My lab uses advanced imaging techniques to study the structure and function of single cells in networks in the intact brain. Although a vast literature describes the development and function of neuronal connectivity, most of this work has been carried out in culture and excised or fixed tissue, where dynamic processes are inferred from static images compared across animals. Little is known about the function of subcellular compartments in the computations carried out by neurons in vivo. The goal of our work is to understand structural and functional changes occurring at synapses during plasticity elicited by sensory stimuli.

My specific interests lie in understanding how visual activity shapes the structure and function of connections between neurons in the visual cortex. During the critical period, closure of one eye leads to a shift in the responses of neurons towards the open eye. My labs current work focuses on the structural basis for this rapid ocular dominance plasticity using in vivo two-photon microscopy to elucidate single cell structure deep in the intact brain. Dendritic spines are the postsynaptic structures of most excitatory synapses in the CNS. Interestingly, spine structure is highly dynamic making the precise morphology of the spine a possible candidate for the coding of synaptic strength. By combining structural two-photon imaging with functional intrinsic signal imaging in the ferret and mouse, we can correlate changes in synaptic structure with changes in response properties of the visual cortex. These experiments have shown increased spine motility as well as increased spine and axon terminal turnover following even one day of monocular deprivation. These synaptic changes occur in the absence of changes in gross dendritic or axonal structure, suggesting that fine scale changes in synaptic connectivity underlie rapid ocular dominance plasticity without an overall remodeling of the pre and postsynaptic scaffold.

My lab is also interested in the mechanisms which underlie structural remodeling at synapses. Imaging carried out in reduced preparations such as the acute brain slice allows us to explore the contributions of different pathways to structural plasticity. Our work has shown that both intracellular pathways and the extracellular matrix are involved in the remodeling of the spine during synaptic plasticity.

Journal Articles

Majewska AK, Newton JR, Sur M. (2006)Remodeling of synaptic structure in sensory cortical areas in vivo.
J Neurosci. 2006 Mar 15;26(11):3021-9.

Oray, S., Majewska, A., Sur, M. (2006) Effects of synaptic activity on dendritic spine motility of developing cortical layer 5 pyramidal neurons. Cerebral Cortex. 2006 May;16(5):730-41.

Oray, S., Majewska, A., Sur, M. (2004) Dendritic spine dynamics are regulated by monocular deprivation and extracellular matrix degradation. Neuron 44:1021-30.

Majewska, A., Sur, M. (2003) Motility of dendritic spines in visual cortex in vivo: changes during the critical period and effects of visual deprivation. Proc. Natl. Acad. Sci. 100(26):16024-9.

Yuste, R., Majewska, A. (2001) On the function of dendritic spines. The Neuroscientist. 75:387-395.

Book Chapters

Brown, E., Majewska, A., Jain, R. K. (2005) Photobleaching and Recovery with Nonlinear Microscopy. In: Handbook of Biological Nonlinear Optical Microscopy. Oxford University Press, Oxford UK. Eds: So P., Masters B. in press

Newton, J.R., Majewska, A., Ellsworth, C., Sur, M. (2005) Reprogramming cortex: the consequences of cross-modal plasticity during development. In: Reprogramming the cerebral cortex, ed., S. Lomber and J. Eggermont. In press

Brown, E., Majewska, A., and Jain, R.K.  (2005) Single and Multiphoton FRAP. In: Yuste R. and Konnerth A., eds. Imaging in Neuroscience and Development: A Laboratory Manual. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York.