Relationship between anxiety and tinnitus development in a rat model.

Tinnitus, the auditory perception of sound without an external environmental stimulus, affects 15% of the human population and is associated with hearing loss. Interestingly, anxiety may be a significant risk factor in tinnitus pathophysiology potentially due to underlying common neural circuits of the auditory and limbic systems. The current study aimed to investigate the effects of stress-induced anxiety on tinnitus development in a rat model.

Traces of phylogeny and ecology in hippocampal neuron numbers.

It is not known how selective pressures shape the numbers of interconnected neurons in defined neural circuits during the phylogeny of mammals. Consequently, models of function are without phylogenetic bounds, and species differences in neuronal makeup cannot be linked to ecological factors that generate selective pressures. Based on data from 65 species belonging to 11 orders, we here provide an analysis of five interconnected neuron populations in the circuitry of the hippocampus, the forebrain region encoding episodic memories.

Structural plasticity in the motor cortex: Differential impacts of learning and Li-iTBS on dendritic spine dynamics.

Low-intensity intermittent theta burst stimulation (Li-iTBS) is a non-invasive brain stimulation technique that uses magnetic pulses to modulate neuronal activity. When applied immediately before a learning event (priming), Li-iTBS has been shown to enhance performance in skilled motor tasks. While its behavioural effects can be long-lasting, the underlying mechanisms remain unclear.

The effect of a synthetic cannabinoid agonist (nabilone) on unimodal tactile illusion correlates with a psychometric scores in healthy volunteers.

Our previous studies showed that dexamphetamine, an indirect dopamine agonist, widens Stimulus Binding Windows (BWs) in healthy subjects. The present study aimed to investigate the effect of nabilone, a synthetic cannabinoid agonist, on the BWs in a unimodal illusion: the tactile funneling illusion (TFI). The study also aimed to study the association between tactile illusion with psychometric scores.

Low intensity rTMS in adolescent mice affects visuomotor behaviour with no impact on visual topography.

Background: Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation technique used as a therapeutic and experimental tool. It is FDA-approved for treating major depressive disorder in adults and has an excellent safety profile. rTMS is less well characterised in children but was recently approved as an augmentative treatment in adolescents (15-21 years).

Corrigendum: Exploring perceived barriers and attitudes in young adults towards antidepressant pharmacotherapy, including the implementation of pharmacogenetic testing to optimize prescription practices.

[This corrects the article DOI: 10.3389/fphar.2024.

A naturalistic analysis of rTMS treatment outcomes for major depressive disorder in West Australian youth.

Objective: Repetitive transcranial magnetic stimulation (rTMS) is an effective, evidence-based treatment for major depressive disorder (MDD) in adults and is publicly funded in Australia. However, there is limited data as to its efficacy and safety in treating MDD in adolescent and youth populations.

Methods: This retrospective report examined routinely collected data of 46 outpatients aged 17 to 25 years old, who received rTMS treatment for MDD in a private TMS clinic.

Exploring perceived barriers and attitudes in young adults towards antidepressant pharmacotherapy, including the implementation of pharmacogenetic testing to optimize prescription practices.

Introduction: The field of pharmacogenetics (PGx) is experiencing significant growth, with increasing evidence to support its application in psychiatric care, suggesting its potential to personalize treatment plans, optimize medication efficacy, and reduce adverse drug reactions. However, the perceived utility and practicability of PGx for psychiatric treatment in youth remains underexplored. This study investigated perceived barriers and attitudes in Australian young adults towards the implementation of PGx testing to guide antidepressant treatment in primary care.

Optimized Theta Burst Stimulation with Extended Intervals Enhances Excitatory-Inhibitory Balance.

Electrical theta burst stimulation (TBS) with different inter-train intervals (ITIs) was first used to characterize bidirectional synaptic plasticity in brain slices. Despite a lack of understanding of mechanism, TBS has been adopted by rTMS research and clinical protocols to drive plasticity in the human brain, with variable results. To uncover how TBS modulates excitability in vivo, we systematically screen the impact of electrical TBS with different ITIs on rodent cortical neurons.

Low intensity repetitive transcranial magnetic stimulation enhances remyelination by newborn and surviving oligodendrocytes in the cuprizone model of toxic demyelination.

In people with multiple sclerosis (MS), newborn and surviving oligodendrocytes (OLs) can contribute to remyelination, however, current therapies are unable to enhance or sustain endogenous repair. Low intensity repetitive transcranial magnetic stimulation (LI-rTMS), delivered as an intermittent theta burst stimulation (iTBS), increases the survival and maturation of newborn OLs in the healthy adult mouse cortex, but it is unclear whether LI-rTMS can promote remyelination. To examine this possibility, we fluorescently labelled oligodendrocyte progenitor cells (OPCs; Pdgfrα-CreER transgenic mice) or mature OLs (Plp-CreER transgenic mice) in the adult mouse brain and traced the fate of each cell population over time.

Non-severe thermal burn injuries induce long-lasting downregulation of gene expression in cortical excitatory neurons and microglia.

Burn injuries are devastating traumas, often leading to life-long consequences that extend beyond the observable burn scar. In the context of the nervous system, burn injury patients commonly develop chronic neurological disorders and have been suggested to have impaired motor cortex function, but the long-lasting impact on neurons and glia in the brain is unknown. Using a mouse model of non-severe burn injury, excitatory and inhibitory neurons in the primary motor cortex were labelled with fluorescent proteins using adeno-associated viruses (AAVs).

Acoustic trauma increases inhibitory effects of amygdala electrical stimulation on thalamic neurons in a rat model.

Acoustic trauma (AT) induced hearing loss elicits plasticity throughout the central auditory pathway, including at the level of the medial geniculate nucleus (MGN). Hearing loss also results in altered neuronal responses in the amygdala, which is involved in sensory gating at the level of the MGN. However, whether these altered responses in the amygdala affect sensory gating at the level of the MGN requires further evaluation.

The effects of caffeine and d-amphetamine on spatial span task in healthy participants.

Unlabelled: Studies that examined the effect of amphetamine or caffeine on spatial working memory (SWM) and verbal working memory (VWM) have used various tasks. However, there are no studies that have used spatial span tasks (SSTs) to assess the SWM effect of amphetamine and caffeine, although some studies have used digit span tasks (DST) to assess VWM. Previous reports also showed that increasing dopamine increases psychosis-like experiences (PLE, or schizotypy) scores which are in turn negatively associated with WM performance in people with high schizotypy and people with schizophrenia.

Dorsal striatum c-Fos activity in perseverative ephrin-A2A5 mice and the cellular effect of low-intensity rTMS.

Introduction: Overreliance on habit is linked with disorders, such as drug addiction and obsessive-compulsive disorder, and there is increasing interest in the use of repetitive transcranial magnetic stimulation (rTMS) to alter neuronal activity in the relevant pathways and for therapeutic outcomes. In this study, we researched the brains of ephrin-A2A5 mice, which previously showed perseverative behavior in progressive-ratio tasks, associated with low cellular activity in the nucleus accumbens. We investigated whether rTMS treatment had altered the activity of the dorsal striatum in a way that suggested altered hierarchical recruitment of brain regions from the ventral striatum to the dorsal striatum, which is linked to abnormal habit formation.

Identifying reproducible resting state networks and functional connectivity alterations following chronic restraint stress in anaesthetized rats.

Background: Resting-state functional MRI (rs-fMRI) in rodent models have the potential to bridge invasive experiments and observational human studies, increasing our understanding of functional alterations in the brains of patients with depression. A major limitation in current rodent rs-fMRI studies is that there has been no consensus on healthy baseline resting-state networks (RSNs) that are reproducible in rodents. Therefore, the present study aimed to construct reproducible RSNs in a large dataset of healthy rats and then evaluate functional connectivity changes within and between these RSNs following a chronic restraint stress (CRS) model within the same animals.

Interactions between Guidance Cues and Neuronal Activity: Therapeutic Insights from Mouse Models.

Topographic mapping of neural circuits is fundamental in shaping the structural and functional organization of brain regions. This developmentally important process is crucial not only for the representation of different sensory inputs but also for their integration. Disruption of topographic organization has been associated with several neurodevelopmental disorders.

Copy number variation in tRNA isodecoder genes impairs mammalian development and balanced translation.

The number of tRNA isodecoders has increased dramatically in mammals, but the specific molecular and physiological reasons for this expansion remain elusive. To address this fundamental question we used CRISPR editing to knockout the seven-membered phenylalanine tRNA gene family in mice, both individually and combinatorially. Using ATAC-Seq, RNA-seq, ribo-profiling and proteomics we observed distinct molecular consequences of single tRNA deletions.

Dexamphetamine widens temporal and spatial binding windows in healthy participants.

Background: The pathophysiology of psychosis is complex, but a better understanding of stimulus binding windows (BWs) could help to improve our knowledge base. Previous studies have shown that dopamine release is associated with psychosis and widened BWs. We can probe BW mechanisms using drugs of specific interest to psychosis.