bluuebunny/crossref_metadata_2025 huggingface dataset:
SOCIOCULTURAL THEORY AND SECOND LANGUAGE LEARNING. James P. Lantolf (Ed.). Oxford: Oxford University Press, 2000. Pp. 297. £20.90 paper.
Authors: Howell Catherine
Published: December 2002

Sociocultural Theory and Second Language Learning, edited by James Lantolf, contains nine research reports and two theoretical papers that introduce the sociocultural tradition to the wider field of second language acquisition (SLA) and provide specific examples of questions and methodologies that emerge from the sociocultural framework. Sociocultural theory expands the types of inquiry addressed by the field of SLA research by suggesting a participation metaphor of language learning as an alternative to, or an expansion of, the more widespread input-output or computational metaphor. Although the book is designed primarily for researchers, most chapters also explore ways that sociocultural theory and research can inform language pedagogy.
CREOLE GENESIS, ATTITUDES, AND DISCOURSE: STUDIES CELEBRATING
CHARLENE J. SATO. John Rickford and Suzanne Romaine (Eds.).
Amsterdam: Benjamins, 1999. Pp. ix + 410. $138.00 cloth.
Authors: Winkler Elizabeth Grace
Published: December 2002

Charlene Sato, a noted scholar in SLA and creole studies, is honored by this text. Many
chapters analyze Hawai‘ian Creole English (HCE), which Sato promoted as a living
language, and it is in that spirit that the editors have included short stories in HCE.
THE BILINGUALISM READER. Li Wei (Ed.). London: Routledge, 2000. Pp. xv + 541. £18.99 paper.
Authors: Major Roy C.
Published: December 2002

This volume consists of a collection of 18 chapters of previously published articles, mostly classic works on bilingualism (all but five were published before 1990). The majority of the authors are very well known and well respected scholars in the field: Auer, Blom, Ching, Clyne, de Bot, Ferguson, Fishman, Galloway, Genesee, Green, Grosjean, Gumperz, Jake, Mackey, Meisel, Milroy, Myers-Scotten, Obler, Paradis, Poplack, Vaid, Wei, and Zatorre. Wei's motivation for this reader is that it serve the dual purpose of compiling many of the important articles on bilingualism, which in many parts of the world are unavailable because of inadequate library facilities, and encourage researchers to read the original works rather than commentaries on them. As Wei put it, “I am nevertheless concerned that a new generation of ‘scholars' might be emerging out of a ‘hear-say' tradition” (p. ix).
EFFECTIVE PROGRAMS FOR LATINO STUDENTS. Robert E. Slavin and Margarita Calderón (Eds.). Mahwah, NJ: Erlbaum, 2001. Pp. ix + 394. $89.95 cloth, $39.95 paper.
Authors: Torres Roberto L.
Published: December 2002

In this book, Slavin and Calderón demonstrate that school-age Hispanic students in the United States can realize their academic expectations and in the process become capable members of society when they are trained in quality educational programs. The authors' educational research expertise presents readers with a selection of recent studies of elementary and secondary instructional programs targeting Latino students. The book's 10 chapters advance a commanding body of performance data that illustrate how Latino students, like any other students, can be successfully educated and empowered and can even excel in an antagonistic American educational culture. The programs researched include numerous educational models specific to Hispanic students as well as adaptations of other national programs.
HANDBOOK OF UNDERGRADUATE SECOND LANGUAGE EDUCATION. Judith W. Rosenthal (Ed.). Mahwah, NJ: Erlbaum, 2000. Pp. xxii + 380. $99.95 cloth, $39.95 paper.
Authors: Ranta Leila
Published: December 2002

This edited volume was inspired by Rosenthal's belief that it is becoming increasingly
more important for American students to know more than one language and that greater
collaboration among educators at colleges and universities will not only be beneficial for the
programs and their students but will also “promote a more language-competent
society” (p. ix). Unfortunately, because of institutional or disciplinary boundaries, many
educators involved in a particular type of second language program may be unaware of colleagues
with similar concerns. This book attempts to bridge this gap by showcasing a wide variety of
undergraduate programs that share the aim of promoting bilingualism among their students.
SECOND LANGUAGE SYNTAX: A GENERATIVE INTRODUCTION. Roger Hawkins. Oxford: Blackwell, 2001. Pp. xviii + 386. $41.95 paper.
Authors: Montrul Silvina
Published: December 2002

This book is intended as an introduction both to the principles and parameters framework (Chomsky, 1981) and to the second language (L2) acquisition of syntactic representations. Hawkins's basic aim is to present evidence for the view that L2 learners progressively build subconscious mental grammars (i.e., a syntactic system) guided by Universal Grammar—an innate, language-specific system. However, this volume is not just an introductory textbook presenting and summarizing the work of other researchers in this particular field. Indeed, the book has another major aim: Within the context of the most current debates on the L2 acquisition of syntactic knowledge, Hawkins introduces his own theory of L2 development, which he terms Modulated Structure Building.
AT WAR WITH DIVERSITY: U.S. LANGUAGE POLICY IN AN AGE OF
ANXIETY. James Crawford. Clevedon, UK: Multilingual Matters, 2000. Pp.
144. $49.95 cloth, $15.95 paper.
LANGUAGE DIVERSITY AND EDUCATION. David Corson. Mahwah,
NJ: Erlbaum, 2001. Pp. xi + 253. $29.95 paper.
Authors: Reagan Timothy
Published: December 2002

The need to recognize the presence and significance of language diversity in educational
settings in the United States has become increasingly apparent to educators and educational policy
makers in recent years. Among the more contentious debates about public
education that we have witnessed have been those concerned directly with language and linguistic
matters, not the least of which have been those dealing with the education of minority-language
students in general and bilingual education programs in particular. Also, frequent touchstones for
educational debate have been efforts to “recognize” African American Vernacular
English as many children's first and dominant language variety—a matter of no
linguistic controversy at all but one of immense political and educational controversy, as events in
Oakland, California, made quite clear. Although of increasing significance and relevance, it is
interesting that relatively few works have sought to target one of the more important audiences
concerned with such debates: future classroom teachers. Issues of language and language
diversity are largely absent from the teacher education literature, and preservice teachers are
relatively unlikely to be exposed in any significant or in-depth way to such matters in their formal
preparation (see Reagan, 1997). As David Corson notes in Language diversity and education, “A major challenge for beginning teachers is to understand how language
differences construct and reflect ideologies and power relations, especially through the work that
teachers do themselves” (p. 96). Fortunately, the two books under review here provide an
excellent start for helping new and future teachers to develop the type of critical language
awareness necessary if they are to meet the needs of their students more adequately.
LES CRÉOLES: L'INDISPENSABLE SURVIE. Marie-Christine Hazaël-Massieux. Paris: Éditions Entente, 1999. Pp. 319. F 150, paper.
Authors: Clements J. Clancy
Published: December 2002

This book, which appears in a series called Langues en Péril“languages in peril,” is an accessible and well-written panoramic view of the French-based creoles spoken in the Caribbean and the Indian Ocean. In her introductory remarks, author Marie-Christine Hazaël-Massieux addresses the confusions regarding the notions of language and dialect, presenting clearly and concisely how a linguistic system can be a language without being written or prestigious or belonging to any given geographical region. She touches on why some of the French-based creoles, such as Louisiana Creole French, may be endangered and extends the definition of an endangered language to include cases in which a creole can lose its “creoleness” through decreolization. This allows her also to discuss the question of diversity among French-based creoles, although, as she points out, this rich diversity is often overlooked for ideological or other reasons.
An integrated approach to the elicitation of customer
requirements for engineering design using picture sorts and
fuzzy evaluation
Authors: YAN WEI , CHEN CHUN-HSIEN , KHOO LI PHENG
Published: December 2002

Product definition is widely accepted as one of the key factors
to be considered in the early stage of product design and
development. It has a direct impact on the success of a new
product in the marketplace. Frequently, product definition is
solicited through the voice of the customer (VoC). As such,
an organization will obtain a prominent competitive edge over
its competitors if it is able to effectively capture the genuine
VoC or the requirements of a customer. Sorting techniques provide
a means to elicit customer requirements. Although a number of
sorting techniques were developed, few of them are able to handle
the uncertainty and imprecision inherited from the VoC and
subjective judgment because of their crisp decision making.
An integrated approach is described, which is based on repeated
single-criterion sorts and fuzzy evaluation, for the elicitation
of customer requirements. The details of the integrated approach
are presented. The approach is validated using a case study
on the design of a wooden golf-club head. The details of the
validation are discussed.
Agent-based collaborative design system and conflict resolution
based on a case-based reasoning approach
Authors: LEE KYUNG HO , LEE KYU-YEUL
Published: December 2002

Under the concept of a global economy, enterprises are assigning
design and production environments around the world in different
areas. A serious issue of information exchange emerges as companies
use traditional hardware and very distinct software appropriate
to their field of expertise. To overcome the problem of low
productivity due to the interruption of information, the concept
of simultaneous engineering and concurrent design becomes very
significant. In this article an agent-based ship design system
is developed to support cooperation in distributed ship design
environments. Above all, the conflicts that occur while sharing
knowledge in the system must be resolved. One approach is to
adopt a case-based conflict resolution strategy formulated to
resolve current conflict on the basis of similar previously
resolved cases in agent-based collaborative design system
environments. To do this, conflict cases that occur in the initial
ship design stage are extracted. On the basis of the extracted
cases, a case base is constructed. In addition, a conflict
resolution handler located in the superagent called a facilitator,
an agent to control other subagents, is developed to treat conflict
problems effectively by case-based reasoning. The case-based
conflict resolution strategy is evaluated by applying it to
a collaborative design process in the initial ship design stage,
especially the machinery outfitting design, the preliminary
design, the hullform design, and the structural design. Through
the help of the collaboration of the design agents, the
facilitator, the conflict resolution handler, and the case-based
system, a designer can make decisions based on similar previously
resolved cases.
Product family modeling and design support: An approach based
on graph rewriting systems
Authors: DU XUEHONG , JIAO JIANXIN , TSENG MITCHELL M.
Published: December 2002

Earlier research on product family design (PFD) often highlights
isolated and successful empirical studies with a limited attempt
to explore the modeling and design support issues surrounding
this economically important class of engineering design problems.
This paper proposes a graph rewriting system to organize product
family data according to the underpinning logic and to model
product derivation mechanisms for PFD. It represents the structural
and behavioral aspects of product families as family graphs
and related graph operations, respectively. The derivation of
product variants becomes a graph rewriting process, in which
family graphs are transformed to variant graphs by applying
appropriate graph rewriting rules. The system is developed in
the language of programmed graph rewriting systems or PROGRES,
which supports the specification of hierarchical graph schema
and parametric rewriting rules. A meta model is defined for
family graphs to factor out those entities common to all product
families. A generic model is defined to describe all specific
entities relevant to particular families. An instance model
describes all product variants for individual customer orders.
A prototype of a graph-based PFD system for office chairs is
also developed. The system can provide an interactive environment
for customers to make choices among product offerings. It also
facilitates design automation of product families and enhances
interactions and negotiations among sales, design, and manufacturing.
A Most Corrupt Election: Louisiana in 1876
Authors: King Ronald F.
Published: December 2002

Two lessons from the 2000 presidential election stand out in particular.
The first is that rules affect results. Elections are highly organized
mechanisms of citizen participation. Established rules specify who can vote,
where and when they can vote, what ballot form registers their vote, and
what outcome constitutes winning. Rules, moreover, determine which officials
count the votes, certify the victor, and declare the election to be
legitimate. The rules governing election contests are not neutral in their
effects. Each variant generally tends to advantage some given set of
claimants and interests; therefore, the choice among election rules is often
controversial, especially when the outcome hangs in the balance. The second,
related lesson is that votes intended do not
necessarily equal votes cast, that votes cast do
not necessarily equal votes recorded, and that votes recorded do not
necessarily equal the official vote total. In each case, there is the matter
of translation, part of which is technical and depends on the ballot
apparatus and part of which is political and depends on the discretionary
decisions of those responsible for managing the electoral process. Problems
of translation do not ordinarily affect who wins, but they can – and have
during certain controversial episodes of U.S. electoral history.
The American Law of Association: The Legal-Political Construction of
Civil Society
Authors: Novak William J.
Published: December 2002

The legal-political status and power of associations in American society
is an age-old historical question. As early as the 1830s, Alexis de
Tocqueville famously observed,
Does Repression Help to Create Labor Parties? The Effect of Police and
Military Intervention on Unions in the United States and Australia
Authors: Archer Robin
Published: December 2002

There are a number of theories which argue that repression can help to
explain why no labor party was established in the United States. These
theories fall into two groups. In one group are versions of the
soft repression thesis. In the other are
versions of the hard repression thesis. These two
theses contradict each other in basic respects.
Fraternal Rhetoric and the Development of the U.S. Welfare State
Authors: Glenn Brian J.
Published: December 2002

In the decades surrounding the turn of the twentieth century, mutual
benefit societies were thriving voluntary organizations that touched the
vast majority of working-class American households. Not only were they
politically powerful as institutional actors, but more importantly, they
were highly influential in providing their members with the ability to
conceive of mutual assistance in a manner other than through the traditional
lens of liberalism. Contrary to what may be considered the prevailing
wisdom, my research reveals that whether they intended to or not, these
organizations taught lessons that gave their members a coherent
justification for supporting the emerging welfare state. There is also a
methodological lesson, which is that membership organizations must be
understood for their indirect social impact as much as their direct
political one.
Ideas and State Capacity, or Business Dominance? A Historical Analysis of
Grazing on the Public Grasslands
Authors: Gonzalez George A.
Published: December 2002

State-centered theorists have forwarded the argument that the role of
ideas and state capacity in the formulation of public policies is evidence
of an autonomous polity. These theorists hold that state capacity and ideas
have an autonomous and independent role in determining state behavior and
public policy development. Reflective of this, statist Christopher Klyza posits
ideas and state capacity as the primary factors in the development of the
policy regime that manages grazing on the public grasslands. I contend, however, that the history of the federal grazing
policy regime is indicative of a business dominance perspective, a
society-centered approach. Specifically,
the livestock industry, a producer group, is the most powerful explanatory
factor in the development of this regime, not ideas or state capacity.
Furthermore, utilizing the cases of the grazing agencies (the U.S. Grazing
Service and later the Bureau of Land Management [BLM]), the U.S. Forest
Service, the National Park Service, and the Environmental Protection Agency
I assail the autonomy that state-centric theorists ascribe to the state's
capacity.
Explaining U.S. Public Lands Politics: State-Sensitive Theory or Business
Dominance Perspective?
Authors: McGrory Klyza Christopher
Published: December 2002

The fundamental difference between George Gonzalez's interpretation of
grazing politics on the United States public lands in the twentieth century,
as well as his other scholarship on public lands politics, and my own is our
macrotheoretical approach. Gonzalez makes use of what he terms a
business dominance perspective, “which holds
that producer groups in conjunction with economic elites dominate federal
policy making.” I, in turn, use a
state-sensitive/pluralist approach, which
Gonzalez refers to as a state-centered approach. Not surprisingly, we offer
differing explanations of the same policies. Before addressing the specifics
of his article, I will focus on the differences of our theoretical
approaches and what I contend are his misunderstandings of a state-sensitive
approach.
I, Too, Am State-Sensitive: A Response to Christopher Klyza
Authors: Gonzalez George A.
Published: December 2002

I would like to thank the editors of this journal for providing this
venue and thus allowing this exchange between myself and Prof. Klyza to take
place. Moreover, I would like to thank Prof. Klyza for his thoughtful
rejoinder. Nevertheless, and not surprisingly, I disagree with his
interpretation of my work. More importantly, however, I disagree with Prof.
Klyza's interpretation of his own work as well as with his interpretation of
the state-centered approach.
Asymmetrical dynamics of voltage spread in retinal horizontal
cell networks
Authors: BENDA J. , BOCK R. , RUJAN P. , AMMERMÜLLER J.
Published: December 2002

Lateral voltage spread in electrically coupled retinal horizontal
cell networks is the substrate of center-surround antagonism
in bipolar and ganglion cells. We studied its spatial and temporal
properties in more detail in turtle L1 horizontal cells by using
a contrast border as light stimulus. Experimental data were
contrasted with expectations from a linear continuum model to
specify the impact of nonlinearities. The assumptions for the
diffusion term of the continuum model were justified by neurobiotin
labeling. Measured voltage spread revealed two different length
constants Λ+ and Λ0, under illuminated
and nonilluminated regions of the retina, respectively, as predicted
by the linear model. Length constants in the illuminated region showed
strong temporal dynamics. For the initial phase of the horizontal cell
responses Λ+ was larger than Λo. This
was also in accordance with the model. Right at the peak of the
response, however, Λ+ dropped below Λo
and did not change any more. It is this temporal reversal of asymmetry
in voltage spread and not the decrease of Λ+ itself that
is lacked by the linear model. The observed independence of the mean
ratio Λ+/Λo from light intensity in both
the peak and the plateau phases of horizontal cell responses contradicts
the linear assumption, too. These two effects have to be addressed
to local nonlinearities in the horizontal cell network like a negative
feedback loop from photoreceptors and/or voltage-dependent conductances.
Due to the failure of the linear model, firm conclusions about the
membrane resistance and the coupling resistance of the horizontal cell
network cannot be drawn from length constant measurements.
Early visual experience and the receptive-field organization
of optic flow processing interneurons in the fly motion pathway
Authors: KARMEIER KATJA , TABOR RICO , EGELHAAF MARTIN , KRAPP HOLGER G.
Published: December 2002

The distribution of local preferred directions and motion
sensitivities within the receptive fields of so-called
tangential neurons in the fly visual system was previously
found to match optic flow fields as induced by certain
self-motions. The complex receptive-field organization
of the tangential neurons and the recent evidence showing
that the orderly development of the fly's peripheral
visual system depends on visual experience led us to investigate
whether or not early visual input is required to establish
the functional receptive-field properties of such tangential
neurons. In electrophysiological investigations of two
identified tangential neurons, it turned out that dark-hatched
flies which were kept in complete darkness for 2 days develop
basically the same receptive-field organization as flies
which were raised under seasonal light/dark conditions
and were free to move in their cages. We did not find any
evidence that the development of the sophisticated receptive-field
organization of tangential neurons depends on sensory experience.
Instead, the input to the tangential neurons seems to be
“hardwired” and the specificity of these cells
to optic flow induced during self-motions of the animal
may have evolved on a phylogenetical time scale.
Role of GABAA-mediated inhibition in controlling
the responses of regular spiking cells in turtle visual cortex
Authors: MANCILLA JAIME G. , ULINSKI PHILIP S.
Published: December 2002

The visual cortex of freshwater turtles contains pyramidal
cells, which have a regular spiking (RS) firing pattern,
and several categories of aspiny, inhibitory interneurons.
The interneurons show diverse firing patterns, including
the fast spiking (FS) pattern. Postsynaptic potentials
(PSPs) evoked in FS cells by visual stimulation of the
retina reach their peak amplitudes as much as 200 ms before
PSPs in RS cells (Mancilla et al., 1998). FS cells could,
consequently, control the amplitudes of light-evoked PSPs
in RS cells by producing disynaptic, feedforward inhibitory
postsynaptic potentials (IPSPs) that overlap in time with
geniculocortical excitatory postsynaptic potentials (EPSPs).
Since FS cells receive recurrent, excitatory inputs from
RS cells, they could also control the amplitudes of light-evoked
PSPs in RS cells via polysynaptic, feedback inhibition.
The in vitro geniculocortical preparation of Pseudemys
scripta was used to characterize the temporal relationships
of EPSPs and IPSPs produced in RS cells by electrical activation
of geniculate afferents and by diffuse light flashes presented
to the retina. GABAA receptor-mediated inhibition
was blocked using extracellular application of bicuculline
(3.5 mM) or intracellular perfusion of picrotoxin (1 μM)
in individual RS cells. Electrical stimulation of thalamic
afferents produced compound PSPs. Blockade of GABAA
receptor-mediated IPSPs with either bicuculline or picrotoxin
provided evidence for both early and late IPSPs in RS cells.
Analysis of the apparent reversal potentials of light-evoked
PSPs indicated the existence of early IPSPs during the
first 140–300 ms following light onset. Light responses
of cells perfused with picrotoxin diverged from control
light responses at about 300 ms after light onset and had
maximum amplitudes that were significantly different from
control light responses. These experiments indicate that
the responses of RS cells to both electrical and natural
stimulation of geniculate afferents are controlled by both
early and late IPSPs, consistent with activation of both
feedforward and feedback pathways.
Connectional and neurochemical subdivisions of the pulvinar
in Cebus monkeys
Authors: SOARES JULIANA G.M. , GATTASS RICARDO , SOUZA AGLAI P.B. , ROSA MARCELLO G.P. , FIORANI MÁRIO , BRANDÃO BRUNO L.
Published: December 2002

Based on cytoarchitectonic criteria, the primate pulvinar
nucleus has been subdivided into medial (PM), lateral (PL),
and inferior (PI) regions. However, these subdivisions
show no correlation with those established by electrophysiological,
immunocytochemical, or neuroanatomical tracer studies.
In this work, we studied the connections of the pulvinar
nucleus of Cebus monkey with visual areas V1,
V2, V4, MT, and PO by means of retrograde fluorescent tracers
injected into these areas. Based on the projection zones
to cortical visual areas, the visual portion of the pulvinar
of Cebus monkey was subdivided into three subregions:
P1, P2, and P3, similar to those described in the macaque
(Ungerleider et al., 1984). In Cebus, P1 includes
the centrolateral portion of traditionally defined PI and
adjacent portion of PL. P2 is located in the dorsal portion
of PL and P3 includes the medial portion of PI and extends
dorsally into adjacent PL and PM. In addition, we studied
the histology of the pulvinar using multiple criteria,
such as cytoarchitecture and myeloarchitecture; histochemistry
for cytochrome oxidase, NADPH-diaphorase, and acetylcholinesterase;
and immunocytochemistry for two calcium-binding proteins,
calbindin and parvalbumin, and for a neurofilament recognized
by the SMI-32 antibody. Some of these stains, mainly calbindin,
showed additional subdivisions of the Cebus pulvinar,
beyond the traditional PI, PL, and PM. Based on this immunohistochemical
staining, the border of PI is moved dorsally above the
brachium of the superior colliculus and PI can be subdivided
in five regions (PIP, PIM, PIC,
PIL, and PILS). Regions P1, P2, and
P3 defined based on efferent connections with cortical
visual areas are not architectonically/neurochemically
homogeneous. Rather they appear to consist of further chemoarchitectonic
subdivisions. These distinct histochemical regions might
be related to different functional modules of visual processing
within one connectional area.
Prenatal and postnatal expression of nitric oxide in the
developing kitten superior colliculus revealed with NADPH
diaphorase histochemistry
Authors: SCHEINER C.A. , KRATZ K.E. , GUIDO W. , MIZE R.R.
Published: December 2002

Nitric oxide (NO) is a neuronal messenger molecule that
mediates pathway refinement in some brain regions. We used
nicotinamide adenine dinucleotide phosphate diaphorase
(NADPHd) histochemistry to examine the development of NO
expression in the superior colliculus (SC) of kittens aged
E28–E58 and P2–P57 and adults in order to determine
if NO expression is correlated with pathway refinement.
At E28, labeled cells were seen only within the subventricular
zone (SVZ). At E36–E41, labeled cells were also found
within the deep gray layer (DGL) of SC. At E51 and E58,
a few labeled neurons were also present in the intermediate
gray layer (IGL). These neurons already had extensive dendritic
fields and well-developed morphologies at the time that
they first expressed nitric oxide synthase (NOS). The number
of neurons labeled in the DGL and IGL increased postnatally,
reaching a peak density between P14 and P35. Neurons within
the optic (OL) and superficial gray layers (SGL) were first
visible at P7 and increased slightly in number until adulthood.
However, SGL-labeled neurons were relatively limited in
number and lightly labeled at all ages examined. We conclude
that (1) NADPHd expression occurs in SC beginning in the
second trimester in kittens and progresses in a ventral
to dorsal pattern between E36–P35; (2) few neurons
in kitten SGL are labeled by NADPHd and these appear relatively
late in postnatal development; and (3) there is no correlation
between NOS expression and retinocollicular pathway refinement
in kittens, a result different from that seen in rodents.
Activation of nicotinic receptors on GABAergic amacrine cells
in the rabbit retina indirectly stimulates dopamine release
Authors: NEAL MICHAEL J. , CUNNINGHAM JOANNA R. , MATTHEWS KIM L.
Published: December 2002

The retina possesses subpopulations of amacrine cells,
which utilize different transmitters, including acetylcholine
(ACh), GABA, and dopamine. We have examined interactions
between these neurones by studying the effects of nicotinic
agonists on GABA and dopamine release. Isolated rabbit
retinas were incubated with [3H]dopamine
and then superfused. Fractions of the superfusate (2 min)
were collected and the [3H]dopamine
in each sample was measured. Endogenous GABA release was
examined by incubating retinas in a small chamber. At 5-min
intervals, the medium was changed and the GABA measured
by high-pressure liquid chromatography (HPLC). Exposure
of the retina to nicotine, epibatidine, and other nicotinic
agonists increased the release of both GABA and dopamine.
The effects of nicotine and epibatidine were blocked by
mecamylamine, confirming an action on nicotinic receptors.
The action of epibatidine on dopamine release was unaffected
by glutamate antagonists but was blocked by picrotoxin
and gabazine. These results suggested that nicotine might
increase dopamine release indirectly by stimulating the
release of GABA, which in turn inhibited the release of
an inhibitory transmitter acting tonically on the dopaminergic
amacrines. Exposure of the retina to GABA caused a small
increase in dopamine release. This hypothetical inhibitory
transmitter was not GABA, an opioid, adenosine, glycine,
nociceptin, a cannabinoid, or nitric oxide because appropriate
antagonists did not affect the resting release of dopamine.
However, metergoline, a 5HT1/5HT2
receptor antagonist, and ketanserin, a 5HT2A
receptor antagonist, but not the 5HT1A antagonist
WAY100635, increased the resting release of dopamine and
blocked the effects of nicotine. The 5HT1A/5HT7
agonist 8-hydroxy DPAT inhibited both the nicotine and
GABA-evoked release of dopamine. We conclude that nicotinic
agonists directly stimulate the release of GABA, but the
evoked release of dopamine is indirect, and arises from
GABA inhibiting the input of an inhibitory transmitter,
which we tentatively identify as serotonin.
Visuomotor properties of corticotectal cells in area 17 and
posteromedial lateral suprasylvian (PMLS) cortex of the cat
Authors: WEYAND THEODORE G. , GAFKA ADELE C.
Published: December 2002

We studied the visuomotor activity of corticotectal (CT)
cells in two visual cortical areas [area 17 and the
posteromedial lateral suprasylvian cortex (PMLS)]
of the cat. The cats were trained in simple oculomotor
tasks, and head position was fixed. Most CT cells in both
cortical areas gave a vigorous discharge to a small stimulus
used to control gaze when it fell within the retinotopically
defined visual field. However, the vigor of the visual
response did not predict latency to initiate a saccade,
saccade velocity, amplitude, or even if a saccade would
be made, minimizing any potential role these cells might
have in premotor or attentional processes. Most CT cells
in both areas were selective for direction of stimulus
motion, and cells in PMLS showed a direction preference
favoring motion away from points of central gaze. CT cells
did not discharge with eye movements in the dark. During
eye movements in the light, many CT cells in area 17 increased
their activity. In contrast, cells in PMLS, including CT
cells, were generally unresponsive during saccades. Paradoxically,
cells in PMLS responded vigorously to stimuli moving at
saccadic velocities, indicating that the oculomotor system
suppresses visual activity elicited by moving the retina
across an illuminated scene. Nearly all CT cells showed
oscillatory activity in the frequency range of 20–90
Hz, especially in response to visual stimuli. However,
this activity was capricious; strong oscillations in one
trial could disappear in the next despite identical stimulus
conditions. Although the CT cells in both of these regions
share many characteristics, the direction anisotropy and
the suppression of activity during eye movements which
characterize the neurons in PMLS suggests that these two
areas have different roles in facilitating perceptual/motor
processes at the level of the superior colliculus.
The relationship between GABA-containing cells and the cholinergic
circuitry in the rabbit retina
Authors: DMITRIEVA NINA A. , LINDSTROM JON M. , KEYSER KENT T.
Published: December 2002

As a part of ongoing efforts to understand the cholinergic
circuitry in the mammalian retina, we studied the coexpression
of nicotinic acetylcholine receptors (nAChRs) and gamma-aminobutyric
acid (GABA), the GABA transporter 1 (GAT-1), or choline
acetyltransferase (ChAT) immunoreactivity in the rabbit
retina. Double-label experiments with monoclonal antibody
210 (mAb 210) against nAChRs and antibodies against GABA
revealed that several populations of GABA-containing amacrine,
displaced amacrine, and ganglion cells displayed nAChR
immunoreactivity. Some of them also exhibited ChAT immunoreactivity
and were identified as the cholinoceptive starburst cells.
Other GABAergic amacrine cells positive for mAb 210 were
not cholinergic. Simultaneous visualization of mAb 210
and GAT-1 immunoreactivity revealed that 10% of GAT-1 immunoreactive
amacrine cells contained nAChRs. Ninety-nine percent of
the GAT-1 labeled cells demonstrated GABA immunoreactivity,
but only 75% of the GABAergic cells were outlined by GAT-1
staining. Neither population of starburst cells exhibited
GAT-1 immunoreactivity. Thus, mAb 210 expressing, GAT-1
positive cells in the rabbit retina constitute a noncholinergic
subset of GABAergic amacrine cells. Taken together, our
results suggest that some GABAergic amacrine cells are
cholinoceptive, raising the possibility that ACh, acting
through nAChRs, can modulate the release of GABA in the
rabbit retina.
Somatostatin inhibits calcium influx into rat rod bipolar
cell axonal terminals
Authors: JOHNSON JULIETTE , CARAVELLI MICHAEL L. , BRECHA NICHOLAS C.
Published: December 2002

In the retina, somatostatin (SST), an inhibitory peptide
that influences neuronal activity, is predominantly expressed
by sparsely occurring amacrine cells. The SST subtype 2A
receptor is expressed by rod bipolar cells, including their
axonal terminals. We used Ca2+-imaging techniques
and the ratiometric Ca2+ indicator dye fura-2
AM to investigate Ca2+ dynamics in rod bipolar
cell terminals. Depolarization of rod bipolar cells by
the addition of high K+ (50 or 100 mM) elicited
a sustained increase in [Ca2+]i
in rod bipolar terminals that returned to basal levels
following K+ removal. The Ca2+ response
was dependent on extracellular Ca2+, and was
inhibited by the Ca2+ channel blocker Cd2+
and by the selective L-type Ca2+ channel blocker,
nimodipine. SST inhibited a K+ depolarization-induced
[Ca2+]i response in rod
bipolar terminals. This inhibition was observed with 1
nM SST and was maximal with 1 μM SST. These findings
indicate that SST may regulate transmitter release from
rod bipolar terminals by activating the SST subtype 2A
receptor through modulation of intracellular Ca2+.
Developmental expression of intracellular targets of cGMP
in rat visual cortex and alteration with dark rearing
Authors: ROY DEBORAH R. SAMANTA , BARNSTABLE COLIN J.
Published: December 2002

We describe the temporal pattern of mRNA expression of
some of the molecular components of the NO/cGMP second
messenger system in the developing rat visual cortex and
the effect of dark rearing on their expression levels using
semiquantitative RT-PCR. mRNA expression for these molecules
was altered by dark rearing in one of three ways: (1) no
change—rod, olfactory, and cone/testis CNG channels,
nonselective cation channels gated by cyclic nucleotides
and highly permeable to Ca2+; (2) decrease—cyclic
nucleotide phosphodiesterases which regulate cyclic nucleotide
levels, and soluble guanylyl cyclase, the key synthetic
enzyme producing cGMP and potently activated by nitric
oxide; and (3) increase—cGMP kinase I, a key enzyme
activated by cGMP to phosphorylate a variety of intracellular
proteins including cytoskeletal elements. These data suggest
important and distinct roles for the cGMP system in both
early and late developmental events in the rat visual cortex.
Processing of scotopic increments and decrements
Authors: PURKISS TODD J. , HUGHES ALAN , DEMARCO PAUL J.
Published: December 2002

Rod and cone photoreceptors send their signals to ON-
and OFF-retinal ganglion cells through different pathways
in the primate retina. We hypothesized that increments
and decrements of light may be processed differently by
the rod-bipolar pathway because of the funneling of the
rod signal through the rod bipolar cell. We tested this
hypothesis using a psychophysical adaptation paradigm,
which has provided evidence that photopic increments and
decrements of light are processed by ON- and OFF-pathways
in the human visual system. We had observers adapt to either
a rapid-on or rapid-off sawtooth waveform, under both photopic
and scotopic conditions. We then measured detection thresholds
for one cycle of a rapid-on or rapid-off sawtooth stimulus.
For photopic stimuli, sawtooth adaptation asymmetrically
raised thresholds for test stimuli in a manner that depended
on the polarity of the adaptation stimulus. For scotopic
stimuli, thresholds were raised, but no significant selective
adaptation effect was found. By repeating the photopic
condition with sawtooth stimuli which had been filtered
using an impulse response function derived for the rod
system, we demonstrated that the lack of selective adaptation
was not a consequence of the sluggish temporal response
of the rod-bipolar pathway. We conclude instead that the
reduced effectiveness of sawtooth adaptation is due to
channeling of rod photoreceptor signals through the rod
bipolar cell before reaching ON- and OFF-ganglion cells.
Bipolar or rectified chromatic detection mechanisms?
Authors: SANKERALLI MARCEL J. , MULLEN KATHY T.
Published: December 2002

It is widely accepted that human color vision is based
on two types of cone-opponent mechanism, one differencing
L and M cone types (loosely termed “red–green”),
and the other differencing S with the L and M cones (loosely
termed “blue–yellow”). The traditional
view of the early processing of human color vision suggests
that each of these cone-opponent mechanisms respond in
a bipolar fashion to signal two opponent colors (red vs.
green, blue vs. yellow). An alternative possibility is
that each cone-opponent response, as well as the luminance
response, is rectified, so producing separable signals
for each pole (red, green, blue, yellow, light, and dark).
In this study, we use psychophysical noise masking to determine
whether the rectified model applies to detection by the
postreceptoral mechanisms. We measured the contrast-detection
thresholds of six test stimuli (red, green, blue, yellow,
light, and dark), corresponding to the two poles of each
of the three postreceptoral mechanisms. For each test,
we determined whether noise presented to the cross pole
had the same masking effect as noise presented to the same
pole (e.g. comparing masking of luminance increments by
luminance decrement noise (cross pole) and luminance increment
noise (same pole)). To avoid stimulus cancellation, the
test and mask were presented asynchronously in a “sandwich”
arrangement (mask-test-mask). For the six test stimuli,
we observed that noise masks presented to the cross pole
did not raise the detection thresholds of the test, whereas
noise presented to the same pole produced a substantial
masking. This result suggests that each color signal (red,
green, blue, and yellow) and luminance signal (light and
dark) is subserved by a separable mechanism. We suggest
that the cone-opponent and luminance mechanisms have similar
physiological bases, since a functional separation of the
processing of cone increments and cone decrements could
underlie both the separation of the luminance system into
ON and OFF pathways as well as the splitting of the cone-opponent
mechanisms into separable color poles.
Survival of retinal ganglion cells after transection of
the optic nerve in adult cats: A quantitative study within two weeks
Authors: WATANABE MASAMI , INUKAI NAOKO , FUKUDA YUTAKA
Published: December 2002

We have previously reported that a small number of retinal
ganglion cells (RGCs) of adult cats survive 2 months after
transection of the optic nerve (ON) and that α cells
have the greatest ability to survive among different types
of RGCs (Watanabe et al., 1995). Here we report the time
course of RGC survival within 15 days after ON transection
using retrograde labeling with DiI injected into the bilateral
lateral geniculate nuclei of cats. The density of DiI-labeled
RGCs in the central retina as well as in the periphery
did not change until day 3 after ON transection, then decreased
rapidly, to 43% of the original density on day 7, and falling
to 19% by day 14. We then intracellularly injected Lucifer
yellow into the DiI-labeled RGCs to examine the difference
in the time course between surviving α and β cells.
Similar to the density change in total surviving RGCs,
the proportion of surviving β cells did not change
until day 3, then decreased rapidly to 65% of the original
density on day 4, falling to 12% by day 14. By contrast,
64% of α cells survived for 14 days after axotomy.
Analysis of regression lines for survival time courses
indicated that death of β cells was characterized with
a rapid period phase from day 3 to day 7 after axotomy
whereas that of α cells lacked it. Axon-like sprouting
from surviving β cells was first recognized in the
nerve fiber layer on day 3, and were later more conspicuous.
Amacrine and ganglion cell contributions to the electroretinogram
in amphibian retina
Authors: AWATRAMANI GAUTAM , WANG JUE , SLAUGHTER MALCOLM M.
Published: December 2002

The neuronal generators of the b- and d-waves
of the electroretinogram (ERG) were investigated in the
tiger salamander retina to determine if amacrine and ganglion
cells contribute to this field potential. Several agents
were used that affect third-order neurons, such as tetrodotoxin,
baclofen, and NMDA agonists and antagonists. Baclofen,
an agent that enhances light responses in third-order neurons,
increased the d-wave and reduced the b-wave.
In contrast, agents that decrease light responses in third-order
neurons had the opposite effect of enhancing the b-wave
and depressing the d-wave. The effect on the d-wave
was particularly pronounced. The results indicate that
third-order neuronal activity influences b- and
d-waves of the ERG. The opposing actions suggest
that the b-wave to d-wave ratio might
serve as an measure of ganglion cell function.
Developmental patterns of protein expression in photoreceptors
implicate distinct environmental versus cell-intrinsic
mechanisms
Authors: JOHNSON P.T. , WILLIAMS R.R. , REESE B.E.
Published: December 2002

The present study has examined the spatial and temporal
expression patterns of various proteins associated with
the structure and function of mature photoreceptor outer
segments in the developing ferret's retina using immunocytochemistry
and RT-PCR. One set of proteins, including rod opsin, arrestin,
and recoverin, was detected progressively in photoreceptors
as they became postmitotic, being expressed well before
the differentiation of outer segments. A second set of
proteins, including β- and γ-transducin, cGMP-phosphodiesterase,
phosducin, rhodopsin kinase, rod cGMP-gated cation channel
protein, and peripherin, displayed a contrasting temporal
onset and pattern of spatial emergence. These latter proteins
first became detectable either shortly before or coincident
with outer segment formation, and were expressed simultaneously
in both older and younger photoreceptor cells. A third
set, the short wavelength-sensitive (SWS) and medium wavelength-sensitive
(MWS) cone opsin proteins, was the last to be detected,
but materialized in a spatio-temporal pattern reminiscent
of the neurogenetic gradient of the cones. These different
spatial and temporal patterns indicate that cellular maturation
must play a primary role in regulating the onset of expression
of some of these proteins, while extrinsic signals must
act to coordinate the expression of other proteins across
photoreceptors of different ages.
Intraretinal analysis of the a-wave of the
electroretinogram (ERG) in dark-adapted intact cat retina
Authors: DERWENT JENNIFER J. KANG , LINSENMEIER ROBERT A.
Published: December 2002

It has often been assumed that the recovery of the a-wave
from its trough is caused by the intrusion of the b-wave.
This study examined the recovery following the a-wave
trough using intraretinal recordings in dark-adapted intact
cat retina. Adult cats were anesthetized and paralyzed. The
vitreal ERG was recorded between the vitreous humor and a reference
electrode near the eye. Intraretinal recordings were made by
referencing a microelectrode to the vitreal electrode. Bright
flashes of diffuse white light were used to elicit a-
and b-waves. Intravitreal injections of
2-amino-4-phosphonobutyrate (APB), cis 2,3-piperidine dicarboxylic
acid (PDA), and kynurenic acid (KYN) were used to block the responses
of bipolar and horizontal cells. Intravitreal injections of UL-FS 49
or DK-AH 269 were used to block Ih, a
hyperpolarization-activated potassium current. Since the microelectrode
was referenced to the vitreal electrode, recordings from the inner
retina showed only the oscillatory potentials and b-waves.
In the inner retina, the potential was flat until the b-wave
became measurable, ∼17 ms from the onset of the flash. The
a-wave started to appear as the microelectrode reached the
photoreceptors and its amplitude increased with depth until the
microelectrode reached the choroid. The a-wave peaked at
∼8 ms in response to flashes that saturated its amplitude and then
began to recover well before any inner retinal responses were
apparent. After injections of APB, PDA, and KYN, vitreal and
intraretinal recordings showed only the a-wave, which
consisted of an increase to peak at ∼10 ms followed by a
recovery to a plateau which was reached at ∼25 ms. Blockers
of Ih reduced the recovery, but did
not eliminate it. The a-wave peaks and partially recovers
before the b-wave intrudes. Both phases survive blockers
of second-order neurons which implies that the photoreceptors generate
both the rising and recovery phase of the a-wave. The recovery
phase may be due to a current generated by the inner segment of
photoreceptors.