Kalman Rubinson

Neural differentiation in the retina of the larval sea lamprey (Petromyzon marinus).

The peripheral retina of the sea lamprey develops in a 5-year-long process in which only certain neurons differentiate each year. The growth of cell layers, the differentiation of the neurons, and the morphology of their dendrites and axons were studied with normal, HRP, and Golgi preparations. Ganglion cells are differentiated in 3-year-old larvae, amacrine and horizontal cells in 4-year-old larvae, photoreceptor cells in stage I transformers, and bipolar cells in stage III transformers. Each new development is expressed as a radial gradient of differentiation. As a result of this protracted and stepped process, lamprey retinal neurons, particularly ganglion cells, differentiate in the absence of other cells to which they will ultimately be connected and may express their individual genetic programs more fully than in other vertebrate retinas. This could account for the unusual relationship of the ganglion cell, inner plexiform, and optic nerve layers and for the very high ratio of displaced to orthotopic ganglion cells.

Efferent projections of the superior olivary nucleus in the frog, Rana catesbeiana.

Following electrolytic lesions of the superior olivary nucleus (SO) of the bullfrog, Rana catesbeiana, the efferent pathways of this nucleus were studied with silver impregnation methods. The major projection was to the ipsilateral principal nucleus of the torus semicircularis. Less conspicuous degeneration was traced to the nuclei magnocellularis and commissuralis of the torus. No contribution was made to the tectum or nucleus isthmi. Other projections of the SO include a sma-ler contralateral projection to these same nuclei and to the ipsilateral nucleus lateralis profundus mesencephali. A system of connections between the acoustic nuclei was invariably interrupted with these lesions and the degeneration seen in the more dorsal acoustic areas was not entirely due to the destruction of SO neurons.

The Central Distribution of VIII Nerve Afferents in Larval Petromyzon marinus

In larval lampreys (body length 30–80 mm), the central projection of VIII nerve afferents was traced with selective silver methods for degenerating axoplasm. In 30–40 mm animals, lateral regions, desc

Designated Discussion: A Preliminary Report on Ascending Thalamic Afferents in Rana pipiens

Afferent fibers from the brainstem to the thalamus of Rana pipiens are traceable, with selective silver methods for degenerating axoplasm, to terminations within describable nuclei.

Efferent projections of the torus semicircularis to the medulla of the tadpole,Rana catesbeiana

Horseradish peroxidase injections into the medulla of tadpoles demonstrate, by back-filling, efferent neurons in the torus semicircularis which project to the ipsilateral superior olive. This projection, as well as one to the vicinity of the efferent neurons of the contralateral VIII and lateral line nerves, is confirmed by tracing anterograde transport following HRP injections into the torus semicircularis. These efferent neurons, located primarily in the principal nucleus of the torus within the terminal field of the projection from the superior olive, represent the only reported descending path to the superior olive and efferent nuclei in a non-mammalian vertebrate.

Vagal Afferent Projections in Rana pipiens, Rana catesbeiana, and Xenopus mülleri

The vagus nerve was transected proximal to the ganglion in Rana pipiens, Rana catesbeiana and Xenopus mulleri. Degeneration, seen with the Nauta and Fink-Heimer I

The Organization of the Optic Tectum in Larval, Transforming, and Adult Sea Lamprey, Petromyzon marinus

The cytoarchitecture and neuronal morphology of the optic tectum were examined in larval, transforming, and adult sea lamprey, Petromyzon marinus. In small larvae, the tectum exhibits a simple two-layer pattern and neurons with rudimentary dendrites of radial or tangential orientation. During growth and transformation to the adult form, the tectum becomes a larger and more prominent brain structure. Tectal neurons, in the adult, are larger than those in the larvae and exhibit more complex dendritic arrays. Radially oriented primary dendrites exhibit higher-order branches with tangential orientation and many tangential dendrites have branches with radial orientation. The appearance of distinct fiber layers is characteristic of the maturing tectum which, in the adult, is differentiated into seven layers of cells and fibers. The major growth of the optic tectum during transformation is accompanied by the maturation of the neural retina and by changes in behavioral responses to visual stimuli.

Septal vein symmetry: implications for endoscopic septum pellucidotomy.

BACKGROUND: Endosopic septum pellucidotomy is used for treating patients with unilateral and specific types of bilateral hydrocephalus. The ideal location for septostomy is controversial; however, an avascular region is preferred. OBJECTIVE: As the septal veins (SVs) are viewed only from one side, we studied the symmetry of the SVs in an attempt to define a safe area for septostomy. METHODS: Sixteen cadaver brains were dissected. The septum pellucidum was exposed bilaterally and divided into 3 regions. SVs of both sides were evaluated according to number, size, distribution, and location relative to common markers on both sides. RESULTS: Each side included 1 to 7 large veins (mean ± standard deviation, 2.3 ± 1.4), 0 to 3 small veins (2.05 ± 1.73), and a total of 2 to 7 veins (4.35 ± 1.53). Of the large veins, 88% were located in the anterior septal region (anterior to the foramen of Monro). Among the 10 brains that were extensively dissected, 90% had asymmetric SVs (either in the number of large veins or in the existence of any veins) in at least 1 of the septal regions, and 50% of brains had asymmetric SVs in the anterior region. CONCLUSION: Distribution of the SVs is asymmetric in most cases. We recommend septostomy be performed at the anterior area of the middle septal region, at the level of the foramen of Monro, mid-height between the corpus callosum and fornix. Careful evaluation of preoperative images and thorough coagulation at the septostomy site are essential to avoid injury to a contralateral large SV.

CELL GROWTH PATTERNS AND LENS GEOMETRY : A QUANTITATIVE STUDY FROM THREE-DIMENSIONAL RECONSTRUCTIONS

The growth of the lens of the sea lamprey, Petromyzon marinus, was studied over the 5 years of larval development. Whole lenses (25) and Golgi-impregnated cells (393) were reconstructed with computer-assisted microscopy. Several cellular geometric parameters (length, width, curvature, surface, volume, shape) were correlated with the position of the cells base on the lens capsular perimeter. Based on these correlations, the cells formed four groups that correspond to the central anterior, germinative, transitional and cortical fiber zones. A fifth zone, containing nuclear fiber cells, never stained. Lens growth is exponential during the 5 years. The anterior epithelium increases in size and in cell number by cell growth and division. The posterior mass increases in cell number by recruitment and increases in size by cell growth. A model is proposed to account for the size and shape of the lens based upon the coupling of anterior and posterior growth patterns. Four zonal boundaries are defined by changes in cell growth patterns. With growth, cells are subsumed into adjacent zones and zonal boundaries move away from the lens center. We find no support for the suggestion that cells migrate centrally.

Walter Riss, PhD, 1925-2015.

established the first interdisciplinary graduate program at Downstate. He was instrumental in promoting or organizing a number of symposia at the New York Academy of Sciences to promote interest in neural evolution, at the Massachusetts Institute of Technology on the subcortical visual system and at Downstate on basic thalamic structure and function. Papers from the last two symposia were published in special issues of Brain, Behavior and Evolution . It is not surprising that Walter inspired and mentored a group of young trainees, ourselves included, to begin careers in vertebrate evolutionary neuroscience. Thinking back on those days with nostalgia, the labs were filled with tanks of frogs, salamanders, turtles, snakes and alligators, some of which caused a commotion when they escaped into the hallway. He will also be remembered for his wit and keen mind, for his skill in the teaching of neuroanatomy and for his role as a model teacher for those of us who worked with him at Downstate. The role of a professor, according to Walter, is to increase knowledge through research, to make knowledge comprehensible to students so that they may carry on investigative and educational efforts and to transmit to them ‘some sense of the enthusiasm’ that the teacher has for his subject matter. He mentored a number of students and fellows including Frank Scalia, Kalman Rubinson, Robert Peterson, Robert Knobler and Elliott Mufson. Perhaps the most characteristic feature of Walter was his corncob pipe, which he smoked all the time. One had to blow away the haze of the smoke to find Walter hidden in his small office. He would often pause in mid-sentence for a long draw on his pipe, but he always We are saddened to note the passing of Walter Riss on May 24, 2015. Walter grew up in New Britain, Conn., USA, and received his undergraduate and postgraduate education at the Universities of Connecticut, Rochester and Kansas, where he trained in physiological psychology and neuroanatomy. He was Professor of Neuroscience and the former Director of the Biological Psychology Graduate Program at the SUNY Downstate Medical Center. Walter was the founder and first Editor-in-Chief of Brain, Behavior and Evolution . The purpose of this journal is to integrate knowledge about the anatomy and physiology of the nervous system with knowledge about its evolution and the evolution of behavior. During his graduate and postdoctoral training, Walter studied the neural mechanisms of sound localization and reproductive physiology. In his early years as Assistant Professor at Downstate, he continued research on the neural and behavioral influences on endocrine development and function. Perhaps excited by the introduction of the new silver-staining methods for tract tracing, which provided a more secure platform for research on comparative neuroanatomy, Walter turned his interest toward the evolution of the nervous system. His early contributions to his new field of endeavor included studies on the amphibian and reptilian visual system and the cytoarchitecture of the reptilian forebrain. In addition, he wrote a number of theoretical papers intended to model the progression of neural circuits from simpler to more complex life forms. Walter was a dynamic and forward-thinking entrepreneur. In initiating the Biological Psychology Program, he Published online: August 12, 2015