Neuromodulatory circuit effects on Drosophila feeding behaviour and metabolism.

Animals have evolved to maintain homeostasis in a changing external environment by adapting their internal metabolism and feeding behaviour. Metabolism and behaviour are coordinated by neuromodulation; a number of the implicated neuromodulatory systems are homologous between mammals and the vinegar fly, an important neurogenetic model. We investigated whether silencing fly neuromodulatory networks would elicit coordinated changes in feeding, behavioural activity and metabolism.

Drosophila learn efficient paths to a food source.

Elucidating the genetic, and neuronal bases for learned behavior is a central problem in neuroscience. A leading system for neurogenetic discovery is the vinegar fly Drosophila melanogaster; fly memory research has identified genes and circuits that mediate aversive and appetitive learning. However, methods to study adaptive food-seeking behavior in this animal have lagged decades behind rodent feeding analysis, largely due to the challenges presented by their small scale.

Distinct pathways for rule-based retrieval and spatial mapping of memory representations in hippocampal neurons.

Hippocampal neurons encode events within the context in which they occurred, a fundamental feature of episodic memory. Here we explored the sources of event and context information represented by hippocampal neurons during the retrieval of object associations in rats. Temporary inactivation of the medial prefrontal cortex differentially reduced the selectivity of rule-based object associations represented by hippocampal neuronal firing patterns but did not affect spatial firing patterns.

Single neuron recordings in dorsal cochlear nucleus (DCN) of awake gerbil.

The auditory responses of neurons in the dorsal cochlear nucleus (DCN) are known to be sensitive to anesthesia, and consequently many studies have used an unanesthetized, decerebrate preparation. Decerebration, however, severs multiple descending pathways to the DCN and is traumatic to the brain, and so sensory responses may be influenced. It was possible, by combining sterile surgery, animal conditioning, and mild restraint to allow recordings in awake gerbils (Merionus unguiculatus).