Koniocellular projections and hand-assisted blindsight

摘要

Vakalopoulos (2008) reviews evidence for the notion that preserved koniocellular (K-cell) pathways may underlie preserved visual abilities in patients suffering from cortical blindness (blind-sight). He suggests that the hand-assisted blindsight we recently reported in a person with a dense quadrantanopia following the surgical severance of Meyer's Loop may be explained by K-cell pathways that terminate in extrastriate cortex. Here we consider the possibility that K-cell axons would survive the severance of the optic radiations and we briefly review the properties of K-cells that project to extrastriate areas. Although we are sympathetic to Vakalopoulo's argument when applied to cases of blindsight following cortical damage (e.g. Patient GY; Weiskrantz, Barbur, & Sahraie, 1995), we think that it is unlikely that preserved koniocellular pathways support the hand-assisted blindsight we uncovered in our participant, MB (Brown, Kroliczak, Demonet, & Goodale, 2008)#