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Biology subjects

Hamilton, J. D.

Publications and source records attributed to Hamilton, J. D..

3 recordsLinked to original sources

Bidirectional modulation of sleep and wakefulness via prefrontal cortical chemogenetics

The cortex is now recognised as a key regulator of sleep. It remains unclear, however, how sleep is affected by changes in cortical activity over different spatial scales. For instance, sleep states are associated with global changes in activity across cortex, but sleep pressure is associated with local variations in cortical activity. Here we use chemogenetic manipulations of a single neuronal population to determine how sleep reflects the spatial scale of cortical activity. Global inhibition of Rbp4-Cre+ neurons increases sleep, but also produces abnormal brief-awakenings and reduces electroencephalogram slow-wave activity, a marker of sleep intensity. In contrast, local inhibition/excitation of Rbp4-Cre+ neurons in the prefrontal but not occipital cortex increases sleep/wake, respectively, whilst preserving normal sleep architecture and electrophysiological features. We conclude that globally altering cortical activity may induce unphysiological sleep due to conflicting sleep-regulatory signals, while locally modulating prefrontal cortex affords bidirectional sleep regulation that leaves naturalistic features intact.

neuroscience↗

Peripheral direct current for suppression of physiologically evoked nociceptive responses at the spinal cord

Electrical neuromodulation is an established non-pharmacological treatment for chronic pain. However, existing devices using pulsatile stimulation are not suitable for all types of chronic pain. Direct current stimulation is a recently developed technology which shows better selectivity for small-diameter fibres. We investigated if this selectivity could be applied to preferentially suppress nociceptive signalling. We applied direct current to the sciatic nerve of rats and compared its effects on spinal activity produced by physiological (non-electrical) stimuli delivered to the foot. Tests were performed across models of neuropathic and inflammatory pain to further clarify potential clinical applications. We found that direct current could effectively suppress activity relating to painful stimuli in both pain models tested. These findings strongly support the use of direct current neuromodulation for chronic pain relief, and suggest that it may be effective at treating a broader range of aberrant pain conditions than existing devices.

neuroscience↗

In vitro and in vivo preclinical studies predict REGEN-COV protection against emergence of viral escape in humans

Monoclonal antibodies against SARS-CoV-2 are a clinically validated therapeutic option against COVID-19. As rapidly emerging virus mutants are becoming the next major concern in the fight against the global pandemic, it is imperative that these therapeutic treatments provide coverage against circulating variants and do not contribute to development of treatment emergent resistance. To this end, we investigated the sequence diversity of the spike protein and monitored emergence of minor virus variants in SARS-COV-2 isolates found in COVID-19 patients or identified from preclinical in vitro and in vivo studies. This study demonstrates that a combination of non-competing antibodies, REGEN-COV, not only provides full coverage against current variants of concern/interest but also protects against emergence of new such variants and their potential seeding into the population in a clinical setting.

microbiology↗