Center-surround vs. distance-independent lateral connectivity in the olfactory bulb

• Published in: Frontiers in neural circuits Vol. 6; p. 34
• Main Authors: Kim, David H, Chang, Andrew Y, McTavish, Thomas S, Patel, Hetal K, Willhite, David C
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Research Foundation 31-05-2012; Frontiers Media S.A
• Subjects: center-surround; Connectivity; Granule cells; Information processing; Interneurons; lateral inhibition; Neural networks; Neuroscience; Olfaction; Olfactory Bulb; Olfactory system; Sensory integration; Smell; Synapses; lateral inhibition; olfaction; olfactory bulb; connectivity; center-surround
• ISSN: 1662-5110; 1662-5110
• DOI: 10.3389/fncir.2012.00034

Lateral neuronal interactions are known to play important roles in sensory information processing. A center-on surround-off local circuit arrangement has been shown to play a role in mediating contrast enhancement in the visual, auditory, and somatosensory systems. The lateral connectivity and the influence of those connections have been less clear for the olfactory system. A critical question is whether the synaptic connections between the primary projection neurons, mitral and tufted (M/T) cells, and their main inhibitory interneurons, the granule cells (GCs), can support a center-surround motif. Here, we study this question by injecting a "center" in the glomerular layer of the olfactory bulb (OB) with a marker of synaptic connectivity, the pseudorabies virus (PRV), then examines the distribution of labeling in the "surround" of GCs. We use a novel method to score the degree to which the data fits a center-surround model vs. distance-independent connectivity. Data from 22 injections show that M/T cells generally form lateral connections with GCs in patterns that lie between the two extremes.