I am very pleased to present this year's proceedings
of the M.R. Bauer Foundation Colloquium Series, Scientific
Retreat, and Distinguished Guest Lecturer Series at Brandeis
University's Volen National Center for Complex Systems.
Now in its eighth year, the generous support of the M.R.
Bauer Foundation has enabled the Volen Center to mount
an impressive series of lectures and informal interactions
that reflect some of the most exciting new developments
in neuroscience. An important part of the Volen Center's
mission is to make known the results of its quickly advancing
work and to offer a forum to discuss them. My colleagues
and I at the Center would like to express our thanks to
the M. R. Bauer Foundation for its ongoing support that
has facilitated learning and communication among the faculty
and students with many of the leading practitioners of
neuroscience.
The M.R. Bauer Colloquium Series hosted six speakers
in 2001-02. Focusing on learning and memory, a group of
speakers highlighted advances in understanding the plasticity,
or adaptability, of the brain during these dynamic processes.
Howard Schulman, Ph.D.,
from the Department of Neurobiology in Stanford University's
School of Medicine, spoke about the role of a critical
regulatory molecule, CaM kinase 11, that may help to form
the biochemical "switch" for memory. Synaptic connections
between neurons form during the brain's development according
to their ongoing use. During learning and memory, the
effectiveness of the information transmitted through the
synapses is modified and strengthened. Calcium serves
as an intracellular signal that triggers a switch as the
neuron is stimulated. György
Buzsáki, M.D., a member of Rutgers University's
Department of Neuroscience, discussed the maintenance
of firing rates and patterns in hippocampus cells. Although
the brain is constantly changing, humans maintain a subjective
sense of continuity in who they are and what they can
do. Buzsáki suggested that bursts of firing neurons
act as a mechanism that creates the equilibrium necessary
for this continuity. David Linden, M.D., from the Department
of Neuroscience at The Johns Hopkins University School
of Medicine, considered the molecular basis of motor learning
in the brain's cerebellum. The goal of his work is to
create a comprehensive model of learning that links molecules,
synapses, cells, networks, and behaviors.
Vision is one of the most challenging areas of neuroscience.
A number of Bauer Colloquium speakers described recent
research developments in the neuroscience of vision. Richard
Thompson, M.D., from the University of Southern California's
Department of Brain and Cognitive Sciences, has studied
the eyeblink as a model of Pavlovian conditioning. In
a series of experiments using electrophysiological recordings,
lesions, stimulation, and anatomical pathway tracing,
he identified a brain circuit necessary for this behavior
in the anterior interpositus of the cerebellum. When protein
synthesis in this region of the brain is blocked, learning
of this response is prevented. Dan
Pollen, M.D., a member of the Department of Neurology
at the University of Massachusetts Medical School, addressed
the elusive and controversial neural correlates of visual
perception. Although some scientists have claimed that
a necessary condition of visual experience is the interaction
between neural representations of an image with representations
of a sense of self, scientists have not yet specified
the sufficient conditions of vision. Alvaro
Pascual-Leone Garcia, M.D., affiliated with Beth Israel
Deaconess Medical Center and Harvard Medical School, talked
about a closely related subject, visual awareness.
Now in its fourth year, the M.R. Bauer Distinguished
Guest Lecturer Series brought two well-known scientists
to campus in the spring for extended visits. Julian Jack,
M.D., a Fellow of the Royal Society of London, is affiliated
with the University Laboratory of Physiology at Oxford
in England. One of the senior figures in neuroscience,
he is known for his outstanding theoretical and experimental
contributions to our understanding of synaptic transmission,
the way in which impulses are sent between nerve cells,
in the central nervous system. He has made the important
analysis of the spread of electric signals along the dendritic
cable system of neurons in the spinal cord. Jack's development
of quantal analysis, or the measurement of the electrical
output of neurons, has been important for understanding
how nerve cells receive information and integrate it.
His public lecture, "Fifty Years of Quantal Analysis:
What Have We Learnt?" addressed the ongoing questions
about the reliability of this research. Because the readings
sometimes produce spurious peaks in output, the approach
may be unable to support any conclusions. However, Jack
asserts that quantal analysis is ideal for separating
pre- and post-synaptic effects, the transmissions recorded
on the input or the output sides of the synapse. More
recent quantal recordings may be helpful in sorting out
pre- and post-synaptic events.
The year's second M.R. Bauer Distinguished Guest Lecturer
was Mary B. Kennedy, M.D., professor of biology at the
California Institute of Technology. Kennedy has done some
of the most important biochemical work in neurobiology
on CaM kinase 11, the calcium molecule that may be the
key to how the brain stores new information. Her research
has focused on the molecular structure and function of
synapses in the central nervous system. While her work
has been devoted to taking apart the synapse and describing
each of the molecules that plays a role there, her public
lecture took a different tack-"Pufting the Synapse Back
Together." Different regions of the brain have been identified
as the locations of different kinds of memory-the dorsolateral
prefrontal cortex, for example, with working memory of
the most recent I 0 to 20 seconds, and the hippocampus
with memory in the range of days to weeks. Is there synaptic
specialization that underlies specialization in different
parts of the brain? No one knows yet whether different
signaling systems are the basis of different functions,
but answering this question will help us understand how
the brain functions as a whole. Kennedy advised that simulations
of synapses must include the spatial arrangements of proteins
in the membrane because they determine the specificity
of the reactions that create the post-synaptic density
relevant to memory storage.
The 2002 Volen Center Retreat sponsored by the M.R. Bauer
Foundation addressed "Cellular and Molecular Approaches
to Neuroscience." As in previous years, the retreat was
held at the Marine Biological Laboratorygt Woods Hole,
Massachusetts, on March 15 and 16. Among this year's speakers,
Michael Welte, Ph.D., W.M. Keck Assistant Professor of
Biology and Rosenstiel Basic Medical Sciences Research
Center at Brandeis, described his work on the tiny motors
that move organelles within cells. While scientists understand
the motors, they do not yet understand the mechanisms
that allow cells to deploy them in a regulated way. Using
genetic, biochemical, and biophysical methods to study
the regulation of lipid droplet transport in cells, Welte
has isolated mutations in the regulator gene called klarthat
may be responsible. Because this gene is also important
for nuclear migration during eye development, it is likely
essential for intracellular transport in general. Donald
Katz, Ph.D., who was recently appointed an assistant professor
of psychology at Brandeis, spoke about taste perception.
While a single neuron may be maximally responsive to different
tastes at different times, there may in fact be three
times as many neurons involved than previously reported.
Taste perception is a dynamic process, Katz asserted,
involving interactions at multiple spatial and temporal
scales. John S. Satterlee, Ph.D., a postdoctoral researcher
in the laboratory of Associate Professor of Neurobiology
Piali Sengupta, spoke about his work on the function and
development of neurons that control our sense of temperature.
Thermosensation is one of the most poorly understood senses,
even though it plays a critical role in regulating behavior
and metabolism. Safterlee has identified four genes that
regulate the thermosensory neuron, and has linked one
of the genes to a role in adaptation to some odorants
as well. Sacha Nelson, Ph.D., an associate professor of
biology and Volen National Center for Complex Systems
at Brandeis, presented his work elucidating how neurons
in the visual cortex respond to special features or patterns
in the world. He is examining single cells in order to
determine how their structures affect their ability to
integrate visual information, as well as networks of cells,
in order to understand how the brain's selective response
to visual stimuli may arise from cooperative interactions.
Scientists are debating whether cortical neurons transmit
information primarily in their firing rates or in the
precise timing of their spikes. Nelson addressed the related
issue of which features of spike trains control plasticity
at cortical synapses. His results, showing joint dependence
on the rate and the relative timing of firing, hold important
implications for which parts of the neural code are most
readily stored for retrieval. Matthias Soller, Ph.D.,
a postdoctoral researcher in the laboratory of Professor
of Biology Kalpana White, spoke about his work on the
posttranscriptional mechanisms of gene regulation involved
in the development and function of the nervous system.
This process can substantially change the outcome of the
information encoded on the DNA. His work focuses on the
erect wing protein in the fruit fly, which he shows is
necessary for proper neuronal function underlying coordinated
movement. Finally, Michael Rosbash, Ph.D., professor of
biology and a Howard Hughes Medical Institute Investigator
at Brandeis, described some of the most important discoveries
he has made about the molecular and genetic components
of biological clocks, crucial for sleep disorders and
depression. His work is responsible for bringing the study
of circadian rhythms into the modern molecular era. He
is now exploiting new microarray technologies to show
how certain genes control biological rhythms, enhancing
our understanding of fruit flies as well as of mammals.
Over the past eight years, the M.R. Bauer Foundation
Colloquium and Scientific Retreat have helped to promote
the exchange of ideas and methods and to advance the study
of neuroscience. In the past four years, the M.R. Bauer
Distinguished Guest Lecturer Series has brought some of
the most accomplished neuroscientists to the University.
Both programs have helped to create a sense of community
among the neuroscientists at Brandeis and those who come
to Brandeis from elsewhere. These proceedings comprise
an essential part of the Volen Center's effort to encourage
scientific collaboration and discussion. I am especially
pleased to recognize the support of the M.R. Bauer Foundation
for continuing to make these activities possible through
its generous funding.
Laurence F. Abbott, Ph.D.
Nancy Lurie Marks Professor of Neuroscience and Director,
Volen National Center for Complex Systems
