current

Current Research

Attention and Eye Movements

To understand how we select certain pieces of information for extensive processing, one line of my research has been focused on the cognitive architecture and neural mechanisms involved in generating eye movements and shifts of visual attention. We have shown that saccadic amplitudes are influenced by preceding reflexive shifts of visual attention, which demonstrates a link between attention and the oculomotor system (see Ro, Pratt, & Rafal, 2000). More recently, using methods we developed for localizing the human frontal eye fields with transcranial magnetic stimulation (TMS) (Ro, Henik, Machado, & Rafal, 1997; Ro, Chiefet, Ingle, Shoup, & Rafal, 1999; Ro, Farnè, & Chang, 2002), we have found that this link may be due to shared neural control of attention and saccades by this region of the brain (Ro, Farnè, & Chang, 2003). In a series of psychophysical and TMS studies, we are now investigating whether the neural circuitry involved in covertly shifting voluntary attention without eye movements are the same as those involved in the actual generation of saccades.

Multisensory Processing

Once some information is selected for more detailed processing, our perceptual systems are often times confronted with the task of integrating information from multiple sensory modalities. My laboratory is also actively researching the ways in which we integrate information from different sensory modalities to provide a coherent representation of an external stimulus. In particular, we have recently been investigating the influences of vision on touch perception (Wallace & Ro, in preparation; Ro, Wallace, Hagedorn, Farnè, & Pienkos, in press). These studies suggest that vision can sometimes enhance touch perception in neurologically normal subjects. For example, we have found that seeing an event associated with a touch, as compared to not seeing such an event, increases tactile sensitivity. Having established some fundamental aspects of these visual alterations in touch perception, we are now designing and conducting experiments to determine the neural bases for these enhancement effects. Our ultimate goal is to induce brain reorganization and recovery of touch perception in neurological patients with touch perception deficits through the use of the unimpaired and more dominant visual modality.

Conscious and Unconscious Visual Processing

Another project that I have been actively involved with has been demonstrating the psychological and neural bases for unconscious processing of visual information. These studies, conducted in patients with hemispatial neglect (e.g. Ro & Rafal, 1996) or blindsight (e.g. Dodds, Machado, Rafal, & Ro, 2002), in neurologically intact participants using visual masking paradigms (Ro, Singhal, Breitmeyer, & Garcia, under revision; Breitmeyer, Ro, & Singhal, in press), as well as TMS of occipital cortex (Ro, Breitmeyer, Burton, & Singhal, 2003), have been consistently revealing that much of the visual information we are confronted with is processed without awareness either in early visual cortex or via the retinotectal pathway. Further experiments investigating retinotectal function in the absence of awareness are currently being conducted with TMS of the visual cortex.

Face Perception

This series of studies investigates whether faces constitute a special class of stimuli in the perception and neural systems. Faces, a class of visual objects that as social beings we frequently encounter, provide biologically relevant information useful for our survival. My work in this area has been focusing on whether faces have prioritization in the visual system. The results from these studies, in conjunction with recent neuroimaging results from other labs, show that faces are in fact very special and prioritized as they tend to capture attention over most other types of objects (see Ro, Russell, & Lavie, 2001; Lavie, Ro, & Russell, 2003).

Constraint Induced Movement Therapy

We are actively collaborating on a joint project with a large group of investigators, primarily from the Texas Medical Center, on a study designed to induce rapid recovery from motor impairment in patients with acute strokes. Preliminary results in this investigation have demonstrated that constraining the unimpaired limb of such patients, which forces the use of the affected limb, produces dramatic cortical reorganization and plasticity, as measured with TMS, leading to functional recovery (Ro, Noser, Boake, Wallace, Gaber, Bernstein, Speroni, De Joya, Burgin, Zhang, Grotta, & Levin, under revision). Click here to be redirected to the CI Project Web Page.