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Juan Marcos Alarcon, PhD

Assistant Professor

Department of Pathology, Division of Neuroscience

Office location: 4-113

Lab Tel: (718) 221- 5325

Office Tel:(718)613-8348

Fax: (718) 270-3313

e-mail: juanmarcos.alarcon@downstate.edu

 

 

 

 

 

Research Interest Summary

Synaptic Plasticity, Encoding, Learning and Memory

Modern physiological and molecular biological studies have shown that enduring changes in synaptic efficacy, a process known as synaptic plasticity, is a fundamental neuronal process underlying various forms of learning and memory. Research in this area has provided useful insights into how the expression of a given type of synaptic plasticity modulates and perhaps reconfigures the activity of the neural network in which this occurs. In the brain most neurons receive multiple synaptic inputs which are potentially capable of inducing synaptic plasticity. This raises a question central to an understanding of how information is processed and stored within a given neuronal circuit, i.e., how are two or more forms of synaptic plasticity integrated at the level of a single neuron? Our work focuses on an examination of the functional properties of the interaction between distinct forms of synaptic plasticity elicited within a neuron. A neuron expressing multiple forms of synaptic plasticity might selectively encode new incoming information and, thus, dramatically modulate both the way that it filters relevant from irrelevant information as well as the way that it exports this information to other cells. We are initially addressing these questions by examining the interaction between distinct forms of synaptic plasticity elicited in different dendritic compartments within the CA1 area of the rodent hippocampus via electrophysiological determinations in vitro slices. Specifically, we ask:

1) How does a neuron integrate various forms of synaptic plasticity elicited in multiple synapses?

2) What are the cellular and molecular mechanisms underlying this process?

3) What impact does this process have on signal integration at neuronal and network level?

4) And, most importantly, is this process relevant for the encoding of memories?

We expect to obtain insights into the functional significance of specific synaptic plasticity associations or interactions between synaptic inputs arriving from different brain regions. The understanding of the rules that result in the prevalence or dismissal of certain forms of synaptic plasticity within a neuron could provide additional insights into the cellular basis of learned behavior.

Left: Cartoon of slice preparation and major afferent inputs. DG, dentate gyrus. SO, stratum oriens; SR, stratum radiatum; SLM, stratum lacunosum moleculare. Right: Photomicrograph of CA1 area. SR, stratum radiatum; SP, stratum pyramidale; re, recording electrode; se, stimulating electrode

 

 

More about my projects

- Compartmentalized Synaptic Plasticity in the Hippocampus

- A Theoretical Approach to Synaptic Plasticity Compartmentalization

- Synaptic Plasticity Correlates of the Hippocampal Spatial Map

 

Selected Publications

  1. Zearfoss, N.R., Alarcon, J.M., Trifilieff, P., Kandel, E, and Richter, J.D. A molecular circuit composed of CPEB-1 and c-Jun controls growth hormone-mediated synaptic plasticity in the mouse hippocampus. J. Neurosci. 2008; 28(34):8502-09.
  2. Nicholls, R.E., Alarcon, J.M., Malleret, G., Vronskaya, S., Grody, M.B. and Kandel, E.R. Transgenic mice lacking NMDAR-dependent LTD exhibit deficits in behavioral flexibility. Neuron2008; 58(1):104-17.
  3. Barco A., Lopez de Armentia M, and Alarcon JM. Synapse-specific stabilization of plasticity processes: The synaptic tagging and capture hypothesis revisited ten years later. Neuroscience & Biobehavioral Reviews 2008; 32(4):831-851.
  4. Etkin A, Alarcón JM, Weisberg S.P, Touzani K, Huang Y-Y, Nordheim A and Kandel E.R. A role in learning for SRF: deletion in the adult forebrain disrupts LTD and the formation of an immediate memory of a novel context. Neuron2006;50(1):127-143.
  5. Alarcon JM, Barco A and Kandel E.R. Capture of L-LTP within and across the apical and basilar dendritic compartments of CA1 pyramidal neurons: synaptic tagging is compartment restricted. J. Neurosci. 2006; 26(1):256-64.
  6. Alarcon, JM, Brito, JA, Hermosilla, T, Atwater, I, Mears, D. and Rojas E. Ion Channel Formation by Alzheimer’s Disease Amyloid b-Peptide (Ab40) in Unilamellar Liposomes is Determined by Anionic Phospholipids. Peptides 2006;27(1):95-104.
  7. Alarcon JM, Malleret M, Vronskava S, Ishii, S, Kandel E.R. and Barco A. Chromatin Acetylation, Memory, and LTP are Impaired in CBP+/- Mice: A Model for Cognitive Deficit in Rubinstein-Taybi Syndrome and for Its Amelioration. Neuron2004; 42: 947-959.
  8. Alarcon JM, Hodgman R, Theis M, Huang Y-S, Kandel E.R. and Richter J.D. Selective modulation of some forms of Schaffer collateral-CA1 synaptic plasticity in mice with a disruption of the CPEB-1 gene. Learning & Memory 2004; 11:318-327.
  9. Barco A, Alarcon JM, Kandel ER. Expression of constitutively active CREB protein facilitates the late phase of long-term potentiation by enhancing synaptic capture. Cell 2002; 108(5): 689-703.

 

Education and Training

1993 - BSc/MSc in Biology, University of Concepcion, Chile

1999 - Ph.D. in Biomedical Sciences, University of Chile, Chile

2000-2004 - Post-doctotoral Fellow,  Center for Neurobiology and Behavior, Columbia University

2005-2007 - Associate Research Scientist, Center for Neurobiology and Behavior, Columbia University

 

Honors and Awards

PEW Latin American Program in the Biomedical Sciences. Postdoctoral Fellow (2000-2001).