One center's experience with complications during the Wada test

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112207/1/epi13046.pd

Spatial attentional shifts: Implications for the role of polysensory mechanisms

Simple reaction times to lateralized visual (Experiment 1) or auditory (Experiment 2) targets were studied in normal subjects. The targets were preceded by a visual or auditory cue located on the same (valid cue), or opposite (invalid cue) side as the subsequent target, or on both sides (neutral cue), with one of four cue target intervals. The validity of visual and auditory cues influenced the speed of response to the visual target but not to the auditory target. It is hypothesized that cross-modal cueing of spatial position works only with modalities for which a movement (e.g. saccade) leads to improved sensory analysis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27570/1/0000614.pd

Letters to the Editor

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65933/1/j.1528-1157.1995.tb00479.x.pd

Frontal lobe lesions in man cause difficulties in suppressing reflexive glances and in generating goal-directed saccades

The frontal eye field (FEF) and superior colliculus (SC) are thought to form two parallel systems for generating saccadic eye movements. The SC is thought classically to mediate reflex-like orienting movements. Thus it can be hypothesized that the FEF exerts a higher level control on a visual grasp reflex. To test this hypothesis we have studied the saccades of patients who have had discrete unilateral removals of frontal lobe tissue for the relief of intractable epilepsy. The responses of these patients were compared to those of normal subjects and patients with unilateral temporal lobe removals. Two tasks were used. In the first task the subject was instructed to look in the direction of a visual cue that appeared unexpectedly 12° to the left or right of a central fixation point (FP), in order to identify a patterned target that appeared 200 ms or more later. In the second “anti-saccade” task the subject was required to look not at the location of the cue but in the opposite direction, an equal distance from FP where after 200 ms or more the patterned target appeared. Three major observations have emerged from the present study. (a) Most frontal patients, with lesions involving both the dorsolateral and mesial cortex had long term difficulties in suppressing disallowed glances to visual stimuli that suddenly appeared in peripheral vision. (b) In such patients, saccades that were eventually directed away from the cue and towards the target were nearly always triggered by the appearance of the target itself irrespective of whether or not the “anti-saccade” was preceded by a disallowed glance. Those eye movements away from the cue were only rarely generated spontaneously across the blank screen during the cue-target time interval. (c) The latency of these visually-triggered saccades was very short (80–140 ms) compared to that of the correct saccades (170–200 ms) to the cue when the cue and target were on the same side, thereby suggesting that the structures removed in these patients normally trigger saccades after considerable computations have already been performed. The results support the view that the frontal lobes, particularly the dorsolateral region which contains the FEF and possibly the supplementary motor area contribute to the generation of complex saccadic eye-movement behaviour. More specifically, they appear to aid in suppressing unwanted reflex-like oculomotor activity and in triggering the appropriate volitional movements when the goal for the movement is known but not yet visible.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46554/1/221_2004_Article_BF00235863.pd

Impairments in orienting to visual stimuli in monkeys following unilateral lesions of the superior sulcal polysensory cortex

Monkeys were tested for head and eye orientation to illuminated lamps in a hemisphere before and after serial, unilateral lesions of the polysensory superior temporal cortex (STS) or control lesions. Following STS lesions they were impaired in orienting to contralateral lamps; this impairment was more severe and persistent when a ipsilateral stimulus in the mirror-image position was simultaneously presented. These findings, together with deficits in manual reaching and grasping observed following STS lesions, support the view that the STS is part of a polysensory system controlling attention and exploratory movements.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26421/1/0000508.pd

The psychologist's role in assessing and facilitating patients' knowledge of advance directives in medical settings: A preliminary investigation

In a time of budgetary shortfalls in the medical industry, an aging population, and an increased emphasis on health care choices, psychologists are being called upon to administer advance medical directive programs to patients. This study reports preliminary findings from a program to assess and facilitate patients' knowledge of advance directives (ADs) by the Psychology Service at the Ann Arbor VA Medical Center. The participant pool included 243 male veteran patients admitted to medical and surgical wards at the hospital. The intervention included the use of a computer-generated prompt for consultation, which was sent to the psychology staff in response to a patient inquiry regarding ADs. It also involved an increased emphasis on the delivery of written material on ADs by the admissions clerks. The intervention appeared to result in a modest increase in patients' knowledge of advance directives. Suggestions are offered for areas that should be emphasized in future attempts to increase patients' knowledge and utilization of advance directives.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44859/1/10880_2005_Article_BF01996131.pd

The functional significance of the visual projection area in the cerebellum.

Most experiments concerned with visual perception deficits have looked at the effects of damage to the traditional parts of the classical projection pathways: the lateral geniculate bodies, superior colliculi, and the visual cortex. Relatively little attention has been paid to another area receiving visual projections: the cortex of the cerebellum. That such an optically active area exists has been known for more than twenty years (Gerard, Marshall, & Saul, 1936; Snider & Stowell, 1942) and the distribution (Snider & associates, 1942-1958), form (Koella, 1959), and sensitivity to drugs (Berry et al., 1959; Haft et al., 1961; Koella, 1959) of visually evoked potentials in this structure have been investigated. [...

Stimulation: History of Brain Mapping

The history of brain mapping using stimulation is long and nonlinear. It started with very imprecise stimulation of the brain using electrical discharges in the early 1800s. With better control of the electrical sources and more precise application of the stimuli, the re\uad al mapping of brain functions began in the 1870s, starting with the easily observed ef\uad fects of activation of neurons in the motor cortex. Work since then has shown that the cerebral mantle is highly specialized and, more interesting, that experience and practice can cause significant alterations of the organization of neurons in the cortex and subcorti\uad cal structures. New techniques to alter neuronal activity are being developed each year and will certainly increase our understanding of how the brain is organized and how it can be modified

Spatial attentional shifts: Further evidence for the role of polysensory mechanisms using visual and tactile stimuli

Normal subjects performed simple reaction time responses to lateralized visual target stimuli (Experiment 1) and lateralized tactile target stimuli (Experiment 2). In each experiment, the lateralized targets were preceded at one of four intervals by a visual or tactile cue located on the same (valid cue), or opposite (invalid cue) side, or on both sides (neutral cue). The validity of the visual and tactile cues influenced the speed of response to either target stimulus. These findings, together with those previously reported ( and , Neuropsychologia 26, 499-509, 1988), are consistent with the view that intra-and inter-modal spatial cueing is effective with modalities that are linked to orienting systems in which movements of the sensory array serve to improve sensory analysis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28240/1/0000693.pd