Select and Cluster: A Method for Finding Functional Networks of Clustered Voxels in fMRI.

Extracting functional connectivity patterns among cortical regions in fMRI datasets is a challenge stimulating the development of effective data-driven or model based techniques. Here, we present a novel data-driven method for the extraction of significantly connected functional ROIs directly from the preprocessed fMRI data without relying on a priori knowledge of the expected activations. This method finds spatially compact groups of voxels which show a homogeneous pattern of significant connectivity with other regions in the brain.

Scale Changes Provide an Alternative Cue For the Discrimination of Heading, But Not Object Motion.

BACKGROUND Understanding the dynamics of our surrounding environments is a task usually attributed to the detection of motion based on changes in luminance across space. Yet a number of other cues, both dynamic and static, have been shown to provide useful information about how we are moving and how objects around us move. One such cue, based on changes in spatial frequency, or scale, over time has been shown to be useful in conveying motion in depth even in the absence of a coherent, motion-defined flow field (optic flow).

When does subliminal affective image priming influence the ability of schizophrenic patients to perceive face emotions?

Background: Deficits in face emotion perception are among the most pervasive aspects of schizophrenia impairments which strongly affects interpersonal communication and social skills.

Material And Methods: Schizophrenic patients (PSZ) and healthy control subjects (HCS) performed 2 psychophysical tasks. One, the SAFFIMAP test, was designed to determine the impact of subliminally presented affective or neutral images on the accuracy of face-expression (angry or neutral) perception.

Spared ability to perceive direction of locomotor heading and scene-relative object movement despite inability to perceive relative motion.

Background: All contemporary models of perception of locomotor heading from optic flow (the characteristic patterns of retinal motion that result from self-movement) begin with relative motion. Therefore it would be expected that an impairment on perception of relative motion should impact on the ability to judge heading and other 3D motion tasks.

Material And Methods: We report two patients with occipital lobe lesions whom we tested on a battery of motion tasks.

A computational study of whole-brain connectivity in resting state and task fMRI.

Background: We compared the functional brain connectivity produced during resting-state in which subjects were not actively engaged in a task with that produced while they actively performed a visual motion task (task-state).

Material And Methods: In this paper we employed graph-theoretical measures and network statistics in novel ways to compare, in the same group of human subjects, functional brain connectivity during resting-state fMRI with brain connectivity during performance of a high level visual task. We performed a whole-brain connectivity analysis to compare network statistics in resting and task states among anatomically defined Brodmann areas to investigate how brain networks spanning the cortex changed when subjects were engaged in task performance.

Visual areas involved in the perception of human movement from dynamic form analysis.

The perception of biological motion combines the analysis of form and motion. However, patient observations by Vaina et al. and psychophysical experiments by Beintema and Lappe showed that humans could perceive human movements (a walker) without local image motion information.