Magnetic Resonance Imaging (MRI)

Spatiotemporal patterns of cortical activation during the perceptual grouping of elements to form illusory shapes were estimated using anatomically constrained magnetoencephalography. Subjects were shown an array of Kanizsa-style figures which were either aligned to form illusory squares or misaligned so that no illusory contour or shape was perceived. Differential activity is more pronounced in the right hemisphere. After a weakly significant modulation at approximately 110 ms in the occipital pole, a prominent peak appears at approximately 155 ms in the lateral occipital cortex.

Darwin's evolutionary approach to organisms' emotional states attributes a prominent role to expressions of emotion in whole-body actions. Researchers in social psychology [1,2] and human development [3] have long emphasized the fact that emotional states are expressed through body movement, but cognitive neuroscientists have almost exclusively considered isolated facial expressions (for review, see [4]). Here we used high-field fMRI to determine the underlying neural mechanisms of perception of body expression of emotion.

Deception is a complex cognitive activity, and different types of lies could arise from different neural systems. We investigated this possibility by first classifying lies according to two dimensions, whether they fit into a coherent story and whether they were previously memorized. fMRI revealed that well-rehearsed lies that fit into a coherent story elicit more activation in right anterior frontal cortices than spontaneous lies that do not fit into a story, whereas the opposite pattern occurs in the anterior cingulate and in posterior visual cortex.

We have performed a noninvasive bilateral optical imaging study of the hemodynamic evoked response to unilateral finger opposition task, finger tactile, and electrical median nerve stimulation in the human sensorimotor cortex. This optical study shows the hemoglobin-evoked response to voluntary and nonvoluntary stimuli. We performed measurements on 10 healthy volunteers using block paradigms for motor, sensory, and electrical stimulations of the right and left hands separately.

Central nervous system habituation in humans was studied using functional magnetic resonance imaging and repeated presentations of single fearful and neutral faces. Habituation of blood-oxygenation-level-dependent (BOLD) signal during exposure to face stimuli, collapsed over fearful and neutral expressions, was evident in the right amygdala and hippocampus, as well as in the medial/inferior temporal cortex bilaterally. In the hippocampus, significantly greater habituation was evident on the right as compared to the left side, which could reflect the visual nature of the stimuli.

Several studies suggest that the nonschizophrenic relatives of schizophrenic patients exhibit structural brain abnormalities that may be manifestations of genes that predispose to schizophrenia. In this work, we examine the utility of such measures for linkage analyses. Subjects were 45 nonpsychotic first-degree adult relatives of schizophrenic patients and 48 normal controls. Sixty contiguous 3-mm coronal, T1-weighted 3D magnetic resonance images of the entire brain were acquired on a 1.5-T magnet. We used factor analysis to derive MRI-based phenotypes for analysis.

The mechanism of ventricular thickening in normal humans was investigated using in vivo MRI. The hypothesis that myocardial laminar sheets contribute to ventricular thickening predominantly via sheet shear and sheet extension, as previously found invasively in canine studies at particular ventricular sites, was tested. In normal human subjects, registered images of myocardial sheet architecture and strain at the mid-left ventricle (mid-LV) at mid-systole were acquired with diffusion and strain MRI.

The pattern and role of brain plasticity in stroke recovery has been incompletely characterized. Both ipsilesional and contralesional changes have been described, but it remains unclear how these relate to functional recovery. Our goal was to correlate brain activation patterns with tissue damage, hemodynamics, and neurologic status after temporary stroke, using functional magnetic resonance imaging (fMRI).

Recent advances in brain imaging techniques, including functional magnetic resonance imaging (fMRI), offer great promise for noninvasive mapping of brain function. However, the indirect nature of the imaging signals to the underlying neural activity limits the interpretation of the resulting maps. The present report represents the first systematic study with sufficient statistical power to quantitatively characterize the relationship between changes in blood oxygen content and the neural spiking and synaptic activity.

Brain-damaged patients experience difficulties in recognizing a face (prosopagnosics), but they can still recognize its expression. The dissociation between these two face-related skills has served as a keystone of models of face processing. We now report that the presence of a facial expression can influence face identification. For normal viewers, the presence of a facial expression influences performance negatively, whereas for prosopagnosic patients, it improves performance dramatically.