Involvement of the subcortical pathway have been studied by de Gelder et. al. (2005). Patient GY suffered an occipital lesion at age 7, and subcortical pathway has been mostly documented in this patient, thinking that post-lesion and experience-dependent plasticity has taken place. There have also been animal studies in rats which showed the role of the midbrain structures. In this case, even without the contribution of the primary sensory cortices, there were still analysis of the affective value of auditory and also, visual stimuli among the tested rats. Also, in the subcortical pathway, visual information are said to be transmitted through the retinotectal pathway and then projected to the extrastriate visual cortex. This is sufficient enough to drive visually guided behavior even if the patient is unaware of the visual stimuli. A function involving oculomotor processes of the superior colliculus has been suggested. This was based on the demonstration of the accurate localization with saccadic eye movements. Retinotectal or secondary visual pathway was suggested to mediate some remaining visual functions in patients with cortical blindness, this pathway project through the pulvinar and then into the dorsal stream of the extrastriate cortex. Also, this pathway has been recommended to be involved with the vision of the cortically blind patients. Not only does this pathway generate accurate visually guided saccades to the unseen stimuli, the patients also can accurately point towards the stimuli which were present within their scotoma.

As said earlier, only a minority of patients with blindsight has shown cortical preservation or sparing, but majority has shown intact superior colliculi. Also, Morris et. al. (1999) investigated similar subcortical pathway in healthy human observer. Facial expressions were subliminally presented to the patients and they were able to say which expression is shown. Therefore much attention is given more on explaining subcortical visual pathway than a spared cortex and this has also been evident in different neuronimaging studies done by de Gelder & Hadjikhani, 2006; de Gelder et al., (2005); Morris et al., (2001); Pegna et al., (2005).
Jacob Jolij and Victor a.F. Lamme, TMS induced affective blindsight reverts to affective blindness when stimulus visibility is increased.

Beatrice de Gelder and Marco Tamietto, Affective Blindness. Scholarpedia, 2(10):3555, 2007.

Tony Ro and Robert Rafal. Visual restoration in cortical blindness: Insights from natural and TMS-induced blindsight. NEUROPSYCHOLOGICAL REHABILITATION 16 (4), 377-396, 2006.

Goodale, M.A., & Milner, a.D. Separate visual pathways for perception and action. Trends in Neurosciences, 15, 20-25, 1992.

Blythe, I.M., Kennard, C., & Ruddock, K.H. Residual vision in patients with retrogeniculate lesions of the visual pathways. Brain, 110(Pt 4), 887-905,…