Methods for Dichoptic Stimulus Presentation in Functional Magnetic Resonance Imaging - A Review

Abstract

Dichoptic stimuli (different stimuli displayed to each eye) are increasingly being used in functional brain imaging experiments using visual stimulation. These studies include investigation into binocular rivalry, interocular information transfer, three-dimensional depth perception as well as impairments of the visual system like amblyopia and stereodeficiency. In this paper, we review various approaches of displaying dichoptic stimulus used in functional magnetic resonance imaging experiments. These include traditional approaches of using filters (red-green, red-blue, polarizing) with optical assemblies as well as newer approaches of using bi-screen goggles.

Maximizing sensitivity for fast GABA edited spectroscopy in the visual cortex at 7 T

“…It may be possible to achieve the same visual angle with head coil mountable goggles near the participant's eyes, minimizing the distance between the screen and the eyes of the participant. 42,43 Still, the electronics in the goggles should not interfere with the magnetic field, and the compatibility with a 7 T scanner may be an issue. Another confound of large voxel sizes is the stronger demands on B 1 and B 0 shimming.…”

Visualisation in-vivo des anomalies cérébrales de l’amblyopie. De l’électro-encéphalogramme quantifié à la magnéto-encéphalographie

“…Mais cette différence ne permet pas de caractériser des sous-types d'amblyopie [4]. Plusieurs travaux ont démontré l'existence d'anomalie d'intégration des stimuli provenant des deux yeux lorsqu'il existe une perturbation de la vision stéréoscopique [14,15]. Ces données sont en faveur d'une inhibition interoculaire.…”

Dichoptic Viewing Methods for Binocular Rivalry Research: Prospects for Large-Scale Clinical and Genetic Studies

“…For the prism stereoscope and lenticular ATS setups, this means the presented image may be distorted as some colors are not in focus (i.e., chromatic aberration). With polarization-based LCS and PPF setups, although full-color viewing of dichoptic stimuli is enabled, these methods can also cause the images to physically darken (Choubey et al, 2009;Pastoor & Wöpking, 1997;Stevens, 2004). For ATS displays, a number of related issues to consider include the following: (1) reduced image brightness in parallax ATS displays as half of the subpixel columns are blocked by the barrier (Choubey et al, 2009;Pastoor & Wöpking, 1997); (2) interpixel gaps (i.e., black mask matrix) in lenticular-type displays can be projected, causing dark regions to appear between observation zones (Holliman et al, 2011; though it can be resolved by slanting the monitor's lenticular lenses: Lipton & Feldman, 2002;Lipton et al, 1985;Lueder, 2011;van Berkel & Clarke, 1997); and (3) light scatter at lenticular lens boundaries causing variation in illumination intensity (Hill & Jacobs, 2006).…”

“…Two types of polarization states (and therefore filters) are commonly used: linear and circular (see Figure 10; for detailed discussion, see Hecht, 2002). However, as both states attenuate the light signal -via the initial PPF on the monitor and subsequently via the PPF on the glasses -the luminance of the images will be reduced (Choubey et al, 2009;Stevens, 2004). Another issue is that because dual-screen PPF setups rely upon the transmissive glass of the partially silvered mirror, it is neither a perfect reflector nor perfect transmitter.…”