Ronald J. Tusa

Learn More
The location and retinotopic organization of visual areas in the cat cortex were determined by systematically mapping visual cortex in over 100 cats. The positions of the receptive fields of single neurons or small clusters of neurons were related to the locations of the corresponding recording sites in the cortex to determine the representations of the(More)
This is the second in a series of papers in which we describe our continuing efforts to define functional units of visual cortex based upon electro-physiological mapping of single and multiple unit activity in both awake and the nitrous oxide anesthetized cats. In the first paper (Tusa, Palmer and Rosenquist, '78), the extent and retinotopic organization of(More)
The location and retinotopic organization of areas 18 and 19 in cat cortex were determined using electrophysiological mapping techniques. These two areas each contain a single representation of the visual hemifield and each has a distinctive cytoarchitecture. The visual hemifield representations in these two areas are nearly mirror images of each other.(More)
OBJECTIVE The study was designed to measure dynamic visual acuity (DVA) during head movement as an assessment of the functional impact of vestibular deficits. STUDY DESIGN The study design was a prospective, clinical study. SETTING The study was performed in a tertiary, ambulatory referral center. PATIENTS Forty-two normal subjects, 29 patients with(More)
The retinotopic organization of cat cortex, in the vicinity of areas 20 and 21 as defined by Heath and Jones ('71), was determined using electrophysiological mapping techniques. Although the topography of the visual field representations in this region of cortex is more complex than that found in areas 17, 18, and 19, this region appears to contain four(More)
Recent studies in rhesus monkeys and human patients have increased our understanding of the role of various cortical regions in the generation of smooth pursuit eye movements. Little is known, though, about the cerebral white matter pathways mediating smooth pursuit. In this paper, we describe both the corticocortical and corticosubcortical projections from(More)
OBJECTIVE To determine whether the cervico-ocular reflex contributes to gaze stability in patients with unilateral vestibular hypofunction. STUDY DESIGN Prospective study. SETTING Tertiary referral center. PATIENTS Patients with unilateral vestibular hypofunction (n = 3) before and after vestibular rehabilitation and healthy subjects (n = 7). (More)
Eye movements evoked by optokinetic and vestibular stimulation were measured by scleral search coil before and up to 8 weeks after unilateral cortical lesions in 11 cats. During both monocular and binocular viewing conditions, several deficits in the velocity-storage component of optokinetic nystagmus (OKN) were found. At low target velocities, the final(More)
OBJECTIVE This study was designed to measure visual acuity during active vertical head movement and to examine its relationship to subjective reports of oscillopsia. STUDY DESIGN This was a prospective, clinical study. SETTING The study was performed in a tertiary, ambulatory referral center. PATIENTS Thirty normal subjects, 13 patients with(More)
Overview. Neurologists are frequently called upon to evaluate patients with vertigo and dizziness and, in some cases, to make sense of abnormal vestibular tests. Consequently, it is useful to have some familiarity with the methods used to test vestibular function. The vestibulo-ocular reflex (VOR) is a reflex that acts at short latency to generate eye(More)