Methods for fine scale functional imaging of tactile motion in human and nonhuman primates.

In the visual and auditory systems specialized neural pathways use motion cues to track object motion and self-motion, and use differential motion cues for figure-ground segregation. To examine the neural circuits that encode motion in the somatosensory system, we have developed neuroimaging methods to study motion processing in human and nonhuman primates. We have implemented stimulus presentation paradigms to examine neural encoding of apparent motion percepts.

Differential fMRI activation to noxious heat and tactile stimuli in parasylvian areas of new world monkeys.

Emerging evidence supports an important role of posterior parasylvian areas in both pain and touch processing. Whether there are separate or shared networks for these sensations remains controversial. The present study compared spatial patterns of brain activation in response to unilateral nociceptive heat (47.

Functional magnetic resonance imaging of awake monkeys: some approaches for improving imaging quality.

Functional magnetic resonance imaging (fMRI) at high magnetic field strength can suffer from serious degradation of image quality because of motion and physiological noise, as well as spatial distortions and signal losses due to susceptibility effects. Overcoming such limitations is essential for sensitive detection and reliable interpretation of fMRI data. These issues are particularly problematic in studies of awake animals.

High-resolution functional magnetic resonance imaging mapping of noxious heat and tactile activations along the central sulcus in New World monkeys.

This study mapped the fine-scale functional representation of tactile and noxious heat stimuli in cortical areas around the central sulcus of anesthetized squirrel monkeys by using high-resolution blood oxygen level-dependent (BOLD) fMRI at 9.4T. Noxious heat (47.

Orientation and Direction-of-Motion Response in the Middle Temporal Visual Area (MT) of New World Owl Monkeys as Revealed by Intrinsic-Signal Optical Imaging.

Intrinsic-signal optical imaging was used to evaluate relationships of domains of neurons in middle temporal visual area (MT) selective for stimulus orientation and direction-of-motion. Maps of activation were elicited in MT of owl monkeys by gratings drifting back-and-forth, flashed stationary gratings and unidirectionally drifting fields of random dots. Drifting gratings, typically used to reveal orientation preference domains, contain a motion component that may be represented in MT.

Intrinsic-signal optical imaging reveals cryptic ocular dominance columns in primary visual cortex of New World owl monkeys.

A significant concept in neuroscience is that sensory areas of the neocortex have evolved the remarkable ability to represent a number of stimulus features within the confines of a global map of the sensory periphery. Modularity, the term often used to describe the inhomogeneous nature of the neocortex, is without a doubt an important organizational principle of early sensory areas, such as the primary visual cortex (V1). Ocular dominance columns, one type of module in V1, are found in many primate species as well as in carnivores.

The organization of orientation-selective, luminance-change and binocular- preference domains in the second (V2) and third (V3) visual areas of New World owl monkeys as revealed by intrinsic signal optical imaging.

Optical imaging was used to map patterns of visually evoked activation in the second (V2) and third (V3) visual areas of owl monkeys. Modular patterns of activation were produced in response to stimulation with oriented gratings, binocular versus monocular stimulation, and stimuli containing wide-field luminance changes. In V2, luminance-change domains tended to lie between domains selective for orientation.