Normalization for Sparse Encoding of Odors by a Wide-Field Interneuron

By Maria Papadopoulou, S. Cassenaer, Thomas Nowotny, Gilles Laurent. 2011

204 citations recorded by the source corpus.

A single neuron is responsible for adaptive normalization in an olfactory circuit generating sparse odor representations. Sparse coding presents practical advantages for sensory representations and memory storage. In the insect olfactory system, the representation of general odors is dense in the antennal lobes but sparse in the mushroom bodies, only one synapse downstream. In locusts, this transformation relies on the oscillatory structure of antennal lobe output, feed-forward inhibitory circuits, intrinsic properties of mushroom body neurons, and connectivity between antennal lobe and mushroom bodies. Here we show the existence of a normalizing negative-feedback loop within the mushroom body to maintain sparse output over a wide range of input conditions. This loop consists of an identifiable “giant” nonspiking inhibitory interneuron with ubiquitous connectivity and graded release properties.

Subfields: Cellular and Molecular Neuroscience, Insect Science, Sensory Systems

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Citations in the corpus

Re-evaluating circuit mechanisms underlying pattern separation (2019, positive): “Global feedback inhibition is provided by a single GABAergic neuron, called the anterior paired lateral (APL) neuron in Drosophila, which is both presynaptic and postsynaptic to virtually all Kenyon cells (Leitch and Laurent, 1996; Liu and Davis, 2009; Papadopoulou et al., 2011), although recent evi”
Feed-Forward versus Feedback Inhibition in a Basic Olfactory Circuit (2015, methodology): “In the locust, a single giant GABAergic neuron (GGN), rather than a group of LHNs, has been shown to provide inhibition to the MB calyx [12, 19].”
Origins of Cell-Type-Specific Olfactory Processing in the Drosophila Mushroom Body Circuit. (2017, unknown): “Second, the locust analog of APL neuron is non-spiking (Papadopoulou et al., 2011), making graded release of neurotransmitter likely in APL neuron as well.”
Oscillatory integration windows in neurons (2016, background): “The odor-evoked oscillatory excitation that KCs receive from PNs is accompanied by feedback inhibition from another network element, a giant GABAergic neuron (GGN) (Papadopoulou et al., 2011; Lei et al., 2013; Lin et al., 2014).”
Conditional modulation of spike-timing-dependent plasticity for olfactory learning (2012, background): “Although sparse codes require larger neuron populations, they are beneficial for memory because they can reduce interference between memory trace”
Sparse, Decorrelated Odor Coding in the Mushroom Body Enhances Learned Odor Discrimination (2014, unknown): “n, left to right, given as number of brain hemispheres [number of flies]: All: 16 [15], 11 [6], 17 [16], 11 [6], 11 [6].”
Closed-loop and activity-guided optogenetic control. (2015, unknown): “Further, it is important to note that manipulation of local populations with single-cell resolution at the scale made possible by recent published studies is already within the range of the number of neurons that have driven behavioral outcomes in mammals ( 1–50 neurons) in pioneering studies of the”
A connectome of a learning and memory center in the adult Drosophila brain (2017, background): “APL is an inhibitory neuron that governs overall levels of activity across the KC population to maintain the sparseness of the odor representation (Papadopoulou et al., 2011; Lin et al., 2014a).”
Functional analysis of a higher olfactory center, the lateral horn (2012, methodology): “C5 is the GGN that provides feedback inhibition to the KCs (Papadopoulou et al., 2011).”