Label-free optical detection of action potential in mammalian neurons

Abstract

Abstract:We describe an optical technique for label-free detection of the action potential in cultured mammalian neurons. Induced morphological changes due to action potential propagation in neurons are optically interrogated with a phase sensitive interferometric technique. Optical recordings composed of signal pulses mirror the electrical spike train activity of individual neurons in a network. The optical pulses are transient nanoscale oscillatory changes in the optical path length of varying peak magnitude and temporal width. Exogenous application of glutamate to cortical neuronal cultures produced coincident increase in the electrical and optical activity; both were blocked by application of a Nachannel blocker, Tetrodotoxin. The observed transient change in optical path length in a single optical pulse is primarily due to physical fluctuations of the neuronal cell membrane mediated by a yet unknown electromechanical transduction phenomenon. Our analysis suggests a traveling surface wave in the neuronal cell membrane is responsible for the measured optical signal pulses. Corrected: 25 July 2017 11. M. E. Spira and A. Hai, "Multi-electrode array technologies for neuroscience and cardiology," Nat. Nanotechnol. 8(2), 83-94 (2013). 12. X. Li, W. Zhou, M. Liu, and Q. Luo, "Synchronized spontaneous spikes on multi-electrode array show development of cultured neuronal network," Conf.

Picosecond-resolution phase-sensitive imaging of transparent objects in a single shot

“…By presenting the images of the optical Kerr effect and the shock wave propagation, we have shown that pCUP can be used for studying nonlinear and ultrafast optics, fluids, and shock-matter interactions. Moreover, pCUP holds a great potential to be used for more complex applications including, but not limited to, detecting the shock wave propagation in inertial confinement fusion (31,32), monitoring of the shock waveassisted drug delivery (49), and imaging and modeling of the cellular action potential propagation (33,34).…”

INS-fOCT: a label-free, all-optical method for simultaneously manipulating and mapping brain function

“…15,23,57 The fast temporal part of the fOCT signal might also involve neuronal membrane displacements (or deformations) during stimulation, which has been detected with phase-sensitive interferometric or low-coherence imaging techniques. [24][25][26][58][59][60][61] Typically, nanometer-scale displacements were detected on a millisecond time scale and were thought to be caused by the swelling and shrinkage of the nerve fiber 24,25,60 and neural cell bodies. 58,61 Akkin et al 25 reported that the nerve displacements accompanied fast light scattering changes.…”

“…[24][25][26][58][59][60][61] Typically, nanometer-scale displacements were detected on a millisecond time scale and were thought to be caused by the swelling and shrinkage of the nerve fiber 24,25,60 and neural cell bodies. 58,61 Akkin et al 25 reported that the nerve displacements accompanied fast light scattering changes. More work will be needed to understand the mechanism underlying the fOCT signals associated with the INSevoked neuronal activities.…”

Emerging neurotechnology for antinoceptive mechanisms and therapeutics discovery

“…More recently, label-free methods of optically detecting single action potentials based on minute changes cell membrane deformations (electromotility) via interferometry (Batabyal et al, 2017) or changes in near-membrane protein methyl resonance peaks via vibrational spectroscopic imaging have also been reported (Lee et al, 2017). These methods offer the advantages of reduced phototoxicity, no risk of photobleaching, and high temporal resolution as compared to calcium imaging.…”