This PDF file contains the front matter associated with SPIE Proceedings Volume 11947, including the Title Page, Copyright information, Table of Contents, and Conference Committee listings.

We apply the NEURON programming environment to simulate how spatially varying heating profiles would impact the temperature differentials needed for infrared neural manipulation. Relative to a single heated zone, using multiple short heated zones along the simulated axon reduced the minimum temperature difference (ΔT) required for neural inhibition, but increased ΔT required for neural stimulation. These changes are mediated by an increase in potassium current density related to the change in temperature along the axon (dT/dx). This increase in potassium current aids in silencing propagating action potentials in the case of inhibition, but hinders a new action potential from being generated in the case of stimulation. Alterations in simulated gating variables underlie the increased potassium current density, and suggest the more frequent changes in dT/dx—associated with cyclic heating—enhance the probability of potassium channels opening. By exploring the role heating patterns can have on neural manipulation, more effective infrared systems can be designed to modulate neural behavior while minimizing the potential for thermal damage.

To study the brain and the related neuronal network activity, many attempts were made to design and develop platforms able to induce and record neuronal signals. However, many brain processes - like memory formation and storage - and diseases - like amnesia or epilepsy - need more basic studies. For these, a bottom-up approach is needed, starting from 2D in-vitro neuronal cultures. In this work, we will present two experimental systems able to optogenetically interact with 2D neuronal networks with patternized light. One system consists in a Digital Light Projector (DLP) integrated in a microscope setup, which can illuminate neurons from the top; the other, is a compact and transportable photonic chip, properly designed to illuminate neurons plated on its surface.

A novel CGH algorithm is proposed for targeted neural stimulation using a few pixel Spatial Light Modulator (SLM) device. This is achieved with the elaboration of standard CGH design algorithms to include a regularized cost function for the discretization of phase and amplitude. The regularized cost function is appropriate for designing holographic masks that can be realized using a few pixel SLM. It is anticipated that these results will contribute to the research efforts towards a portable in vivo optogenetic system.