Data from: Lesions to right posterior parietal cortex impair visual depth perception from disparity but not motion cues

The posterior parietal cortex (PPC) is understood to be active when
observers perceive three-dimensional (3D) structure. However, it is not
clear how central this activity is in the construction of 3D spatial
representations. Here, we examine whether PPC is essential for two aspects
of visual depth perception by testing patients with lesions affecting this
region. First, we measured subjects' ability to discriminate depth
structure in various 3D surfaces and objects using binocular disparity.
Patients with lesions to right PPC (N = 3) exhibited marked perceptual
deficits on these tasks, whereas those with left hemisphere lesions (N =
2) were able to reliably discriminate depth as accurately as control
subjects. Second, we presented an ambiguous 3D stimulus defined by
structure from motion to determine whether PPC lesions influence the rate
of bistable perceptual alternations. Patients' percept durations for
the 3D stimulus were generally within a normal range, although the two
patients with bilateral PPC lesions showed the fastest perceptual
alternation rates in our sample. Intermittent stimulus presentation
reduced the reversal rate similarly across subjects. Together, the results
suggest that PPC plays a causal role in both inferring and maintaining the
perception of 3D structure with stereopsis supported primarily by the
right hemisphere, but do not lend support to the view that PPC is a
critical contributor to bistable perceptual alternations.