The Influence of Vagus Nerve and Spinal Cord Stimulation on the Ictal Fast Ripple Activity in a Spike-and-Wave Rat Model of Seizures

Single-interface bioelectronic medicines - concept, clinical applications and preclinical data

Presently, large groups of patients with various diseases are either intolerant, or irresponsive to drug therapies and also intractable by surgery. For several diseases, one option which is available for such patients is the implantable neurostimulation therapy. However, lacking closed-loop control and selective stimulation capabilities, the present neurostimulation therapies are not optimal and are therefore used as only "third" therapeutic options when a disease cannot be treated by drugs or surgery. Addressing those limitations, a next generation class of closed-loop controlled and selective neurostimulators generically named bioelectronic medicines seems within reach. A sub-class of such devices is meant to monitor and treat impaired functions by intercepting, analyzing and modulating neural signals involved in the regulation of such functions using just one neural interface for those purposes. The primary objective of this review is to provide a first broad perspective on this type of single-interface devices for bioelectronic therapies. For this purpose, the concept, clinical applications and preclinical studies for further developments with such devices are here analyzed in a narrative manner.

Electrical stimulation in animal models of epilepsy: A review on cellular and electrophysiological aspects

Epilepsy is a debilitating condition, primarily refractory individuals, leading to the search for new efficient therapies. Electrical stimulation is an important method used for years to treat several neurological disorders. Currently, electrical stimulation is used to reduce epileptic crisis in patients and shows promising results. Even though the use of electricity to treat neurological disorders has grown worldwide, there are still many caveats that must be clarified, such as action mechanisms and more efficient stimulation treatment parameters. Thus, this review aimed to explore the comprehension of the main stimulation methods in animal models of epilepsy using rodents to develop new experimental protocols and therapeutic approaches.

A New Rat Model of Seizures Suitable for Screening Antiepileptic Electrical Stimulation Therapies

The antiepileptic effects of the electrical stimulation therapies developed for patients with intractable epilepsies depend critically on the stimulation parameters, including the pulse duration, current, and frequency. Consequently, optimization of such therapies requires many animals for testing each of the stimulation parameters alone or in combination, which is costly and time consuming. This drawback could be reduced by testing several stimulation paradigms in each animal, but this requires an animal model of long-lasting seizures allowing such repetitive tests. This study was performed to validate such a model of long-lasting seizures. The present analysis was performed on electrocorticogram and intracortical signals collected from the somatosensory cortex of 11 Sprague Dawley rats. A protocol of controlled intravenous infusion of pentylenetetrazol (PTZ) was developed to induce spike-and-wave (SW) seizures and maintain stable those seizures for the whole experimental time. SW discharges were induced and maintained stable for 2 h in all rats through a two-stage infusion of PTZ. During the first stage, the SW discharges were induced by 2.5 min infusion of 10 mg/kg/min PTZ. During the second stage, the SW discharges were maintained at a stable level of frequency and power for 2 h via a 0.21 mg/kg/min PTZ infusion rate. The proposed animal model of seizures is characterized by SW discharges which remain stable for 2 h. This 2-h long time interval allows repetitive tests with different stimulation parameters in each animal, which may lead to a significant reduction of the number of animals necessary for optimizing electrical stimulation therapies developed to inhibit seizures.