Cortical pathology in multiple sclerosis detected by the T1/T2-weighted ratio from routine magnetic resonance imaging.

Objective: In multiple sclerosis, neuropathological studies have shown widespread changes in the cerebral cortex. In vivo imaging is critical, because the histopathological substrate of most measurements is unknown.

Methods: Using a novel magnetic resonance imaging analysis technique, based on the ratio of T1- and T2-weighted signal intensities, we studied the cerebral cortex of a large cohort of patients in early stages of multiple sclerosis.

Intra- and interscanner variability of magnetic resonance imaging based volumetry in multiple sclerosis.

Brain volumetric measurements in multiple sclerosis (MS) reflect not only disease-specific processes but also other sources of variability. The latter has to be considered especially in multicenter and longitudinal studies. Here, we compare data generated by three different 3-Tesla magnetic resonance scanners (Philips Achieva; Siemens Verio; GE Signa MR750).

Acute infarcts cause focal thinning in remote cortex via degeneration of connecting fiber tracts.

Objective: To study remote effects distant from acute ischemic infarcts by measuring longitudinal changes of cortical thickness in connected brain regions as well as changes in microstructural integrity in connecting fiber tracts.

Methods: Thirty-two patients (mean age 71 years) underwent a standardized protocol including multimodal MRI and clinical assessment both at stroke onset and 6 months after the event. Cortex connected to acute infarcts was identified by probabilistic diffusion tensor tractography starting from the acute lesion.

Impact of regional cortical and subcortical changes on processing speed in cerebral small vessel disease.

Slowed processing speed is common in elderly subjects and frequently related to cerebral small vessel disease. Previous studies have demonstrated associations between processing speed and subcortical ischemic lesions as well as cortical alterations but the precise functional-anatomical relationships remain poorly understood. Here we assessed the impact of both cortical and subcortical changes on processing speed by measuring regional cortical thickness and regional lesion volumes within distinct white-matter tracts.

Incident subcortical infarcts induce focal thinning in connected cortical regions.

Objective: Brain atrophy is common in subcortical ischemic vascular disease, but the underlying mechanisms are poorly understood. We set out to examine the effects of incident subcortical infarcts on cortical morphology.

Methods: A total of 276 subjects with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, an inherited small vessel disease, were enrolled in a prospective study.

Face perception in the mind's eye.

Perceptual filling-in occurs when visual stimuli are recognized in impoverished viewing conditions. Whether missing information is filled-in during face perception and which stages might be involved in this process are still unresolved questions. Because an identity can be brought to mind by seeing eyes only, we hypothesized that missing information might be filled-in from a memory trace for the whole face identity.

Top-down activation of fusiform cortex without seeing faces in prosopagnosia.

Face processing can be modified by bottom-up and top-down influences, but it is unknown how these processes interact in patients with face-recognition impairments (prosopagnosia). We investigated a prosopagnosic with lesions in right occipital and left fusiform cortex but whose right fusiform gyrus is intact and still activated during face-processing tasks. P.

Rapid influence of emotional scenes on encoding of facial expressions: an ERP study.

In daily life, we perceive a person's facial reaction as part of the natural environment surrounding it. Because most studies have investigated how facial expressions are recognized by using isolated faces, it is unclear what role the context plays. Although it has been observed that the N170 for facial expressions is modulated by the emotional context, it was not clear whether individuals use context information on this stage of processing to discriminate between facial expressions.

Recognition of facial expressions is influenced by emotional scene gist.

Recognition of facial expressions has traditionally been investigated by presenting facial expressions without any context information. However, we rarely encounter an isolated facial expression; usually, we perceive a person's facial reaction as part of the surrounding context. In the present study, we addressed the question of whether emotional scenes influence the explicit recognition of facial expressions.

Neural correlates of perceiving emotional faces and bodies in developmental prosopagnosia: an event-related fMRI-study.

Many people experience transient difficulties in recognizing faces but only a small number of them cannot recognize their family members when meeting them unexpectedly. Such face blindness is associated with serious problems in everyday life. A better understanding of the neuro-functional basis of impaired face recognition may be achieved by a careful comparison with an equally unique object category and by a adding a more realistic setting involving neutral faces as well facial expressions.

Impaired face and body perception in developmental prosopagnosia.

Prosopagnosia is a deficit in face recognition in the presence of relatively normal object recognition. Together with older lesion studies, recent brain-imaging results provide evidence for the closely related representations of faces and objects and, more recently, for brain areas sensitive to faces and bodies. This evidence raises the issue of whether developmental prosopagnosics may also have an impairment in encoding bodies.

Body expressions influence recognition of emotions in the face and voice.

The most familiar emotional signals consist of faces, voices, and whole-body expressions, but so far research on emotions expressed by the whole body is sparse. The authors investigated recognition of whole-body expressions of emotion in three experiments. In the first experiment, participants performed a body expression-matching task.

Beyond the face: exploring rapid influences of context on face processing.

Humans optimize behavior by deriving context-based expectations. Contextual data that are important for survival are extracted rapidly, using coarse information, adaptive decision strategies, and dedicated neural infrastructure. In the field of object perception, the influence of a surrounding context has been a major research theme, and it has generated a large literature.

Context influences early perceptual analysis of faces--an electrophysiological study.

Electrophysiological and hemodynamic correlates of processing isolated faces have been investigated extensively over the last decade. A question not addressed thus far is whether the visual scene, which normally surrounds a face or a facial expression, has an influence on how the face is processed. Here we investigated this issue by presenting faces in natural contexts and measuring whether the emotional content of the scene influences processing of a facial expression.