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1.
Psychiatry Res ; 164(2): 97-105, 2008 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-18938066

RESUMO

Schizophrenia patients exhibit deficits in various stages of visual information processing. Despite recent informative efforts to examine visual processing in schizophrenia with functional magnetic resonance imaging (fMRI), much remains unknown about the basic function, structure, and organization of key early visual processing areas in schizophrenia. This study examined magnitude and topography of regional brain activity in three early visual processing areas: early retinotopically organized areas (V1-V4), motion-sensitive areas (human area MT, hMT+), and object-recognition areas (lateral occipital complex, LO). Using visual stimuli that are known to preferentially activate each respective region, we compared responses in these areas in 22 schizophrenia patients and 19 normal controls. Activity in all three regions was of similar amplitude in schizophrenia patients and normal controls. Activity in retinotopically organized areas and hMT+ showed good spatial overlap between groups. However, activation of LO was more widely distributed in patients compared with normal controls. The findings of abnormal spatial organization of LO in schizophrenia patients may converge with behavioral evidence of deficits in schizophrenia patients for object-recognition tasks that are believed to be mediated by LO activity.


Assuntos
Córtex Cerebral/fisiopatologia , Esquizofrenia/fisiopatologia , Adulto , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Lobo Occipital/fisiopatologia , Percepção Espacial , Percepção Visual
2.
Biol Psychiatry ; 62(6): 642-51, 2007 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-17217932

RESUMO

BACKGROUND: In cigarette smokers, the most commonly reported areas of brain activation during visual cigarette cue exposure are the prefrontal, anterior cingulate, and visual cortices. We sought to determine changes in brain activity in response to cigarette cues when smokers actively resist craving. METHODS: Forty-two tobacco-dependent smokers underwent functional magnetic resonance imaging, during which they were presented with videotaped cues. Three cue presentation conditions were tested: cigarette cues with subjects allowing themselves to crave (cigarette cue crave), cigarette cues with the instruction to resist craving (cigarette cue resist), and matched neutral cues. RESULTS: Activation was found in the cigarette cue resist (compared with the cigarette cue crave) condition in the left dorsal anterior cingulate cortex (ACC), posterior cingulate cortex (PCC), and precuneus. Lower magnetic resonance signal for the cigarette cue resist condition was found in the cuneus bilaterally, left lateral occipital gyrus, and right postcentral gyrus. These relative activations and deactivations were more robust when the cigarette cue resist condition was compared with the neutral cue condition. CONCLUSIONS: Suppressing craving during cigarette cue exposure involves activation of limbic (and related) brain regions and deactivation of primary sensory and motor cortices.


Assuntos
Comportamento Aditivo/psicologia , Comportamento Aditivo/terapia , Encéfalo/fisiologia , Sinais (Psicologia) , Abandono do Hábito de Fumar/psicologia , Fumar/terapia , Percepção Visual/fisiologia , Adulto , Mapeamento Encefálico , Feminino , Lateralidade Funcional/fisiologia , Giro do Cíngulo/fisiologia , Humanos , Sistema Límbico/fisiologia , Imageamento por Ressonância Magnética , Masculino , Modelos Neurológicos , Córtex Motor/fisiologia , Vias Neurais/fisiologia , Fumar/psicologia , Nicotiana , Tabagismo/psicologia , Tabagismo/terapia
3.
Neuroimage Clin ; 5: 100-8, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25009771

RESUMO

INTRODUCTION: Although social cognitive impairments are key determinants of functional outcome in schizophrenia their neural bases are poorly understood. This study investigated neural activity during imitation and observation of finger movements and facial expressions in schizophrenia, and their correlates with self-reported empathy. METHODS: 23 schizophrenia outpatients and 23 healthy controls were studied with functional magnetic resonance imaging (fMRI) while they imitated, executed, or simply observed finger movements and facial emotional expressions. Between-group activation differences, as well as relationships between activation and self-reported empathy, were evaluated. RESULTS: Both patients and controls similarly activated neural systems previously associated with these tasks. We found no significant between-group differences in task-related activations. There were, however, between-group differences in the correlation between self-reported empathy and right inferior frontal (pars opercularis) activity during observation of facial emotional expressions. As in previous studies, controls demonstrated a positive association between brain activity and empathy scores. In contrast, the pattern in the patient group reflected a negative association between brain activity and empathy. CONCLUSIONS: Although patients with schizophrenia demonstrated largely normal patterns of neural activation across the finger movement and facial expression tasks, they reported decreased self perceived empathy and failed to show the typical relationship between neural activity and self-reported empathy seen in controls. These findings suggest that patients show a disjunction between automatic neural responses to low level social cues and higher level, integrative social cognitive processes involved in self-perceived empathy.


Assuntos
Encéfalo/fisiopatologia , Empatia/fisiologia , Comportamento Imitativo/fisiologia , Rede Nervosa/fisiopatologia , Esquizofrenia/fisiopatologia , Psicologia do Esquizofrênico , Adulto , Mapeamento Encefálico , Emoções/fisiologia , Expressão Facial , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa , Autorrelato
4.
Brain Stimul ; 4(3): 125-36, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21777872

RESUMO

With the recent approval by the Food and Drug Administration (FDA) of Deep Brain Stimulation (DBS) for Parkinson's Disease, dystonia and obsessive compulsive disorder (OCD), vagus nerve stimulation (VNS) for epilepsy and depression, and repetitive transcranial magnetic stimulation (rTMS) for the treatment of depression, neuromodulation has become increasingly relevant to clinical research. However, these techniques have significant drawbacks (eg, lack of special specificity and depth for the rTMS, and invasiveness and cumbersome maintenance for DBS). This article reviews the background, rationale, and pilot studies to date, using a new brain stimulation method-low-intensity focused ultrasound pulsation (LIFUP). The ability of ultrasound to be focused noninvasively through the skull anywhere within the brain, together with concurrent imaging (ie, functional magnetic resonance imaging [fMRI]) techniques, may create a role for research and clinical use of LIFUP. This technique is still in preclinical testing and needs to be assessed thoroughly before being advanced to clinical trials. In this study, we review over 50 years of research data on the use of focused ultrasound (FUS) in neuronal tissue and live brain, and propose novel applications of this noninvasive neuromodulation method.


Assuntos
Encéfalo/fisiopatologia , Terapia por Ultrassom/métodos , Humanos
5.
Clin EEG Neurosci ; 40(2): 78-83, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19534301

RESUMO

Approximately 50% of patients with Major Depressive Disorder (MDD) respond to the first antidepressant medication prescribed, and fewer than one-third experience remission of symptoms. The most significant challenge in the management of MDD, therefore, is selection of the antidepressant medication that is most likely to lead to response or to remission for an individual patient. There is a growing body of evidence that certain clinical neurophysiologic techniques may be useful for selecting the medication that is most likely benefit each patient. Use of low resolution electromagnetic tomography (LORETA), loudness dependent auditory evoked potentials (LDAEP), and resting state quantitative electroencephalography (QEEG) in the clinical setting is increasingly supported by studies indicating that these techniques may help identify particular medications that are most likely to lead to response or remission. The current state of evidence supporting the use of each technique is reviewed.


Assuntos
Antidepressivos/uso terapêutico , Transtorno Depressivo Maior/tratamento farmacológico , Encéfalo/fisiopatologia , Transtorno Depressivo Maior/fisiopatologia , Eletroencefalografia , Fenômenos Eletrofisiológicos , Potenciais Evocados Auditivos , Humanos , Tomografia
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