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Identifier

000423477

Title

Γενετική και μοριακή διερεύνηση της εξοικείωσης στη D. melanogaster

Alternative Title

Genetic and molecular analysis of habituation in D. melanogaster

Author

Σεμελίδου, Ουρανία

Thesis advisor

Σαββάκης, Χαράλαμπος

Reviewer

Σκουλάκης, Ευθύμιος
Ταβερναράκης, Νεκτάριος
Δελιδάκης, Χρήστος
Καραγωγέως, Δόμνα
Ποϊράζη, Παναγιώτα
Ζέρβας, Χρήστος

Abstract

Habituation is the process that enables salience filtering, precipitating perceptual changes that alter the value of environmental stimuli. To discern the neuronal circuits underlying habituation to brief inconsequential stimuli, we developed a novel olfactory habituation paradigm, identifying two phases of the response that engage distinct neuronal circuits. Responsiveness to the continuous odor stimulus is maintained initially, a phase we term habituation latency, and requires Rutabaga Adenylyl-Cyclase-depended neurotransmission from GABAergic Antennal Lobe Interneurons and activation of excitatory Projection Neurons (PNs) and the Mushroom Bodies. In contrast, habituation depends on the inhibitory PNs of the middle Antenno-Cerebral Track, requires inner Antenno-Cerebral Track PN activation and defines a temporally distinct phase. Collectively, our data support the involvement of Lateral Horn excitatory and inhibitory stimulation in habituation. In parallel, we investigated the neuronal subsets that underlie dishabituation, the instant recovery of naive response after exposure to a novel stimulus. We have demonstrated that exposure to mechanical stimuli results in dishabituation of the olfactory response and we identified two neuronal subsets, the dopaminergic PPL1 and the octopaminergic anterior paired lateral (APL) neurons, which are necessary for response recovery after electric shock stimulation. Innervation of the Mushroom bodies by these neurons and further activation of the Lateral Horn underlines the role of these neuropils in modulation of the response and proposes a novel role for them in dishabituation. Finally, we examined the role of serotonin, which has been linked to various disorders, including schizophrenia and anxiety disorders, in habituation to electric shock. We have demonstrated that serotonin is necessary for normal habituation, and mutations on the serotonergic receptors disrupt this process. Collectively, our results provide essential cellular substrates for future analyses of the molecular mechanisms that govern the duration and transition between the distinct temporal habituation phases, and dishabituation.

Language

English

Subject

Drosophila

Neuronal circuits

Olfaction

Όσφρηση

Νευρωνικά κυκλώματα

Issue date

2019-07-17

Collection

School/Department--School of Medicine--Department of Medicine--Doctoral theses