@article {67771, title = {A connectome of the central complex reveals network motifs suitable for flexible navigation and context-dependent action selection.}, journal = {eLife}, volume = {10}, year = {2021}, month = {2021 Oct 26}, abstract = {

Flexible behaviors over long timescales are thought to engage recurrent neural networks in deep brain regions, which are experimentally challenging to study. In insects, recurrent circuit dynamics in a brain region called the central complex (CX) enable directed locomotion, sleep, and context- and experience-dependent spatial navigation. We describe the first complete electron-microscopy-based connectome of the CX, including all its neurons and circuits at synaptic resolution. We identified new CX neuron types, novel sensory and motor pathways, and network motifs that likely enable the CX to extract the fly{\textquoteright}s head-direction, maintain it with attractor dynamics, and combine it with other sensorimotor information to perform vector-based navigational computations. We also identified numerous pathways that may facilitate the selection of CX-driven behavioral patterns by context and internal state. The CX connectome provides a comprehensive blueprint necessary for a detailed understanding of network dynamics underlying sleep, flexible navigation, and state-dependent action selection.

}, issn = {2050-084X}, doi = {10.7554/eLife.66039}, author = {Hulse, Brad K and Haberkern, Hannah and Franconville, Romain and Turner-Evans, Daniel B and Takemura, Shin-ya and Wolff, Tanya and Noorman, Marcella and Dreher, Marisa and Dan, Chuntao and Parekh, Ruchi and Hermundstad, Ann M and Rubin, Gerald M and Jayaraman, Vivek} } @article {65722, title = {The neuroanatomical ultrastructure and function of a biological ring attractor.}, journal = {Neuron}, volume = {108}, year = {2020}, month = {2020 Oct 14}, pages = {145-63}, abstract = {

Neural representations of head direction (HD) have been discovered in many species. Theoretical work has proposed that the dynamics associated with these representations are generated, maintained, and updated by recurrent network structures called ring attractors. We evaluated this theorized structure-function relationship by performing electron-microscopy-based circuit reconstruction and RNA profiling of identified cell types in the HD system of Drosophila melanogaster. We identified motifs that have been hypothesized to maintain the HD representation in darkness, update it when the animal turns, and tether it to visual cues. Functional studies provided support for the proposed roles of individual excitatory or inhibitory circuit elements in shaping activity. We also discovered recurrent connections between neuronal arbors with mixed pre- and postsynaptic specializations. Our results confirm that the Drosophila HD network contains the core components of a ring attractor while also revealing unpredicted structural features that might enhance the network{\textquoteright}s computational power.

}, issn = {1097-4199}, doi = {10.1016/j.neuron.2020.08.006}, author = {Turner-Evans, Daniel B and Jensen, Kristopher T and Ali, Saba and Paterson, Tyler and Sheridan, Arlo and Ray, Robert P and Wolff, Tanya and Lauritzen, J Scott and Rubin, Gerald M and Bock, Davi D and Jayaraman, Vivek} } @article {48990, title = {The insect central complex.}, journal = {Current Biology : CB}, volume = {26}, year = {2016}, month = {2016 Jun 06}, pages = {R453-7}, abstract = {

Hordes of tourists flock to Washington, D.C. every spring to see the cherry trees blossom. Once in the city, they must find their way to the Tidal Basin where the Japanese trees grow. Fortunately, a number of visual landmarks can help them to navigate. In 1910, the United States Congress passed The Height of Buildings Act, limiting the elevation of commercial and residential structures in D.C. to 130 feet. Thus, the 555-foot-tall Washington Monument often looms large against the horizon, serving as an anchor point to help set the tourists{\textquoteright} sense of direction. Once their heading is set, they can lose sight of the monument behind buildings or groups of tall Scandinavian visitors and still use their internal compass to navigate to the Basin. This compass keeps track of their paces and turns and updates their sense of where they are and where they need to go. Yet while their heading informs their actions, it does not dictate them. Tourists who have been to D.C. in the past can, for example, use remembered views to alter their routes to avoid crowds. On an even finer scale, their leg movements also depend on their current state - they might increase the frequency and length of their strides if hunger pangs compete with their desire to see cherry blossoms, for example. The way in which these disparate cues and motivations influence exploration is a neuroscience mystery across creatures large and small.

}, keywords = {Animals, Brain, Cues, Insecta, Spatial Navigation, Vision, Ocular}, issn = {1879-0445}, doi = {10.1016/j.cub.2016.04.006}, author = {Turner-Evans, Daniel B and Jayaraman, Vivek} }