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Background: The EEG technique has decades of valid applications in clinical and experimental neurophysiology. EEG equipment and data analysis methods have been characterized by remarkable developments, but the skin-to-electrode signal transfer remains a challenge for EEG recording.New method: A novel quasi-dry system - the polymer wick-based electrode - was developed to overcome the limitations of conventional dry and wet silver/silver-chloride (Ag/AgCl) electrodes for EEG recording.Results: Nine participants completed an auditory oddball protocol with simultaneous EEG acquisition using both the conventional Ag/AgCl and the wick electrodes. Wick system successfully recorded the expected P300 modulation.Comparison with existing method(s): Standard ERP analysis, residual random noise analysis, and single trial analysis of the P300 wave were performed in order to compare signal acquired by both electrodes. It was found that the novel wick electrode performed similarly to the conventional Ag/AgCl electrodes.Conclusions: The developed wick electrode appears to be a reliable alternative for EEG research, representing a promising halfway alternative between wet and dry electrodes. (C) 2016 Elsevier B.V. All rights reserved., This research is partially sponsored by the Foundation for Science and Technology (COMPETE Program) under the individual fellowship (SFRH/BD/93831/2013), the projects FCOMP-01-0124-FEDER-010190 (Ref. PTDC/SAU-ENB/116850/2010) and UID/CTM/50025/2013 and the European Union, FP7-PEOPLE Marie Curie IAPP project, grant number 610950., info:eu-repo/semantics/publishedVersion

Background An unfavourable yet necessary side-effect of stereotaxic surgery involves the social isolation of post-surgery rats, in order to protect their wound site or skull-mounted implant from damage. Social isolation can cause a myriad of behavioural and physiological changes that are detrimental to the well-being of rats, with potential negative implications for a range of experimental paradigms. New method . Female Sprague Dawley rats ( n = 40) were implanted onto the skull with a novel 3D-printed headstage socket that surrounded an electrode connector. The socket accommodated a removable stainless-steel headcap for the purposes of protecting the implant. Rats were pair-housed following surgery, and their behaviour was monitored for up to several weeks under two experimental conditions that involved EEG recording and deep-brain stimulation, as well as behavioural test sessions inside an open-field maze. Rat weights were compared between individually- and pair-housed rats at up to 3 weeks post-surgery. Results These experiments were successfully carried out using pair-housed rats, with no damage or complications observed regarding the implant and its headcap. Rats were able to carry out a range of normal behaviours including running, grooming, foraging and sleeping. Compared to individually-housed rats, pair-housed rats gained less weight over the 3 weeks post-implantation period. Comparison with existing method(s) . This method offers additional protection compared to group-housed post-surgical rats that lack the protective headcap. It is also potentially more practical and versatile than a fully-implantable device for the safe post-surgery group housing of rodents. Conclusions This implant design can reduce the cost of rodent upkeep, whilst potentially avoiding a myriad of behavioural and physiological changes that are known to result from social isolation.

Transmeningeal pharmacotherapy for cerebral cortical disorders requires drug delivery through the subdural/subarachnoid space, ideally with a feedback controlled mechanism. We have developed a device suitable for this function. The first novel component of the apparatus is a silicone rubber strip equipped with (a) fluid-exchange ports for both drug delivery and local cerebrospinal fluid (CSF) removal, and (b) EEG recording electrode contacts. This strip can be positioned between the dura and pia maters. The second novel component is an implantable dual minipump that directs fluid movement to and from the silicone strip and is accessible for refilling and emptying the drug and CSF reservoirs, respectively. This minipump is regulated by a battery-powered microcontroller integrating a bi-directional radiofrequency (RF) communication module. The entire apparatus was implanted in 5 macaque monkeys, with the subdural strip positioned over the frontal cortex and the minipump assembly secured to the cranium under a protective cap. The system was successfully tested for up to 8 months for (1) transmeningeal drug delivery using acetylcholine (ACh) and muscimol as test compounds, (2) RF-transmission of neocortical EEG data to assess the efficacy of drug delivery, and (3) local CSF removal for subsequent diagnostic analyses. The device can be used for (a) monitoring neocortical electrophysiology and neurochemistry in freely behaving nonhuman primates for more than 6 months, (b) determining the neurobiological impact of subdural/subarachnoid drug delivery interfaces, (c) obtaining novel neuropharmacological data on the effects of central nervous system (CNS) drugs, and (d) performing translational studies to develop subdural pharmacotherapy devices.