The effects of ethanol on memory and neuroplasticity in a vertebrate and an invertebrate model of learning

Sloss, Ian (2016) The effects of ethanol on memory and neuroplasticity in a vertebrate and an invertebrate model of learning. Doctoral thesis (PhD), University of Sussex.

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Abstract

Binge drinking is characterised by cycles of ethanol intoxication and withdrawal and is thought to be highly deleterious for the normal functioning of the nervous system. The behavioural and neurophysiological consequences of rapid escalation of blood alcohol concentration and subsequent withdrawal, and their effects on learning and memory and underlying neural circuitry can be studied in suitable animal models. Here, spatial and instrumental learning as well as hippocampal LTP were assessed in C57BL/6J mice for the effects of adolescent intermittent ethanol (AIE) and other ethanol treatments. AIE treatment did not impair spatial or non-spatial memory when tested in adulthood. However, if mice were trained whilst intoxicated during AIE treatment, spatial memory was impaired. Post-training injections of ethanol impaired performance in operant conditioning. A rapid rise and fall in ethanol concentration, prior to stimulation, blocked LTP induction in drug naïve hippocampal slices; an effect that was not seen if the ethanol concentration was gradually increased and decreased. Moreover, AIE treatment caused an NMDA receptor-dependent transient increase in hippocampal LTP. The second part of this study used a novel molluscan model Lymnaea stagnalis and demonstrated that high concentrations of ethanol blocked acquisition and retrieval of an associative memory. However, if acquisition occurred in the presence of ethanol then memory could also be retrieved under ethanol, demonstrating ethanol state dependency. By utilising the cerebral giant cells, a modulatory neuron type with known involvement in memory formation, it was found that ethanol reduced the tonic firing frequency as well as the peak-to-trough and half-width parameters of individual action potentials. The development of in vivo and in vitro ethanol treatment and test protocols, and the findings based on their use, open up new avenues for future systematic investigations on ethanol’s effects on behaviour and underlying neural circuitry in both vertebrate and invertebrate model systems.

Item Type: Thesis (Doctoral)
Schools and Departments: School of Life Sciences > Neuroscience
Subjects: B Philosophy. Psychology. Religion > BF Psychology > BF0207 Psychotropic drugs and other substances
R Medicine > RC Internal medicine > RC0321 Neurosciences. Biological psychiatry. Neuropsychiatry
Depositing User: Library Cataloguing
Date Deposited: 09 Nov 2016 09:22
Last Modified: 09 Nov 2016 09:22
URI: http://sro.sussex.ac.uk/id/eprint/65381

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