The determination of the projection of the visual field on to the lateral geniculate nucleus in the cat

Henschen (1897, 1898) was the first to provide direct evidence in favour of a retinotopic projection in the lateral geniculate nucleus (LGN). He described a woman suffering from blindness of the lower left quadrants of both visual fields who was subsequently found to have a lesion limited to the dorsal half of the right LGN. Actually these early observations are not in accord with the later experimental studies on primates by Brouwer and subsequent workers (see below). Further early human clinico-pathological observations were made by Wilbrand & Saenger (1904), Ronne (1913, 1914) and Winkler (1912), but the extreme rarity of sufficiently restricted lesions, particularly in the nucleus itself, made it unlikely that the details of the retinotopic projection in the LGN would be unravelled in this way. By enucleating the eye of a cat and studying the distribution of the secondary degeneration in each LGN, Minkowski (1913) provided the first direct experimental evidence that the crossed and uncrossed optic fibres were distributed differently in the nucleus (cf. Minkowski, 1920) and that the binocular part of a visual field projected only to the medial part. The first detailed study of the retinotopic projection in the LGN was, however, carried out by Brouwer and his colleagues (Brouwer, Zeeman & Houwer, 1923). By making small retinal lesions and subsequently studying the degenerating fibres in Marchi preparations they established the quadrantic projections ofthe retina in the rabbit and cat and the quadrantic and intraquandrantic projections of the central and peripheral retinal segments in the monkey (Brouwer & Zeeman, 1925, 1926; Overbosch, 1927). Further details in respect to the monkey were added by Brody (1934), Penman