activity using light has opened up unprecedented possibilities in the quest of
understanding functionality of the nervous system. Light offers great
advantages over electrophysiology such as: incredible spatial resolution, which
is limited by the diffraction of light, contact-less probing capabilities,
which avoids physical damage and interference with neural activity during
recording, and simultaneous recording from large ensemble of neurons. However,
in order to record an optical signal from a neuron, the electrical signal must
be converted into an optical signal via a molecular reporter. The use of a
reporter to translate the language of the neurons from electrons to photons
currently has two major limitations: photobleaching and photodamage.
In order to
address the above limitations of the current state-of-the-art optical neural
recording devices, we have develop a novel imaging technique which avoids the
use of molecular reporters and relies on the neuron’s intrinsic changes during
an action potential. The main premise for our work is the following: light
reflected from the surface of a neuron is partially linearly polarized and the
degree of linear polarization is a function of neural activity. In order to
capture this neural activity, we have developed polarization sensitive imaging
sensor with high spatial and temporal resolution. In this talk, I will describe
the key components of our imaging system, such as nanofabrication of
sub-wavelength metallic nanostructures acting as linear polarization filters
and monolithic integration of nanostructures with imaging arrays; image
processing algorithms tailored for this new class of sensora and validation of
this imaging technique via in-vivo recording of neural activity from the
antenna lobe of a locust.