Distributed network organization underlying feeding behavior in the mollusk Lymnaea

The aim of the work reviewed here is to relate the properties of individual neurons to network organization and behavior using the feeding system of the gastropod mollusk, Lymnaea. Food ingestion in this animal involves sequences of rhythmic biting movements that are initiated by the application of a chemical food stimulus to the lips and esophagus. We investigated how individual neurons contribute to various network functions that are required for the generation of feeding behavior such as rhythm generation, initiation ('decision making'), modulation and hunger and satiety. The data support the view that feeding behavior is generated by a distributed type of network organization with individual neurons often contributing to more than one network function, sharing roles with other neurons. Multitasking in a distributed type of network would be 'economically' sensible in the Lymnaea feeding system where only about 100 neurons are available to carry out a variety of complex tasks performed by millions of neurons in the vertebrate nervous system. Having complementary and potentially alternative mechanisms for network functions would also add robustness to what is a 'noisy' network where variable firing rates and synaptic strengths are commonly encountered in electrophysiological recording experiments

A qualitative study of using nicotine products for smoking cessation after discharge from residential drug and alcohol treatment in Australia

Introduction: Tobacco smoking is highly prevalent among alcohol and other drugs (AOD) service clients and, despite interest in quitting, abstinence is rarely sustained. Nicotine products may assist after discharge from residential treatment services, but little is known about client receptivity to them. This study examined AOD withdrawal service clients' experiences of two types of nicotine products for smoking cessation post-discharge, combination nicotine replacement therapy (cNRT) and nicotine vaping products (NVP). Methods: We held semi-structured telephone interviews with 31 Australian AOD service clients in a clinical trial of a 12-week smoking cessation intervention using Quitline support plus cNRT or NVP delivered post-discharge from a smoke-free residential service. We asked about health and social factors, nicotine cravings, Quitline experience, and barriers and facilitators to cNRT or NVP, then thematically analysed data. Results: cNRT and NVP were described by participants as feasible and acceptable for smoking cessation. For most participants, cost limited cNRT access post study, as did difficulty navigating NVP prescription access. Quitline support was valued, but not consistently used, with participants noting low assistance with NVP-facilitated cessation. Participants considered both cessation methods acceptable and socially supported, and sought information on decreasing nicotine use via NVP. Discussion and Conclusions: AOD service clients highly valued receiving cNRT or NVP with behavioural support for smoking reduction or abstinence. Both interventions were acceptable to service clients. Findings suggest a potential need to examine both whether NVP use should be permitted in this context, and guidance on the individual suitability of cNRT or NVP.</p

A two-neuron system for adaptive goal-directed decision-making in Lymnaea

During goal-directed decision-making, animals must integrate information from the external environment and their internal state to maximize resource localization while minimizing energy expenditure. How this complex problem is solved by the nervous system remains poorly understood. Here, using a combined behavioural and neurophysiological approach, we demonstrate that the mollusc Lymnaea performs a sophisticated form of decision-making during food-searching behaviour, using a core system consisting of just two neuron types. The first reports the presence of food and the second encodes motivational state acting as a gain controller for adaptive behaviour in the absence of food. Using an in vitro analogue of the decision-making process, we show that the system employs an energy management strategy, switching between a low- and high-use mode depending on the outcome of the decision. Our study reveals a parsimonious mechanism that drives a complex decision-making process via regulation of levels of tonic inhibition and phasic excitation