The Intrinsic Connectome of the Rat Amygdala

Abstract

The connectomes of nervous systems or parts there of are becoming important subjects of study as the amount of connectivity data increases. Because most tract-tracing studies are performed on the rat, we conducted a comprehensive analysis of the amygdala connectome of this species resulting in a meta-study. The data were imported into the neuroVIISAS system, where regions of the connectome are organized in a controlled ontology and network analysis can be performed. A weighted digraph represents the bilateral intrinsic (connections of regions of the amygdala) and extrinsic (connections of regions of the amygdala to non-amygdaloid regions) connectome of the amygdala. Its structure as well as its local and global network parameters depend on the arrangement of neuronal entities in the ontology. The intrinsic amygdala connectome is a small-world and scale-free network. The anterior cortical nucleus (72 in- and out-going edges), the posterior nucleus (45), and the anterior basomedial nucleus (44) are the nuclear regions that posses most in- and outdegrees. The posterior nucleus turns out to be the most important nucleus of the intrinsic amygdala network since its Shapley rate is minimal. Within the intrinsic amygdala, regions were determined that are essential for network integrity. These regions are important for behavioral (processing of emotions and motivation) and functional (memory) performances of the amygdala as reported in other studies.

A mesoscale connectome of the mouse brain

“…Previous studies on connectivity considered global organizational principles from a graph-theory perspective 26–28 . We transformed our weighted, directed, connectivity matrix (Fig.…”

Network science and the human brain: Using graph theory to understand the brain and one of its hubs, the amygdala, in health and disease

“…Graph theory has recently been used to study the connectome of the rat amygdala (Schmitt et al, ). Schmitt et al performed a meta‐analysis of tract‐tracing data from more than 2,000 publications that described fiber connections to, from, or within the amygdala of the rat.…”

“…Network studies and graph theory are now beginning to provide novel insights into the complex interactions that mediate the functions of the amygdala and how these interactions are altered in a wide range of neurological and psychiatric conditions. CONNECTOME OF THE RAT AMYGDALA Graph theory has recently been used to study the connectome of the rat amygdala (Schmitt et al, 2012). Schmitt et al performed a meta-analysis of tract-tracing data from more than 2,000 publications that described fiber connections to, from, or within the amygdala of the rat.…”

The Cognitive Social Network in Dreams: Transitivity, Assortativity, and Giant Component Proportion Are Monotonic

“…Assortativity is high in the phonological network (Vitevitch, ) and word association network (Gravino, Servedio, Barrat, & Loreto, ). Assortativity is also high in the brain (Eguíluz, Chialvo, Cecchi, Baliki, & Apkarian, ) and amygdala (Schmitt et al., ).…”

“…Two friends with a friend in common tend to be friends, so transitivity tends to be high in social networks. Other small-world networks are the brain with its connections (review in Bullmore & Sporns, 2009) and the amygdala with its internal connections (Schmitt et al, 2012). Because associations have long been considered important in dreams (e.g., Freud, 1953;Foulkes, 1985), it is noteworthy that words linked by associations form small-world networks.…”