People / Reijmers Laboratory

Leon Reijmers, Ph.D.
Assistant Professor
Department of Neuroscience
136 Harrison Ave - Stearns 328B
Boston, MA 02111
Phone: (617) 636-0301
Fax: (617) 636-2413
Leon.Reijmers@tufts.edu

Search for recent publications by Leon Reijmers

Research Interests

The lab studies how a neuronal network can store a memory. Transgenic mice are used to tag neurons that are activated during memory encoding. The tag can be used to image, analyze and manipulate these neurons. For example, tagged neurons can be analyzed for changes in gene expression, thereby elucidating molecular mechanisms of memory encoding. Also, tagged neurons can be selectively manipulated in order to control behavioral expression of a memory.

One of the transgenic mice used in the lab is called the TetTag mouse. TetTag stands for “Tet”racycline controlled “Tag”ging of activated neurons. The mouse can translate the transient activation of the c-fos promoter sequence during memory encoding into long-lasting expression of a reporter gene. After behavioral analysis in a memory test, neurons activated during memory formation can be visualized using immunohistochemistry. The first study with the TetTag mouse localized neurons in the amygdala that encode a fear memory (Reijmers et al., Science 317, 1230-1233, 2007).

For future studies, the TetTag mouse will be used to further analyze tagged neurons using genomic and proteomic approaches. The aim is to detect dynamic changes within selected neurons after they are recruited to encode a memory. The chance of detecting these changes is significantly increased by using the TetTag mouse, because it enables a selective analysis of neurons defined by function instead of spatial proximity.

A major advantage of the TetTag mouse is its potential to manipulate a functional neuronal circuit. The aim is to control behavioral expression of a memory. This can be achieved by upgrading the TetTag mouse with TetO regulated genes that can change the firing properties of tagged neurons. For example, genetically encoded receptors will be used to reversibly activate or silence neurons. These receptors include both light and ligand activated channels that allow for control of neuronal activity with high spatial and temporal resolution.

Lab Members

Josh Ainsley, Ph.D. - Postdoctoral Associate

Selected Publications

N. Matsuo, L.G. Reijmers, M. Mayford (2008). Spine-type specific recruitment of newly synthesized AMPA receptors with learning. Science, 319, 1104-1107

L.G. Reijmers, B.L. Perkins, N. Matsuo, M. Mayford (2007). Localization of a stable neural correlate of associative memory. Science 317, 1230-1233

L.G. Reijmers, J.K. Coats, M.T. Pletcher, T. Wiltshire, L.M. Tarantino, M. Mayford (2006). A mutant mouse with a highly specific contextual fear-conditioning deficit found in an N-ethyl-N-nitrosourea (ENU) mutagenesis screen. Learning and Memory 13, 143-149

J.C. Von Frijtag, A. Kamal, L.G. Reijmers, L.H. Schrama, R. van den Bos, B.M. Spruijt (2001). Chronic imipramine treatment partially reverses the long-term changes of hippocampal synaptic plasticity in socially stressed rats. Neuroscience Letters 309, 153-156

L.G. Reijmers, K. Hoekstra, J.P. Burbach, J.M. van Ree, B.M. Spruijt (2001). Long-term impairment of social memory in the rat after social defeat is not restored by desglycinamide-vasopressin. Neuroscience Letters 305, 145-148

L.G. Reijmers, J.M. van Ree, B.M. Spruijt, J.P. Burbach, D. De Wied (1998). Vasopressin metabolites: a link between vasopressin and memory? Progress in Brain Research 119, 523-535

L.G. Reijmers, P.M. Vanderheyden, B.W. Peeters (1995). Changes in prepulse inhibition after local administration of NMDA receptor ligands in the core region of the rat nucleus accumbens. European Journal of Pharmacology 272, 131-138