Regional cerebral correlates of global motion perception

Abstract

We used a psychophysical task to measure sensitivity to motion direction in 50 stroke patients with unilateral brain lesions and 85 control subjects. Subjects were asked to discriminate the overall direction of motion in dynamic stochastic random dot displays in which only a variable proportion of the spots moved in a single direction while the remainder moved randomly. Behavioural and neurophysiological evidence shows that the middle temporal (MT/V5) and middle superior temporal (MST) areas in the macaque monkey are indispensably involved in the perception of this type of motion. In human subjects too, lesions in the same region disrupt performance on this task. Here we assessed more extensively the correlation between direction sensitivity for global motion and the anatomical locus of the lesion. Thresholds for perceiving the direction of global motion were impaired in the visual field contralateral to the lesion in patients with lesions in the occipitoparietal and parietotemporal areas involving the human analogue of areas MT/V5 and MST, but not by lesions in the occipito-temporal or anterior frontal areas. Patients with lesions involving the anterior temporal or parietal lobes displayed poor performance for stimuli presented in either visual field, which is consistent with the large and bilateral receptive fields in these areas in monkeys. The perception of global motion was also more impaired in the centripetal than the centrifugal direction in the hemifield contralateral to the MT/V5 lesion. Surprisingly, thresholds were normal in all patients when the displays contained static but not dynamic visual noise, suggesting that their deficit reflects an inability to filter out dynamic noise. Although frequent repeated testing of some patients whose lesion involved the human homologue of MT was accompanied by an improvement in performance, this was no greater than in other patients who received training on different motion tasks.

Distinct mechanisms of form-from-motion perception in human extrastriate cortex

“…Alternatively, VM as well as FfM perception might have been impaired in this patient group. Linking this FfM deficit to damage in temporo-parietal cortex in close proximity to MT+/V5 agrees with neuroimaging studies that have consistently shown that MT+/V5 (that primarily codes for VM) is activated by FfM stimuli (de Jong et al, 1994;Dupont et al, 1997;Goebel et al, 1998;Tootell & Taylor, 1995;Watson et al, 1993) and agrees with previous lesion studies showing that damage to MT+/V5 leads to impaired VM perception (Barton et al, 1995;Greenlee et al, 1995;Vaina et al, 2001). Our lesion analysis suggests that damage did not extend posteriorly to include area KO, which is an area that has been involved in FfM perception and is activated by VM and FfM stimuli (Dupont et al, 1997;Van Oostende et al, 1997; but see also Zeki, Perry, & Bartels, 2003).…”

“…Each random dot field contained 1000 dots (diameter: 0.68 • ). A percentage of the dots was programmed to be displaced with a velocity of 2 • /s in the tested direction (signal dots) -comparable to velocities used in previous studies in groups of brain damaged patients (Schenk & Zihl, 1997b: 1 • /s; Barton et al, 1995: 3.5 • /s; Vaina et al, 2001: 2.9 • /s). The percentage of coherent motion (%CM) was defined as the number of signal dots divided by the total number of dots and multiplied by 100.…”

“…Deficient VM perception has been linked to bilateral or unilateral damage in lateral temporo-occipital cortex (Barton, Sharpe, & Raymond, 1995;Blanke, Landis, Mermoud, Spinelli, & Safran, 2003;Greenlee, Lang, Mergner, & Seeger, 1995;Vaina, Cowey, Eskew, LeMay, & Kemper, 2001) in close proximity to area MT+/V5 as defined anatomically (Dumoulin et al, 2000) and functionally by neuroimaging studies (de Jong, Shipp, Skidmore, Frackowiak, & Zeki, 1994;Dupont et al, 1997;Goebel, Khorram-Sefat, Muckli, Hacker, & Singer, 1998;Tootell & Taylor, 1995;Watson et al, 1993) and intracranial electrical stimulation (Blanke, Landis, Safran, & Seeck, 2002). Deficient FfM perception (with preserved VM perception) has been linked to different brain regions including unilateral temporo-occipital (Vaina, 1989) or temporo-parieto-occipital cortex (Regan et al, 1992), and bilateral parietal (Schenk & Zihl, 1997a) or temporo-occipital cortex (Cowey & Vaina, 2000).…”

Smooth Pursuit Eye Movements to Isoluminant Targets

“…Lesions of MT result in retinotopic deficits of pursuit initiation (Newsome et al 1985), whereas lesions to MSTl are followed by pronounced directional deficits during maintained pursuit toward the lesioned brain hemisphere (Dürsteler and Wurtz 1988). The importance of area MT for the perception of motion was furthermore established by studies in human patients (Vaina et al 2001;Zihl et al 1983). In neuroimaging studies, the human MT/MST complex (hMT) is typically the region showing the largest activation with motion stimuli (Culham et al 2001;Tootell et al 1995;Watson et al 1993;Zeki et al 1991), and transcranial magnetic stimulation over area hMT selectively disrupts visual motion processing (Hotson et al 1994).…”

Visual perception in prediagnostic and early stage Huntington's disease

“…Functional differentiation continues into the cortex, with regional specialization for motion, color, faces, spatial relationships, and other visual features (Wandell, 1999). For example, the human homolog to MT, a region specialized for motion perception, has been localized to occipital-parietal and occipital-temporal cortical regions (Vaina et al, 2001). Object and facial recognition is carried out within the ventral pathway projecting from the occipital to inferior temporal cortex.…”