Biology subjects

Graff, P. S.

Publications and source records attributed to Graff, P. S..

2 recordsLinked to original sources

bioRxiv2024

Flexible 3D kirigami probes for in vitro and in vivo neural applications

Three-dimensional (3D) microelectrode arrays (MEAs) are gaining popularity as brain-machine interfaces and platforms for studying electrophysiological activity. Interactions with neural tissue depend on the electrochemical, mechanical, and spatial features of the recording platform. While planar or protruding two-dimensional MEAs are limited in their ability to capture neural activity across layers, existing 3D platforms still require advancements in manufacturing scalability, spatial resolution, and tissue integration. In this work, we present a customizable, scalable, and straightforward approach to fabricate flexible 3D kirigami MEAs containing both surface and penetrating electrodes, designed to interact with the 3D space of neural tissue. These novel probes feature up to 512 electrodes distributed across 128 shanks in a single flexible device, with shank heights reaching up to 1 mm. We successfully deployed our 3D kirigami MEAs in several neural applications, both in vitro and in vivo, and identified spatially dependent electrophysiological activity patterns. Flexible 3D kirigami MEAs are therefore a powerful tool for large-scale electrical sampling of complex neural tissues while improving tissue integration and offering enhanced capabilities for analyzing neural disorders and disease models where high spatial resolution is required.

neuroscience↗

bioRxiv2024

Ongoing activation of visual cortex and superior colliculus in the rd10 mouse model of retinitis pigmentosa

Efforts in vision restoration have been focused on a condition called Retinitis Pigmentosa, where photoreceptors in the retina degenerate while the rest of the visual pathway remain mostly intact. Retinal implants that replace the phototransduction process by stimulating retinal ganglion cells have shown promising but limited results in patients so far. Apart from technical limitations, cross-modal plasticity of visual areas might contribute to this problem. We therefore investigated if the primary visual cortex (V1) of the rd10 mouse model for retinal degeneration became more sensitive to auditory or tactile sensory inputs, potentially hindering retinal stimulation. After reaching complete blindness confirmed by the lack of optomotor responses, activity in visual cortex and superior colliculus (SC) was recorded using Neuropixels probes. While we could not find any significant differences in tactile or auditory responses compared to wildtype mice, the local field potential revealed distinct oscillatory events (0.5 - 6 Hz) in V1 and SC resembling previously observed aberrant activity in the retina of rd10 mice. Further absence of cross-modal plasticity was confirmed by a lacking increase in zif268 expression in V1 after tactile stimulation. We therefore propose that aberrant retinal activity is transmitted to higher visual areas where it prevents cross-modal changes.

neuroscience↗