Author : Adrienn Gabriella Varga
Release : 2017
Genre : Animal navigation
Kind : eBook
Book Rating : /5 ( reviews)
Book Synopsis The Neural Basis of Head Direction and Spatial Context in the Insect Central Complex by : Adrienn Gabriella Varga
Download or read book The Neural Basis of Head Direction and Spatial Context in the Insect Central Complex written by Adrienn Gabriella Varga. This book was released on 2017. Available in PDF, EPUB and Kindle. Book excerpt: A question of wide importance in neuroscience is how the brain controls behavior. How does sensory information get transformed into a spatially organized representation about our current state in the world and how is this abstract representation utilized when producing motor commands that lead to successful navigation? When navigating in a complex environment, all animals must encode information about their position and orientation in a rich sensory environment. In vertebrates this may occur by means of distributed activity across several navigation circuits located in the hippocampal formation. Arthropods, however, lack a hippocampal formation and thus it is unclear what circuits mediate navigation. A wide range of studies indicate that the central complex (CX), is not only involved in directional sensory information processing and the control of motor commands, but also plays a role in orientation coding in polarized light guided navigation and landmark orientation. All of these neural mechanisms point in the direction that single neurons in the CX might be directly involved in head direction coding, as well as other aspects of adaptive navigation. In the work described in this dissertation I used multi-channel extracellular recording techniques to uncover the neural correlates of head direction coding and spatial context cues in the cockroach CX. Specifically, I used tetrodes to record the activity of single neurons in the CX while the animal was passively rotated around on a platform surrounded by a circular arena (Chapter 2). In the same setting I also recorded local field potentials (LPFs) in the CX to uncover how navigational information modulates the network’s activity in a more global manner (Chapter 3). I found that single units, as well as LFPs in the cockroach CX encode the animal’s head direction relative to a salient visual cue. However, when landmarks are not available to the animal, both single neuron and network-level activity can rely upon idiothetic motion cues to update the animal’s relative heading in a landmark-free setting. In addition to these results, I found that a subpopulation of single neurons and some of the LFP frequency bands encoded the rotation direction history of the animal, a common spatial context cue. These results suggest that the CX navigation circuit is involved in environmental context discrimination processes that might be utilized by spatial memory circuits in the insect brain.Taken together, these results provide a solid foundation for future studies on the neural basis of adaptive navigation in insects. By placing these results in a wider context of adaptive navigation in all animals and by comparing them to the mechanisms described in mammalian navigation circuits, these data also contribute to a broad comparative approach to understand the general principles of navigation, as well as the diversity of the neural substrates of navigation across evolutionarily distinct animals.
