the visual neurosciences

[...]... to the external limiting membrane, b the rods, c the cones, b¢ the rod nuclei on the inner part of the external granular layer, c¢ the cone nucleus, and d the inner nuclear layer The outer segments of the cone are incomplete since they were shriveled by the osmic acid The outer segments of the rods are shown as they would appear in a fresh condition Fig 1 From the peripheral region of the retina The. .. location of the primary visual area, and he suggested a scheme for the way in which the visual fields are mapped on the primary visual cortex Henschen recognized that the left hemisphere receives its input from the right visual field and the upper bank of the calcarine fissure from the upper retina, hence the lower visual field But Henschen also suggested that the periphery of the visual field is projected... the right side of the Head, and the fibres on the left side of both nerves uniting in the same place, and after union going into the Brain in the nerve which is on the left side of the Head, and these two Nerves meeting in the Brain in such manner that their fibres make but one entire Species or Picture, half of which on the right side of the Sensorium comes from the right side of both Eyes through the. .. of both optick Nerves to the place where the Nerves meet, and from thence on the right side of the Head into the Brain, and the other half on the left side of the Sensorium comes in like manner from the left side of both Eyes For the optick Nerves of such Animals as look the same way with both Eyes (as of Men, Dogs, Sheep, Oxen & cet.) meet before they come into the brain, but the optick Nerves of such... toward the ora serrata With a reduction in their number, the rods have the same course as the adjacent cone fibers Otherwise, all courses are as previously described Fig 4 At the border of the macula lutea The diagonal course of the rod and cone fibers is even more marked Figs 5–7 These figures show the cones in the macula lutea and the fovea centralis a is the outer limiting membrane in all cases next to the. .. its relation to visual function Image formation The cornea and lens form an inverted image of the visual scene at the back of the eye The optics of image formation in the vertebrate eye were unknown until the theoretical and experimental advances of the seventeenth century Prior to that time, scientists were troubled by the idea of an upsidedown image in the eye even though they knew of the camera obscura,... suffer from a visual disorder stemming from a defect of the retina or the visual centers of the brain Effective treatment of these visual impairments is possible in only a few types of cases because we lack the basic knowledge to understand the dysfunction underlying these disorders Although we have made significant progress in the visual neurosciences, much remains to be done The scope of the overall... through the brain Inouye devised a three-dimensional coordinate system for recording the entry and exit wounds He then calibrated the course of the bullet through the brain and estimated the extent of the damage it would have caused to the primary visual cortex or the optic radiations Based on his study of visual field defects in 29 patients, Inouye produced a map of the representation of the visual. .. provided by the measure that an engineer would naturally use when specifying the magnitude of a signal in a noisy background, the SNR This is the ratio of the response to the signal divided by the standard deviation of the responses with no signal present The measure d-prime in signal detection theory estimates from the psychometric responses the SNR of the representation of the stimuli on the decision... 1964) To obtain comparable curves for the neural responses, they used the following method: they assumed that there was another neuron, which they called the anti-neuron, with exactly the same properties as the one they were recording from but having a reversed directional preference; they then took the number of impulses in each trial, and said that it signaled the preferred direction if it was a number . union going thence into the Brain in the Nerve which is on the right side of the Head, and the fibres on the left side of both nerves uniting in the same place, and after union going into the Brain in the. from the right side of both Eyes through the right side of both optick Nerves to the place where the Nerves meet, and from thence on the right side of the Head into the Brain, and the other half. At the border of the macula lutea. The diagonal course of the rod and cone fibers is even more marked. Figs. 5–7. These figures show the cones in the macula lutea and the fovea centralis. a is the