Publications by authors named "Alexandre A Hoeller"

Article Synopsis
  • The study found a negative association between the phosphorylation of ERK1,2 in the amygdala and anxiety symptoms in patients with drug-resistant epilepsy.
  • In rats, lower levels of P-ERK1,2 in the amygdala correlated with increased anxiety-related behavior but showed a positive correlation with freezing during fear conditioning.
  • The results indicate that ERK1/2 in the basolateral amygdala is necessary for learned defensive behaviors but does not affect innate anxiety responses, highlighting different mechanisms for these two types of behaviors.
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The central autonomic network, which is connected to the limbic system structures including the amygdala (AMY) and anterior hippocampus (aHIP), regulates the sympathetic and parasympathetic modulation of visceromotor, neuroendocrine, pain, and behavior manifestations during stress responses. Heart rate variability (HRV) is useful to estimate the cardiac autonomic tone. The levels of phosphorylation on the Ser831 and Ser845 sites of the GluA1 subunit of the AMPAr (P-GluA1-Ser845 and P-GluA1-Ser831) are useful markers of synaptic plasticity.

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The quantitative analysis of electroencephalogram (qEEG) is a suitable tool for mental fatigue (MF) assessment. Here, we evaluated the effects of MF on behavioral performance and alpha power spectral density (PSD) and the association between early alpha PSD reactivity and long-term behavioral MF impairments. Nineteen right-handed adults (21.

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Excessive mental workload represent a critical risk factor for workplace accidents. Heart rate variability (HRV) is a non-invasive low cost electrophysiological autonomic biomarker related to emotional and cognitive regulation. Several studies report that mental overload impairs parasympathetic-mediated HRV indices (e.

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The cholinergic system is one of the most important neurotransmitter systems in the brain with key roles in autonomic control and the regulation of cognitive and emotional responses. However, the precise mechanism by which the cholinergic system influences behaviour is unclear. Adult hippocampal neurogenesis (AHN) is a potential mediator in this context based on evidence, which has identified this process as putative mechanism of antidepressant action.

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Objectives: Sleepiness and cognitive impairment are common symptoms observed in patients with epilepsy. We investigate whether self-reported sleepiness is associated with cognitive performance in patients with refractory mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). Seventy-one consecutive patients with MTLE-HS were evaluated with the Stanford Sleepiness Scale (SSS) before neuropsychological evaluation.

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Article Synopsis
  • Fear is a conscious response to threats that triggers stress reactions, and in some patients with mesial temporal lobe epilepsy (MTLE-HS), this can result in seizures accompanied by fear, known as ictal fear (IF).
  • The study investigated the levels of the GluA1 subunit in the amygdala and specific phosphorylation states in the anterior hippocampus of MTLE-HS patients and found significant differences between those with and without IF.
  • Lower levels of GluA1 in the amygdala and phosphorylated GluA1 in the anterior hippocampus were identified as potential biomarkers for predicting the presence of ictal fear, achieving an overall accuracy of 89.3%.
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Background: Recent studies have reported that Heart Rate Variability (HRV) indices remain reliable even during recordings shorter than 5 min, suggesting the ultra-short recording method as a valuable tool for autonomic assessment. However, the minimum time-epoch to obtain a reliable record for all HRV domains (time, frequency, and Poincare geometric measures), as well as the effect of respiratory rate on the reliability of these indices remains unknown.

Methods: Twenty volunteers had their HRV recorded in a seated position during spontaneous and controlled respiratory rhythms.

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Article Synopsis
  • Interictal hypometabolism in the temporal lobe of patients with mesial temporal lobe epilepsy (MTLE-HS) is detected using FDG-PET imaging, revealing that left-sided hypometabolism relates to verbal memory problems, while right-sided hypometabolism affects nonverbal memory.
  • In a study comparing 32 surgically treated MTLE-HS patients to 21 healthy controls, the epilepsy patients scored significantly lower on several cognitive tests, indicating impaired memory and language functions.
  • Despite exploring the relationship between mitochondrial enzyme activities and cognitive test performances, the study found no significant associations, suggesting that memory impairments in MTLE-HS are not linked to the measured enzymatic activities in the affected temporal lobe regions
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(1) Objectives: Epilepsy disorder is likely to increase with aging, leading to an increased incidence of comorbidities and mortality. In spite of that, there is a lack of information regarding this issue and little knowledge of cognitive and emotional responses in aging subjects following epileptogenesis. We investigated whether and how aging distress epilepsy-related behavioral and biochemical outcomes are associated with cognition and emotion.

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Behavioral and neuroendocrine responses following threatening situations promote the release of corticosterone, which is known to modulate trauma-related learning and memory process. However, it remains unknown whether the aversive learning generated by interoceptive fear conditioning is affected by glucocorticoid modulation. Therefore, the present study aimed to investigate the role of dexamethasone suppression in encoding and expression of pentylenetetrazole-induced olfactory fear conditioning (OFC) and in contextual second-order conditioning promoted by the conditioned odor.

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The potential efficacy of cannabinoid receptor ligands for the treatment of epilepsy remains controversial; cannabis components that act via cannabinoid type 1 (CB1) receptors produce anticonvulsant effects in animal models despite treatment with the CB receptor agonist reliably inducing convulsions in various species. Moreover, the potential role of cannabinoid receptor type 2 (CB2) to modulate seizures remains under-investigated. This study assessed the effects of the selective CB2 receptor agonist, AM1241, on pentylenetetrazole (PTZ)-induced seizures in rats.

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Article Synopsis
  • The cholinergic system significantly affects emotional processing, particularly in anxiety, as shown in a study where rats given pilocarpine displayed long-lasting anxiogenic responses lasting for months.
  • The research indicated that pilocarpine altered the HPA axis function, resulting in increased corticosterone (a stress hormone) and reduced levels of receptor proteins in the hippocampus, which are involved in stress regulation.
  • Administering memantine, an NMDA receptor antagonist, before pilocarpine reduced anxiety-like behaviors but did not change the effects on NMDA receptor expression, pointing to a complex relationship between cholinergic activation, anxiety, and receptor regulation.
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Article Synopsis
  • * The study investigates the effects of an enriched environment (EE) on fear extinction and how it relates to NPY-Y1 receptor modulation, using an experimental PTSD approach with rats.
  • * Results show that rats in an EE context experienced improved fear extinction, which was hindered by blocking Y1 receptors, indicating that NPY signaling in the hippocampus is essential for better context recognition and reduced fear generalization.
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The epileptogenesis process involves cell signaling events associated with neuroplasticity. The mitogen-activated protein kinases (MAPKs) integrate signals originating from a variety of extracellular stimuli and may regulate cell differentiation, survival, cell death and synaptic plasticity. Here we compared the total and phosphorylated MAPKs (ERK1/2, JNK1/2 and p38(MAPK)) levels in the neocortex and hippocampus of adult Swiss male mice quantified by western blotting analysis 48 h after the last injection of pentylenetetrazole (PTZ), according to the kindling protocol (35 mg/kg, i.

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Article Synopsis
  • Recent findings indicate that substance P (SP) plays a significant role in anxiety and epilepsy disorders, with its levels changing in response to stress.
  • The study examined how NK1 receptors in the dorsal hippocampus and lateral septum affect anxiety-like behaviors in rats after a pilocarpine injection, with results showing long-lasting anxiety effects.
  • The NK1 receptor antagonist FK888 was found to inhibit the anxiety responses when infused into the dorsal hippocampus but not when injected into the lateral septum, highlighting the specific role of the dorsal hippocampus in this anxiogenic response.
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Article Synopsis
  • The cholinergic system plays a role in regulating emotions, with the muscarinic receptor agonist pilocarpine inducing anxiety in rats over extended periods (24 hours to 3 months).
  • Rats treated with pilocarpine exhibited changes in behavior in an elevated plus-maze test, where anxiolytic treatment with diazepam blocked anxiety responses, while anxiogenic treatment did not affect them.
  • Electroencephalographic recordings showed increased theta activity in the hippocampus, illustrating long-term electrophysiological changes that suggest the muscarinic system could be a target for anxiety disorder treatments.
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Rationale: There is extensive evidence indicating the influence of seizures on emotional responses observed in human and animals, but so far few studies are focusing on the behavioral profile of animals that do not have seizures despite being treated with convulsant agents.

Objectives: We aimed to establish the behavioral profile, biochemical, and electrographic features of rats submitted to the pilocarpine model of temporal lobe epilepsy

Methods: Rats treated with pilocarpine (20 to 350 mg/kg, i.p.

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Article Synopsis
  • The study explores how modulation of glutamate transmission can offer neuroprotection against excitotoxicity in neurodegenerative diseases and acute brain events.
  • It evaluates the effects of NMDA preconditioning on behavioral and EEG responses in mice, specifically focusing on spike-wave discharges and seizure behaviors after administering quinolinic acid.
  • Findings indicate that NMDA preconditioning increases spike-wave activity but protects against behavioral seizures from subsequent QA exposure, suggesting a potential therapeutic pathway for reducing seizure severity.
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Central injections of serotonin (5-HT) produce hyperdipsic and hypnogenic behavioral effects that are correlated to decreased Fos-immunorreactivity of 5-HT neurons in free-feeding pigeons. We herein (1) probed the role of 5-HT(1A) receptors on the 5-HT- or 8-OH-DPAT-evoked postprandial behaviors and (2) described the sleep-waking states (waking, W; drowsiness, D; slow-wave sleep, SWS; rapid-eye movement sleep, REMS) and sleep architecture of free-feeding pigeons after these treatments. Latency, frequency and duration of feeding, drinking, preening, exploratory and sleep-like behaviors (SLB) were examined after intracerebroventricular (ICV) injections of 5-HT (0, 50 or 150 nmol) or 8-OH-DPAT (DPAT, 0 or 30 nmol) in pigeons pretreated with the 5-HT(1A) antagonist WAY100635 (WAY, 0, 0.

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Central injections of serotonin (5-HT) in food-deprived/refed pigeons evoke a sequence of hypophagic, hyperdipsic and sleep-like responses that resemble the postprandial behavioral sequence. Fasting-refeeding procedures affect sleep and drinking behaviors "per se". Here, we describe the behavioral profile and long-term food/water intake following intracerebroventricular (ICV) injections of 5-HT (50, 150, 300 nmol/2 μl) in free-feeding/drinking pigeons.

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Rationale: Behavioral consequences of convulsive episodes are well documented, but less attention was paid to changes that occur in response to subconvulsant doses of drugs.

Objectives: We investigated short- and long-term effects of a single systemic injection of a subconvulsant dose of pilocarpine on the behavior of rats as evaluated in the elevated plus maze.

Methods And Results: Pilocarpine induced an anxiogenic-like profile 24 h later, and this effect persisted for up to 3 months (% of time spent on open arms at 24 h, control = 35.

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The distribution of tryptophan hydroxylase (TPH)-containing perikarya and processes in the brainstem and diencephalon of the pigeon (Columba livia) were investigated using single-labeling chromogenic and double-labeling fluorescence immunohistochemical methods for TPH and 5-HT. TPH-immunoreactive (TPH-ir) perikarya were seen extending from the caudal medulla to mid-hypothalamic levels, located in brainstem regions previously described as containing 5-HT-ir somata. Brainstem TPH-ir cell clusters (the midline raphe, and the dorsolateral and ventrolateral serotonergic cell groups) and the circumventricular cerebrospinal fluid-contacting neurons in the taenia choroidea (in the caudal brainstem), recessus infundibuli and paraventricular organ (in the hypothalamus) were shown to co-express 5-HT immunoreactivity.

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The effects of systemic injections of the 5HT(1A) receptor agonist 8-OH-DPAT on the spontaneous ingestive, maintenance, locomotor and sleep-like behaviours, and the sleep/waking-related hippocampal electrographic activity were investigated in pigeons. 8-OH-DPAT (0.06, 0.

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