Short Term Synaptic Plasticity Across Multiple Electrosensory Maps in the Weakly Electric Fish Apteronotus leptorhynchus

Abstract

The electrosensory lateral line lobe (ELL) is the first order electrosensory processing station in the brain of the electric fish Apteronotus leptorhynchus, and is the only nucleus to receive input from electroreceptors on the skin. The ELL is subdivided into three maps: the centromedial segment (CMS), centrolateral segment (CLS), and lateral segment (LS) which receive input from tuberous electroreceptors processing high frequency signals. Two feedback pathways from higher order nuclei, the nucleus praemenintialis (nP) and the eminentia posterior granularis (EGp) are integral to processing in the ELL and show synaptic plasticity on various time scales. This thesis focuses on characterizing short term plasticity (STP) in nP-ELL synapses between the CMS, CLS and LS, and the development of an in vitro slice containing the entire direct feedback pathway. We find that LS pyramidal cells show greater facilitation in response to high frequency stimulation of direct feedback fibres as compared to CMS.