X and Y cells in the lateral geniculate nucleus of macaque monkeys.

Abstract

SUMMARY1. Cells of the lateral geniculate nucleus (l.g.n.) in macaque monkeys were sorted into two functional groups on the basis of spatial summation of visually evoked neural signals.2. Cells were called X cells if their responses to contrast reversal of fine sine gratings were at the f-ndamental temporal modulation frequency with null positons one quarter of a cycle away from positions for peak response. Cells were called Y cells if their responses to such stimuli were at twice the modulation frequency and were approximately independent of spatial phase.3. Ninety-nine percent of the cells in the four dorsal parvocellular layers of the l.g.n. were X cells; about seventy-five percent of the cells in the two ventral magnocellular layers were also X cells. The remainder were Y cells.4. We confirmed previous findings that magnocellular cells had a shorter latency of response to electrical stimulation of the optic chiasm.5. Magnocellular cells had much higher contrast sensitivities than did parvocellular cells.6. Therefore, two distinct classes of X cells exist in the macaque l.g.n.: parvocellular X cells and magnocellular X cells. The great difference in their properties suggests that they have different functions in vision. The Y cells in the magnocellular layers form a third functional group with spatial properties distinctly different from the X cells.

Optical coherence tomography, frequency-doubling technology, and colour Doppler imaging in ocular hypertension

“…The cells that present a nonlinear response to contrast and are therefore responsible for this illusion are a subgroup of M cells, called My cells, that overall represent just 3% of all the retinal ganglion cells. 41 FDT showed high sensitivity and specificity in detecting functional impairment of a highly selective and limited cell population, thus demonstrating that it is extremely sensitive for the detection of early alterations in ganglion cells. However, the most intriguing question is, why is a thinning in the RNFL and an increase in the PSD index found with FDT in OH?…”

Biological image motion processing: A review

“…The remaining neurons are those located in the magnocellular layers of the LGN. These receive a broad band chromatic input without color opponency and have a high contrast sensitivity (Kaplan and Shapley, 1982).…”

“…It is recognized that the opponent ceils in the parvocellular layers do have some achromatic contrast sensitivity, but their contrast thresholds are very high (Kaplan and Shapley, 1982: Hicks rt ai.. 1983: Lennie rt trl.. 1984) about an order of magnitude higher than cells in the magnocellular layers. at least for medium and low spatial frequencies.…”

“…It would appear that a most significant portion of motion sensitivity is mediated by the cells in the magnoceliular layers of the LGN. These cells can be subdivided into two classes, X and Y (Blakemore and Vital-Durand, 1981;Kaplan and Shapley, 1982).…”

Orientation selectivity in cat primary visual cortex: local and global measurement

“…A recent study based on the model [42] reported that well-defi ned LGN spike trains reduce the noise and elevate the response to the preferred stimulus. It is known that the relay cells are distributed nonrandomly in the LGN of cats and monkeys [43][44][45][46][47] . So the alignment of the receptive fields of relay cells in the LGN [1,5,7,8] could also …”