RESUMEN
Different types of resistance to passive movement, i.e. hypertonia, were described in schizophrenia spectrum disorders (SSD) long before the introduction of antipsychotics. While these have been rediscovered in antipsychotic-naïve patients and their non-affected relatives, the existence of intrinsic hypertonia vs drug-induced parkinsonism (DIP) in treated SSD remains controversial. This integrative review seeks to develop a commonly accepted framework to specify the putative clinical phenomena, highlight conflicting issues and discuss ways to challenge each hypothesis and model through adversarial collaboration. The authors agreed on a common framework inspired from systems neuroscience. Specification of DIP, locomotor paratonia (LMP) and psychomotor paratonia (PMP) identified points of disagreement. Some viewed parkinsonian rigidity to be sufficient for diagnosing DIP, while others viewed DIP as a syndrome that should include bradykinesia. Sensitivity of DIP to anticholinergic drugs and the nature of LPM and PMP were the most debated issues. It was agreed that treated SSD should be investigated first. Clinical features of the phenomena at issue could be confirmed by torque, EMG and joint angle measures that could help in challenging the selectivity of DIP to anticholinergics. LMP was modeled as the release of the reticular formation from the control of the supplementary motor area (SMA), which could be challenged by the tonic vibration reflex or acoustic startle. PMP was modeled as the release of primary motor cortex from the control of the SMA and may be informed by subclinical echopraxia. If these challenges are not met, this would put new constraints on the models and have clinical and therapeutic implications.
Asunto(s)
Antipsicóticos , Enfermedad de Parkinson Secundaria , Trastornos Psicóticos , Esquizofrenia , Humanos , Esquizofrenia/complicaciones , Esquizofrenia/tratamiento farmacológico , Antipsicóticos/uso terapéutico , Hipertonía Muscular/etiología , Hipertonía Muscular/tratamiento farmacológico , Trastornos Psicóticos/tratamiento farmacológicoRESUMEN
In the 19th century, postmortem brain examination played a central role in the search for the neurobiological origin of psychiatric and neurological disorders. During that time, psychiatrists, neurologists, and neuropathologists examined autopsied brains from catatonic patients and postulated that catatonia is an organic brain disease. In line with this development, human postmortem studies of the 19th century became increasingly important in the conception of catatonia and might be seen as precursors of modern neuroscience. In this report, we closely examined autopsy reports of eleven catatonia patients of Karl Ludwig Kahlbaum. Further, we performed a close reading and analysis of previously (systematically) identified historical German and English texts between 1800 and 1900 for autopsy reports of catatonia patients. Two main findings emerged: (i) Kahlbaum's most important finding in catatonia patients was the opacity of the arachnoid; (ii) historical human postmortem studies of catatonia patients postulated a number of neuroanatomical abnormalities such as cerebral enlargement or atrophy, anemia, inflammation, suppuration, serous effusion, or dropsy as well as alterations of brain blood vessels such as rupture, distension or ossification in the pathogenesis of catatonia. However, the exact localization has often been missing or inaccurate, probably due to the lack of standardized subdivision/nomenclature of the respective brain areas. Nevertheless, Kahlbaum's 11 autopsy reports and the identified neuropathological studies between 1800 and 1900 made important discoveries, which still have the potential to inform and bolster modern neuroscientific research in catatonia.
Asunto(s)
Autopsia , Encéfalo , Catatonia , Neurociencias , Humanos , Encéfalo/patología , Catatonia/diagnóstico , Catatonia/historia , Catatonia/patología , Neurobiología/historia , Neurociencias/historia , Autopsia/historia , Autopsia/métodos , Historia del Siglo XIXRESUMEN
BACKGROUND: Although the concept of schizophrenia is still widely presented as having replaced that of dementia praecox, studies have shown that the former was broader than the latter, resulting in a more complex diagnostic redistribution. However, this is poorly documented by quantitative approaches. AIMS: We sought to test the hypothesis that the use of the concept of schizophrenia had caused a diagnostic redistribution and to quantify it. METHOD: A retrospective study, based on admission register archives of the Strasbourg University Clinic of Psychiatry was conducted. The frequency of diagnoses given to patients were examined at two key time periods: one before (TP1) and one after (TP2) the introduction of the schizophrenia concept (established between 1926 and 1928). Eight main diagnoses related to schizophrenia were considered. RESULTS: Patients diagnosed with schizophrenia at TP2 mainly received the diagnoses of dementia praecox but also depression, hebephrenia, manic depressive illness, hysteria, paraphrenia, catatonia and mania at TP1. Dementia praecox and hebephrenia were the most relayed by schizophrenia. Bayesian sensitivity analyses confirmed the robustness of our data against distinct scenarios challenging our hypothesis. CONCLUSIONS: Our results confirm the broadening of the concept of schizophrenia compared to that of dementia praecox but also qualify the different concepts supposed to have been impacted. They provide unique quantitative data that define the contours of the diagnostic redistribution thus provoked. They also give relevant input in the current context where the need to rethink the DSM/ICD concept of schizophrenia is still debated.
Asunto(s)
Trastorno Bipolar , Esquizofrenia Hebefrénica , Humanos , Teorema de Bayes , Estudios Retrospectivos , Esquizofrenia ParanoideRESUMEN
Abnormal movements are intrinsic to some forms of endogenous psychoses. Spontaneous dyskinesias are observed in drug-naïve first-episode patients and at-risk subjects. However, recent descriptions of spontaneous dyskinesias may actually represent the rediscovery of a more complex phenomenon, 'parakinesia' which was described and documented in extensive cinematographic recordings and long-term observations by German and French neuropsychiatrists decades before the introduction of antipsychotics. With the emergence of drug induced movement disorders, the description of parakinesia has been refined to emphasize the features enabling differential diagnosis with tardive dyskinesia. Unfortunately, parakinesia was largely neglected by mainstream psychiatry to the point of being almost absent from the English-language literature. With the renewed interest in motor phenomena intrinsic to SSD, it was timely not only to raise awareness of parakinesia, but also to propose a scientifically usable definition for this phenomenon. Therefore, we conducted a Delphi consensus exercise with clinicians familiar with the concept of parakinesia. The original concept was separated into hyperkinetic parakinesia (HPk) as dyskinetic-like expressive movements and parakinetic psychomotricity (PPM), i.e., patient's departing from the patient's normal motion style. HPk prevails on the upper part of the face and body, resembling expressive and reactive gestures that not only occur inappropriately but also appear distorted. Abnormal movements vary in intensity depending on the level of psychomotor arousal and are thus abated by antipsychotics. HPk frequently co-occurs with PPM, in which gestures and mimics lose their naturalness and become awkward, disharmonious, stiff, mannered, and bizarre. Patients are never spontaneously aware of HPk or PPM, and the movements are never experienced as self-dystonic or self-alien. HPk and PPM are highly specific to endogenous psychoses, in which they are acquired and progressive, giving them prognostic value. Their differential diagnoses and correspondences with current international concepts are discussed.
RESUMEN
Catatonia has been defined by ICD-11 as a nosologically unspecific syndrome. Previous neuropsychiatric conceptions of catatonia such as Wernicke-Kleist-Leonhard's (WKL) one, have isolated chronic catatonic entities, such as progressive periodic catatonia (PPC) and chronic system catatonias (CSC). This study aimed at comparing the clinical and neuropsychological features of PPC, CSC and non-catatonic patients, all diagnosed with a schizophrenia spectrum disorder (SSD). The clinical and cognitive measures were compared among 53 SSD patients, first by separating catatonic (C-SSD, n = 27) and non-catatonic patients (NC-SSD, n = 26), and second, by separating PPC (n = 20), CSC (n = 6) and NC-SSD patients. Bayes factors were used to compare the model with 1 or 2 catatonic groups. We found that PPC had a more frequent schizo-affective presentation, higher levels of depression and less positive psychotic symptoms than both CSC and NC-SSD. CSC patients had an earlier illness onset, a poorer cognitive functioning, and higher antipsychotics doses than both PPC and NC-SSD. Most differences between C- and NC-SSD were accounted by characteristics of either PPC or CSC. The model with 2 catatonic groups clearly outperformed that with 1 catatonic group. Our results point to a substantial clinical heterogeneity of 'catatonia' within the SSD population and suggest that distinguishing (at least) 2 chronic catatonic phenotypes (PPC and CSC) may represent a relevant step to apprehend this heterogeneity. It is also a more parsimonious attempt than considering the around 32.000 distinct catatonic presentations resulting from the combinations of 3 out of 15 polythetic criteria for ICD-11 catatonia.
RESUMEN
In the first half of the 20th century, well before the antipsychotic era, paratonia, Gegenhalten and psychomotor hypertonia were described as new forms of hypertonia intrinsic to particular psychoses and catatonic disorders. A series of astute clinical observations and experiments supported their independence from rigidity seen in Parkinson's disease. After World War II, motor disorders went out of fashion in psychiatry, with drug-induced parkinsonism becoming the prevailing explanation for all involuntary resistance to passive motion. With the 'forgetting' of paratonia and Gegenhalten, parkinsonism became the prevailing reading grid, such that the rediscovery of hypertonia in antipsychotic-naive patients at the turn of the 21st century is currently referred to as "spontaneous parkinsonism", implicitly suggesting intrinsic and drug-induced forms to be the same. Classical descriptive psychopathology gives a more nuanced view in suggesting two non-parkinsonian hypertonias: (i) locomotor hypertonia corresponds to Ernest Dupré's paratonia and Karl Kleist's reactive Gegenhalten; it is a dys-relaxation phenomenon that often needs to be activated. (ii) Psychomotor hypertonia is experienced as an admixture of assistance and resistance that partially overlaps with Kleist's spontaneous Gegenhalten, but was convincingly isolated by Henri Claude and Henri Baruk thanks to electromyogram recordings; psychomotor hypertonia is underpinned by "anticipatory contractions" of cortical origin, occurrence of which in phase or antiphase with the movement accounted for facilitation or opposition to passive motions. This century-old knowledge is not only of historical interest. Some results have recently been replicated in dementia and as now known to involve specific premotor systems.
RESUMEN
Since January 1st 2022, catatonia is (again) recognized as an independent diagnostic entity in the 11th revision of the International Classification of Diseases (ICD-11). This is a relevant time to systematically review how the concept of catatonia has evolved within the 19th century and how this concept changed under the influence of a wide variety of events in the history of psychiatry. Here, we systematically reviewed historical and modern German and English texts focusing on catatonic phenomena, published from 1800 to 1900. We searched five different electronical databases (https://archive.org, www.hathitrust.org, www.books.google.de, https://link.springer.com and PubMed) and closely reviewed 60 historical texts on catatonic symptoms. Three main findings emerged: First, catatonic phenomena and their underlying mechanisms were studied decades before Karl Ludwig Kahlbaum's catatonia concept of 1874. Second, Kahlbaum not only introduced catatonia, but, more generally, also called for a new classification of psychiatric disorders based on a comprehensive analysis of the entire clinical picture, including the dynamic course and cross-sectional symptomatology. Third, the literature review shows that between 1800 and 1900 catatonic phenomena were viewed to be 'located' right at the interface of motor and psychological symptoms with the respective pathophysiological mechanisms being discussed. In conclusion, catatonia can truly be considered one of the most exciting and controversial entity in both past and present psychiatry and neurology, as it occupies a unique position in the border territory between organic, psychotic and psychogenic illnesses.
RESUMEN
Current classification systems use the terms "catatonia" and "psychomotor phenomena" as mere a-theoretical descriptors, forgetting about their theoretical embedment. This was the source of misunderstandings among clinicians and researchers of the European collaboration on movement and sensorimotor/psychomotor functioning in schizophrenia and other psychoses or ECSP. Here, we review the different perspectives, their historical roots and highlight discrepancies. In 1844, Wilhelm Griesinger coined the term "psychic-motor" to name the physiological process accounting for volition. While deriving from this idea, the term "psychomotor" actually refers to systems that receive miscellaneous intrapsychic inputs, convert them into coherent behavioral outputs send to the motor systems. More recently, the sensorimotor approach has drawn on neuroscience to redefine the motor signs and symptoms observed in psychoses. In 1874, Karl Kahlbaum conceived catatonia as a brain disease emphasizing its somatic - particularly motor - features. In conceptualizing dementia praecox Emil Kraepelin rephrased catatonic phenomena in purely mental terms, putting aside motor signs which could not be explained in this way. Conversely, the Wernicke-Kleist-Leonhard school pursued Kahlbaum's neuropsychiatric approach and described many new psychomotor signs, e.g. parakinesias, Gegenhalten. They distinguished 8 psychomotor phenotypes of which only 7 are catatonias. These barely overlap with consensus classifications, raising the risk of misunderstanding. Although coming from different traditions, the authors agreed that their differences could be a source of mutual enrichment, but that an important effort of conceptual clarification remained to be made. This narrative review is a first step in this direction.
Asunto(s)
Catatonia , Neurociencias , Trastornos Psicóticos , Catatonia/diagnóstico , Catatonia/terapia , Consenso , Humanos , Desempeño Psicomotor , Trastornos Psicóticos/diagnósticoRESUMEN
BACKGROUND: Several lines of evidence suggest alterations in both hypothalamic-pituitary-thyroid (HPT) axis and dopamine (DA) function in depressed patients. However, the functional relationships between HPT and DA systems have not been well defined. METHODS: We examined thyrotropin (TSH) response to 0800 h and 2300 h protirelin (TRH) challenges, and adrenocorticotropic hormone (ACTH), cortisol and growth hormone (GH) responses to apomorphine (APO, a DA receptor agonist), in 58 drug-free DSM-IV major depressed inpatients without a suicidal behavior, and 22 healthy hospitalized controls. RESULTS: Compared with controls, patients showed 1) lower basal serum 2300 h-TSH, 2300 h-∆TSH, and ∆∆TSH (difference between 2300 h-∆TSH and 0800 h-∆TSH) levels, and 2) lower cortisol response to APO (∆COR). A negative relationship between ∆∆TSH values and hormonal responses to APO was observed in the depressed group, but not in the control group. When patients were classified on the basis of their ∆∆TSH status, patients with reduced ∆∆TSH values (< 2.5 mU/L) showed hormonal APO responses comparable to those of controls. Patients with normal ∆∆TSH values exhibited lower ∆ACTH, ∆COR, and ∆GH values than patients with reduced ∆∆TSH values and controls. CONCLUSION: Taken together, these results suggest that hypothalamic DA function is unaltered in depressed patients with HPT dysregulation (i.e., increased hypothalamic TRH drive leading to altered TRH receptor chronesthesy on pituitary thyrotrophs). Conversely, hypothalamic DA-receptor function is decreased in patients with normal HPT axis activity. These findings are discussed in the context of the role of TRH as a homeostatic neuromodulator in depression.
Asunto(s)
Depresión , Dopamina , Sistema Hipotálamo-Hipofisario , Glándula Tiroides , Hormona Adrenocorticotrópica/sangre , Depresión/sangre , Depresión/fisiopatología , Dopamina/fisiología , Hormona de Crecimiento Humana/sangre , Humanos , Hidrocortisona/sangre , Sistema Hipotálamo-Hipofisario/fisiopatología , Glándula Tiroides/fisiopatología , Tirotropina/sangre , Hormona Liberadora de Tirotropina/sangreRESUMEN
While the ICD-DSM paradigm has been a major advance in clinical psychiatry, its usefulness for biological psychiatry is debated. By defining consensus-based disorders rather than empirically driven phenotypes, consensus classifications were not an implementation of the biomedical paradigm. In the field of endogenous psychoses, the Wernicke-Kleist-Leonhard (WKL) pathway has optimized the descriptions of 35 major phenotypes using common medical heuristics on lifelong diachronic observations. Regarding their construct validity, WKL phenotypes have good reliability and predictive and face validity. WKL phenotypes come with remarkable evidence for differential validity on age of onset, familiality, pregnancy complications, precipitating factors, and treatment response. Most impressive is the replicated separation of high- and low-familiality phenotypes. Created in the purest tradition of the biomedical paradigm, the WKL phenotypes deserve to be contrasted as credible alternatives with other approaches currently under discussion.â©.
Mettre la traduction ES.
Mettre la traduction FR.
Asunto(s)
Manual Diagnóstico y Estadístico de los Trastornos Mentales , Fenotipo , Trastornos Psicóticos/clasificación , Trastornos Psicóticos/diagnóstico , Encefalopatía de Wernicke/clasificación , Encefalopatía de Wernicke/diagnóstico , Humanos , Reproducibilidad de los ResultadosRESUMEN
Over the last three decades, movement disorder as well as sensorimotor and psychomotor functioning in schizophrenia (SZ) and other psychoses has gained greater scientific and clinical relevance as an intrinsic component of the disease process of psychotic illness; this extends to early psychosis prediction, early detection of motor side effects of antipsychotic medication, clinical outcome monitoring, treatment of psychomotor syndromes (e.g. catatonia), and identification of new targets for non-invasive brain stimulation. In 2017, a systematic cooperation between working groups interested in movement disorder and sensorimotor/psychomotor functioning in psychoses was initiated across European universities. As a first step, the members of this group would like to introduce and define the theoretical aspects of the sensorimotor domain in SZ and other psychoses. This consensus paper is based on a synthesis of scientific evidence, good clinical practice and expert opinions that were discussed during recent conferences hosted by national and international psychiatric associations. While reviewing and discussing the recent theoretical and experimental work on neural mechanisms and clinical implications of sensorimotor behavior, we here seek to define the key principles and elements of research on movement disorder and sensorimotor/psychomotor functioning in psychotic illness. Finally, the members of this European group anticipate that this consensus paper will stimulate further multimodal and prospective studies on hypo- and hyperkinetic movement disorders and sensorimotor/psychomotor functioning in SZ and other psychotic disorders.
Asunto(s)
Consenso , Trastornos del Movimiento/fisiopatología , Desempeño Psicomotor/fisiología , Trastornos Psicóticos/fisiopatología , Esquizofrenia/fisiopatología , Animales , Congresos como Asunto , Europa (Continente)/epidemiología , Humanos , Trastornos del Movimiento/diagnóstico , Trastornos del Movimiento/epidemiología , Trastornos del Movimiento/psicología , Estudios Prospectivos , Trastornos Psicóticos/diagnóstico , Trastornos Psicóticos/epidemiología , Esquizofrenia/diagnóstico , Esquizofrenia/epidemiologíaRESUMEN
INTRODUCTION: Magnetic resonance imaging (MRI) shows slight spatial variations in brain white matter (WM). We used quantitative multi-parametric MRI to evaluate in what respect these inhomogeneities could correspond to WM subtypes with specific characteristics and spatial distribution. MATERIALS AND METHODS: Twenty-six controls (12 women, 38 ±9 Y) took part in a 60-min session on a 3T scanner measuring 7 parameters: R1 and R2, diffusion tensor imaging which allowed to measure Axial and Radial Diffusivity (AD, RD), magnetization transfer imaging which enabled to compute the Macromolecular Proton Fraction (MPF), and a susceptibility-weighted sequence which permitted to quantify R2* and magnetic susceptibility (χm). Spatial independent component analysis was used to identify WM subtypes with specific combination of quantitative parameters values. RESULTS: Three subtypes could be identified. t-WM (track) mostly mapped on well-formed projection and commissural tracts and came with high AD values (all p < 10(-18)). The two other subtypes were located in subcortical WM and overlapped with association fibers: f-WM (frontal) was mostly anterior in the frontal lobe whereas c-WM (central) was underneath the central cortex. f-WM and c-WM had higher MPF values, indicating a higher myelin content (all p < 1.7 10(-6)). This was compatible with their larger χm and R2, as iron is essentially stored in oligodendrocytes (all p < 0.01). Although R1 essentially showed the same, its higher value in t-WM relative to c-WM might be related to its higher cholesterol concentration. CONCLUSIONS: Thus, f- and c-WMs were less structured, but more myelinated and probably more metabolically active regarding to their iron content than WM related to fasciculi (t-WM). As known WM bundles passed though different WM subtypes, myelination might not be uniform along the axons but rather follow a spatially consistent regional variability. Future studies might examine the reproducibility of this decomposition and how development and pathology differently affect each subtype.
Asunto(s)
Imagen de Difusión Tensora , Imagen por Resonancia Magnética , Sustancia Blanca/diagnóstico por imagen , Adulto , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Our purpose was to validate a reliable method to capture brain activity concomitant with hallucinatory events, which constitute frequent and disabling experiences in schizophrenia. Capturing hallucinations using functional magnetic resonance imaging (fMRI) remains very challenging. We previously developed a method based on a two-steps strategy including (1) multivariate data-driven analysis of per-hallucinatory fMRI recording and (2) selection of the components of interest based on a post-fMRI interview. However, two tests still need to be conducted to rule out critical pitfalls of conventional fMRI capture methods before this two-steps strategy can be adopted in hallucination research: replication of these findings on an independent sample and assessment of the reliability of the hallucination-related patterns at the subject level. To do so, we recruited a sample of 45 schizophrenia patients suffering from frequent hallucinations, 20 schizophrenia patients without hallucinations and 20 matched healthy volunteers; all participants underwent four different experiments. The main findings are (1) high accuracy in reporting unexpected sensory stimuli in an MRI setting; (2) good detection concordance between hypothesis-driven and data-driven analysis methods (as used in the two-steps strategy) when controlled unexpected sensory stimuli are presented; (3) good agreement of the two-steps method with the online button-press approach to capture hallucinatory events; (4) high spatial consistency of hallucinatory-related networks detected using the two-steps method on two independent samples. By validating the two-steps method, we advance toward the possible transfer of such technology to new image-based therapies for hallucinations. Hum Brain Mapp 38:4966-4979, 2017. © 2017 Wiley Periodicals, Inc.
Asunto(s)
Encéfalo/diagnóstico por imagen , Encéfalo/fisiopatología , Alucinaciones/diagnóstico por imagen , Alucinaciones/fisiopatología , Imagen por Resonancia Magnética/métodos , Adulto , Antipsicóticos/uso terapéutico , Mapeo Encefálico/métodos , Femenino , Alucinaciones/tratamiento farmacológico , Humanos , Masculino , Reproducibilidad de los Resultados , Esquizofrenia/diagnóstico por imagen , Esquizofrenia/tratamiento farmacológico , Esquizofrenia/fisiopatologíaRESUMEN
PURPOSE: Locked-in syndrome and vegetative state are distinct outcomes from coma. Despite their differences, they are clinically difficult to distinguish at the early stage and current diagnostic tools remain insufficient. Since some brain functions are preserved in locked-in syndrome, we postulated that networks of spontaneously co-activated brain areas might be present in locked-in patients, similar to healthy controls, but not in patients in a vegetative state. METHODS: Five patients with locked-in syndrome, 12 patients in a vegetative state and 19 healthy controls underwent a resting-state fMRI scan. Individual spatial independent component analysis was used to separate spontaneous brain co-activations from noise. These co-activity maps were selected and then classified by two raters as either one of eight resting-state networks commonly shared across subjects or as specific to a subject. RESULTS: The numbers of spontaneous co-activity maps, total resting-state networks, and resting-state networks underlying high-level cognitive activity were shown to differentiate controls and locked-in patients from patients in a vegetative state. Analyses of each common resting-state network revealed that the default mode network accurately distinguished locked-in from vegetative-state patients. The frontoparietal network also had maximum specificity but more limited sensitivity. CONCLUSIONS: This study reinforces previous reports on the preservation of the default mode network in locked-in syndrome in contrast to vegetative state but extends them by suggesting that other networks might be relevant to the diagnosis of locked-in syndrome. The aforementioned analysis of fMRI brain activity at rest might be a step in the development of a diagnostic biomarker to distinguish locked-in syndrome from vegetative state.
Asunto(s)
Mapeo Encefálico/métodos , Red Nerviosa/diagnóstico por imagen , Estado Vegetativo Persistente/diagnóstico por imagen , Cuadriplejía/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Red Nerviosa/fisiopatología , Estado Vegetativo Persistente/fisiopatología , Cuadriplejía/fisiopatología , Adulto JovenRESUMEN
BACKGROUND: During the last years, many investigations focused on spontaneously active cerebral networks such as the default-mode network. A data-driven technique, the independent component analysis, allows segregating such spontaneous (co-)activity maps (SAM) from noise in functional magnetic resonance imaging (fMRI) time series. The inter-rater reliability of manual selection of not only the default-mode network but all SAMs remained to be assessed. NEW METHOD: The current study was performed on 20 min (400 volumes) fMRI time series of 30 healthy participants. SAMs' selection criteria were first established on past experience and from the literature. The inter-rater reliability of SAMs vs non-SAMs manual selection was then investigated from 250 independent components per participant. RESULTS: Inter-rater Kappa coefficient was of 0.89 ± 0.01 on whole analysis, and 0.88 ± 0.09 on participant per participant analysis. COMPARISON WITH EXISTING METHODS: Without focusing on specific and predetermined SAMs only, our criteria allow a reliable selection of all SAMs including the idiosyncratic networks. CONCLUSIONS: The proposed SAM's selection criteria are reliable enough to allow scientific exploration of all SAMs at the single subject level.
Asunto(s)
Mapeo Encefálico , Encéfalo/fisiología , Procesos Mentales/fisiología , Análisis de Componente Principal , Adulto , Encéfalo/irrigación sanguínea , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Redes Neurales de la Computación , Variaciones Dependientes del Observador , Oxígeno/sangre , Reproducibilidad de los ResultadosRESUMEN
Cognition has become a target for therapeutic intervention and favoring arousal could be a way to help patients. Working memory is an arousal dependent cognitive function. This study used functional MRI (fMRI) as a surrogate marker of working memory to evaluate the sensitivity of patients' hypoactive regions to arousal in a subpopulation of rehabilitated patients. Are hypoactive regions sensitive to arousal? Does the deficit result from arousal deficit or improper coupling with cognitive activity? Eighteen patients and matched controls were recruited. Participants performed a working memory task during combined electroencephalographic (EEG) and fMRI measurements. Cortical regions sensitive to arousal were defined as those which were inversely correlated with low EEG frequencies. Overlap between the arousal-sensitive and hypoactive regions was assessed by mutual information. Arousal-cognitive coupling was evaluated by the correlation between the arousal effect and the task effect. In the patient group, most hypoactive voxels were sensitive to arousal and corresponded to the prefronto-parietal network. But patients had no arousal deficit. Although arousal seems to improve cognitive activity in most of the patients' cortical areas, this coupling appears to be specifically disturbed in their hypoactive regions. In conclusion, although increasing arousal may help cognition, it may do so in an unspecific way.
Asunto(s)
Nivel de Alerta/fisiología , Encéfalo/irrigación sanguínea , Trastornos del Conocimiento/etiología , Memoria a Corto Plazo/fisiología , Esquizofrenia/complicaciones , Esquizofrenia/patología , Adulto , Encéfalo/patología , Mapeo Encefálico , Electroencefalografía/métodos , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética/métodos , Masculino , Pruebas Neuropsicológicas , Oxígeno/sangre , Escalas de Valoración Psiquiátrica , Adulto JovenRESUMEN
PURPOSE: To take into account the echo time (TE) influence on arterial spin labeling (ASL) signal when converting it in regional cerebral blood flow (rCBF). Gray matter ASL signal decrease with increasing TE as a consequence of the difference in the apparent transverse relaxation rates between labeled water in capillaries and nonlabeled water in the tissue (δR 2*). We aimed to measure ASL/rCBF changes in different parts of the brain and correct them. MATERIALS AND METHODS: Fifteen participants underwent ASL measurements at TEs of 9.7-30 ms. Decreases in ASL values were localized by statistical parametric mapping. The corrections assessed were a subject-per-subject adjustment, an average δR 2* value adjustment, and a two-compartment model adjustment. RESULTS: rCBF decreases associated with increasing TEs were found for gray matter and were corrected using an average δR 2* value of 20 s(-1) . Conversely, for white matter, rCBF values increased with increasing TEs (δR 2* = -23 s(-1)). CONCLUSION: Our correction was as good as using a two-compartment model. However, it must be done separately for the gray and white matter rCBF values because the capillary R 2* values are, respectively, larger and smaller than those of surrounding tissues.
Asunto(s)
Circulación Cerebrovascular/fisiología , Imagen Eco-Planar/métodos , Angiografía por Resonancia Magnética/métodos , Marcadores de Spin , Adulto , Tiempo de Circulación Sanguínea , Angiografía Cerebral/métodos , Arterias Cerebrales/fisiología , Corteza Cerebral/irrigación sanguínea , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modelos Cardiovasculares , Fibras Nerviosas Mielínicas/fisiología , Muestreo , Sensibilidad y EspecificidadRESUMEN
Most brain functional connectivity methods in fMRI require a brain parcellation into functionally homogeneous regions. In this work we propose a novel parcellation approach based on a spatial hierarchical clustering, that provides clusters within a multi-level framework. The method has the advantage of producing several brain parcellations rather than a single one from a fixed size-homogeneity criterion. Results obtained on real data demonstrate the relevance of the approach. Finally, a connectivity study shows the benefit of a prior multi-level parcellation of the brain.