Endodermal sinus tumor and mucinous cystadenofibroma of the ovary. Occurrence in an 82-year-old woman.

We encountered an unusual ovarian tumor consisting of a mixture of typical endodermal sinus tumor (EST) and mucinous cystadenofibroma that occurred in the ovary of an 82-year-old female patient. The EST component showed the classic histologic features of this tumor. Serum alpha-fetoprotein (AFP) level was not determined. Tumor stains were negative for AFP but positive for alpha-1-antitrypsin. The malignant germ cell component was intimately associated with the benign mucinous component. Focal production of epithelial mucin and carcinoembryonic antigen (CEA) in the EST component suggested a probable association between the two tumor types. The tumor was confined to one ovary, and the patient is disease-free 2 years after surgical therapy. This neoplasm is unique not only for the malignant germ cell component occurring in an 82-year-old woman, but for the unusual combination of tumor types. The pathogenesis is unknown.

Adenoid cystic-like tumor of the prostate gland. A report of two cases and review of the literature on "adenoid cystic carcinoma" of the prostate.

Two prostatic neoplasms that closely resemble adenoid cystic carcinoma of the salivary glands, but in the authors' opinion merit separate designation, are reported. Most of the well-documented examples of prostatic lesions interpreted as "adenoid cystic carcinoma" appear to have been similar to the cases reported herein. The lesions in this report, which the authors have designated as adenoid cystic-like tumors, occurred in men of 60 and 68 years of age who presented with urinary tract obstruction and had transurethral resection of the prostate. Both neoplasms were associated with a minor component of prostatic adenocarcinoma of the usual acinar type. Each adenoid cystic-like tumor had areas that closely resembled basal cell hyperplasia of the prostate, and one had conspicuous foci of squamous differentiation. One patient had a radical prostatectomy and is well six years after operation. The other patient was treated with transurethral resection and irradiation and is well eight months after operation. The prognosis associated with this neoplasm appears to be excellent on the basis of the limited experience to date.

Mechanisms of static and dynamic stereopsis in foveal cortex of the rhesus monkey.

1. The sensation of stereoscopic depth rests on the central neural processing of signals evoked by the two retinal images of a single object in space. It was our purpose in this study to investigate in the behaving monkey the binocular cortical mechanisms that might underlie the ability to recognize the relative position and motion of objects in three-dimensional space.2. The large majority of neurones studied in A17 (n = 245), and all neurones studied in A18 (n = 21), were functionally connected to both eyes, and a substantial proportion (75%) of these neurones were sensitive to positional binocular disparity. On the basis of their depth sensitivity profile, four types of stereoscopic neurones were recognized, each type characteristically sensitive to visual contours appearing in depth farther than, at, or nearer than the point of binocular fixation.3. Tuned excitatory and tuned inhibitory neurones display binocular facilitation and binocular suppression respectively, to stimuli over a narrow range of small disparities, including zero disparity, with more or less pronounced reciprocal responses to stimuli with larger disparities. These neurones, the tuned excitatory in particular, may be considered to be the substrate for central fusion of slightly disparate retinal images, and to provide the basis for the neural mechanisms leading to three-dimensional perception of objects with high stereoacuity (fine stereopsis).4. Two other sets of reciprocally organized neurones, near and far neurones, respond differentially to wider ranges of crossed and uncrossed disparities. The near neurones are activated by stimuli in front of and inhibited by stimuli behind fixation. The far neurones have the reciprocal depth sensitivity. These neural elements may be regarded as active in the processing of binocular information leading to qualitative depth estimates in the presence of double vision (coarse stereopsis).5. Binocular response selectivity for the direction of object motion-in-depth depends chiefly upon monocular sensitivity to the direction of retinal image motion, a property we observed in about one half of the foveal neurones. Cortical neurones with the same directional sensitivity for monocular stimuli in both eyes display coarse binocular selectivity for the trajectory of object motion but provide unambiguous signals for the direction of motion, towards the right or towards the left within the depth domain of the neurone. A small group of neurones (3%) displays opposite and opponent directional sensitivity for stimuli in the two eyes. Their binocular response, therefore, is best when the two retinal images move in opposite directions at the same time, a condition that obtains with motion directly towards or away from the animal with little or no lateral movement. These directionally dual-opponent cells usually have coarse or no selectivity for position-in-depth.6. The results of this study indicate that basic mechanisms for the stereoscopic analysis of the position (static) and motion (dynamic) of objects in space relative to one another are present at early stages of binocular interaction in the visual cortex of primates, and that they are in effective action during normal binocular vision.

Parietal lobe mechanisms for directed visual attention.

1. Experiments were made on the cortex of the inferior parietal lobule in 10 hemispheres of six alert, behaving monkeys. The electrical signs of the impulse discharges of single cortical cells were recorded as the monkeys executed tasks requiring them to fixate stationary visual targets, track those which moved slowly, and to make saccadic movements to foveate those which suddenly jumped from one locus to another within the field of view. A total of 907 neurons of area 7 were identified in terms of their physiological properties, particularly the correlation of their activity with the oculomotor components of these behavioral acts of directed visual attention; 480 of these were located by cytoarchitectural layer. Most identifiable cells of area 7 are visuomotor neurons, in a special and conditional sense. Their discharge frequencies increase before and during those steady fixations and movements of the eyes which secure and maintain foveation of objects, but only if the visual targets engaged are linked by a strong motivational drive; in our experiments, one between thirst and the light whose dimming the animal has learned to detect for liquid reward. We have identified and studied three major classes of neurons in area 7. 2. The visual fixation neurons (57%) accelerate discharge synchronously with fixation of a visual object the animal desires. The incremented discharge continues until reward, but then declines abruptly even when there is no immediate shift of the line of gaze. Fixation neurons are relatively inactive during those casual fixations by which the animal insepcts the surrounding environment. Mist fixation neurons subtend gaze fields limited to one quadrant or half of the total gaze field. The sum of the gaze fields of the fixation neurons in one hemisphere is weighted moderately toward the contralateral side. Fixation cells also discharge during slow pursuit movements in any direction so long as the movement stays within the gaze field of the neuron under study. About 40% of fixation cells are suppressed before and during saccadic movements of the eyes to a new target within the gaze field of the fixation cell. Those suppressed are located preferentially in layer V of the cortex. Suppression is maximal for saccades directed contralaterally to the hemisphere under study. 3. Visual tracking neurons are active during oculomotor pursuit of slowly moving visual objects, not during steady fixations. They show a marked directional but no laterality relation, and are suppressed before and during a visually evoked saccade superimposed on the smooth pursuit movement. The rate of discharge is a flat function of tracking speed so that these cells do not appear to emit signals which specify the speed of smooth pursuit movements. 4. The saccade neurons are active before and during visually evoked saccadic movements of the eyes but not before spontaneous saccades, no matter whether made in light or near darkness. The discharge of saccade neurons leads the eye movement by as much as 150 ms (mean, 73 ms)...

Neuronal coding by cortical cells of the frequency of oscillating peripheral stimuli.

One class of neurons in the somatic sensory cortex of unanesthetized monkeys is rhythmically entrained by sinusoidal mechanical stimulation of the skin of the hand at low frequencies. A second class, which is linked to Pacinian afferents, increases its rate of discharge in response to high-frequency peripheral stimuli but is not entrained. The vibratory sense is served by two distinct classes of cortical cells. The code for the group sensitive to low-frequency stimuli is the temporal order of impulses; for the high-frequency group the code is the labeled line.

Neural basis of the sense of flutter-vibration.

Comparison of human detection thresholds for oscillatory movement of the skin of the hand with response properties of first-order myelinated mechanoreceptive afferents from the monkey's hand, activated in an identical stimulus pattern, indicates that flutter-vibration is a dual form of mechanical sensibility, served peripherally by two different sets of fibers.