bluuebunny/crossref_metadata_2025 huggingface dataset:
Hasidism and the Challenge of Geography: The Polish Background to the Spread of the Hasidic Movement
Authors: Teller Adam
Published: April 2008

One of the most significant phenomena in the course of modern Jewish history is undoubtedly the astonishing success of the hasidic movement in winning and retaining large numbers of followers. What is even more remarkable is that this process took a relatively short time to come to fruition: It is widely agreed that at the death of the Ba‘al Shem Tov (who is often still regarded as the founder of the movement) in 1760, his circle numbered no more than a few dozen initiates, but by the 1820s, the movement had become dominant in the Jewish society of large swathes of eastern Europe, particularly Ukraine and Galicia.1 Many different explanations for this success have been proposed: Hasidism's attraction has been variously perceived as a result of its being a movement of religious revival and reform, a movement of social protest and class struggle, a movement popularizing elite Jewish mystical thought, and a movement of social reconstruction.2 In terms of social structure, all scholars agree that Hasidism's main innovation—and a major factor in its success—was the creation of the figure of the zaddik: a charismatic spiritual leader who acts as an intermediary between the individual hasid and God and provides answers to all problems, whether they are spiritual or earthly.3 However, relatively little attention has been paid to the social organization of the early hasidic movement as a whole, which allowed Jews from all over eastern Europe to find their place and nurture their new identity as hasidim.4 My goal here is to examine the development of Hasidism as a social movement from the perspective of the structures that it created to solidify the bond between the zaddik and the hasid. In particular, I shall focus on the ways in which the new movement overcame the geographic barriers separating Jews in different parts of eastern Europe.
Rethinking Karaism: Between Judaism and Islam
Authors: Polliack Meira
Published: April 2008

Since the late nineteenth century, scholars have tried to explain Karaism in light of comparative scripturalist trends in the history of religion. These trends manifest a common desire to reinstate the revelational text (i.e., the Hebrew Bible, the Qur'an) as the sole basis for religious law and practice. They deny or considerably delimit, on the other hand, the role of “received tradition” (i.e., Jewish torah she-be‘al peh, Islamic Sunnah) as an independent or complementary source of religious authority and legislation. Consequently, the Karaites’ rejection of Jewish oral law as codified in the Mishnah and Talmud and their attempt to reinstate the Hebrew Bible (in its entirety) as the binding source for Jewish law and religious practice, have often been described as the Jewish variation on the theme of sola scriptura.1
Intertextuality and Its Meaning in Natan Zach's “'Enosh keair yamav” (As for man, his days are as grass)
Authors: Shoham Reuven
Published: April 2008

Natan Zach, a prominent subversive Israeli poet, began publishing his poetry in the mid-1950s, together with a group of young poets who felt obliged to transform Hebrew poetry. This group included poets and critics such as Moshe Dor, Arye Sivan, Yehuda Amichai, David Avidan, Gershon Shaked, and Benjamin Harshav (Hrushovski). They published their first poems and essays in Likra't (Toward), a journal that they founded, and their group took on the same name. Only four issues of the journal appeared between 1952 and 1954. Zach was one of the outstanding poets in this group. His first book of poetry, Shirim ri'shonim (Early Poems), was published in 1955. His second book, Shirim shonim (Diverse Poems, 1960), totally changed the Israeli canon in terms of its themes and its poetic texture.
Borderline Cases: National Identity and Territorial Affinity in A. B. Yehoshua's Mr. Mani
Authors: Morahg Gilead
Published: April 2008

A. B. Yehoshua's growing eminence as one of Israel's foremost literary artists has been attended by his emergence as one of the more powerful voices of the secular Zionist left. A highly self-aware writer, Yehoshua has been scrupulously deliberate in separating the intellectual pragmatism of his political writing from the imaginative structures and aesthetic integrity of his literary works. But the generic distinction between polemical essay and imaginative fiction does not preclude overlapping areas of concern as well as a common basis of values and beliefs. Consequently, Yehoshua's essays often prove to be useful means of enhancing the understanding of his fictional works.
Authors: Levenson Alan T.
Published: April 2008

Michael Stanislawski's description of Flavius Josephus's autobiography captures the principal thesis of this elegant reflection on the use of autobiography as a historical source: “I see the Vita not as an ‘autobiography of a very special kind’ but precisely the opposite: as an exemplar of a genre (or series of connected genres) in which an author's life-story is crafted by a highly partial, both conscious and unconscious, selection of which episodes of his or her life to retell, refracted through an ever-changing sense of selfhood” (23). Not one of the seven samples ranks highly in terms of historical accuracy or absence of bias. But as the subtitle conveys, the real value of these autobiographies lies in their ability to reflect the self-fashioning of a literary identity, the tensions of the times (in Josephus's case, the loyal Jew and the virtuous Roman), and the individual's quest for definition in relation to the larger society.
Authors: Weitzman Steven
Published: April 2008

Ronald Hendel's Remembering Abraham is a synthetic work that draws on diverse methodological approaches to tease out the interplay of past and present in the Bible's depiction of history. The plasticity of collective memory—the idea that a community's memory of the past changes as that community changes—is a key idea for this book, part of which is a study of the Bible's portrait of Abraham as a reflection of Israel's evolving identity. Hendel is no minimalist, however. For him, biblical history is not simply an invented memory without connection to what really happened, but a pastiche of memory and myth—a reflection of genuine historical experience framed within fictionalized representation. Remembering Abraham is something of a pastiche itself—several of its chapters reproduce previously published work—but the juxtaposition of these studies has value in its own right, offering students and general readers an accessible introduction to how a clear-headed and well-informed scholar distinguishes history from myth in the Bible—and why, in the end, the Bible resists such a distinction.
Authors: Diamond Eliezer
Published: April 2008

Although it is a truism that there are fundamental methodological differences between the Ishmaelean and Aqiban schools of halakhic midrash, scholars have struggled to find a larger framework that explains the reasons for these divergences. Azzan Yadin has rendered an important service by proposing an overarching theory of hermeneutics that encompasses and informs the Ishmaelean approach to legal midrash. What follows is a brief summary and assessment of Yadin's line of argument.
Authors: Pickus Keith
Published: April 2008

The intense response to Götz Aly's recently published book, Hitlers Volksstaat: Raub, Rassenkrieg und nationaler Sozialismus, attests to the continued interest in studies related to Germany's “Jewish Question” and the forces that motivated German citizens to support National Socialism. The scholarship produced decades ago by Paul Massing, Peter Pulzer, Fritz Stern, and George Mosse and reenergized by Christopher Browning and Daniel Goldhagen in the 1990s has produced a rich and detailed analysis of the role that Jews occupied within the German national community. Not surprisingly, the origins and manifestations of anti-Semitism occupy center stage within this body of work, and less antagonistic relations between Jews and Gentiles in Germany receive scant attention. Studies that depict Gentile supporters of Jews and Judaism are virtually nonexistent. Alan Levenson's monograph, Between Philosemitism and Antisemitism, compels us to reconsider the continuum of attitudes toward Jews that existed in Germany from the establishment of the Kaiserreich to the advent of Nazism. The book's eight essays, all of which have been previously published, probe the limits of philosemitism within an anti-Semitic environment and flesh out the opposite end of the societal spectrum from those occupied by German anti-Semitism (xi).
Authors: Y. Michal Bodemann
Published: April 2008

Over the past decade, we have seen a substantial number of books written on the entirely unlikely reemergence of Jewish life in both German states and the relationship of the Jewish communities to their German environment. Among the major contributions are those by Michael Brenner, Erica Burgauer (not Burgbauer, as in this book), Ulrike Offenberg, Micha Brumlik, Jael Geis, Jeffrey Herf, Juliane Wetzel and Angelika Königseder, Frank Stern, this reviewer, as well as a handful of others. Jay Geller's study, therefore, could not explore new terrain, but it does present us with a wide overview of the early period and a material-rich, diligently researched presentation of the postwar period. As such, it is clearly a new basic reference work for this early period of German–Jewish life.
Authors: Meyer Michael A
Published: April 2008

Bibliographers, archivists, and librarians supply the materials without which the work of historical scholars would not be possible. Yet too often, their enterprise is simply taken for granted. We forget that the vocations in which they engage possess their own history and that their most outstanding practitioners deserve remembrance when we write of the development of Jewish scholarship. At Hebrew Union College, Jacob Rader Marcus and Herbert Zafren used to give a course for graduate students on Jewish bibliography, displaying and discussing all of the classical works in the field from the seventeenth century onward. The orientation it gave the students was invaluable. Today, we have the two very helpful volumes by Shimeon Brisman—A History and Guide to Judaic Bibliography (1977) and A History and Guide to Judaic Encyclopedias and Lexicons (1987)—yet I wonder how many graduate students have looked at them carefully.
Causal reasoning using geometric analysis
Authors: KARA LEVENT BURAK , STAHOVICH THOMAS F.
Published: April 2008

We describe an approach that uses causal and geometric reasoning
to construct explanations for the purposes of the geometric
features on the parts of a mechanical device. To identify the
purpose of a feature, the device is simulated with and without
the feature. The simulations are then translated into a
“causal-process” representation, which allows
qualitatively important differences to be identified. These
differences reveal the behaviors caused and prevented by the
feature and thus provide useful cues about the feature's
purpose. A clear understanding of the feature's purpose,
however, requires a detailed analysis of the causal connections
between the caused and prevented behaviors. This presents a
significant challenge because one has to understand how a behavior
that normally takes place affects (or is affected by) another
behavior that is normally absent. This article describes techniques
for identifying such elusive relationships. These techniques
employ a set of rules that can determine if one behavior enables
or disables another that is spatially and temporally far away.
They do so by geometrically examining the traces of the causal
processes in the device's configuration space. Using the
results of this analysis, our program can automatically generate
text output describing how the feature performs its function.
Knowledge transformers: A link between learning and creativity
Authors: SIM SIANG KOK , DUFFY ALEX H.B.
Published: April 2008

The purpose of this paper is to investigate whether knowledge transformers that are featured in the learning process are also present in the creative process. First, this was achieved by reviewing accounts of inventions and discoveries with the view of explaining them in terms of knowledge transformers. Second, this was achieved by reviewing models and theories of creativity and identifying the existence of the knowledge transformers. The investigation shows that there is some evidence to show that the creative process can be explained through knowledge transformers. Hence, it is suggested that one of links between learning and creativity is through the knowledge transformers.
Special Issue: Understanding, representing, and reasoning about
style
Authors: ECKERT CLAUDIA M. , DO ELLEN YI-LUEN
Published: April 2008

Style is a word that people think they understand. Most people
recognize artifacts like buildings and clothes as being exemplars of
particular styles, and they know words like Rococo and Art Deco as names
for styles. They can recognize stylistic similarities not only in one sort
of artifact but also across wide ranges of different things, such as
buildings, furniture, artworks, clothes, music, and even manners. However,
“style” is a slippery notion: the word has been used in a
variety of senses since the ancient Greeks first thought about the
differences in how people wrote or painted, and it is still used to refer
to different things.
Foreign Policy Activism and Power in the House of Representatives: Black Members of Congress and South Africa, 1968–1986
Authors: Tillery Alvin B.
Published: April 2008

On 3 October 1986, the 99th Congress—acting at the behest of the Congressional Black Caucus (CBC)—voted to override President Ronald Reagan’s veto of the Comprehensive Anti-Apartheid Act (CAAA). The passage of this bill, which placed strict economic sanctions on the white supremacist regime in South Africa, was a watershed moment in American politics for two reasons. First, veto overrides in the foreign policy-making arena are an exceedingly rare form of legislative action. More importantly, this was the first time in American history that the members of a minority group were able to use their positions within the Congress to translate a parochial desire into foreign policy against the will of a sitting president.
Cicero's Prosecution of Gaius Verres: A Roman View of the Ethics of Acquisition of Art
Authors: Miles Margaret M.
Published: April 2008

Cicero's speeches and essays—especially the Verrines—were widely read in France and England during the late eighteenth and early nineteenth centuries, when they were used in public debates about the fate of art in wartime. The early development of the concept of “cultural property” owed much to careful readings and citations of Cicero's views. The main charge brought against Verres in 70 B.C. was extortion during his term as governor of Sicily, but in the course of his prosecution Cicero depicts Verres as a rapacious collector of art who even took cult statues from temples for his private collection. This portrait of a “collector” who felt entitled to anything he could get and who abused his official authority to acquire works of art was recalled and used in debates about “collecting” many centuries later. This paper examines how Ciceronian views contributed to the development of the concept of art as cultural property.
The Trade in Looted Antiquities and the Return of Cultural
Property: A British Parliamentary Inquiry
Authors: Gill David , Chippindale Christopher
Published: April 2008

The British parliamentary report on Cultural Property: Return and Illicit Trade was published in 2000. Three key areas were addressed: the illicit excavation and looting of antiquities, the identification of works of art looted by Nazis, and the return of cultural property now residing in British collections. The evidence presented by interested parties—including law enforcement agencies and dealers in antiquities—to the Culture, Media and Sport Committee is assessed against the analysis of collecting patterns for antiquities. The lack of self regulation by those involved in the antiquities market supports the view that the British Government needs to adopt more stringent legislation to combat the destruction of archaeological sites by looting.
Culture and the Digital Copyright Chimera: Assessing the International Regulatory System of the Music Industry in Relation to Cultural Diversity
Authors: Curtis Johnlee Scelba
Published: April 2008

This article examines the international legal regime that governs cultural commodities by providing an up-to-date stocktaking in the field. In doing so, this paper focuses on the music industry, both as the general backdrop and as a context in which to observe the evolution of the current regulatory regime. It includes a review of the history of the commoditization process of musical goods, the requisite legislative and judicial decisions, the international regulatory environment, and a tripartite case study. By reviewing various approaches and examining several recent arenas where the issues have been implicated, the author demonstrates that, in its current form, the international copyright regime is not sufficiently supportive of diversity in cultural property.
Diplomats, Banana Cowboys, and Archaeologists in Western Honduras: A History of the Trade in Pre-Columbian Materials
Authors: Luke Christina
Published: April 2008

This paper explores access to the Honduran past with a focus on northwestern Honduras, particularly the Ulua Valley. The foundations of national patrimony legislation and the practice of collecting antiquities are used to explore whether the disassociation of the archaeological community from the collecting sphere over the last several decades has better protected the archaeological record. I argue that early field expeditions led by U.S. archaeologists, the shipment of their finds to U.S. institutions, and subsequent massive looting galvanized Honduran efforts aimed at national patrimony legislation. The roles of the U.S. government and U.S.-based businesses as negotiating bodies in the early days of Honduran expeditions from 1890 to 1940 are explored in detail, particularly in the sphere of opening up the region to collectors and the role of the U.S. antiquities market. We can understand the early days of collecting in Honduras precisely because of the close relationships once forged between collectors, museums, and archaeologists, networks that have now disappeared because of current conceptions of archaeological ethics. The changing definition of a collector represents a key point throughout this analysis; at one time archaeologists, museums, and businesses were the primary collectors. The shift from the labelcollectortoarchaeologistis explored through the lens of the development of archaeology as a discipline, with a particular emphasis on context, and the contemporary legislative efforts aimed at cultural heritage projection. The essay concludes with a look at recent archaeological work in the region and the increasingly strict cultural patrimony legislation, specifically the 2004 U.S.–Honduran Memorandum of Understanding.
Thinking in terms of law and mortality
Authors: Greenawalt K
Published: April 2008

The author lays a blueprint for distinctions between legal and moral rules and socially accepted behavior, situations in which these distinctions set different standards of conduct, and the relationship among them. Several of the more common paradigms of cultural property disputes are then fit into the patterns of legal and moral rules and obligations, thus establishing a framework for the discussion of how to evaluate ethical or moral behaviors in varying circumstances. The author also considers the relevance of deontological and consequentialist arguments for the return of cultural property, as well as avoidance strategies by which a country of origin can make a claim for restitution while ignoring the long-term questions of the legitimacy, power, and responsibilities of national governments. The author concludes by emphasizing the difficulties in basing arguments concerning cultural property on moral evaluations and conclusions.
Codes of ethics for conservation
Authors: Sease C
Published: April 2008

This article examines the codes of ethics of the British, Canadian, Australian, and American professional conservation organizations and evaluates their success in meeting the needs of the discipline as it grows and matures. Specific issues that are currently of concern to conservators are examined, including the application of a single document to a diverse profession, reversibility of treatment, preventive conservation, cultural sensitivity, and the antiquities trade. The fact that none of these codes are enforceable is considered as well as the issue of accreditation and what it means. While these codes are reasonably successful in setting forth the principles that should guide conservation work for straightforward cases, they are less successful in providing guidance for complex issues such as those presented by cultural sensitivity and the antiquities trade.
The ethics of art dealing
Authors: Marks P
Published: April 2008

The ethics of dealing in antiquities may be discussed in two parts: first, the ethical standards that govern the trade and its relation to clients, and second, the new legal standards that affect dealers and collectors arising from political ambitions in the international relations between source and market nations. Friction between these competing interests began with the ratification of the UNESCO Convention in 1972 and the passage of the Cultural Property Implementation Act in 1983. Unrealistic political approaches to the illicit trade in antiquities have exacerbated rather than solved the problem. A resolution of the conflicts, contradictions, and ambiguities of the present situation can be achieved by stressing the safety of objects and archaeological sites over partisan goals. A satisfactory denouement can be achieved through a partnership between source countries and the market, through an abandonment of retentionist export controls, and through the establishment of an open, free, and rational coalition. Any solution to present difficulties ought to acknowledge the value of continuing to collect and preserve antiquities in private and public collections.
The ethics of collecting
Authors: Sackler EA
Published: April 2008

The author questions the concepts underlying ethnological collections of art and artifacts in the context of the Native American Graves Protection and Repatriation Act (NAGPRA). Alternatives to traditional Western anthropological and art historical methods of collection and display of sacred Native American material are found in traditional Native American philosophy and practice. The contemporary fashion among curators for contextualization of displayed objects from Indigenous cultures is critiqued in the light of broader ethical concerns regarding the appropriateness of collecting sacred objects from living Indigenous Peoples.
The American archaeological record: authority to dig, power to interpret
Authors: McLaughlin RH
Published: April 2008

Legal regulation of the archaeological record has played a subtle though instrumental role in the shaping of American anthropology. Most studies of connections between politics and archaeology in analogous contexts have, however, focused on nationalisms and the popular political orchestration of archaeology. This paper grounds an analysis of the American case in legal apparatuses, disciplinary changes in anthropology, and a shift in the expression of American nationalism between the Antiquities Act of 1906 and the Native American Graves Protection and Repatriation Act of 1990. The article argues that archaeology has attained broader social significance as archaeologists now consult native peoples in the practice of archaeology. Though archaeology remains a politicized science it has become a more broadly negotiated one and the historical and cultural issues it faces may yet find resolution through laws and responsive disciplinary practices that envision a society enhanced by cultural difference.
Cultural heritage protection: legitimacy, property, and functionalism
Authors: Müller MM
Published: April 2008

This article argues that the question of whether the nation-state or the international community is the legitimate guardian of cultural property can only be answered with reference to what we expect measures of protection of our cultural heritage to accomplish. The very concept of 'protection' is at stake, and two different schools (object-centrism versus functionalism) are to be distinguished. Whereas object centrism focuses on the cultural object and its protection as a value in its own right, functionalism argues that the cultural heritage cannot even be identified as such without reference to society and its meaning for societal processes of acculturation and socialization. This article endorses functionalism and develops a perspective that includes identity and cross-cultural communication as the most important functions of all cultural heritage. These two criteria should guide our thinking about the legitimate guardian of cultural heritage in general.
Case note. The Brother Jonathan decision: treasure salvor's 'actual possession' of shipwreck gives rise to federal jurisdiction for title claim
Authors: Shapreau CJ
Published: April 2008

The Supreme Court issued its decision in Spring 1998 in California and State Lands Commission v Deep Sea Research, Inc. making the noteworthy holding that treasure salvors that have 'actual possession' of shipwrecks located on a state's submerged lands will not be ousted from federal court jurisdiction on Eleventh Amendment immunity grounds. Calling into question the Supreme Court's previous opinion involving shipwreck litigation in Florida Dept. of State v. Treasure Salvors, Inc., decided in 1982, the Court has made clear that claims for title to such submerged artifacts can now be fully adjudicated in federal court. In making this significant ruling, and in redefining what constitutes a 'colorable claim' to title in shipwrecks under the Abandoned Shipwreck Act, the Court resuscitated legal precedent that predates the 1865 sinking of shipwrecked Brother Jonathan.
Gain control from beyond the classical receptive field in primate
primary visual cortex
Authors: WEBB BEN S. , TINSLEY CHRIS J. , BARRACLOUGH NICK E. , PARKER AMANDA , DERRINGTON ANDREW M.
Published: April 2008

Gain control is a salient feature of information processing throughout
the visual system. Heeger (1991, 1992) described a mechanism that could
underpin gain control in primary visual cortex (V1). According to this model,
a neuron's response is normalized by dividing its output by the sum of
a population of neurons, which are selective for orientations covering a
broad range. Gain control in this scheme is manifested as a change in the
semisaturation constant (contrast gain) of a V1 neuron. Here we examine how
flanking and annular gratings of the same or orthogonal orientation to that
preferred by a neuron presented beyond the receptive field modulate
gain in V1 neurons in anesthetized marmosets (Callithrix
jacchus). To characterize how gain was modulated by surround
stimuli, the Michaelis–Menten equation was fitted to response
versus contrast functions obtained under each stimulus
condition. The modulation of gain by surround stimuli was modelled best
as a divisive reduction in response gain. Response gain varied with the
orientation of surround stimuli, but was reduced most when the
orientation of a large annular grating beyond the classical receptive
field matched the preferred orientation of neurons. The strength of
surround suppression did not vary significantly with retinal
eccentricity or laminar distribution. In the marmoset, as in macaques
(Angelucci et al., 2002a, b), gain control over the
sort of distances reported here (up to 10 deg) may be mediated by feedback
from extrastriate areas.
Desensitization of the photoresponse in Limulus ventral
photoreceptors by protein kinase C precedes rhabdomere disorganization
and endocytosis
Authors: DABDOUB ALAIN , JINKS ROBERT N. , WANG YOUJUN , BATTELLE BARBARA-ANNE , PAYNE RICHARD
Published: April 2008

Limulus photoreceptors utilize the phosphoinositide pathway
to generate light-induced single photon events (quantum bumps) that sum
to form the depolarizing receptor potential. The protein kinase C (PKC)
activator, (−)-indolactam V (ILV) rapidly desensitizes the light
response in Limulus ventral nerve photoreceptors. Within 10
min of extracellular application, 100 nM (−)-ILV caused a
decrease in the mean amplitude of quantum bumps to 38% of control
values. PKC activation by (−)-ILV also causes photosensitive
membrane disorganization and endocytosis. To investigate whether this
precedes desensitization of the electrical response, we fixed cells
after 10-min incubation with 25 μM (−)-ILV, a concentration
sufficient to cause a 1000-fold desensitization of the receptor
potential. The photosensitive microvilli of these photoreceptors
remained narrow, densely packed, and well organized. Increasing the
incubation time to 60 min did, however, induce disorganization and
swelling of the microvilli and endocytosis of the photosensitive
membrane, as previously reported. Measurement of membrane capacitance
did not indicate a significant reduction in membrane area accompanying
desensitization by (−)-ILV. PKC-induced reduction in light
sensitivity therefore precedes the detection of ultrastructural changes
in the rhabdomeral membrane and is not due to a net loss of
membrane.
The identity of metarhodopsin III
Authors: KOLESNIKOV ALEXANDER V. , GOLOBOKOVA ELENA Yu. , GOVARDOVSKII VICTOR I.
Published: April 2008

A fast-scanning dichroic microspectrophotometer was used to trace
products of rhodopsin photolysis (metarhodopsins I/II/III and
later) in structurally intact amphibian rod outer segments (ROSs) and
metabolically active rods. The instrument allows the recording of
absorbance spectra with a time resolution better than 1 s, and to
discriminate between products with similar absorbance spectra that
differ with respect to the orientation of their chromophore in the
photoreceptor membrane. We demonstrate that metarhodopsin III is in a
pH-reversible equilibrium with metarhodopsin II and that the
metarhodopsin III chromophore is orientated with respect to the
membrane plane even more strictly than the 11-cis retinal in
“dark” rhodopsin. This indicates that all-trans
retinal in metarhodopsin III is still attached to its native binding site
on opsin. The kinetic scheme of the decay of metarhodopsins is presented
in which metarhodopsin III lies in a shunt pathway from metarhodopsin
II to retinal. Formation of metarhodopsin III was detected at bleaches
as low as ≈ 3%, contrary to previous reports that it is not formed
at below 10% bleaches. Another product that is spectrally similar to
metarhodopsin III, termed P440, appears at later stages of photolysis
as the result of the decay of metarhodopsin II and metarhodopsin III.
The chromophoric group in P440 is orientated preferentially across the
disk membrane. The final product(s) in isolated ROS, where the
reduction of retinal to retinol is blocked, consists of a mixture of a
free retinal and retinal possibly attached to different binding sites
in the membrane. In metabolically active rods the later products are
quickly converted to retinol. We conclude that metarhodopsin III
represents a specific conformational state of metarhodopsin where the
chromophoric binding site is still occupied by all-trans retinal.
Hence, the formation and decay of metarhodopsin III may be limiting for the
rate of rhodopsin regeneration and photoreceptor dark adaptation.
The effect of retinal growth on the postnatal development and
distribution of displaced retinal ganglion cells in the retina of the
chameleon (squamata)
Authors: OTT MATTHIAS , BELLINTANI-GUARDIA BRENO
Published: April 2008

Retinal ganglion cells (RGCs) usually increase their dendritic field
area with postnatal retinal growth. The mechanisms that regulate the
postnatal shape of dendritic arbors in the growing retina are not well
understood. Quantitative studies suffer from the difficulty of labeling
specific subpopulations of RGCs selectively including their dendritic
processes. In this study, we labeled displaced retinal ganglion cells
(DGC) that are known to project to the accessory optic system (AOS) in
juvenile and adult chameleons by retrograde transport of dextran
amines. The complete population of DGCs was quantitatively screened for
the effects of postnatal retinal growth on cell morphology, dendritic
field coverage, and dendritic arbor size. The adult eye contained 2000
DGCs/retina. This number was already present at birth. The smaller
size of the hatchling eye (approximately 1/3 of the adult size) led
to higher densities of DGCs. The greatest accumulation of juvenile DGCs
(two-fold higher compared to the adult) was found in the periphery of
the retina where the greatest surface expansion was observed. DGC
dendritic field areas were adjusted proportionally to this expansion in
order to maintain a constant dendritic coverage. The increase of
dendritic fields was mediated by two putative passive mechanisms:
First, an elongation of individual dendrites similar to previous
reports of postnatal RGC development in the retina of goldfish and
chicks. Second, and more prominent, we observed that neighboring
dendrites were pulled apart from each other. This resulted in a looser
spacing of the initially tightly packed dendrites of each dendritic
arbor. This dispersal of dendrites over a larger area was, due to its
passive nature, proportional to the increase of the retinal surface and
preserved a constant dendritic coverage irrespective of the
animal's age and eye size.
Strategies of shape representation in macaque visual area V2
Authors: HEGDÉ JAY , VAN ESSEN DAVID C.
Published: April 2008

Contours and surface textures provide powerful cues used in image
segmentation and the analysis of object shape. To learn more about how
the visual system extracts and represents these visual cues, we studied
the responses of V2 neurons in awake, fixating monkeys to complex
contour stimuli (angles, intersections, arcs, and circles) and texture
patterns such as non-Cartesian gratings, along with conventional bars
and sinusoidal gratings. Substantial proportions of V2 cells conveyed
information about many contour and texture characteristics associated
with our stimuli, including shape, size, orientation, and spatial
frequency. However, the cells differed considerably in terms of their
degree of selectivity for the various stimulus characteristics. On
average, V2 cells responded better to grating stimuli but were more
selective for contour stimuli. Metric multidimensional scaling and
principal components analysis showed that, as a population, V2 cells
show strong correlations in how they respond to different stimulus
types. The first two and five principal components accounted for 69%
and 85% of the overall response variation, respectively, suggesting
that the response correlations simplified the population representation
of shape information with relatively little loss of information.
Moreover, smaller random subsets of the population carried response
correlation patterns very similar to the population as a whole,
indicating that the response correlations were a widespread property of
V2 cells. Thus, V2 cells extract information about a number of higher
order shape cues related to contours and surface textures and about
similarities among many of these shape cues. This may reflect an
efficient strategy of representing cues for image segmentation and
object shape using finite neuronal resources.
Functional relationship between nucleus isthmi and tectum in
teleosts: Synchrony but no topography
Authors: NORTHMORE DAVID P.M. , GALLAGHER SHAWN P.
Published: April 2008

Neural activity in the optic tectum was compared with activity in the
nucleus isthmi (NI) of both goldfish and sunfish with the aim of
understanding how the two brain structures interact to process visual
information. The two species yielded very similar results. Superficial
tectum responds reliably to visual stimulation with topographically
organized receptive fields; deep tectum and NI respond to stimulation
throughout the field of the contralateral eye and habituate rapidly.
Bursts of large-amplitude spiking in NI occur spontaneously and in
response to contralateral visual stimulation. These NI bursts correlate
with activity bursts across the tectal lobe on the same side,
especially in the deeper layers. NI bursts may also synchronize with
spiking activity in deep tectum. Trains of small-amplitude spikes in NI
can be elicited by both ipsilateral and contralateral stimulation, but
are not reflected in tectal activity. Simultaneous recordings from two
sites in one NI were almost identical, suggesting that NI operates as a
functional unit, broadcasting the same message across the ipsilateral
tectal lobe.
The density recovery profile: A method for analysis of points in
the plane applicable to retinal studies
Authors: RODIECK R.W.
Published: April 2008

MacDRP is a Macintosh application that calculates Density
Recovery Profiles.
Chromatin immunoprecipitation identifies photoreceptor transcription factor targets in mouse models of retinal degeneration: New findings and challenges
Authors: PENG GUANG-HUA , CHEN SHIMING
Published: April 2008

The transcription factors, Otx2, Crx, Nrl, and Nr2e3, expressed by retinal photoreceptor cells are essential for photoreceptor gene expression, development, and maintenance. Malfunction of any of these factors due to genetic mutations causes photoreceptor disease. Protein–protein interaction studies suggest that these factors may form a regulatory network centered on Crx. To understand how these factors regulate photoreceptor gene transcriptionin vivo, we have employed chromatin immunoprecipitation (ChIP) assays to assess the ability of these proteins to bind to regulatory sequences of photoreceptor genes in the retina of wild-type and mutant mice with photoreceptor degeneration. This paper summarizes the advantages and limitations of ChIP, using examples from our studies to demonstrate how this technique has contributed to our understanding of the regulation of photoreceptor gene expression. We report that Crx, Otx2, Nrl, and Nr2e3 co-occupy the promoter/enhancer, but not the region 3′ of selected Crx target genes, in a retina-specific fashion. We identified Crx-dependent (Nr2e3) and Crx-independent (Otx2 and Nrl) target binding using Crx knockout mice (Crx−/−), suggesting that individual factors may use distinct mechanism(s) for binding and regulating target genes. Consistent with ChIP results, we also found that Otx2, a close family member of Crx, can activate the promoter of rod and cone genes in HEK293 cells, implicating Otx2 in regulating photoreceptor gene expression. These findings provide important information for understanding how photoreceptor transcription factors regulate photoreceptor gene expression and the mechanisms by which mutations in these factors cause transcriptional dysregulation and photoreceptor degeneration.
Anesthesia can cause sustained hyperglycemia in C57/BL6J
mice
Authors: BROWN E.T. , UMINO Y. , LOI T. , SOLESSIO E. , BARLOW R.
Published: April 2008

Effects of anesthesia on the blood glucose of C57/BL6J mice were
evaluated under conditions commonly used for testing retinal sensitivity
with electroretinographic (ERG) recordings. We evaluated the effects of
four anesthetics: nembutal (50 mg/kg), pentothal (100 mg/kg),
avertin (240 mg/kg), and ketamine/xylazine (100 mg/kg) using
saline as control. We measured blood glucose (BG) levels from tail vein
blood before and 15 and 60 min following intraperitoneal injections.
Fifteen minutes postinjection, all four anesthetics and saline elevated BG
with ketamine/xylazine and avertin having substantially greater
effects than nembutal, pentothal, and saline. Only the effects of
ketamine/xylazine and avertin persisted throughout the test period.
Sixty minutes after injecting ketamine/xylazine BG remained elevated
at 400 ± 42 mg/dl, a 167% increase over preinjection levels.
Sixty minutes after injecting avertin BG was 288 ± 10 mg/dl, a
59% increase over preinjection levels. No sustained elevation in BG was
detected 60 min following injection of nembutal, pentothal, or saline.
Because BG can affect the amplitude of the ERG, caution should be
exercised in the use of ketamine/xylazine or avertin. The choice of
anesthesia may also be important in diabetes and metabolism research where
changes in blood glucose could impact physiological processes.
Generation, characterization, and molecular cloning of theNoerg-1mutation of rhodopsin in the mouse
Authors: PINTO LAWRENCE H. , VITATERNA MARTHA H. , SHIMOMURA KAZUHIRO , SIEPKA SANDRA M. , MCDEARMON ERIN L. , FENNER DEBORAH , LUMAYAG STEPHEN L. , OMURA CHIAKI , ANDREWS ANNE W. , BAKER MATTHEW , INVERGO BRANDON M. , OLVERA MARISSA A. , HEFFRON EDWARD , MULLINS ROBERT F. , SHEFFIELD VAL C. , STONE EDWIN M. , TAKAHASHI JOSEPH S.
Published: April 2008

We performed genome-wide mutagenesis of C57BL/6J mice using the mutagenN-ethyl-N-nitrosourea (ENU) and screened the third generation (G3) offspring for visual system alterations using electroretinography and fundus photography. Several mice in one pedigree showed characteristics of retinal degeneration when tested at 12–14 weeks of age: no recordable electroretinogram (ERG), attenuation of retinal vessels, and speckled pigmentation of the fundus. Histological studies showed that the retinas undergo a photoreceptor degeneration with apoptotic loss of outer nuclear layer nuclei but visual acuity measured using the optomotor response under photopic conditions persists in spite of considerable photoreceptor loss. TheNoerg-1mutation showed an autosomal dominant pattern of inheritance in progeny. Studies in early postnatal mice showed degeneration to occur after formation of partially functional rods. TheNoerg-1mutation was mapped genetically to chromosome 6 by crossing C57BL/6J mutants with DBA/2J or BALB/cJ mice to produce an N2 generation and then determining the ERG phenotypes and the genotypes of the N2 offspring at multiple loci using SSLP and SNP markers. Fine mapping was accomplished with a set of closely spaced markers. A nonrecombinant region from 112.8 Mb to 115.1 Mb was identified, encompassing the rhodopsin (Rho) coding region. A single nucleotide transition from G to A was found in the Rho gene that is predicted to result in a substitution of Tyr for Cys at position 110, in an intradiscal loop. This mutation has been found in patients with autosomal dominant retinitis pigmentosa (RP) and results in misfolding of rhodopsin expressedin vitro. Thus, ENU mutagenesis is capable of replicating mutations that occur in human patients and is useful for generatingde novomodels of human inherited eye disease. Furthermore, the availability of the mouse genomic sequence and extensive DNA polymorphisms made the rapid identification of this gene possible, demonstrating that the use of ENU-induced mutations for functional gene identification is now practical for individual laboratories.
Pharmacological studies of the mouse cone electroretinogram
Authors: SHARMA SUMIT , BALL SHERRY L. , PEACHEY NEAL S.
Published: April 2008

Electroretinography provides a useful noninvasive approach to evaluate cone pathway activity. Despite wide application of the cone ERG to characterize retinal function in transgenic mice and mouse models of human hereditary retinal disease, the cellular origins of the mouse cone ERG have not been well defined. Here, we address this issue using a pharmacological approach that has been previously applied to other species. Agents that block receptor activation at well-defined retinal loci were dissolved in saline and injected into the vitreous of anesthetized adult BALBc/ByJ mice; cone ERGs were recorded 1–2 h later. Analysis of the resulting waveforms indicated that the mouse cone ERG includes a cornea-negative component that is derived from the activity of cone photoreceptors and retinal glial (Müller) cells. Similar to other species, activity of cone depolarizing bipolar cells contributes a large amplitude cornea-positive potential to the mouse cone ERG. In contrast to primate but similar to rat, the mouse cone ERG includes only a small contribution from hyperpolarizing bipolar cell activity. The inner retina appears to contribute to both thea- andb-waves of the mouse cone ERG. These results provide a foundation for interpreting changes in the waveform of the mouse cone ERG that may be observed following genetic alteration or other experimental treatment.
Stimulus size and intensity alter fundamental receptive-field properties of mouse retinal ganglion cellsin vivo
Authors: SAGDULLAEV BOTIR T. , MCCALL MAUREEN A.
Published: April 2008

The receptive field (RF) of most retinal ganglion cells (RGCs) is comprised of an excitatory center and an antagonistic surround. Interactions between these RF elements shape most of the visual responses of RGCs. To begin to investigate center-surround interactions of mouse RGCs quantitatively, we characterized their responses in anin vivopreparation to a variety of spot and full-field stimuli. When RGCs were stimulated with a spot that matched the cell's RF center diameter (optimal spot), all RGCs could be categorized as either ON- or OFF-center. In all RGCs, full-field stimulation significantly reduced both the peak and the mean firing rates evoked with an optimal spot stimulus. Full-field stimulation revealed differences in other response properties between ON- and OFF-center RGCs. With a full-field stimulus, the duration of the OFF-center RGCs response was reduced making them more transient, while the duration of the ON-center RGCs increased making them more sustained. Of most interest, full-field stimulation altered the RF center response sign in approximately half of the OFF-center RGCs, which became either OFF/ON or ON only. In contrast, all ON-center and the other OFF-center cells conserved their RF response sign in the presence of the full-field stimulus. We propose that sign-altering OFF-center RGCs possess an additional RF surround mechanism that underlies this alteration in their response. Of general interest these results suggest that the sole use of full-field stimulation to categorize visual response properties of RGCs does not adequately reflect their RF organization and, therefore, is not an optimal strategy for their classification.
Independent visual threshold measurements in the two eyes of freely
moving rats and mice using a virtual-reality optokinetic system
Authors: DOUGLAS R.M. , ALAM N.M. , SILVER B.D. , MCGILL T.J. , TSCHETTER W.W. , PRUSKY G.T.
Published: April 2008

Slow horizontal head and body rotation occurs in mice and rats when
the visual field is rotated around them, and these optomotor movements can
be produced reliably in a virtual-reality system. If one eye is closed,
only motion in the temporal-to-nasal direction for the contralateral eye
evokes the tracking response. When the maximal spatial frequency capable
of driving the response (“acuity”) was measured under
monocular and binocular viewing conditions, the monocular acuity was
identical to the binocular acuity measured with the same rotation
direction. Thus, the visual capabilities of each eye can be measured under
binocular conditions simply by changing the direction of rotation. Lesions
of the visual cortex had no effect on the acuities measured with the
virtual optokinetic system, whereas perceptual thresholds obtained
previously with the Visual Water Task are. The optokinetic acuities were
also consistently lower than acuity estimates from the Visual Water Task,
but contrast sensitivities were the same or better. These data show that
head-tracking in a virtual optokinetic drum is driven by subcortical,
lower frequency, and contralateral pathways.