Visualization of Central Olfactory Pathways in a Model Brain: Universal Principles of Structural Organization Across Taxa

Abstract

This thesis in clinical psychology has two main parts, answering the two main research problems. This scientific project includes visualization of neural pathways connecting the primary olfactory centre to higher association regions in a small insect brain for the purpose of comparing anatomical organization of the olfactory system in species of different taxa. The noctuid moth Heliothis virescens, which is particularly well adapted to chemical communication, is used as model organism. By utilizing the technique of fluorescent staining combined with confocal microscopy, the three main antennocerebral tracts and their target areas, the lateral protocerebrum and calyces of mushroom bodies, are labeled and visualized. The second part of the thesis includes a relatively comprehensive theoretical discussion of universal principles of olfactory structural organization across taxa. This discussion is founded on the experimental investigation (using the anatomy of

Heliothis virescens as a basis for comparison, and keeping its main focus on the olfactory structures identified by confocal microscopy), but is not limited to this. It is a general discussion of organizational principles in vertebrates and invertebrates, and includes research on other organisms and olfactory structures beyond what was identified in the experimental study. Clear evidence of universal principles of structural – and functional olfactory organization is found, and it is argued that the study of different taxa is a way for psychologists to gain further knowledge about human behavior.