Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
1.
PLoS One ; 10(3): e0119500, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25798822

RESUMEN

Several studies have investigated the neural basis of effortful emotion regulation (ER) but the neural basis of automatic ER has been less comprehensively explored. The present study investigated the neural basis of automatic ER supported by 'implementation intentions'. 40 healthy participants underwent fMRI while viewing emotion-eliciting images and used either a previously-taught effortful ER strategy, in the form of a goal intention (e.g., try to take a detached perspective), or a more automatic ER strategy, in the form of an implementation intention (e.g., "If I see something disgusting, then I will think these are just pixels on the screen!"), to regulate their emotional response. Whereas goal intention ER strategies were associated with activation of brain areas previously reported to be involved in effortful ER (including dorsolateral prefrontal cortex), ER strategies based on an implementation intention strategy were associated with activation of right inferior frontal gyrus and ventro-parietal cortex, which may reflect the attentional control processes automatically captured by the cue for action contained within the implementation intention. Goal intentions were also associated with less effective modulation of left amygdala, supporting the increased efficacy of ER under implementation intention instructions, which showed coupling of orbitofrontal cortex and amygdala. The findings support previous behavioural studies in suggesting that forming an implementation intention enables people to enact goal-directed responses with less effort and more efficiency.


Asunto(s)
Atención/fisiología , Encéfalo/fisiología , Emociones/fisiología , Respuesta Galvánica de la Piel , Intención , Imagen por Resonancia Magnética/métodos , Adolescente , Adulto , Femenino , Voluntarios Sanos , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Neuroimagen , Reconocimiento Visual de Modelos , Adulto Joven
2.
Neuropsychologia ; 67: 159-74, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25527112

RESUMEN

Self-deception and impression-management comprise two types of deceptive, but generally socially acceptable behaviours, which are common in everyday life as well as being present in a number of psychiatric disorders. We sought to establish and dissociate the 'normal' brain substrates of self-deception and impression-management. Twenty healthy participants underwent fMRI scanning at 3T whilst completing the 'Balanced Inventory of Desirable Responding' test under two conditions: 'fake good', giving the most desirable impression possible and 'fake bad' giving an undesirable impression. Impression-management scores were more malleable to manipulation via 'faking' than self-deception scores. Response times to self-deception questions and 'fake bad' instructions were significantly longer than to impression-management questions and 'fake good' instructions respectively. Self-deception and impression-management manipulation and 'faking bad' were associated with activation of medial prefrontal cortex (mPFC) and left ventrolateral prefrontal cortex (vlPFC). Impression-management manipulation was additionally associated with activation of left dorsolateral prefrontal cortex and left posterior middle temporal gyrus. 'Faking bad' was additionally associated with activation of right vlPFC, left temporo-parietal junction and right cerebellum. There were no supra-threshold activations associated with 'faking good'. Our neuroimaging data suggest that manipulating self-deception and impression-management and more specifically 'faking bad' engages a common network comprising mPFC and left vlPFC. Shorter response times and lack of dissociable neural activations suggests that 'faking good', particularly when it comes to impression-management, may be our most practiced 'default' mode.


Asunto(s)
Encéfalo/fisiología , Decepción , Percepción Social , Adulto , Mapeo Encefálico , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Corteza Prefrontal/fisiología , Adulto Joven
3.
Cogn Emot ; 29(2): 319-31, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-24678930

RESUMEN

Emotion regulation (ER) is vital to everyday functioning. However, the effortful nature of many forms of ER may lead to regulation being inefficient and potentially ineffective. The present research examined whether structured practice could increase the efficiency of ER. During three training sessions, comprising a total of 150 training trials, participants were presented with negatively valenced images and asked either to "attend" (control condition) or "reappraise" (ER condition). A further group of participants did not participate in training but only completed follow-up measures. Practice increased the efficiency of ER as indexed by decreased time required to regulate emotions and increased heart rate variability (HRV). Furthermore, participants in the ER condition spontaneously regulated their negative emotions two weeks later and reported being more habitual in their use of ER. These findings indicate that structured practice can facilitate the automatic control of negative emotions and that these effects persist beyond training.


Asunto(s)
Inteligencia Emocional , Aprendizaje , Adolescente , Adulto , Inteligencia Emocional/fisiología , Emociones , Femenino , Frecuencia Cardíaca , Humanos , Masculino , Persona de Mediana Edad , Estimulación Luminosa , Adulto Joven
4.
Front Hum Neurosci ; 8: 688, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25309380

RESUMEN

The neural basis of progress monitoring has received relatively little attention compared to other sub-processes that are involved in goal directed behavior such as motor control and response inhibition. Studies of error-monitoring have identified the dorsal anterior cingulate cortex (dACC) as a structure that is sensitive to conflict detection, and triggers corrective action. However, monitoring goal progress involves monitoring correct as well as erroneous events over a period of time. In the present research, 20 healthy participants underwent functional magnetic resonance imagining (fMRI) while playing a game that involved monitoring progress toward either a numerical or a visuo-spatial target. The findings confirmed the role of the dACC in detecting situations in which the current state may conflict with the desired state, but also revealed activations in the frontal and parietal regions, pointing to the involvement of processes such as attention and working memory (WM) in monitoring progress over time. In addition, activation of the cuneus was associated with monitoring progress toward a specific target presented in the visual modality. This is the first time that activation in this region has been linked to higher-order processing of goal-relevant information, rather than low-level anticipation of visual stimuli. Taken together, these findings identify the neural substrates involved in monitoring progress over time, and how these extend beyond activations observed in conflict and error monitoring.

5.
Front Hum Neurosci ; 8: 376, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24936178

RESUMEN

Studies investigating the neurophysiological basis of intrapersonal emotion regulation (control of one's own emotional experience) report that the frontal cortex exerts a modulatory effect on limbic structures such as the amygdala and insula. However, no imaging study to date has examined the neurophysiological processes involved in interpersonal emotion regulation, where the goal is explicitly to regulate another person's emotion. Twenty healthy participants (10 males) underwent fMRI while regulating their own or another person's emotions. Intrapersonal and interpersonal emotion regulation tasks recruited an overlapping network of brain regions including bilateral lateral frontal cortex, pre-supplementary motor area, and left temporo-parietal junction. Activations unique to the interpersonal condition suggest that both affective (emotional simulation) and cognitive (mentalizing) aspects of empathy may be involved in the process of interpersonal emotion regulation. These findings provide an initial insight into the neural correlates of regulating another person's emotions and may be relevant to understanding mental health issues that involve problems with social interaction.

6.
Front Hum Neurosci ; 6: 349, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23335893

RESUMEN

Subjective assessment of emotional valence is typically associated with both brain activity and autonomic arousal. Accurately assessing emotional salience is particularly important when perceiving threat. We sought to characterize the neural correlates of the interaction between behavioral and autonomic responses to potentially threatening visual and auditory stimuli. Twenty-five healthy male subjects underwent fMRI scanning whilst skin conductance responses (SCR) were recorded. One hundred and eighty pictures, sentences, and sounds were assessed as "harmless" or "threatening." Individuals' stimulus-locked, phasic SCRs and trial-by-trial behavioral assessments were entered as regressors into a flexible factorial design to establish their separate autonomic and behavioral neural correlates, and convolved to examine psycho-autonomic interaction (PAI) effects. Across all stimuli, "threatening," compared with "harmless" behavioral assessments were associated with mainly frontal and precuneus activation with specific within-modality activations including bilateral parahippocampal gyri (pictures), bilateral anterior cingulate cortex (ACC) and frontal pole (sentences), and right Heschl's gyrus and bilateral temporal gyri (sounds). Across stimulus modalities SCRs were associated with activation of parieto-occipito-thalamic regions, an activation pattern which was largely replicated within-modality. In contrast, PAI analyses revealed modality-specific activations including right fusiform/parahippocampal gyrus (pictures), right insula (sentences), and mid-cingulate gyrus (sounds). Phasic SCR activity was positively correlated with an individual's propensity to assess stimuli as "threatening." SCRs may modulate cognitive assessments on a "harmless-threatening" dimension, thereby modulating affective tone and hence behavior.

7.
Neuroimage ; 57(4): 1552-60, 2011 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-21664277

RESUMEN

The perception and judgement of social hierarchies forms an integral part of social cognition. Hierarchical judgements can be either self-referential or allocentric (pertaining to two or more external agents). In psychiatric conditions such as dissocial personality disorder and schizophrenia, the impact of hierarchies may be problematic. We sought to elucidate the brain regions involved in judging allocentric social hierarchies. Twenty-two healthy male subjects underwent three fMRI scans. During scanning, subjects answered questions concerning visually-presented target pairs of human individual's relative superiority within a specific social hierarchy or their perceived degree of social alliance (i.e., whether they were "friends or enemies"). Subjects also made judgements relating to target pairs' age, gender and fame to control for confounding factors and performed a baseline numerical task. Response times increased in line with hypothesized ascending executive load. Both social hierarchy and social alliance judgements activated left ventrolateral prefrontal cortex (VLPFC), left dorsal inferior frontal gyrus (IFG) and bilateral fusiform gyri. In addition, social alliance judgements activated right dorsal IFG and medial prefrontal cortex. When compared directly with social alliance, social hierarchy judgements activated left orbitofrontal cortex. Detecting the presence of social hierarchies and judging other's relative standing within them implicates the cognitive executive, in particular the VLPFC. Our finding informs accounts of 'normal' social cognition but our method also provides a means of probing the dissocial brain in personality disorder and schizophrenia where executive function may be dysfunctional.


Asunto(s)
Mapeo Encefálico , Juicio/fisiología , Percepción/fisiología , Corteza Prefrontal/fisiología , Percepción Social , Femenino , Jerarquia Social , Humanos , Interpretación de Imagen Asistida por Computador , Imagen por Resonancia Magnética , Masculino , Tiempo de Reacción , Adulto Joven
8.
Neuroimage ; 57(3): 1154-61, 2011 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-21571075

RESUMEN

Investigating auditory hallucinations that occur in health may help elucidate brain mechanisms which lead to the pathological experience of auditory hallucinations in neuropsychiatric disorders such as schizophrenia. In this study, we investigated healthy individuals who reported auditory hallucinations whilst falling asleep (hypnagogic hallucinations; HG) and waking up (hypnopompic hallucinations; HP). In an initial behavioural study, we found that subjects with a history of auditory HG/HP hallucinations (n = 26) reported significantly greater subjective sensitivity to environmental sounds than non-hallucinator controls (n = 74). Then, two fMRI experiments were performed. The first examined speech-evoked brain activation in 12 subjects with a history of auditory HG/HP hallucinations and 12 non-hallucinator controls matched for age, gender and IQ. The second fMRI experiment, in the same subjects, probed how brain activation was modulated by auditory attention using a bimodal selective attention paradigm. In the first experiment, the hallucinator group demonstrated significantly greater speech-evoked activation in the left supramarginal gyrus than the control group. In the second experiment, directing attention towards the auditory (vs. visual) modality induced significantly greater activation of the anterior cingulate gyrus in the hallucinator group than in the control group. These results suggest that hallucination proneness is associated with increased sensitivity of auditory and polysensory association cortex to auditory stimulation, an effect which might arise due to enhanced attentional bias from the anterior cingulate gyrus. Our data support the overarching hypothesis that top-down modulation of auditory cortical response characteristics may be a key mechanistic step in the generation of auditory hallucinations.


Asunto(s)
Atención/fisiología , Mapeo Encefálico , Encéfalo/fisiopatología , Potenciales Evocados Auditivos/fisiología , Alucinaciones/fisiopatología , Estimulación Acústica , Femenino , Humanos , Interpretación de Imagen Asistida por Computador , Imagen por Resonancia Magnética , Masculino , Adulto Joven
9.
Int J Neurosci ; 120(5): 335-43, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20402571

RESUMEN

The clock drawing (CD) task involves visual integration skills associated with parietal lobe function. Seven mild Alzheimer's Disease (AD) patients and 11 healthy elderly controls (EC) underwent functional magnetic resonance imaging (fMRI) scanning while viewing a radial motion (RM) task. This RM task in EC activated the bilateral secondary visual cortex and parietal regions, whereas AD patients activated only the right-sided secondary visual cortex. The magnitude of the fMRI signal in the left superior parietal lobe was positively correlated with performance on the CD task in AD patients. These findings suggest that complex visuospatial processing impairments reflect the underlying AD neuropathology in parietal regions.


Asunto(s)
Enfermedad de Alzheimer/fisiopatología , Enfermedad de Alzheimer/psicología , Desempeño Psicomotor/fisiología , Percepción Espacial/fisiología , Percepción Visual/fisiología , Anciano , Estudios de Casos y Controles , Lateralidad Funcional , Humanos , Imagen por Resonancia Magnética/métodos , Lóbulo Parietal/fisiopatología , Corteza Visual/fisiopatología
10.
Dement Geriatr Cogn Disord ; 29(2): 176-88, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20215749

RESUMEN

BACKGROUND/AIMS: Visuospatial impairments are known to occur in Alzheimer's disease (AD). We hypothesised that functional magnetic resonance imaging (fMRI) response in task-related brain regions would be impaired in patients with AD during the task and that treatment with acetyl cholinesterase inhibitors would enhance activations in brain regions concerned with this visual perceptual processing. METHOD: Ten AD subjects were neuropsychologically assessed and underwent fMRI imaging whilst performing a series of visuospatial perception tasks, before and after treatment with acetyl cholinesterase inhibitors. Eleven healthy elderly comparison subjects were also scanned twice. RESULTS: Regions of increased brain activation in AD included the left precuneus, left cuneus, left supramarginal gyrus, right parieto-temporal cortex and right inferior parietal lobule. Further, increased activation in the left precuneus was found to correlate significantly with improved functioning of activities of daily living. CONCLUSIONS: We believe this to be the first fMRI study that, after controlling for the confound of repeat scanning, demonstrates altered patterns of brain activation associated with visuospatial processing following treatment in patients with AD. The treatment-related improvement of visual perception in AD may rely on enhanced attentional mechanisms, thereby possibly supporting independent living through improvement on activities of daily living.


Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/psicología , Inhibidores de la Colinesterasa/uso terapéutico , Percepción Espacial/efectos de los fármacos , Percepción Visual/efectos de los fármacos , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/patología , Corteza Cerebral/patología , Interpretación Estadística de Datos , Progresión de la Enfermedad , Femenino , Fijación Ocular , Humanos , Procesamiento de Imagen Asistido por Computador , Estudios Longitudinales , Imagen por Resonancia Magnética , Masculino , Percepción de Movimiento/fisiología , Corteza Motora/patología , Pruebas Neuropsicológicas , Oxígeno/sangre , Lóbulo Parietal/patología , Estimulación Luminosa , Resultado del Tratamiento
11.
Am J Psychol ; 123(4): 447-53, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-21291161

RESUMEN

In the executive model of deception, the telling of a lie necessitates the inhibition of a veridical prepotent response (the truth), and such inhibition incurs a temporal penalty, manifest as a longer response time. If memory processes are engaged in generating such truths, then memory function should affect truthful and deceptive response times. To investigate this we examined the relationship between performance on a semantic knowledge deception task and a test of verbal memory in 40 college students. We found that verbal memory performance differentially affects the temporal parameters of truth and deception.


Asunto(s)
Decepción , Función Ejecutiva , Recuerdo Mental , Tiempo de Reacción , Aprendizaje Verbal , Adolescente , Adulto , Femenino , Humanos , Masculino , Revelación de la Verdad , Adulto Joven
12.
Open Neuroimag J ; 3: 48-53, 2009 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-19572020

RESUMEN

Limited behavioural repertoire impacts quality of life in chronic schizophrenia. We have previously shown that the amount of movement exhibited by patients with schizophrenia is positively correlated with the volume of left anterior cingulate cortex and that this quantity of movement can be increased by modafinil. However, increased movement in itself may be of limited clinical significance. Hence, we sought to analyse the 'structure' of spontaneous movement in patients with schizophrenia and to examine whether the chunking of spontaneous activity has a neuroanatomical basis. 'Actiwatches' were used to record spontaneous motor activity over a 20 hour period in sixteen male patients with schizophrenia. Time-series data were analysed for the number of discrete spontaneous activities, which might indicate a degree of structure to ongoing activity. Subjects underwent a whole-brain structural MRI scan. The 'number of discrete movement epochs' correlated with volumes of regions within bilateral rostro-ventral putamen and temporal poles. These data suggest that in people with schizophrenia the volume of bilateral putamen may influence the complexity of their behaviours, as distinct from the overall amount of behaviour. The results are presented in the context of a large body of previous research examining the role of the basal ganglia in motor and cognitive pattern generation.

13.
Psychiatry Res ; 172(3): 175-9, 2009 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-19395244

RESUMEN

Of the few studies that have directly investigated the neuroanatomical correlates of delusions in patients with recent-onset schizophrenia, a number have paradoxically reported a positive correlation between delusion severity and regional grey matter volume. In order to explore this relationship, 31 patients with first-episode schizophrenia (FES) underwent a clinical interview and a T1-weighted structural MRI scan. Patients' scores on the Delusions subscale of the Positive and Negative Syndrome Scale were correlated with the volume of every voxel in their grey matter images in SPM99. Patients' delusion scores were found to correlate with the volume of a cluster of voxels located in the dorso-medial frontal cortex, centred on the medial frontal gyrus. Post-hoc analysis revealed that this 'region-of-correlation' was volumetrically reduced in the FES patients relative to a group of 21 matched healthy controls. The results of this study support the hypothesis that while a certain level of structural brain atrophy is necessary for delusion formation in patients with FES, excessive structural atrophy may in fact preclude the formation of highly systematized delusions.


Asunto(s)
Deluciones/patología , Deluciones/psicología , Lóbulo Frontal/patología , Imagen por Resonancia Magnética , Esquizofrenia/patología , Psicología del Esquizofrénico , Adolescente , Adulto , Análisis de Varianza , Estudios de Casos y Controles , Femenino , Lateralidad Funcional , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Escalas de Valoración Psiquiátrica , Esquizofrenia/diagnóstico , Factores de Tiempo , Adulto Joven
14.
Psychiatry Res ; 172(2): 109-16, 2009 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-19324533

RESUMEN

The neural basis of visuospatial deficits in Alzheimer's disease is unclear. We wished to investigate the neural basis of visuospatial perception in patients with Alzheimer's disease compared with healthy elderly comparison subjects using functional magnetic resonance imaging (fMRI). Twelve patients with AD and thirteen elderly comparison subjects were investigated. The patients were recruited from the local clinic and comparison subjects were from spouses and community. All participants underwent fMRI whilst viewing visuospatial stimuli and structural MRI, and findings were analysed using voxel-based morphometry. The comparison group activated V5, superior parietal lobe, parieto-occipital cortex and premotor cortices. The AD group demonstrated hypoactivation in the above regions and instead showed greater activation in inferior parietal lobule and activated additional areas. There was no structural atrophy above and beyond that found globally in patients in the identified regions of BOLD activation. To our knowledge, this is the first study to explore the neuroanatomy of perception of depth and motion in Alzheimer's disease. These specific functional deficits in AD provide evidence for an underlying patho-physiological basis for the clinically important symptom of visuospatial disorientation in patients with AD.


Asunto(s)
Enfermedad de Alzheimer/fisiopatología , Encéfalo/fisiopatología , Percepción de Profundidad/fisiología , Percepción de Movimiento/fisiología , Percepción Visual/fisiología , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/diagnóstico , Trastornos del Conocimiento/diagnóstico , Trastornos del Conocimiento/fisiopatología , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Pruebas Neuropsicológicas , Orientación/fisiología , Oxígeno/sangre , Percepción Espacial/fisiología , Análisis y Desempeño de Tareas
15.
Neuroimage ; 40(3): 1411-8, 2008 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-18308586

RESUMEN

Behavioural and functional anatomical responses exhibited by humans support the hypothesis that deception involves the prefrontal executive. Functional neuroimaging studies have demonstrated that ventrolateral prefrontal cortex (among other areas) is activated during lying, compared with telling the truth. However, despite some consistencies discernible across studies, problems remain concerning experimental validity, e.g., the expediencies of experimenter-sanctioned cued-deception (i.e., subjects being told when to lie); such 'lies' may not have comprised adequate proxies for 'real-life' deception. In this experiment, we attempted to address such confounding issues by designing an fMRI paradigm in which subjects chose when to lie (thereby minimising cue-dependency), using spoken words, concerning intimate material, which they regarded as 'embarrassing'; and where further control conditions required them to 'comply' with their examiners or to 'defy' them (by withholding pre-specified responses). The main effect of lying revealed significant activation of ventrolateral prefrontal cortices. These results replicate and extend our previous findings to those circumstances under which subjects are allowed to choose when to deceive.


Asunto(s)
Detección de Mentiras/psicología , Corteza Prefrontal/fisiología , Voz/fisiología , Adulto , Mapeo Encefálico , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad
16.
Prog Neuropsychopharmacol Biol Psychiatry ; 32(2): 531-8, 2008 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-18061326

RESUMEN

OBJECTIVE: This study explored the concurrent courses of the neuroanatomical and neuropsychological changes that occurred over the first 2-3 years of illness in patients with first-episode schizophrenia (FES). METHODS: Fifty-two patients with FES underwent neuropsychological testing and a structural magnetic resonance imaging (sMRI) scan within three months of their first presentation to mental health services with psychotic symptoms (time1). Patients' cognitive performance was evaluated via an extensive neuropsychological test battery, which assessed 9 cognitive domains. Of the 52 patients at time1, 32 returned 2-3 years later (time2) for follow-up neuropsychological testing, and 20 of these also underwent follow-up sMRI. MR images were preprocessed in SPM99. Grey matter volumes of patients' whole-brain, frontal lobes and temporal lobes were calculated by convolving the preprocessed images with manually-drawn binary masks. RESULTS: Patients exhibited longitudinal improvements in full-scale IQ, performance IQ and visual memory. In contrast, concurrent reductions in grey matter were observed for the whole-brain (3% reduction) and the frontal lobe (3.65% reduction). Furthermore, the extent of patients' whole-brain and frontal-lobe grey matter changes were positively correlated with longitudinal changes in verbal learning and memory. DISCUSSION: The results of this study suggest that while the early stages of schizophrenia are associated with a mild improvement in patients' overall cognitive functioning, they are also associated with progressive grey matter atrophy.


Asunto(s)
Encéfalo/patología , Pruebas Neuropsicológicas/estadística & datos numéricos , Esquizofrenia/diagnóstico , Psicología del Esquizofrénico , Adolescente , Adulto , Atrofia/patología , Trastornos del Conocimiento/diagnóstico , Trastornos del Conocimiento/patología , Trastornos del Conocimiento/psicología , Femenino , Estudios de Seguimiento , Lóbulo Frontal/patología , Humanos , Pruebas de Inteligencia/estadística & datos numéricos , Estudios Longitudinales , Imagen por Resonancia Magnética/estadística & datos numéricos , Masculino , Trastornos de la Memoria/diagnóstico , Trastornos de la Memoria/psicología , Estudios Prospectivos , Esquizofrenia/patología , Lóbulo Temporal/patología , Aprendizaje Verbal/clasificación
17.
Am J Psychiatry ; 164(7): 1082-9, 2007 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-17606660

RESUMEN

OBJECTIVE: While schizophrenia has long been considered a disorder of brain connectivity, few studies have investigated white matter abnormalities in patients with first-episode schizophrenia, and even fewer studies have investigated whether there is progressive white matter pathology in the disease. METHOD: The authors obtained a T1-weighted structural magnetic resonance imaging (MRI) scan on 41 patients with first-episode schizophrenia. These first-episode schizophrenia patients were analyzed relative to 47 age- and sex-matched healthy comparison subjects who also underwent an MRI scan. Of the baseline participants, 25 first-episode schizophrenia patients and 26 comparison subjects returned 2 to 3 years later for a follow-up scan. To identify regional volumetric white matter differences between the two groups at baseline, voxel-based morphometry in statistical parametric mapping-2 (SPM2) was used, while tensor-based morphometry was used to identify the longitudinal changes over the follow-up interval. RESULTS: The first-episode schizophrenia patients exhibited volumetric deficits in the white matter of the frontal and temporal lobes at baseline, as well as volumetric increases in the white matter of the frontoparietal junction bilaterally. Furthermore, these first-episode schizophrenia patients lost considerably more white matter over the follow-up interval relative to comparison subjects in the middle and inferior temporal cortex bilaterally. CONCLUSIONS: These results indicate that patients with schizophrenia exhibit white matter abnormalities at the time of their first presentation of psychotic symptoms to mental health services and that these abnormalities degenerate further over the initial years of illness. Given the role that white matter plays in neural communication, the authors suggest that these white matter abnormalities may be a cause of the dysfunctional neural connectivity that has been proposed to underlie the symptoms of schizophrenia.


Asunto(s)
Encéfalo/patología , Imagen por Resonancia Magnética/estadística & datos numéricos , Esquizofrenia/patología , Adolescente , Adulto , Factores de Edad , Atrofia/patología , Encéfalo/fisiopatología , Estudios de Cohortes , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Lateralidad Funcional/fisiología , Humanos , Estudios Longitudinales , Masculino , Modelos Neurológicos , Vías Nerviosas/patología , Vías Nerviosas/fisiopatología , Esquizofrenia/diagnóstico , Esquizofrenia/fisiopatología , Factores Sexuales
18.
Neuroreport ; 18(5): 435-9, 2007 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-17496799

RESUMEN

Although there is substantial evidence indicating that patients with first-episode schizophrenia exhibit both anatomical and electrophysiological abnormalities, there has been little research investigating the relationship between these two indices. We acquired structural magnetic resonance images and resting electroencephalographic recordings from 19 patients with schizophrenia, both at the time of their first presentation to mental health services and 2-3 years subsequently. Patients' grey matter images were parcellated into four brain lobes, and slow-wave, alpha- and beta-electroencephalographic power was calculated in four corresponding cortical regions. Although grey matter volume decreased longitudinally, particularly fronto-parietally, electroencephalographic power increased in the slow-wave and beta-frequency bands. These results suggest that first-episode schizophrenia may be associated with abnormally elevated levels of neural synchrony.


Asunto(s)
Mapeo Encefálico , Neuroanatomía , Esquizofrenia/patología , Esquizofrenia/fisiopatología , Adolescente , Adulto , Edad de Inicio , Electroencefalografía/métodos , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Estudios Longitudinales , Imagen por Resonancia Magnética/métodos , Masculino , Escalas de Valoración Psiquiátrica , Análisis Espectral
19.
Psychiatry Res ; 155(1): 11-9, 2007 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-17399959

RESUMEN

Alzheimer's disease (AD) is associated with widespread brain atrophy including structures subserving memory. We applied an improved structural detection methodology to examine the less well known progression of atrophy in early-stage AD. We sought to i) longitudinally study volumetric differences in patients with early-stage AD and healthy volunteers; and ii) test the hypothesis that hippocampal volumes would be correlated with clinically relevant cognitive function. Seven patients and eleven healthy subjects underwent two structural MRI scans and neuropsychological assessments. Scans were normalised to a study-specific template and 'morphologically opened' to reduce tissue misclassification. Using brain-parcellation, patient atrophy was localised to left fusiform and parahippocampal gyri, whilst left hippocampal volumes were correlated with a cognitive performance measure. A whole-brain search methodology, showed that patients had reduced volumes including fronto-temporal regions bilaterally, in hippocampi and amygdalae and right cerebellum. Whole-brain correlational analyses revealed that cognitive performance was correlated with volumes of both hippocampi, superior temporal gyri and left insula. Neither group exhibited significant longitudinal volumetric changes. Utilising a novel methodology, we have shown that in early-stage AD, clinically relevant cognitive deficits are correlated with regionally specific grey-matter volumes, which are detectable at an early stage of the illness.


Asunto(s)
Enfermedad de Alzheimer/diagnóstico , Enfermedad de Alzheimer/epidemiología , Lóbulo Frontal/patología , Imagen por Resonancia Magnética/normas , Lóbulo Temporal/patología , Anciano , Atrofia/epidemiología , Atrofia/patología , Trastornos del Conocimiento/diagnóstico , Trastornos del Conocimiento/epidemiología , Demografía , Diagnóstico Precoz , Femenino , Hipocampo/patología , Humanos , Masculino , Pruebas Neuropsicológicas , Índice de Severidad de la Enfermedad
20.
J Psychiatr Res ; 41(8): 645-51, 2007 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16626741

RESUMEN

We aimed to investigate cerebellar structural abnormalities and their functional significance in patients with schizophrenia. Forty right-handed men with schizophrenia and 40 sex, age and handedness matched controls underwent a volumetric magnetic resonance scan with 1 mm3 isotropic spatial resolution. Cerebellar grey- and white-matter volumes were analysed using voxel-based morphometry. Patients with schizophrenia completed a battery of neuropsychological tests assessing sustained attention (continuous performance test), memory (Hopkins memory test) and executive function (verbal fluency and Wisconsin card sorting tests). Patients with schizophrenia exhibited significantly increased cerebellar vermis white-matter volume compared with controls. By contrast, total cerebellar volume, and grey- and white-matter volumes of cerebellar hemispheres were not significantly different between groups. Increased vermis white-matter volume in patients was associated with poor verbal fluency performance. We concluded that increased white-matter in the cerebellar vermis, possibly suggesting anomalous connectivity, may be associated with verbal executive dysfunction in men with chronic schizophrenia.


Asunto(s)
Cerebelo/patología , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Esquizofrenia/diagnóstico , Adulto , Enfermedad Crónica , Humanos , Masculino , Escalas de Valoración Psiquiátrica , Valores de Referencia , Lenguaje del Esquizofrénico , Conducta Verbal/fisiología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...