Biology subjects

Palenicek, T.

Publications and source records attributed to Palenicek, T..

5 recordsLinked to original sources

bioRxiv2025

Microstate in rats EEG: a proof of concept study

The electroencephalogram (EEG) reflecting brain activity can be characterized through brief periods of stable neural activity patterns that recur over time and are referred to as microstates. Microstates are related to a range of cognitive processes, and their analysis has become an increasingly popular tool for studying human brain function. While microstates have been extensively studied in humans, their presence and characteristics in animal models have yet to be as thoroughly investigated. This study aims to address this gap by detecting and characterizing microstates in EEGs of rats collected using a superficial electrode system corresponding to homological areas of the human 10-20 system. Specifically, we demonstrate the presence of microstates in rats EEG; those can be captured by the same metrics as in humans. We define these microstates, describe them through topology and parameters, and identify the EEG frequency bands and intracranial sources that predominantly determine microstate topography. These findings have important implications for the use of microstates as a preclinical tool for investigating brain functions, detecting new biomarkers of brain diseases, and translating this knowledge to humans.

animal behavior and cognition↗

bioRxiv2024

Behavioral pharmacology of mescaline - the role of serotonin 5-HT2A, 5-HT2B, 5-HT2C and 5-HT1A receptors

RationaleMescaline is a classical psychedelic compound with a phenylethylamine structure that primarily acts on serotonin 5-HT2A/C receptors, but also binds to 5-HT1A and 5-HT2B receptors. Despite being the first psychedelic ever isolated and synthesized, the precise role of different serotonin receptor subtypes in its behavioral pharmacology is not fully understood. ObjectivesIn this study, we aimed to investigate how selective antagonists of 5-HT2A, 5-HT2B, 5-HT2C, and 5-HT1A receptors affect the behavioral changes induced by subcutaneous administration of mescaline (at doses of 10, 20, and 100 mg/kg) in rats. MethodsWe used adult male Wistar rats in all our experiments. We evaluated locomotor activity using the open field test, and assessed sensorimotor gating deficits by measuring prepulse inhibition (PPI) of acoustic startle reaction (ASR). ResultsWhile the highest dose of mescaline induced hyperlocomotion, which almost all the other antagonists reversed, the PPI deficits were selectively normalized by the 5-HT2A antagonist. The 5-HT2C antagonist partially reversed the small decrease in locomotor activity induced by lower doses of mescaline. ConclusionOur findings suggest that mescaline-induced changes in behavior are primarily mediated by the 5-HT2A receptor subtype, with less pronounced contributions from the 5-HT2C receptor. The other antagonists had limited effects.

animal behavior and cognition↗

bioRxiv2024

Effects of serotonergic psychedelics on synaptogenesis and immediate early genes expression - comparison with ketamine, fluoxetine and lithium

BackgroundRecent evidence suggests that psychedelics are able to induce rapid and long-lasting antidepressant effects. The generally acknowledged explanation for these traits is the phenomenon of neuroplasticity, although exact underlying molecular mechanisms remain unclear. AimsThis study investigates selected neuroplastic effects of psilocin, lysergic acid diethylamide (LSD) and N,N-dimethyltryptamine (DMT) in direct comparison with ketamine, fluoxetine and lithium after acute (1 h) and/or prolonged (24 h) treatment in vitro. MethodsRat primary cortical cultures were treated with 10 {micro}M psilocin, 1 {micro}M lysergic acid diethylamide (LSD), 90 {micro}M N, N-dimethyltryptamine (DMT), 1 {micro}M ketamine, 10 {micro}M fluoxetine and 5 mM lithium. Analysis of synaptic puncta was performed; puncta of presynaptic marker synapsin I/II, postsynaptic density protein 95 (PSD-95), and their co-localization (established synapse) were assessed 24 h after drug treatment. Next, expressions of immediate early genes (IEGs) encoding activity-regulated cytoskeleton-associated protein (Arc), early growth response 1 (Egr1), and neuronal PAS (Per-ArntSim) domain protein 4 (Npas4) were analysed 1 and 24 h after drug treatments. ResultsPsilocin increased synaptic puncta count and induced Arc expression. The effect to promote synaptogenesis was comparable to ketamine and lithium; ketamine additionally increased PSD-95 puncta count. LSD and DMT didnt induce any significant effect. Interestingly, fluoxetine had no effect on synaptic puncta count, but upregulated Egr1 and Npas4. ConclusionsPsilocin demonstrated a significant neuroplastic effect comparable to that of ketamine and lithium, adding another piece of evidence to its profile as a promising therapeutic agent.

neuroscience↗

bioRxiv2024

Unveiling Stimulus Transduction Artifacts in Auditory Steady-State Response Experiments: Characterization, Risks, and Mitigation Strategies

This scientific paper addresses the potential risk of spurious responses in neuroscientific auditory steady-state response (ASSR) experiments attributed to transduction artifacts. The focus is particularly on click train stimuli, given their spectral content in the frequency range of interest (e.g., 40 Hz). Building upon a pilot experiment demonstrating the existence of the artifact in a phantom head, this study focuses on the characterization of stimulus artifacts in extended measurements with phantoms and the evaluation of associated risks in experiments involving human subjects. The investigation is divided into two parts: the first part scrutinizes stimulus artifact properties crucial for mitigation, while the second part assesses risks in ASSR experiments with human subjects based on the characterized artifact. The discussion covers stimulus characterization, experimental setups with phantoms, and experiments with human subjects, exploring potential sources of the artifact, its spatial properties, and the influence of re-referencing. The results reveal the role of headphone cables as a source of stimulus artifacts, along with the surprising impact of headphone transducers. The study emphasizes the need for careful experimental design and data analysis to avoid misinterpretations of stimulus artifacts as genuine brain responses in ASSR experiments.

neuroscience↗

bioRxiv2022

Antibiotic-induced dysbiosis does not potentiate the effect of lipopolysaccharide insult in male Wistar rats

The present study investigated whether neonatal exposure to the proinflammatory endotoxin lipopolysaccharide (LPS) followed by antibiotic (ATB)-induced dysbiosis in early adulthood could induce schizophrenia-like behavioral changes in adult male rats. The combination of these two stressors resulted in decreased weight gain, but no significant behavioral abnormalities were observed. LPS treatment resulted in adult rats hypoactivity and induced anxiety-like behavior in the social recognition paradigm, but these behavioral changes were not exacerbated by ATB-induced gut dysbiosis. ATB treatment seriously disrupted the gut bacterial community, but dysbiosis did not affect locomotor activity, social recognition, and acoustic reactivity in adult rats. Fecal bacterial community analyzes showed no differences between the LPS challenge exposed/unexposed rats, while the effect of ATB administration was decisive regardless of prior LPS exposure. ATB treatment resulted in significantly decreased bacterial diversity, suppression of Clostridiales and Bacteroidales, and increases in Lactobacillales, Enterobacteriales, and Burkholderiales. The persistent effect of LPS on some aspects of behavior suggests a long-term effect of early toxin exposure that was not observed in ATB-treated animals. However, an anti-inflammatory protective effect of ATB cannot be assumed because of the increased abundance of pro-inflammatory, potentially pathogenic bacteria (Proteus, Suttrella) and the elimination of the bacterial families Ruminococcaceae and Lachnospiraceae, which are generally considered beneficial for gut health.

neuroscience↗