Section: Figures

Scott Waddell, Ph.D.

Academic Role: Associate Professor

Faculty Appointment(s) In:
   Neurobiology

Other Affiliation(s):
   Interdisciplinary Graduate Program
   Program in Neuroscience

Figures

Figure 1. Memory-relevant neurons revealed by enhancer trap-driven expression of Green Fluorescent Protein. c305a specifically labels Mushroom Body a´b´ neurons and c739 specifically labels ab neurons. DPM neurons can be visualized and manipulated using c316.

Figure 2. Model for aversive olfactory conditioning and DPM neuron-dependent memory processing. a | Training. Odour input through projection neurons (PN) activates a sparse parallel array (red) of mushroom body Kenyon cells (KC) that project in the α′β′ (light blue) and αβ (pink) lobes. The reinforcing effect of punitive shock is delivered to the mushroom body by dopaminergic modulatory neurons (DA, orange). Activated synapses are coloured yellow. The encoded memory gains specificity through its reliance on coincident DA release onto Kenyon cells that have been activated by odour. Therefore, although DA is released onto all Kenyon cells, synaptic plasticity is only induced at the output synapses (blue circles) of the red neurons. b | Short-term memory (STM) retrieval. Re-exposure to the conditioned odour activates the learning-modified red Kenyon cells. Output through the modified Kenyon cell α′β′ and αβ output synapses (blue circles) leads to an aversive conditioned response.  Plasticity was also induced at the α′β′ Kenyon cell–dorsal paired medial (DPM) neuron synapse, but transmission through this synapse is not required for short-term memory. c | Memory consolidation. Spontaneous activity (open blue triangle) in the projection neurons after training occasionally drives the red α′β′and αβ Kenyon cell neurons. Activity in the red α′β′neurons strongly drives DPM neurons (green) through the modified α′β′ Kenyon cell–DPM synapse. DPM neurons feedback onto all α′β′ and forward onto all αβ Kenyon cells. Although DPM neurons release transmitter on all Kenyon cells, consolidation is neuron specific because it is reliant on the cells’ history (that is, only the red neuron synapses that were modified during training can be consolidated) and coincident red Kenyon cell and DPM neuron activity after training. Each time the red Kenyon cells are spontaneously activated over the next hour, the recurrent α′β′ Kenyon cell–DPM neuron loop consolidates the output synapses in the red αβ Kenyon cell neurons (larger blue circle), while plasticity in the red α′β′ neuron output synapses (blue/red circle) wanes. d | Middle-term memory (MTM) retrieval. Re-exposure to the conditioned odour activates the red Kenyon cell neurons. However, only transmission from the consolidated αβ Kenyon cell output synapses (larger blue circle) is required to elicit the aversive conditioned response.

Office: LRB 725
Phone: 508-856-6804
E-mail: Scott.Waddell@umassmed.edu
Keywords: Neurobiology, Organisms - Drosophila, Learning and Memory, Neural Plasticity, Genetics

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