Functional Electrochemistry: On-Nerve Assessment of Electrode Materials for Electrochemistry and Functional Neurostimulation.

Emerging therapies in bioelectronic medicine highlight the need for deeper understanding of electrode material performance in the context of tissue stimulation. Electrochemical properties are characterized on the benchtop, facilitating standardization across experiments. On-nerve electrochemistry differs from benchtop characterization and the relationship between electrochemical performance and nerve activation thresholds are not commonly established.

Development of an acute ovine model of polycystic ovaries to assess the effect of ovarian denervation.

Introduction: Polycystic ovary syndrome (PCOS) seems to be associated with increased ovarian sympathetic nerve activity and in rodent models of PCOS reducing the sympathetic drive to the ovary, through denervation or neuromodulation, improves ovulation rate. We hypothesised that sympathetic nerves work with gonadotropins to promote development and survival of small antral follicles to develop a polycystic ovary phenotype.

Methods: Using a clinically realistic ovine model we showed a rich sympathetic innervation to the normal ovary and reinnervation after ovarian transplantation.

Human-relevant near-organ neuromodulation of the immune system via the splenic nerve.

Neuromodulation of immune function by stimulating the autonomic connections to the spleen has been demonstrated in rodent models. Consequently, neuroimmune modulation has been proposed as a new therapeutic strategy for the treatment of inflammatory conditions. However, demonstration of the translation of these immunomodulatory mechanisms in anatomically and physiologically relevant models is still lacking.

Quantification of clinically applicable stimulation parameters for precision near-organ neuromodulation of human splenic nerves.

Neuromodulation is a new therapeutic pathway to treat inflammatory conditions by modulating the electrical signalling pattern of the autonomic connections to the spleen. However, targeting this sub-division of the nervous system presents specific challenges in translating nerve stimulation parameters. Firstly, autonomic nerves are typically embedded non-uniformly among visceral and connective tissues with complex interfacing requirements.

Feasibility of kilohertz frequency alternating current neuromodulation of carotid sinus nerve activity in the pig.

Recent research supports that over-activation of the carotid body plays a key role in metabolic diseases like type 2 diabetes. Supressing carotid body signalling through carotid sinus nerve (CSN) modulation may offer a therapeutic approach for treating such diseases. Here we anatomically and histologically characterised the CSN in the farm pig as a recommended path to translational medicine.

An Overrepresentation of High Frequencies in the Mouse Inferior Colliculus Supports the Processing of Ultrasonic Vocalizations.

Mice are of paramount importance in biomedical research and their vocalizations are a subject of interest for researchers across a wide range of health-related disciplines due to their increasingly important value as a phenotyping tool in models of neural, speech and language disorders. However, the mechanisms underlying the auditory processing of vocalizations in mice are not well understood. The mouse audiogram shows a peak in sensitivity at frequencies between 15-25 kHz, but weaker sensitivity for the higher ultrasonic frequencies at which they typically vocalize.

Potassium channel activator attenuates salicylate-induced cochlear hearing loss potentially ameliorating tinnitus.

High dose sodium salicylate causes moderate, reversible hearing loss and tinnitus. Salicylate-induced hearing loss is believed to arise from a reduction in the electromotile response of outer hair cells (OHCs) and/or reduction of KCNQ4 potassium currents in OHCs, which decreases the driving force for the transduction current. Therefore, enhancing OHC potassium currents could potentially prevent salicylate-induced temporary hearing loss.

A preclinical physiological assay to test modulation of knee joint pain in the spinal cord: effects of oxycodone and naproxen.

Sensory processing in the spinal cord during disease states can reveal mechanisms for novel treatments, yet very little is known about pain processing at this level in the most commonly used animal models of articular pain. Here we report a test of the prediction that two clinically effective compounds, naproxen (an NSAID) and oxycodone (an opiate), are efficacious in reducing the response of spinal dorsal horn neurons to noxious knee joint rotation in the monosodium iodoacetate (MIA) sensitized rat. The overall objective for these experiments was to develop a high quality in vivo electrophysiology assay to confidently test novel compounds for efficacy against pain.

Adult plasticity in the subcortical auditory pathway of the maternal mouse.

Subcortical auditory nuclei were traditionally viewed as non-plastic in adulthood so that acoustic information could be stably conveyed to higher auditory areas. Studies in a variety of species, including humans, now suggest that prolonged acoustic training can drive long-lasting brainstem plasticity. The neurobiological mechanisms for such changes are not well understood in natural behavioral contexts due to a relative dearth of in vivo animal models in which to study this.

The hippocampal physiology of approaching middle-age: early indicators of change.

Age-related cognitive decline presents serious lifestyle challenges, and anatomical changes to the hippocampus are often implicated in clinical conditions later in life. However, relatively little is known about how hippocampal physiology is altered in the transition to middle-age, when early detection may offer the best opportunity for successful treatment. High-yield extracellular recording is a powerful tool for understanding brain function in freely moving animals at single-cell resolution and with millisecond precision.

Dissecting natural sensory plasticity: hormones and experience in a maternal context.

There is a growing consensus that the auditory system is dynamic in its representation of behaviorally relevant sounds. The auditory cortex in particular seems to be an important locus for plasticity that may reflect the memory of such sounds, or functionally improve their processing. The mechanisms that underlie these changes may be either intrinsic because they depend on the receiver's physiological state, or extrinsic because they arise from the context in which behavioral relevance is gained.

Sex differences and androgen influences on midbrain auditory thresholds in the green treefrog, Hyla cinerea.

Reproductive hormones can modulate communication-evoked behavior by acting on neural systems associated with motivation; however, recent evidence suggests that modulation occurs at the sensory processing level as well. The anuran auditory midbrain processes communication stimuli, and is sensitive to steroid hormones. Using multiunit electrophysiology, we tested whether sex and circulating testosterone influence auditory sensitivity to pure tones and to the natural vocalization in the green treefrog, Hyla cinerea.

Female reproductive state influences the auditory midbrain response.

Female behavioral responses to sensory stimuli can be highly variable across the reproductive cycle. Female green treefrogs (Hyla cinerea) use the male vocal signal to locate and choose a mate. Gravid females approach a vocalizing male to mate but do not approach if they have recently mated.

Neurochemical correlates of male polymorphism and alternative reproductive tactics in the Azorean rock-pool blenny, Parablennius parvicornis.

In the common Azorean rock-pool blenny, Parablennius parvicornis, males exhibit alternative reproductive morphologies: (1) larger males defend nest sites, provide parental care, have anal glands (involved in pheromone release), testicular glands, and low gonad:body weight ratio (GSI) and (2) smaller, younger, males do not defend nests, have reduced glands and high GSI. These smaller non-nesting males behave as satellites (associated with nests) or sneakers (moving among nests), attempting to achieve parasitic fertilizations via sperm competition. In non-mammals, arginine vasotocin (AVT) is a key hypothalamic peptide involved in the control of reproductive behavior and physiology, and several fish species that exhibit alternative male reproductive morphs show polymorphism in AVT brain chemistry.