Stressful stimuli in healthy subjects trigger activation of a consistent and reproducible set of brain regions; yet, the notion that there is a single and constant stress neuromatrix is not ...sustainable. Indeed, after chronic stress exposure there is activation of many brain regions outside that network. This suggests that there is a distinction between the acute and the chronic stress neuromatrix. Herein, a new working model is proposed to understand the shift between these networks. The understanding of the factors that modulate these networks and their interplay will allow for a more comprehensive and holistic perspective of how the brain shifts 'back and forth' from a healthy to a stressed pattern and, ultimately, how the latter can be a trigger for several neurological and psychiatric conditions.
Preclinical imaging studies offer a unique access to the rat brain, allowing investigations that go beyond what is possible in human studies. Unfortunately, these techniques still suffer from a lack ...of dedicated and standardized neuroimaging tools, namely brain templates and descriptive atlases. Here, we present two rat brain MRI templates and their associated gray matter, white matter and cerebrospinal fluid probability maps, generated from ex vivo Formula: see text-weighted images (90 µm isotropic resolution) and in vivo T
-weighted images (150 µm isotropic resolution). In association with these templates, we also provide both anatomical and functional 3D brain atlases, respectively derived from the merging of the Waxholm and Tohoku atlases, and analysis of resting-state functional MRI data. Finally, we propose a complete set of preclinical MRI reference resources, compatible with common neuroimaging software, for the investigation of rat brain structures and functions.
Stress is a well-established trigger for a number of neuropsychiatric disorders, as it alters both structure and function of several brain regions and its networks. Herein, we conduct a longitudinal ...neuroimaging study to assess how a chronic unpredictable stress protocol impacts the structure of the rat brain and its functional connectome in both high and low responders to stress. Our results reveal the changes that stress triggers in the brain, with structural atrophy affecting key regions such as the prelimbic, cingulate, insular and retrosplenial, somatosensory, motor, auditory and perirhinal/entorhinal cortices, the hippocampus, the dorsomedial striatum, nucleus accumbens, the septum, the bed nucleus of the stria terminalis, the thalamus and several brain stem nuclei. These structural changes are associated with increasing functional connectivity within a network composed by these regions. Moreover, using a clustering based on endocrine and behavioural outcomes, animals were classified as high and low responders to stress. We reveal that susceptible animals (high responders) develop local atrophy of the ventral tegmental area and an increase in functional connectivity between this area and the thalamus, further spreading to other areas that link the cognitive system with the fight-or-flight system. Through a longitudinal approach we were able to establish two distinct patterns, with functional changes occurring during the exposure to stress, but with an inflection point after the first week of stress when more prominent changes were seen. Finally, our study revealed differences in functional connectivity in a brainstem-limbic network that distinguishes resistant and susceptible responders before any exposure to stress, providing the first potential imaging-based predictive biomarkers of an individual's resilience/vulnerability to stressful conditions.
•Functional asymmetries are necessary for cognitive and emotional function.•Lateralized structural and functional adaptation can be observed throughout life.•In physiological conditions, lateralized ...plasticity is necessary for CNS specialized functions.•In pathological conditions, such plasticity can be adaptive or maladaptive, depending on the stimulus and age of onset.•Mechanisms underlying left/right differences in plasticity remain elusive.
The brain is inherently asymmetrical. How that attribute, manifest both structurally (volumetric, cytological, molecular) as well as functionally, relates to cognitive function, is not fully understood. Since the early descriptions of Paul Broca and Marc Dax it has been known that the processing of language in the brain is fundamentally asymmetrical. Contemporary imaging studies have corroborated early observations, and have also revealed significant functional links to multiple other systems, such as those sub serving memory or emotion.
Recent studies have demonstrated that laterality is both plastic and adaptive. Learning and training have shown to affect regional changes in asymmetry, such as that observed in the volume of the planum temporale associated with musical practice. Increasing task complexity has been demonstrated to induce recruitment of contralateral regions, suggesting that laterality is a manifestation of functional reserve. Indeed, in terms of cognitive function, successful aging is often associated with a reduction of asymmetrical activity.
The goal of this review is to survey and critically appraise the current literature addressing brain laterality, both morphological and functional, with particular emphasis on the asymmetrical plasticity associated with environmental factors and training. The plastic recruitment of contralateral areas associated with aging and unilateral lesions will be discussed in the context of the loss of asymmetry as a compensatory mechanism, and specific instances of maladaptive plasticity will be explored.
A hybrid technique is proposed to enhance the localization performance of a time difference of arrival (TDOA) deployed in non-line-of-sight (NLOS) suburban scenario. The idea was to use Machine ...Learning framework on the dataset, produced by the ray tracing simulation, and the Channel Impulse Response estimation from the real signal received by each sensor. Conventional localization techniques mitigate errors trying to avoid NLOS measurements in processing emitter position, while the proposed method uses the multipath fingerprint information produced by ray tracing (RT) simulation together with calibration emitters to refine a Machine Learning engine, which gives an extra layer of information to improve the emitter position estimation. The ray-tracing fingerprints perform the target localization embedding all the reflection and diffraction in the propagation scenario. A validation campaign was performed and showed the feasibility of the proposed method, provided that the buildings can be appropriately included in the scenario description.
Chronic stress is a major risk factor for several human disorders that affect modern societies. The brain is a key target of chronic stress. In fact, there is growing evidence indicating that ...exposure to stress affects learning and memory, decision making and emotional responses, and may even predispose for pathological processes, such as Alzheimer's disease and depression. Lipids are a major constituent of the brain and specifically signaling lipids have been shown to regulate brain function. Here, we used a mass spectrometry-based lipidomic approach to evaluate the impact of a chronic unpredictable stress (CUS) paradigm on the rat brain in a region-specific manner. We found that the prefrontal cortex (PFC) was the area with the highest degree of changes induced by chronic stress. Although the hippocampus presented relevant lipidomic changes, the amygdala and, to a greater extent, the cerebellum presented few lipid changes upon chronic stress exposure. The sphingolipid and phospholipid metabolism were profoundly affected, showing an increase in ceramide (Cer) and a decrease in sphingomyelin (SM) and dihydrosphingomyelin (dhSM) levels, and a decrease in phosphatidylethanolamine (PE) and ether phosphatidylcholine (PCe) and increase in lysophosphatidylethanolamine (LPE) levels, respectively. Furthermore, the fatty-acyl profile of phospholipids and diacylglycerol revealed that chronic stressed rats had higher 38 carbon(38C)-lipid levels in the hippocampus and reduced 36C-lipid levels in the PFC. Finally, lysophosphatidylcholine (LPC) levels in the PFC were found to be correlated with blood corticosterone (CORT) levels. In summary, lipidomic profiling of the effect of chronic stress allowed the identification of dysregulated lipid pathways, revealing putative targets for pharmacological intervention that may potentially be used to modulate stress-induced deficits.
Introduction
Catatonia is a treatable but often undiagnosed condition in children and adolescents. The majority of Pediatric catatonia cases occur at a puberal ages. It is associated with ...neurodevelopmental disorders. In these cases the diagnosis can be more difficult due to the overlap of symptoms.
Objectives
Report the case of a 11- year - old girl who developed catatonia. She had a previous psychiatry history of intellectual disability, delayed speech and motor slowness. She had a positive Lorazepam challenge test with resolution of the most catatonic symptoms. More studies were completed and according to the clinical history the diagnosis of autistic spectrum disorder was made.
Genetic test revealed a Phelan Mc Dermid Syndrom.
Methods
A year 11-year-old girl presented to the pediatric emergency department with a 2- days history of worsening anxiety and rigidity, seeming lost and distant. The previous 4 months there was a history of progressive functional and social decline. Her speech was minimal and she required assistance with dressing and feeding. She displayed stereotypias and mannerism. All medical studies were unremarkable. A Lorazepam challenge test (2 mg IV) showed evidence of response. She recovered from catatonia and the basal situation was studied. She was diagnosed of autistic espectrum disorder attending the psychiatric and medical history. Apart from other medical studies, a genetic test showed a mutation in a gene called SHANK 3 according to a Phelan Mc Dermid Syndrom.
Results
Pediatric catatonia is associated with neurodevelopmental disorders such as autistic spectrum disorders. There is not always a clear identifiable cause and it is necessary to rule out possible organic causes of pediatric catatonia. The treatment is similar to adults. It is essential to do a complete medical and psychiatric history to an accurate diagnosis such as an autistic spectrum disorder. Genetic testing must be included. In this case, genetics showed a Phelan Mc Dermid Syndrom with a delayed diagnosis. This disorder can cause a wide range of symptoms varying in severity. These symptoms could include global developmental disorders, intellectual disability, delayed speech, autistic spectrum disorders and minor dysmorphic features.
Conclusions
It is crutial to emphasize the high incidence of catatonic symptoms in individuals with Phelan Mc Dermid Syndrome as catatonia often goes unrecognized or undertreated in individuals with developmental disabilities. Significant cognitive and behavioral regression beyond a baseline level of disability has been reported. This case also highlights the relevance of genetic testing in the work of individuals with intellectual disabilities and acute psychiatric illness or regression. Symptoms indicative of catatonia may occur in context of infections, hormonal status and stressful life events. Treatment is centered on the symptoms.
Disclosure of Interest
None Declared
Introduction
The COVID-19 outbreak imposed several periods of lockdown to stop the pandemic, with a determinant impact on access to mental health services. In Portugal, the first State of Emergency ...was declared on the 18th of March 2020, with the obligation of mandatory confinement and circulation restriction. Restrictive measures were alleviated on the 2nd of May 2020.
Objectives
We aimed to investigate the impact of the first confinement on the maintenance or loss of psychiatric and psychological follow-up. Also, we aimed to explore the outcomes in the mental health of losing psychiatric or psychological consultations.
Methods
We conducted an online survey among the Portuguese population to evaluate demographic, clinical and mental health variables (STAI, DASS-21, PHQ, OCI-R, Quality of Life QoL and PSS). Individuals were invited to answer the survey at two timepoints: third week of March 2020 and third week of May 2020. Concerning the first timepoint, we used independent t-tests to compare the mental health variables in the individuals who loss and who did not lose consultations. Then, we evaluated the impact of losing consultations across time in those individuals who continued responding in the second timepoint, through a Linear Fixed Model. All the analyses were performed using JASP software.
Results
From the total sample (n=2040), 334 individuals (84.4% female gender) had psychiatric and/or psychological consultations previously to the confinement. In March 2020, the individuals who maintained the consultations (35.0%) showed best mental health indicators in the QoL Self Evaluation (p=0.002), QoL Satisfaction (p=0.037), STAI State (p<0.001), DASS-21 (p=0.001), PHQ (p<0.001), OCI-R (p=0.002) and PSS (p<0.001). Among the matched individuals who answered the survey in May 2020 (n=93), we found that the group who maintained follow-up (n=24) did not improve significantly more than the other group (n=69) for any of the mental health variables in study.
Conclusions
The results indicate that stopping psychiatric and psychological follow-up represented worse mental health outcomes at the beginning of the first confinement. However, anxiety feelings improved at the end of the first confinement, which happened independently of psychiatric/ psychological follow-up.
Disclosure of Interest
None Declared
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