Biology subjects

Suminski, A. J.

Publications and source records attributed to Suminski, A. J..

3 recordsLinked to original sources

bioRxiv2019

A Truly Injectable Neural Stimulation Electrode Made From an In-Body Curing Polymer/Metal Composite

Implanted neural stimulation and recording devices hold vast potential to treat a variety of neurological conditions, but the invasiveness, complexity, and cost of the implantation procedure greatly reduce access to an otherwise promising therapeutic approach. To address this need, we have developed a novel electrode that begins as an uncured, flowable pre-polymer that can be injected around a neuroanatomical target to minimize surgical manipulation. Referred to as the Injectrode, the electrode conforms to target structures forming an electrically conductive interface which is orders of magnitude less stiff than conventional neuromodulation electrodes. To validate the Injectrode, we performed detailed electrochemical and microscopy characterization of its material properties and validated the feasibility of using it to electrically stimulate the nervous system in rats and swine. The silicone-metal-particle composite performed very similarly to pure wire of the same metal (silver) in all measures, including exhibiting a favorable cathodic charge storage capacity (CSCC) and charge injection limits compared to the clinical LivaNova stimulation electrode and silver wire electrodes. By virtue of being simpler than traditional electrode designs, less invasive, and more cost-effective, the Injectrode has the potential to increase the adoption of neuromodulation therapies for existing and new indications.

bioengineering↗

bioRxiv2019

μECoG Recordings Through a Thinned Skull

The studies described in this paper for the first time characterize the acute and chronic performance of optically transparent thin-film {micro}ECoG grids implanted on a thinned skull as both an electrophysiological complement to existing thinned skull preparation for optical recordings/manipulations, and a less invasive alternative to epidural or subdurally placed {micro}ECoG arrays. In a longitudinal chronic study, {micro}ECoG grids placed on top of a thinned skull maintain impedances comparable to epidurally placed {micro}ECoG grids that are stable for periods of at least one month. Optogenetic activation of cortex is also reliably demonstrated through the optically transparent ECoG grids acutely placed on the thinned skull. Finally, spatially distinct electrophysiological recordings were evident on {micro}ECoG electrodes placed on a thinned skull separated by 500-750{micro}m, as assessed by stimulation evoked responses using optogenetic activation of cortex as well as invasive and epidermal stimulation of the sciatic and median nerve at chronic time points. Neural signals were collected through a thinned skull in multiple species, demonstrating potential utility in neuroscience research applications such as in vivo imaging, optogenetics, calcium imaging, and neurovascular coupling.

neuroscience↗

bioRxiv2019

Propagating patterns of activity across motor cortex facilitate movement initiation

Voluntary movement initiation involves the modulation of neurons in the primary motor cortex (M1) around movement onset. Yet, similar modulations of M1 activity occur during movement planning when no movement occurs. Here, we show that a sequential spatio-temporal pattern of excitability based on beta oscillation amplitude attenuation propagates across M1 prior to the initiation of reaching movements in one of two oppositely oriented directions along the rostro-caudal axis. Using spatiotemporal patterns of intracortical microstimulation, we find that reaction time increases significantly when stimulation is delivered against but not with the natural propagation orientation suggesting that movement initiation requires a precise recruitment pattern in M1. Functional connections among M1 units emerge at movement onset that are oriented along the same rostro-caudal axis but not during movement planning. Finally, we show that beta amplitude profiles can more accurately decode muscle activity when these patterns conform to the natural propagating patterns. These findings provide the first causal evidence that large-scale, spatially organized propagating patterns of cortical excitability and activity are behaviorally relevant and may be a necessary component of movement initiation.

neuroscience↗