CRIS

Permanent URI for this communityhttps://investigadores.udd.cl/handle/123456789/1

Browse

Search Results

Now showing 1 - 4 of 4

Some of the metrics are blocked by your
consent settings
Structural brain abnormalities in schizophrenia in adverse environments: examining the effect of poverty and violence in six Latin American cities
(2020)
Nicolas A. Crossley
;
Andre Zugman
;
Francisco Reyes-Madrigal
;
Leticia S. Czepielewski
;
Mariana N. Castro
<jats:title>Summary</jats:title><jats:sec id="S0007125020001439_sec_a1"><jats:title>Background</jats:title><jats:p>Social and environmental factors such as poverty or violence modulate the risk and course of schizophrenia. However, how they affect the brain in patients with psychosis remains unclear.</jats:p></jats:sec><jats:sec id="S0007125020001439_sec_a2"><jats:title>Aims</jats:title><jats:p>We studied how environmental factors are related to brain structure in patients with schizophrenia and controls in Latin America, where these factors are large and unequally distributed.</jats:p></jats:sec><jats:sec id="S0007125020001439_sec_a3" sec-type="methods"><jats:title>Method</jats:title><jats:p>This is a multicentre study of magnetic resonance imaging in patients with schizophrenia and controls from six Latin American cities. Total and voxel-level grey matter volumes, and their relationship with neighbourhood characteristics such as average income and homicide rates, were analysed with a general linear model.</jats:p></jats:sec><jats:sec id="S0007125020001439_sec_a4" sec-type="results"><jats:title>Results</jats:title><jats:p>A total of 334 patients with schizophrenia and 262 controls were included. Income was differentially related to total grey matter volume in both groups (<jats:italic>P</jats:italic> = 0.006). Controls showed a positive correlation between total grey matter volume and income (<jats:italic>R</jats:italic> = 0.14, <jats:italic>P</jats:italic> = 0.02). Surprisingly, this relationship was not present in patients with schizophrenia (<jats:italic>R</jats:italic> = −0.076, <jats:italic>P</jats:italic> = 0.17). Voxel-level analysis confirmed that this interaction was widespread across the cortex. After adjusting for global brain changes, income was positively related to prefrontal cortex volumes only in controls. Conversely, the hippocampus in patients with schizophrenia, but not in controls, was relatively larger in affluent environments. There was no significant correlation between environmental violence and brain structure.</jats:p></jats:sec><jats:sec id="S0007125020001439_sec_a5" sec-type="conclusions"><jats:title>Conclusions</jats:title><jats:p>Our results highlight the interplay between environment, particularly poverty, and individual characteristics in psychosis. This is particularly important for harsh environments such as low- and middle-income countries, where potentially less brain vulnerability (less grey matter loss) is sufficient to become unwell in adverse (poor) environments.</jats:p></jats:sec>
Scopus© Citations 10 1
Some of the metrics are blocked by your
consent settings
Association between spontaneous internal carotid artery dissection and perivascular adipose tissue attenuation on computed tomography angiography
(2023)
Kevin Cheng
;
Andrew Lin
;
STECHER GUZMAN, XIMENA PATRICIA
;
Tomas Bernstein
;
Paulo Zuñiga
<jats:sec><jats:title>Background:</jats:title><jats:p> Spontaneous cervical artery dissection (sCAD) is a leading cause of ischemic stroke in young patients. Studies using high-resolution magnetic resonance imaging and positron emission tomography have suggested vessel wall inflammation to be a pathogenic factor in sCAD. Computed tomography (CT) attenuation of perivascular adipose tissue (PVAT) is an established non-invasive imaging biomarker of inflammation in coronary arteries, with higher attenuation values reflecting a greater degree of vascular inflammation. </jats:p></jats:sec><jats:sec><jats:title>Objectives:</jats:title><jats:p> We evaluate the CT attenuation of PVAT surrounding the internal carotid artery (PVAT<jats:sub>carotid</jats:sub>) with and without spontaneous dissection. </jats:p></jats:sec><jats:sec><jats:title>Methods:</jats:title><jats:p> Single-center prospective observational study of 56 consecutive patients with CT-verified spontaneous dissection of the internal carotid artery (ICA). Of these patients, six underwent follow-up computed tomography angiography (CTA). Twenty-two patients who underwent CTA for acute neurological symptoms but did not have dissection formed the control group. Using semi-automated research software, PVAT<jats:sub>carotid</jats:sub> was measured as the mean Hounsfield unit (HU) attenuation of adipose tissue within a defined volume of interest surrounding the ICA. </jats:p></jats:sec><jats:sec><jats:title>Results:</jats:title><jats:p> PVAT<jats:sub>carotid</jats:sub> was significantly higher around dissected ICA compared with non-dissected contralateral ICA in the same patients (−58.7 ± 10.2 vs −68.9 ± 8.1 HU, p < 0.0001) and ICA of patients without dissection (−58.7 ± 10.2 vs −69.3 ± 9.3 HU, p < 0.0001). After a median follow-up of 89 days, there was a significant reduction in PVAT<jats:sub>carotid</jats:sub> around dissected ICA (−57.5 ± 13.4 to −74.3 ± 10.5 HU, p < 0.05), while no change was observed around non-dissected contralateral ICA (−71.0 ± 4.4 to −74.1 ± 4.1 HU, p = 0.19). ICA dissection was an independent predictor of PVAT<jats:sub>carotid</jats:sub> following multivariable adjustment for age and the presence of ICA occlusion. </jats:p></jats:sec><jats:sec><jats:title>Conclusion:</jats:title><jats:p> PVAT<jats:sub>carotid</jats:sub> is elevated in the presence of sCAD and may decrease following the acute event. </jats:p></jats:sec>
3 1Scopus© Citations 5
Some of the metrics are blocked by your
consent settings
Multidimensional inhibitory signatures of sentential negation in behavioral variant frontotemporal dementia
(2022)
Mariano N Díaz-Rivera
;
Agustina Birba
;
Sol Fittipaldi
;
Débora Mola
;
Yurena Morera
<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Background</jats:title> <jats:p>Processing of linguistic negation has been associated to inhibitory brain mechanisms. However, no study has tapped this link via multimodal measures in patients with core inhibitory alterations, a critical approach to reveal direct neural correlates and potential disease markers.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>Here we examined oscillatory, neuroanatomical, and functional connectivity signatures of a recently reported Go/No-go negation task in healthy controls and behavioral variant frontotemporal dementia (bvFTD) patients, typified by primary and generalized inhibitory disruptions. To test for specificity, we also recruited persons with Alzheimer's disease (AD), a disease involving frequent but nonprimary inhibitory deficits.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>In controls, negative sentences in the No-go condition distinctly involved frontocentral delta (2–3 Hz) suppression, a canonical inhibitory marker. In bvFTD patients, this modulation was selectively abolished and significantly correlated with the volume and functional connectivity of regions supporting inhibition (e.g. precentral gyrus, caudate nucleus, and cerebellum). Such canonical delta suppression was preserved in the AD group and associated with widespread anatomo-functional patterns across non-inhibitory regions.</jats:p> </jats:sec> <jats:sec> <jats:title>Discussion</jats:title> <jats:p>These findings suggest that negation hinges on the integrity and interaction of spatiotemporal inhibitory mechanisms. Moreover, our results reveal potential neurocognitive markers of bvFTD, opening a new agenda at the crossing of cognitive neuroscience and behavioral neurology.</jats:p> </jats:sec>
Scopus© Citations 18 4
Some of the metrics are blocked by your
consent settings
Dysconnectivity in Schizophrenia Revisited: Abnormal Temporal Organization of Dynamic Functional Connectivity in Patients With a First Episode of Psychosis
(2022)
Juan P Ramirez-Mahaluf
;
Ángeles Tepper
;
Luz Maria Alliende
;
Carlos Mena
;
Carmen Paz Castañeda
<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Background and Hypothesis</jats:title> <jats:p>Abnormal functional connectivity between brain regions is a consistent finding in schizophrenia, including functional magnetic resonance imaging (fMRI) studies. Recent studies have highlighted that connectivity changes in time in healthy subjects. We here examined the temporal changes in functional connectivity in patients with a first episode of psychosis (FEP). Specifically, we analyzed the temporal order in which whole-brain organization states were visited.</jats:p> </jats:sec> <jats:sec> <jats:title>Study Design</jats:title> <jats:p>Two case-control studies, including in each sample a subgroup scanned a second time after treatment. Chilean sample included 79 patients with a FEP and 83 healthy controls. Mexican sample included 21 antipsychotic-naïve FEP patients and 15 healthy controls. Characteristics of the temporal trajectories between whole-brain functional connectivity meta-states were examined via resting-state functional MRI using elements of network science. We compared the cohorts of cases and controls and explored their differences as well as potential associations with symptoms, cognition, and antipsychotic medication doses.</jats:p> </jats:sec> <jats:sec> <jats:title>Study Results</jats:title> <jats:p>We found that the temporal sequence in which patients’ brain dynamics visited the different states was more redundant and segregated. Patients were less flexible than controls in changing their network in time from different configurations, and explored the whole landscape of possible states in a less efficient way. These changes were related to the dose of antipsychotics the patients were receiving. We replicated the relationship with antipsychotic medication in the antipsychotic-naïve FEP sample scanned before and after treatment.</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>We conclude that psychosis is related to a temporal disorganization of the brain’s dynamic functional connectivity, and this is associated with antipsychotic medication use.</jats:p> </jats:sec>
Scopus© Citations 17 1

CRIS

Browse

Filters

Settings

Sort By

Results per page

Search Results