vocalizations and synthetic stimuli within the IC of female and male mice, both urethane anesthetized and unanesthetized. We compared responses to ultrasonic vocalizations (USVs) with other vocalizations in the mouse repertoire and related vocal responses to frequency tuning, IC subdivisions, and sex. Responses to lower frequency, broadband social vocalizations were widespread in IC, well represented throughout the tonotopic axis, across subdivisions, and in both sexes. Responses to USVs were much more limited. Although we observed some differences in tonal and vocal responses by sex and subdivision, representations of vocal responses by sex and subdivision were largely the same. For most units, responses to vocal signa
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Mashup Score: 1Nonbinary 2D Distribution Tool Maps Autonomic Nerve Fiber Clustering in Lumbosacral Ventral Roots of Rhesus Macaques - 14 day(s) ago
Neuromodulation of the peripheral nervous system (PNS) by electrical stimulation may augment autonomic function after injury or in neurodegenerative disorders. Nerve fiber size, myelination, and distance between individual fibers and the stimulation electrode may influence response thresholds to electrical stimulation. However, information on the spatial distribution of nerve fibers within the PNS is sparse. We developed a new two-dimensional (2D) morphological mapping tool to assess spatial heterogeneity and clustering of nerve fibers. The L6-S3 ventral roots (VRs) in rhesus macaques were used as a model system to map preganglionic parasympathetic, γ-motor, and α-motor fibers. Random and ground truth distributions of nerve fiber centroids were determined for each VR by light microscopy. The proposed tool allows for nonbinary determinations of fiber heterogeneity by defining the minimum distance between nerve fibers for cluster inclusion and comparisons with random fiber distributions
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Mashup Score: 2Forebrain EAAT3 Overexpression Increases Susceptibility to Amphetamine-Induced Repetitive Behaviors - 15 day(s) ago
Obsessive-compulsive disorder (OCD) is a debilitating psychiatric disorder characterized by intrusive obsessive thoughts and compulsive behaviors. Multiple studies have shown the association of polymorphisms in the SLC1A1 gene with OCD. The most common of these OCD-associated polymorphisms increases the expression of the encoded protein, excitatory amino acid transporter 3 (EAAT3), a neuronal glutamate transporter. Previous work has shown that increased EAAT3 expression results in OCD-relevant behavioral phenotypes in rodent models. In this study, we created a novel mouse model with targeted, reversible overexpression of Slc1a1 in forebrain neurons. The mice do not have a baseline difference in repetitive behavior but show increased hyperlocomotion following a low dose of amphetamine (3 mg/kg) and increased stereotypy following a high dose of amphetamine (8 mg/kg). We next characterized the effect of amphetamine on striatal cFos response and found that amphetamine increased cFos throug
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Mashup Score: 0Dissociating Mechanisms That Underlie Seasonal and Developmental Programs for the Neuroendocrine Control of Physiology in Birds - 15 day(s) ago
Long-term programmed rheostatic changes in physiology are essential for animal fitness. Hypothalamic nuclei and the pituitary gland govern key developmental and seasonal transitions in reproduction. The aim of this study was to identify the molecular substrates that are common and unique to developmental and seasonal timing. Adult and juvenile quail were collected from reproductively mature and immature states, and key molecular targets were examined in the mediobasal hypothalamus (MBH) and pituitary gland. qRT-PCR assays established deiodinase type 2 ( DIO2 ) and type 3 ( DIO3 ) expression in adults changed with photoperiod manipulations. However, DIO2 and DIO3 remain constitutively expressed in juveniles. Pituitary gland transcriptome analyses established that 340 transcripts were differentially expressed across seasonal photoperiod programs and 1,189 transcripts displayed age-dependent variation in expression. Prolactin ( PRL ) and follicle-stimulating hormone subunit beta ( FSHβ )
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Mashup Score: 1Repetition Suppression Reveals Cue-Specific Spatial Representations for Landmarks and Self-Motion Cues in the Human Retrosplenial Cortex - 17 day(s) ago
The efficient use of various spatial cues within a setting is crucial for successful navigation. Two fundamental forms of spatial navigation, landmark-based and self-motion-based, engage distinct cognitive mechanisms. The question of whether these modes invoke shared or separate spatial representations in the brain remains unresolved. While nonhuman animal studies have yielded inconsistent results, human investigation is limited. In our previous work ([Chen et al., 2019][1]), we introduced a novel spatial navigation paradigm utilizing ultra-high field fMRI to explore neural coding of positional information. We found that different entorhinal subregions in the right hemisphere encode positional information for landmarks and self-motion cues. The present study tested the generalizability of our previous finding with a modified navigation paradigm. Although we did not replicate our previous finding in the entorhinal cortex, we identified adaptation-based allocentric positional codes for b
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#eNeuro blog Beyond the Paper | @h_calligaro, in the lab of @SatchinPanda at @salkinstitute for Biological Studies, tells us about his interest in circadian rhythms and discusses the unexpected findings from his first author publication. https://t.co/opBBj9whQ0 https://t.co/NvsmWBcV5X