Research
Archer fish
We selected this fish species to serve as our model due to its remarkable ability to shoot down insects found on foliage above the water level, and its ability to learn to distinguish between artificial targets presented on a computer monitor in an experimental setting. Thus, the Archer fish can provide the fish equivalent of a monkey or a human subject that can report psychophysical decisions and make controlled and sophisticated experimental procedures possible. We test the Archer fish on "human like" tasks that examine attentional, perceptual and social processes.
Stereoscope
This technique takes advantage of the fact that visual input, once received by the retina, is propagated in an eye-specific fashion throughout the early stages of the visual system. This monocular segregation is retained up to layer IV of striate cortex. Since, there are relatively few monocular neurons beyond area V1, activation of extra striate areas is not eye-dependent. Given that observers are not explicitly aware of the eye to which a visual stimulus is projected and perceive the images from different eyes as ‘fused’, manipulating the eye-of-origin of the stimulus provides a useful tool for isolating monocular versus binocular neural channels. Thus, the logic of our studies is as follows: If perceptual performance is enhanced when an image (or two images) is presented to a single eye versus interocularly to different eyes, we can infer that the monocular advantage is a product of neural facilitation within lower levels of the visual pathway.
fMRI
Imaging techniques suffer from a “cortico-centric” bias by virtue of the complications of imaging subcortical structures in humans. We examine how much of the activation observed in imaging studies reflects real neural computation and how much is a result of mirroring subcortical activations. We will examine this question by employing the stereoscope technique in order to dissociate effects of subcortical and cortical regions. We suggest that lower subcortical regions can modulate and influence the functioning of higher cortical attentional structures. Accordingly, experimental manipulations influencing those subcortical structures should also be manifested in the pattern of activation at higher cortical regions. We examine the influence of eye-of-origin manipulation, which should influence lower parts of the visual system, on the pattern of activation at higher cortical regions. If a specific cognitive ability is mainly related to subcortical structures and the higher cortical activations observed during those tasks is only an epiphenomenon, than eye-of-origin manipulation should modulate the pattern of activation in those regions (even though they themselves are indifferent to the visual information eye-of-origin). In addition, we also examine the pattern of activation in subcortical regions, which should be modulated by the eye-of-origin modulation.
