Postnatal maturation of cortical microcircuit function in barrel cortex

• Applicant: Professor Dr. Fritjof Helmchen
• Subject Area: Molecular Biology and Physiology of Neurons and Glial Cells
• Term: from 2010 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 141272880

• Final Report Year: 2016

Final Report Abstract

Based on the technical difficulties and limitations encountered in the first funding period 2010-2013, we shifted our focus from chronic to acute in vivo two-photon calcium imaging of neuronal activity in the neocortex of juvenile mice. Using classic synthetic calcium indicators, we established in vivo two-photon calcium imaging of spontaneous and sensory-evoked activity in mice between postnatal day 10 (P10) and P28. For sensory stimulation, we developed a novel stimulation system to probe sensory coding during development (applying lateral deflections and axial ‘tapping’). Employing in vivo two-photon calcium imaging as well as multi-electrode recordings (in collaboration with the group of Heiko Luhmann, University of Mainz), we characterized the responses to whisker deflections of barrel cortex neurons in anesthetized mice between P10 to P28, resulting in a submitted manuscript, now under review at Cerebral Cortex. Moreover, we further extended our collaboration with the Luhmann group and carried out a collaborative project to study sensory-evoked activity in juvenile barrel cortex with silicon-probes. We collected a comprehensive data set regarding the amplitude-dependence, the adaptation behavior, and the cross-barrel spread of whiskerevoked responses during postnatal development. The results of this second project are currently written up as a manuscript to be submitted soon. Together, the results of these two collaborative studies within the BaCoFun consortium represent a highly valuable experimental data set and provide significant insights with respect to the layer-specific maturation of sensory coding in barrel cortex during development.

Publications

• (2013) Barrel cortex function, Prog Neurobiol. 103:3-27
  Feldmeyer D, Brecht M, Helmchen F, Petersen CC, Poulet JF, Staiger JF, Luhmann HJ, Schwarz C
  
• (2013) Behavior-dependent recruitment of longrange projection neurons in somatosensory cortex, Nature 499,336–340
  Chen J, Carta S, Schneider B, Helmchen F
  
• (2013) Online correction of lickinginduced brain motion during two-photon imaging with a tunable lens. Journal of Physiology 591(19):4689-98
  Chen JL, Pfäffli OA, Voigt FF, Margolis DJ, Helmchen F
  
• (2014) Tactile frequency discrimination is enhanced by circumventing neocortical adaptation. Nature Neuroscience, 17(11):1567-73
  Musall S, von der Behrens W, Mayrhofer JM, Weber B, Helmchen F, Haiss F
  
• (2015) Pathway-specific reorganization of projection neurons in somatosensory cortex during learning. Nature Neuroscience, 18(8):1101-8
  Chen JL, Margolis DJ, Stankov A, Sumanovski LT, Schneider BL, Helmchen F
  
• (2015) Sparse, reliable, and long-term stable representation of periodic whisker deflections in the mouse barrel cortex. Neuroimage, 115:52-63
  Mayrhofer JM, Haiss F, Helmchen F, Weber B
  
• (2016) Layer-specific refinement of sensory coding in developing mouse barrel cortex. Cerebral Cortex
  van der Bourg A, Yang J-W, Reyes-Puerta V, Laurenczy B, Wieckhorst M, Stüttgen MC, Luhmann HJ, Helmchen F
  
• (2016) Long-range population dynamics of anatomically defined neocortical networks. Elife, pii: e14679
  Chen JL, Voigt FF, Javadzadeh M, Krueppel R, Helmchen F