Impulsivity is often considered a risk factor for drug addiction; however, not all evidence supports this view. In the present study, we used a food reward delay-discounting task (DDT) to categorize rats as low-, middle-, and high-impulsive but failed to find any difference among these groups in the acquisition and maintenance of cocaine self-administration (SA), regardless of electrical footshock punishment. Additionally, there were no group differences in locomotor responses to acute cocaine in rats with or without a history of cocaine SA. Unexpectedly, chronic cocaine SA selectively increased impulsive choice in low-impulsive rats. Resting-state fMRI analysis revealed a positive correlation between impulsivity and cerebral blood volume in the midbrain, thalamus, and auditory cortex. Using these three regions as seeds, we observed a negative correlation between impulsivity and functional connectivity between the midbrain and frontal cortex, as well as between the thalamus and frontal cortex (including th...

Human brain banks are essential for studying a wide variety of neurological and neurodegenerative diseases, yet the variability in postmortem interval (PMI)—the time from death to tissue preservation—poses significant challenges due to rapid cellular decomposition, protein alterations, and RNA degradation. Furthermore, the postmortem transcriptomic alterations occurring within distinct cell types are poorly understood. In this study, we analyzed the effect of a 3 h postmortem interval on single-nucleus RNA signatures in the brains of wild-type (WT) and PS19 mice, a common model of tauopathy. We observed that basic quality control metrics (such as the number of genes and reads per cell), total nuclei counts, and RNA integrity number (RINe) remained consistent across all samples, regardless of PMI or genotype. However, a 3 h PMI diminished the number of genes differentially expressed between PS19 and WT mice, suggesting an impact of delayed processing on the detection of disease-specific transcriptomic signa...

The striatum is the primary input nucleus of the basal ganglia, integrating a dense plexus of inputs from the cerebral cortex and thalamus to regulate action selection and learning. Neuroanatomical mapping of the striatum and its subcompartments has been carried out extensively in rats and mice, nonhuman primates, and cats allowing comparative neuroanatomy studies to derive heuristics about striatal composition and function. Here, we systematically map corticostriatal topography from motor, somatosensory, auditory, and visual cortices as well as thalamostriatal parafascicular (PfN) inputs in the Mongolian gerbil. We also map a pathway reported in mice from medial vestibular nucleus to the PfN that could convey vestibular information to the striatum. Our findings align with those of similar studies in other rodents, indicating homologous neuroanatomical connectivity patterns within the corticostriatal projectome across Rodentia. We observed corticostriatal peaks of dense labeling for each input with a diffu...

Beta event-related spectral perturbation, including bilateral movement-related beta desynchronization (MRBD) and postmovement beta synchronization (PMBS), can be evoked by unilateral speed movement. A potential correlation might exist between power (de)synchronization and interhemispheric coherence during movement execution. However, during the PMBS phase, the existence of interhemispheric coupling and the effect of speed on it are largely undiscovered. To answer this question, we investigated eight healthy, right-handed volunteers using a combination of electroencephalography, transcranial magnetic stimulation, and electromyography. We explored interhemispheric (directed) coherence during isotonic right index finger abduction movements at two speeds: ballistic and self-paced. We discovered that (1) interhemispheric coherence was greater during the PMBS than during the MRBD period. Furthermore, ballistic movement induced a larger coherence during the PMBS period, but not during the MRBD period. (2) In the ...

Stress is a common occurrence for military personnel. This can include the stress of deployment and active combat. Anxiety is considered a reaction to stress, and with anxiety-related disorders on the rise, it is imperative that stress be considered a preexisting condition when studying a number of neurological conditions. To determine the effects of stress on the behavioral outcomes of traumatic brain injury (TBI), we used a 3 d acute unpredictable stress (AUS) model followed by blast-induced neurotrauma (BINT) to assess social anhedonia and anxiety-like behaviors in male and female rats. The animals were divided into four groups including unstressed and uninjured control (Con), stress-only animals (AUS), injury-only animals (BINT), and animals that received both stress and injury (AUS + BINT). In the males, behavioral tests such as elevated plus and three-chamber sociability (3-CS) showed that stress plays a dominant role in determining behavioral outcomes after TBI with the AUS + BINT animals behaving m...

When attempting to concurrently perform two distinct cognitive tasks, the performance of either task is frequently compromised. This phenomenon is known as dual-task interference. Although multiple task features have been postulated to influence on dual-task interference, the primary determinant remains unclear. The determinant factor causing dual-task interference is an important issue to understand its mechanism and associated functions including switching tasks and planning task order. The present study investigated this issue using monkeys and three behavioral tasks requiring distinct cognitive processes (spatial working memory, SWM; working memory and long-term memory of objects, PA; object working memory, DMS) and manipulating task pair (SWM and PA or SWM and DMS), task order (fixed or randomized), and task difficulty (different delay lengths). The task introduced first showed better performance as compared with the task introduced second, suggesting the task order as an important factor. However, th...

Vestibular research is essential for understanding and treating disorders such as vertigo and Meniere's disease. The vestibulo-ocular reflex (VOR) is a key method for assessing vestibular function and an essential tool for diagnosing vertigo. Traditionally, the VOR comprises angular VOR (aVOR) and translational VOR (tVOR), which originate from the vestibular semicircular canals (SCCs) and otolith organs, respectively. VOR consists of both fast-phase and slow-phase eye movements, which functionally interact to contribute to gaze control. However, to calculate the gain and phase parameters of the VOR, it is common practice to exclude fast-phase information superimposed on slow-phase eye movements. As a result, the information contained in the fast phase has not been fully utilized. OVAR is primarily used to evaluate otolith function, as there is no SCC input during its steady state. It is widely accepted that fast-phase nystagmus (FPN) during OVAR is generated by periodic otolith inputs via the central vesti...

Early psychosis (EP) is a critical period for psychotic disorders during which the brain undergoes rapid and significant functional and structural changes ( [Shinn et al., 2017][1]). The Human Connectome Project (HCP) is a global effort to map the human brain's connectivity in health and disease. Here we focus on HCP-EP subjects (i.e., those within 5 years of the initial psychotic episode) to determine macro- and microstructural alterations in EP (HCP-EP sample, n  = 179: EP, n  = 123, controls, n  = 56) and their association with clinical outcomes (i.e., symptoms severity) in HCP-EP. We carried out analyses of deformation-based morphometry (DBM), scalar indices from the diffusion tensor imaging (DTI), and tract-based spatial statistics (TBSS). Lastly, we conducted correlation analyses focused on the midbrain (DBM and DTI) to examine associations between its structure and clinical symptoms. Our results show that the midbrain displays robust alteration in its structure (DBM and DTI) in the voxel-based analy...

Alpha (8–12 Hz) oscillations and default mode network (DMN) activity dominate the brain's intrinsic activity in the temporal and spatial domains, respectively. They are thought to play crucial roles in the spatiotemporal organization of the complex brain system. Relatedly, both have been implicated, often concurrently, in diverse neuropsychiatric disorders, with accruing electroencephalogram (EEG)/magnetoencephalogram and functional magnetic resonance imaging (fMRI) data linking these two neural activities both at rest and during key cognitive operations. Prominent theories and extant findings thus converge to suggest a mechanistic relationship between alpha oscillations and the DMN. Here, we leveraged simultaneous EEG–fMRI data acquired before and after alpha-frequency transcranial alternating current stimulation ( α -tACS) and observed that α -tACS tightened the dynamic coupling between spontaneous fluctuations in alpha power and DMN connectivity (especially, in the posterior DMN, between the posterior c...

Mitral cells (MCs) and tufted cells (TCs) in the olfactory bulb (OB) act as an input convergence hub and transmit information to higher olfactory areas. Since first characterized, they have been classed as distinct projection neurons based on size and location: laminarly arranged MCs with a diameter larger than 20 µm in the mitral layer (ML) and smaller TCs spread across both the ML and external plexiform layers (EPL). Recent in vivo work has shown that these neurons encode complementary olfactory information, akin to parallel channels in other sensory systems. Yet, many ex vivo studies still collapse them into a single class, mitral/tufted, when describing their physiological properties and impact on circuit function. Using immunohistochemistry and whole-cell patch–clamp electrophysiology in fixed or acute slices from adult mice, we attempted to align in vivo and ex vivo data and test a soma size-based classifier of bulbar projection neurons using passive and intrinsic firing properties. We found that the...