Co-Planar Stereotaxic Atlas of the Human Brain—3-Dimensional Proportional System: An Approach to Cerebral Imaging, J. Talairach, P. Tournoux. Georg Thieme Verlag, New York (1988), 122 pp., 130 figs. DM 268

I have developed "tennis elbow" from lugging this book around the past four weeks, but it is worth the pain, the effort, and the aspirin. It is also worth the (relatively speaking) bargain price. Including appendixes, this book contains 894 pages of text. The entire panorama of the neural sciences is surveyed and examined, and it is comprehensive in its scope, from genomes to social behaviors. The editors explicitly state that the book is designed as "an introductory text for students of biology, behavior, and medicine," but it is hard to imagine any audience, interested in any fragment of neuroscience at any level of sophistication, that would not enjoy this book. The editors have done a masterful job of weaving together the biologic, the behavioral, and the clinical sciences into a single tapestry in which everyone from the molecular biologist to the practicing psychiatrist can find and appreciate his or

Principles of Neural Science

Recent studies of eye movements in reading and other information processing tasks, such as music reading, typing, visual search, and scene perception, are reviewed. The major emphasis of the review is on reading as a specific example of cognitive processing. Basic topics discussed with respect to reading are (a) the characteristics of eye movements, (b) the perceptual span, (c) integration of information across saccades, (d) eye movement control, and (e) individual differences (including dyslexia). Similar topics are discussed with respect to the other tasks examined. The basic theme of the review is that eye movement data reflect moment-to-moment cognitive processes in the various tasks examined. Theoretical and practical considerations concerning the use of eye movement data are also discussed.

/pdf/eye-movements-in-reading-and-information-processing-20-years-3z5ay8hdwc.pdf

Eye movements in reading and information processing: 20 years of research.

The physical contrast of simple images such as sinusoidal gratings or a single patch of light on a uniform background is well defined and agrees with the perceived contrast, but this is not so for complex images. Most definitions assign a single contrast value to the whole image, but perceived contrast may vary greatly across the image. Human contrast sensitivity is a function of spatial frequency; therefore the spatial frequency content of an image should be considered in the definition of contrast. In this paper a definition of local band-limited contrast in images is proposed that assigns a contrast value to every point in the image as a function of the spatial frequency band. For each frequency band, the contrast is defined as the ratio of the bandpass-filtered image at the frequency to the low-pass image filtered to an octave below the same frequency (local luminance mean). This definition raises important implications regarding the perception of contrast in complex images and is helpful in understanding the effects of image-processing algorithms on the perceived contrast. A pyramidal image-contrast structure based on this definition is useful in simulating nonlinear, threshold characteristics of spatial vision in both normal observers and the visually impaired.

/pdf/contrast-in-complex-images-59l23ahsde.pdf

Contrast in complex images.

Population-based study からみた神経予後不良因子の検討

The aim of this thesis was to assess the vision screening system and ocular status in Sweden of today, yesterday and tomorrow and to compare the prevalence of ocular disease before and after screening and treatment with special focus on amblyopiaScreening has been defmed by the United States Commission of Chronic Illness (1957) as "the presumptive identification of unrecognized disease or defect by the application oftests, examinations or other procedures, which can be rapidly applied Screening tests sort out apparently well persons who probably have a disease from those who probably do not" The screening system for eye disorders was introduced in the whole country in the beginning of 1970 and has not been evaluated in a greater area and for a longer period Neither has an evaluation been done according to WHO's instructions Amblyopia is the most common cause to visual impairment in one eye The visual system is developing mostly in the first years of life and it is important to treat amblyopia in early childhood The three first papers are retrospective studies and the fourth a prospective study The study group in the first and second paper consisted of all children born 1982 in three Swedish cities from newborn until the age of 10 years The children have been tested eight to nine times at the Child Health Care Centres and in school during this time The sensitivity and specificity of visual screening were 92% and 97% respectively The prevalence of ametropia was 77%, strabismus 31%, amblyopia ≤ 7 29% and organic lesions 02% We compared the prevalence of amblyopia today with the time before screening was introduced in Sweden This comparison shows that serious amblyopia has been reduced about 10 times with screening and treatmentLoss of vision in the non-amblyopic eye was investigated by studying patients with amblyopia at four visual rehabilitation centres Approximately 12% of the people with amblyopia ≤ 03 will eventually become visually handicapped due to lesions in the better eyeDespite visual screening and treatment there are some children left with residual amblyopia We investigated ways to improve the system by lowering the age for visual acuity examination from 4 to 3 years and at the same time two vision charts were compared We found that the testability rate for 3-year-olds was almost the same for the Lea Symbol chart and the HVOT chart (828% and 848% respectively) Testability was about 10% higher at 4 years The positive predictive value was lower at 3 years (58%) than has previously been found at 4 years (72%)Conclusion: In these studies we have found that screening is justified for the following reasons: visual screening is efficient in terms of sensitivity and specificity and many important ocular conditions are detected in this process; the prevalence of serious amblyopia is greatly reduced by screening and treatment; loss of vision in the non-amblyopic eye is a significant problem, which can be greatly reduced by screening and treatment, thereby saving expenses for the societyThe following has been found regarding the design of visual screening: visual acuity testing is efficient in detecting visual disorders from 4 years and up; visual acuity can be tested at 3 years, but with lower positive predictive value; the most widely used charts in Sweden and internationally, the HVOT chart and the Lea Symbols chart perform equally well in visual acuity testing of 3-year-old and 4-year-old children

https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1600-0420.2001.790306.x

Visual screening of Swedish children: An ophthalmological evaluation

Background: Studies of extraocular muscle (EOM) by magnetic resonance imaging (MRI) need to be extended to normal subjects of different ages to obtain data on the muscle thickness, cross-sectional area, and the volume of EOM and other orbital tissues. Methods: Forty-two orbits of 21 normal subjects in three age groups with an age range of 19–70 years were examined with surface-coil MRI. The transverse and sagittal images were used to measure the thickness of the four rectus muscles during fixation in different gaze positions. The coronal images with eyes in the primary position were used to calculate the cross-sectional areas. The volumes of all six EOM, orbital fatty tissue, the optic nerve and the eyeball were measured in the coronal plane and in either the transverse or the sagittal plane. Results: The horizontal muscles were thinner than vertical muscles. Muscle volume was larger in SR (superior rectus) than in IR (inferior rectus), larger in SO (superior oblique) than in IO (inferior oblique), and the same in LR (lateral rectus) as in MR (medial rectus). No significant differences were found in the values of the cross-sectional area in any image plane between the three age groups. There were no significant differences in muscle thickness and size and fatty tissue volume between age groups. The muscle thickness was linearly correlated to the angle of the eye deviation for all four rectus muscles, both in the ”on” and ”off” directions of the muscles. Conclusions: The study provides quantitative data, in normal subjects of different ages, on the thickness and size of EOM and the volume of other orbital tissues by MRI, to serve as a basis for further studies on the morphological changes of EOM in various orbital diseases.

MRI measurements of normal extraocular muscles and other orbital structures.

The aim of this study was to evaluate the visual screening system in Sweden. We have made a retrospective investigation of the results of screening for ocular disease and visual impairment of all c ...

Screening for visual and ocular disorders in children, evaluation of the system in Sweden.

Responses of primary and secondary muscle spindle endings of the ankle extensor and flexor muscles in the cat were studied in the absence of fusimotor activation by applying length changes of triangular form over a large range of velocities. Both position and velocity responses were determined. No differences were obtained in these responses between endings in extensor and flexor muscles or between endings in fast and slow muscles. It was found necessary to subdivide the velocity responses into two different components based on the great difference in time course of their transients. Mathematical expressions for the two components are given in an Appendix. They were denoted the ‘quick’ and the ‘slow’ velocity responses respectively. Primary and secondary endings differed both with respect to the ‘quick’ and the ‘slow’ components of the velocity response. Endings with response characteristics typical of both primary and secondary endings were distinguished as a special group. They have been referred to as endings of intermediate type. Some possible spindle mechanisms responsible for the observed properties of the spindle endings are discussed.

Gunnar Lennerstrand

Papers

Visual screening of Swedish children: An ophthalmological evaluation

MRI measurements of normal extraocular muscles and other orbital structures.

Screening for visual and ocular disorders in children, evaluation of the system in Sweden.

Position and Velocity Sensitivity of Muscle Spindles in the Cat. I. Primary and Secondary Endings Deprived of Fusimotor Activation

A population-based study of ocular abnormalities in premature children aged 5 to 10 years.