Hanein, Y. | Search bioRxiv

bioRxiv2022

A new high-resolution three-dimensional retinal implant: System design and preliminary human results

The NR600 retinal prosthetic device is a unique newly developed implant intended to restore visual perception to people who lost their vision due to retinal degenerative diseases. The miniature implant captures the visual image in place of the damaged photoreceptor cells and creates the electrical stimulation required to activate the preserved retinal cell layers. The NR600 system transduces visual signal into electrical signals that are delivered to the retina via an array of needle shaped electrodes to minimize electrical activation levels and improve stimulation localization. NR600 consists of two components: A miniature implantable chip and eyeglasses set worn by the patient. The eyeglasses deliver power and control the implantable device. In this report, we present the NR600 system design, its optical, electrical, and electro-chemical characteristics, and preliminary results from human subjects.

bioengineering↗

bioRxiv2018

The emergence of dynamical instantaneous memory in the spontaneous activity of spatially confined neuronal assemblies in vitro

Understanding the dynamics between communicating cell assemblies is essential for deciphering the neural code and identifying the mechanism underlying memory formation. In this work, in order to unveil possible emergent intrinsic memory phenomena in the communication between cell assemblies, we study the spontaneous dynamics of in vitro spatially confined inter-connected neuronal circuits grown on multi-electrode arrays. The spontaneous dynamics of the global network was characterized by the coupling of the activity independently generated by each circuit. The asymptotic functional connectivity of the network reflected its modular organization. Instantaneous functional connectivity maps on ten seconds epochs, revealed more complex dynamical states with the simultaneous activation of distinct circuits. When looking at the similarity of the generated network events, we observed that spontaneous network events occurring at temporal distances below two dozens of seconds had an average higher similarity compared to randomly played network events. Such a memory phenomenon was not observed in networks where spontaneous events were less frequent and in networks topologically organized as open lines. These results support the hypothesis that dynamical instantaneous memory, characterized by drifting network dynamics with decaying degree of similarity, is an intrinsic property of neuronal networks.

neuroscience↗