Biology subjects

Dempsey, B.

Publications and source records attributed to Dempsey, B..

3 recordsLinked to original sources

bioRxiv2021

An executive center for the intake of liquids

It has long been known that orofacial movements for feeding can be triggered, coordinated, and often rhythmically organized at the level of the brainstem, without input from higher centers. We uncover two nuclei that can organize the movements for ingesting fluids in mammals. These neuronal groups, defined by unique transcriptional codes and developmental origins, IRtPhox2b and Peri5Atoh1, are located, respectively, in the intermediate reticular formation of the medulla and around the motor nucleus of the trigeminal nerve. They are premotor to all jaw-opening and tongue muscles. Stimulation of either, in awake animals, opens the jaw, while IRtPhox2b alone also protracts the tongue. Moreover, stationary stimulation of IRtPhox2b entrains a rhythmic alternation of tongue protraction and retraction, synchronized with jaw opening and closing, that mimics lapping. Finally, fiber photometric recordings show that IRtPhox2b is active during volitional lapping. Our study identifies one of the long hypothesized subcortical nuclei underpinning a stereotyped feeding behavior.

neuroscience↗

bioRxiv2021

A novel reticular oscillator in the brainstem synchronizes neonatal crying with breathing

Human speech can be divided into short, rhythmically-timed elements, similar to syllables within words. Even our cries and laughs, as well as the vocalizations of other species, are periodic. However, the cellular and molecular mechanisms underlying the tempo of mammalian vocalizations remain unknown. Here we describe rhythmically-timed neonatal mouse vocalizations that occur within single breaths, and identify a brainstem node that structures these cries, which we name the intermediate reticular oscillator (iRO). We show that the iRO acts autonomously and sends direct inputs to key muscles in order to coordinate neonatal vocalizations with breathing, as well as paces and patterns these cries. These results reveal that a novel mammalian brainstem oscillator embedded within the conserved breathing circuitry plays a central role in the production of neonatal vocalizations.

neuroscience↗

bioRxiv2020

Everything Under Control? Comparing Knepp Estate rewilding project with 'traditional nature conservation

Rewilding is an increasingly prominent concept in conservation, but one that has attracted controversy. Debate frequently focuses on control, with rewilding presented as reducing human control of nature. Opposition to rewilding often stems from a perceived lack of control - and associated perception of increased risk and uncertainty. I explore the concept of control in conservation. I identify that control is not a simple, linear concept, but consists of multiple dimensions. Using a lens of control, I compare two ethnographic case studies: the Sussex Wildlife Trusts Old Lodge nature reserve; and Knepp Estate, one of the most influential rewilding projects in the UK. These sites ostensibly represent high-control and low-control examples of conservation. I outline how Old Lodge does not exert precise control in all respects, but rather involves elements of uncertainty and negotiation. I describe how Knepps model of rewilding reduces control in some dimensions but increases it in others. I conclude that, while Knepps rewilding does represent a significant conceptual departure from traditional conservation, it should not be characterised simplistically as an approach that reduces control. Based on this analysis, I argue that reduction of control should not be assumed to underpin the concept of rewilding. Rather, there is interplay between different control dimensions that combine to form different configurations of control. With this understanding, debate about rewilding - and conservation more broadly - can avoid simplistic characterisations of reducing control and become instead an active discussion of what configuration of control is desired. This analysis could be seen negatively by those who argue that Knepps version of rewilding does not sufficiently reduce human control of nature. In contrast, Knepps approach can be seen positively as opening new conceptual space while retaining human involvement. It supports the argument that versions of rewilding can be legitimate, innovative components of plural conservation strategies.

ecology↗