Frank Scalia

Amygdaloid Nucleus: New Afferent Input from the Vomeronasal Organ

Terminal degeneration stained by the Fink-Heimer technique was found in the medial and cortical amygdaloid nuclei in a discrete zone after lesions were inflicted in the accessory olfactory bulb but not after lesions were made in the main olfactory bulb in the rabbit. Since the accessory olfactory bulb receives the endings of the vomeronasal nerve, the mediocortical complex of the amygdala is the central projection area for the vomeronasal sensory organ. The vomeronasal organ is seen as having new potential significance in sexual and feeding behavior because the cortical amygdaloid nucleus projects to the anterior, medial hypothalamus and the ventromedial nucleus.

THE OPTIC TRACTS OF RANA PIPIENS1

In man, the retina is known to establish important connections with the diencephalon and mesencephalon. A study of the emergence of these connections in lower forms should provide valuable information on the development and evolution of these brain stem regions. Towards this end studies on the visual system of lower vertebrates are presently a concern of this laboratory. A study on the optic system of a urodele has already been presented (Riss et al. 1963) and work on a reptile is in progress. The present paper describes the optic system of an anuran, Rana pipiens. Two different versions of the optic connections of Anura have been reported in the literature. One version (Bellonci 1888 and Wlassak 1893) described optic fibers traversing the diencephalon but terminating almost exclusively in the midbrain. The othcr viewpoint, favored by Gaupp (1899) and Herrick (1925), described the optic pathways of Anura as terminating profusely in the thalamus as well as the midbrain. Bellonci ( 1888) published one of the earliest comparative investigations on the visual system of vertebrates using normal material. His study included many different species of tailed and tailless amphibians. In the thalamus of Anura (in addition to the corporis geniculati thalami of earlier authors), he reported two hitherto undescribed areas of neuropil which are now prominently associated with optic fibers. One area of neuropil found in the anterior thalamus, dorsal to the corporis geniculati thalami, was named the anterior superior nucleus of the corporis geniculati thalami. This area was later renamed by Herrick (1925, p. 454), the nucleus of Bellonci, and still later (Herrick 1933), the neuropil of the nucleus of Bellonci. The second area of neuropil was situated in the caudal thalamus and was called, by Bellonci, the posterior

Loss and displacement of ganglion cells after optic nerve regeneration in adult Rana pipiens

After studying pathway selection in the brain of Rana pipiens during unilateral optic nerve regeneration, several frogs were allowed to survive for lengthy periods for use in the present investigation. Retina flat-mounts were prepared from both eyes at 42-50 weeks postoperation. In some cases, HRP was infiltrated into both optic nerves prior to sacrifice to assist in identifying retinal ganglion cells. All specimens showed reduced cell-densities in the ganglion cell layer of the eye that had sustained the nerve regeneration. In addition, many ganglion cells were displaced, abnormally, into the inner plexiform layer, and the normally-situated cells formed irregular bands and islands in some parts of the retina. Cell-counts showed an apparently time-related change in neuron number ranging from a loss of 41% compared with the unaffected eye at 42 weeks, to losses as great as 71% at 50 weeks. The probable number of displaced amacrine cells in the ganglion cell layer, assumed to be unaffected by the experiment, was estimated at a maximum of 16%. Possible factors underlying the loss and displacement of ganglion cells are discussed.

The anti-retinotopic organization of the frog's optic nerve

In Rana pipiens, axons marked by the intraretinal application of horseradish peroxidase (HRP) were traced within the optic nerve and tract. Axons arising from dorsal regions of the peripheral retina collect at the dorsal end of the elongate optic disc and form a compact group on the dorsal side of the nerve. Correspondingly, ventral axons locate on the ventral side of the nerve. However, nasal and temporal peripheral axons share passage on both the nasal and temporal sides of the nerve, segregating only upon reaching the brain. The ultimate sorting of nasal and temporal axons in the brain, following their intermingling in the optic nerve, supports the operation of a chemoaffinity mechanism, rather than passive mechanical guidance.

Retinal Projections to the Olivary Pretectal Nucleus in the Tree Shrew and Comparison with the Rat

The olivary pretectal nucleus has been shown to exist in the tree shrew and rat, in which it receives a dense projection of retinal axons. The nucleus is present in the pretectal region of other mamma

ANATOMICAL ASPECTS OF THE EVOLUTION OF THE LIMBIC AND OLFACTORY SYSTEMS AND THEIR POTENTIAL SIGNIFICANCE FOR BEHAVIOR

It is our intention in this presentation to review briefly the history of thought concerning the limbic structures or rhinencephalon. Following the brief review, the anatomical connections of the limbic system and the olfactory system in vertebrates will be described. The basic pattern of connections as seen in mammals, amphibia and the lamprey will be emphasized. Finally, the significance of the connections will be considered. In general, we may anticipate that the connections we will describe support our view that the olfactory system evolved from the limbic system rather than the traditional views that the limbic system is either separable from the olfactory system or evolved from the olfactory system. Moreover, the limbic system will be described in theoretical terms as a system which is responsive to the internal milieu, whereas the olfactory system, a derivative of the limbic system, is responsive to the external chemical milieu.

Expression patterns of Ephs and ephrins throughout retinotectal development in Xenopus laevis

The Eph family of receptor tyrosine kinases and their ligands the ephrins play an essential role in the targeting of retinal ganglion cell axons to topographically correct locations in the optic tectum during visual system development. The African claw‐toed frog Xenopus laevis is a popular animal model for the study of retinotectal development because of its amenability to live imaging and electrophysiology. Its visual system undergoes protracted growth continuing beyond metamorphosis, yet little is known about ephrin and Eph expression patterns beyond stage 39 when retinal axons first arrive in the tectum. We used alkaline phosphatase fusion proteins of EphA3, ephrin‐A5, EphB2, and ephrin‐B1 as affinity probes to reveal the expression patterns of ephrin‐As, EphAs, ephrin‐Bs, and EphBs, respectively. Analysis of brains from stage 40 to adult frog revealed that ephrins and Eph receptors are expressed throughout development. As observed in other species, staining for ephrin‐As displayed a high caudal to low rostral expression pattern across the tectum, roughly complementary to the expression of EphAs. In contrast with the prevailing model, EphBs were found to be expressed in the tectum in a high dorsal to low ventral gradient in young animals. In animals with induced binocular tectal innervation, ocular dominance bands of alternating input from the two eyes formed in the tectum; however, ephrin‐A and EphA expression patterns were unmodulated and similar to those in normal frogs, confirming that the segregation of axons into eye‐specific stripes is not the consequence of a respecification of molecular guidance cues in the tectum.

Retinal projections in the short-tailed fruit bat, Carollia perspicillata, as studied using the axonal transport of cholera toxin B subunit: Comparison with mouse.

To provide a modern description of the Chiropteran visual system, the subcortical retinal projections were studied in the short‐tailed fruit bat, Carollia perspicillata, using the anterograde transport of eye‐injected cholera toxin B subunit, supplemented by the silver‐impregnation of anterograde degeneration following eye removal, and compared with the retinal projections of the mouse. The retinal projections were heavily labeled by the transported toxin in both species. Almost all components of the murine retinal projection are present in Carollia in varying degrees of prominence and laterality. The projections: to the superior colliculus, accessory optic nuclei, and nucleus of the optic tract are predominantly or exclusively contralateral; to the dorsal lateral geniculate nucleus and posterior pretectal nucleus are predominantly contralateral; to the ventral lateral geniculate nucleus, intergeniculate leaflet, and olivary pretectal nucleus have a substantial ipsilateral component; and to the suprachiasmatic nucleus are symmetrically bilateral. The retinal projection in Carollia is surprisingly reduced at the anterior end of the dorsal lateral geniculate and superior colliculus, suggestive of a paucity of the relevant ganglion cells in the ventrotemporal retina. In the superior colliculus, in which the superficial gray layer is very thin, the projection is patchy in places where the layer is locally absent. Except for a posteriorly located lateral terminal nucleus, the other accessory optic nuclei are diminutive in Carollia, as is the nucleus of the optic tract. In both species the cholera toxin labeled sparse groups of apparently terminating axons in numerous regions not listed above. A question of their significance is discussed. J. Comp. Neurol. 523:1756–1791, 2015.

Eph/ephrin gradients in the retinotectal system of Rana pipiens: developmental and adult expression patterns.

Eph/ephrin‐receptor/ligand A and B families play a variety of roles during CNS development, including patterning the retinotectal projection. However, the alignment of their expression gradients with developing retinotectal maps and gradients of cellular development is not well understood in species whose midbrain tecta undergo a protracted anterior to posterior development. By using anatomical tracing methods and 3H‐thymidine neuronography, we have mapped the retinotectal projection and the spatiotemporal progression of tectal cellular development onto Eph/ephrin expression patterns in the tectum of larval Rana pipiens, as studied by means of in situ affinity analysis with fusion proteins. EphA expression is maximal in anterior tectum (and temporal retina); ephrin‐A expression is maximal at the posterior pole (and nasal retina). EphB expression is graded in the early larva, where it is maximal in the posterior tectum just anterior to the posterior pole (and in the ventral retina). Tectal EphB expression becomes uniform at later stages and remains so in the adult, although its retinal expression remains maximal ventrally. In the early larva, EphA, EphB, and ephrin‐A protein gradients are parallel to each other and align with the temporonasal axis of the retinal projection. The early EphB expression maximum overlaps the boundary between the mantle layer of newly postmitotic cells and the posterior, epithelial region of cell proliferation, suggesting that the expression maximum is associated with the initial migrations of the postmitotic cells. Ephrin‐B expression was detected in the olfactory bulb and dorsal retina at all ages, but not in the tectum. J. Comp. Neurol. 514:30–48, 2009.

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