Visually driven intrinsic plasticity

In mammals including humans, proper development of the cortex is heavily dependent on sensory experience. Neurons in sensory cortex are subject to a “use it or lose it” rule, whereby if they are deprived of sensory input during a critical period of development, they lose the ability to respond altogether. This loss of responsiveness could occur through synaptic changes (synaptic plasticity), or through changes in the intrinsic ability of neurons to fire action potentials (intrinsic plasticity).

Up until now experience-dependent development has largely been ascribed to  synaptic plasticity mechanisms.  In the cover article in this week’s issue of Neuron, (Nataraj et al., Neuron 68, 750–762, November 18, 2010), Brandeis postdocs Kiran Nataraj, Nicolas Le Roux, Marc Nahmani and Sandrine Lefort from the lab of Professor Gina Turrigiano show that a form of intrinsic plasticity termed “long-term potentiation of intrinsic excitability”, or LTP-IE, plays an important role in experience-dependent refinements of cortical circuits. This study shows that sensory drive normally keeps cortical output neurons active by triggering LTP-IE, and sensory deprivation reduces the ability of these neurons to fire by preventing the activation of this form of plasticity. This suggests that LTP-IE serves a “use it or lose it” function in cortical output neurons, gating cortical output by keeping active neurons responsive, while suppressing the output of  inactive neurons.

Brandeis alums at the Society for Neuroscience Meeting

The 40th Society for Neuroscience Meeting was held this week in San Diego.  Among the more than 31,000 attendees were numerous present and past members of the Brandeis Neuroscience community. Attending this meeting is scientifically rewarding and accompanied by reunions with undergraduate, graduate, and postdoc alumni, now working around the world.

Marder lab postdocs: from the left, Dr. Mike Nusbaum, Professor, U. Pennsylvania Medical School; Dr. Lingjun Li, Assoc. Professor of Chemistry, U. Wisconsin; Dr. Farzan Nadim, Professor, Rutgers and NJIT; Dr. Eve Marder, Professor, Brandeis ; Dr. Dirk Bucher, Asst. Professor, Whitney Laboratory, U. Florida; Dr. Astrid Prinz, Assoc. Professor, Emory; Dr. Jorge Golowasch, Professor, Rutgers and NJIT; Dr. Patsy Dickinson (sabbatical visitor at Brandeis), Professor, Bowdoin College.

Brandeis undergraduate Ryan Maloney, ’11, presenting his poster to ex-Brandeis postdocs Dr. John Birmingham, Assoc. Professor, Santa Clara U., and Dirk Bucher.

Brandeis undergraduate Toly Rinberg, ’11; Alex Williams, Bowdoin College; and Dr. Michael Oshinsky ’92, Professor, Thomas Jefferson Medical School.

Dr. Mike Nusbaum and Dr. Jim Weimann (Brandeis PhD, ’92) remembering old times.

Also sighted were: Dr. Andy Christie, PhD ’94 now faculty, Mount Desert Island Marine Labs; Dr. Cyrus Billimoria, PhD, ’05, now Research Faculty Boston U.; Dr. Stefan Pulver, Ph.D. ’09 now postdoc Cambridge U. (UK), Dr. Aryn Gittis (class of ’01), PhD UCSD, now postdoc at Stanford, Dr. Tepring Piquado, Ph.D. ’10, now at UC Irvine, Dr. Raj Stewart, Ph.D ’08, now at Johns Hopkins, Dr. Mark Miller, PhD ’08, now postdoc at UCSF. Other former Brandeis postdocs included Dr. Alfredo Fontanini from the Katz lab and Dr. Arianna Maffei from the Turrgiano lab, now both Asst. Professors at Stony Brook.

Illuminating career paths in the sciences for high school students

On November 5th, the Van Hooser lab in the Biology Department hosted nine high school students from Hyde Park’s Boston Preparatory Charter Public School (BPCPS) for both a tour of the lab and an open question session about the specific goals of the lab’s research, and about science careers in general.

Boston Prep serves students from disadvantaged areas of Boston, with 76% qualifying for free and reduced price lunch and 92% being of minority racial backgrounds. As part of a rigorous educational program that seeks to prepare them for college and beyond, BPCPS sophmores visit various area businesses twice a year for hands-on learning about the careers open to them. The school has been nationally recognized for its academic excellence. It also bucks trends in the sciences — while nationwide there is a noted drop-off in interest in the sciences as students enter high school, particularly among young women,  (Osborne, Simon, and Collins 2003; American Assoc. of University Women, 1992), students at Boston Prep retain a high interest in the sciences throughout their tenure there, and female students actually become more interested in the sciences in high school.

Assistant Professor Steve Van Hooser led the students through a brief introduction to life in an academic science lab and his personal career path, before discussing his lab’s focus on the visual system and the impact that basic research has on everyday life and understanding. The students then took a tour of the lab, and were able to visualize neurons under the lab’s 2-photon microscope. After the visit, Steve noted, “It was terrific to be able to talk with such promising young people and to share a little of the brain science we are doing here at Brandeis.  The students asked really insightful questions about our studies, the use of animals in research, and the clinical applications of basic research.  It is exciting to think about what these students will be doing in 15 years.”

Those interested in hosting a future visit from students can contact Jenn Wolff from the Van Hooser lab (jwolff at, or contact Danielle Pape at BPCPS directly ( dpape at (617)333-6688 ext. 126 )

TNFα Signaling Maintains the Ability of Cortical Synapses to Express Synaptic Scaling

The brain has billions of neurons that receive, analyze, and store information about internal and external conditions, and are highly interconnected. To prevent either hyperexcitability (epilepsy) or hyopexcitability (catatonia) of brain circuits, neurons possess an array of “homeostatic” plasticity mechanisms that serve to stabilize average neuronal firing.

Synaptic scaling is one such form of homeostatic plasticity that acts like a synaptic thermostat, and allows neurons to turn up or down the gain of synaptic transmission to stabilize average activity. The signaling pathways that allow neurons to perform this neat trick are incompletely understood, and it has been controversial whether neurons do this in a cell-autonomous manner, or whether synaptic scaling is induced in response to release of soluble factors such as the pro-inflammatory cytokine TNFα.

A study published this week in Journal of Neuroscience by Brandeis postdoctoral fellow Celine Steinmetz and Professor Gina Turrigiano helps to resolve this controversy by showing that TNFα is not instructive for synaptic scaling, but instead is critical for maintaining  synapses in a plastic state in which they are able to express synaptic scaling. This study suggests that glial cells serve a permissive role in maintaining synaptic plasticity through release of soluble factors such as TNFα, while neurons actively adjust their synaptic thermostat in response to cell-autonomous changes in their own activity.

Connecting with underrepresented minorities in the sciences

For the past six years, Brandeis has been participating yearly at two undergraduate-oriented conferences in an effort to recruit the best minority students for the life sciences graduate programs. These two conferences are: SACNAS (Society for advancing Hispanics/chicanos and Native American in science) and ABRCMS (Annual Biomedical research conference for minority students).

This year SACNAS was held at Anaheim, CA during September 30 and October 3. Professor Jim Morris and 2 graduate students represented Brandeis and interacted with post-docs, graduate students, pre college teachers, undergrads and other 300 exhibitors. The theme of this year conference was Science, Technology & Diversity for a Sustainable Future. In addition, SACNAS combined efforts with MAES (Society for Mexican American engineers and scientists) in order to make the experience more interdisciplinary.

For the past 30 years SACNAS has been holding this conference to enforce the underrepresented minority population in science to pursue advanced degrees, careers, and positions of leadership. A Brandeis SACNAS chapter was created over a year ago, in order to provide information and give access to professional tools to all the undergrads interested in pursuing careers in science. This year, the Brandeis SACNAS chapter was recognized during the meeting as a new chapter, and 9 of our undergraduates participated in the conference; 2 of them Angel Garcia and Kerwin Vega, presented their research in the poster sessions. You can also connect with the Brandeis chapter on Facebook.

– Yaihara Fortis

The Changing Face of Science Reflected in Exciting New Courses

Exciting advances in science are reflected in at least 9 new courses to be offered by the Division of Science. From epigenetics to medicinal enzymology to stem cells to MATLAB, these courses will expose students to some of the frontiers of new knowledge in science.

Details of the courses offered can be found on the following pages

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