Representation of the visual field in the human occipital cortex - A magnetic resonance imaging and perimetric correlation

Objectives: To evaluate the retinotopic map of the human occipital cortex b y correlating magnetic resonance imaging (MRI) findings with visual field d efects in patients with occipital lobe infarcts and to assess the compatibi lity between our cliniconeuroimaging findings and the location of lesions p redicted by the classic Holmes map and a revised map. Methods: Magnetic resonance images were obtained in 14 patients with occipi tal lobe infarcts. Visual field analysis was performed with tangent screen, the Goldmann perimeter, and the Humphrey Field Analyzer. Based on the patt ern of visual field deficit, the location of the lesion in the mesial occip ital lobe in each patient was predicted using the Holmes map and other reti notopic maps of the occipital cortex. The predicted location of the lesion was then compared with its actual location shown on MRI to assess the compa tibility between our data and the other maps. These maps determine retinoto pic correlates of the medial occipital lobe, but they cannot establish corr elates of the striate cortex (V1). The medial occipital representation of c entral vision was evaluated by regression analysis. Results: The MRI correlations in this study confirmed gross estimates of th e retinotopic organization of the occipital cortex. However, our findings d id not correlate exactly with the Holmes map. We determined that the centra l 15 degrees of vision occupies 37% of the total surface area of the human medial occipital lobe. Based on our data, a refined retinotopic map is pres ented. Conclusions: The resolution of conventional MRI testifies to its considerab le value in localizing occipital lobe lesions. Our findings support, and re fine, the Holmes map of the human occipital cortex.