QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

The Journal of Neuroscience, February 11, 2009, 29(6):1719-1734; doi:10.1523/JNEUROSCI.4249-08.2009

This Article Full Text Full Text (PDF) Supplemental Data Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Brown, C. E. Articles by Murphy, T. H. Search for Related Content PubMed PubMed Citation Articles by Brown, C. E. Articles by Murphy, T. H.

 Previous Article  |  Next Article 

Development/Plasticity/Repair
In Vivo Voltage-Sensitive Dye Imaging in Adult Mice Reveals That Somatosensory Maps Lost to Stroke Are Replaced over Weeks by New Structural and Functional Circuits with Prolonged Modes of Activation within Both the Peri-Infarct Zone and Distant Sites

Craig E. Brown,¹ Khatereh Aminoltejari,¹ Heidi Erb,¹ Ian R. Winship,² and Timothy H. Murphy¹

¹Department of Psychiatry, Brain Research Center, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3, and ²Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada T6G 2R7

Correspondence should be addressed to Dr. Timothy H. Murphy, 4N1-2255 Wesbrook Mall, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3. Email: thmurphy{at}interchange.ubc.ca

After brain damage such as stroke, topographically organized sensory and motor cortical representations remap onto adjacent surviving tissues. It is conceivable that cortical remapping is accomplished by changes in the temporal precision of sensory processing and regional connectivity in the cortex. To understand how the adult cortex remaps and processes sensory signals during stroke recovery, we performed in vivo imaging of sensory-evoked changes in membrane potential, as well as multiphoton imaging of dendrite structure and tract tracing. In control mice, forelimb stimulation evoked a brief depolarization in forelimb cortex that quickly propagated to, and dissipated within, adjacent motor/hindlimb areas (<100 ms). One week after forelimb cortex stroke, the cortex was virtually unresponsive to tactile forelimb stimulation. After 8 weeks recovery, forelimb-evoked depolarizations reemerged with a characteristic pattern in which responses began within surviving portions of forelimb cortex (<20 ms after stimulation) and then spread horizontally into neighboring peri-infarct motor/hindlimb areas in which depolarization persisted 300–400% longer than controls. These uncharacteristically prolonged responses were not limited to the remapped peri-infarct zone and included distant posteromedial retrosplenial cortex, millimeters from the stroke. Structurally, the remapped peri-infarct area selectively exhibited high levels of dendritic spine turnover, shared more connections with retrosplenial cortex and striatum, and lost inputs from lateral somatosensory cortical regions. Our findings demonstrate that sensory remapping during stroke recovery is accompanied by the development of prolonged sensory responses and new structural circuits in both the peri-infarct zone as well as more distant sites.

Key words: stroke; plasticity; somatosensory cortex; dendritic spine; motor cortex; membrane potential

---

Received Sept. 3, 2008; revised Dec. 17, 2008; accepted Jan. 7, 2009.

Correspondence should be addressed to Dr. Timothy H. Murphy, 4N1-2255 Wesbrook Mall, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3. Email: thmurphy{at}interchange.ubc.ca

This article has been cited by other articles:

				I. R. Winship and T. H. Murphy Remapping the Somatosensory Cortex after Stroke: Insight from Imaging the Synapse to Network Neuroscientist, October 1, 2009; 15(5): 507 - 524. [Abstract] [PDF]

				A. Sigler, M. H. Mohajerani, and T. H. Murphy Imaging rapid redistribution of sensory-evoked depolarization through existing cortical pathways after targeted stroke in mice PNAS, July 14, 2009; 106(28): 11759 - 11764. [Abstract] [Full Text] [PDF]

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help