Cellular Organization Of The Brain And Thoracic Ganglia Of The Praying Mantis
Location
Lobby in front of Auditorium
Department
Biology
Abstract
The praying mantis is a charismatic, predatory insect that depends on vision for prey identification. Although our lab has published extensively on the psychophysics and neurophysiology of prey recognition, little is known about the underlying neuroanatomy. We analyzed the anatomy of the brain and thoracic ganglia of several mantis species using the similarly sized cockroach, Gromphadorhina portentosa as a benchmark. Cockroaches (Blattodea) are the sister taxon to the Mantodea. Preparations included toluidine blue and horseradish peroxidase stained whole mounts, and serial sections stained for the neurotransmitters acetylcholine and GABA (gamma-aminobutyric acid). Overall, basic anatomical organization of the mantis cerebral ganglia (“brain”), and thoracic/abdominal ganglia followed the general orthopteroid bauplan but with several specializations. The latter included relatively larger optic lobes containing ommatidia in which six (of the eight) retinula cells elongated the entire length of each ommatidia. The ommatidia each contained supporting cells at their distal tips. The next more proximal optic lobe ganglion, the lamina, was densely packed with lamina monopolar cells whose axons projected through the first optic chiasm to the next more proximal ganglion called the medulla. In turn, the medulla projected to an unusual, multilayered lobula complex at the base of the optic lobe. The cerebral ganglia consisted of three pair of bilaterally symmetrical fused ganglia, the proto-, deuto-, and tritocerebal ganglia (from dorsal to ventral). The protocerebrum contained three robust, transverse axon pathways that spanned the width of the protocerebrum. The cerebral ganglia of all mantises that we examined had highly complex mushroom bodies with dense concentrations of Kenyon cells atop robust calyces. Mushroom bodies have been associated with complex sensory processing in arthropods. In addition, the center of the protocerebrum housed an elaborated central body complex with efferents displaying ACh-like immunoreactivity. Elaborated mushroom bodies and central complexes have been associated both with complex sensory processing and complex control of motor behaviors in arthropods (analogous to the roles played by the basal ganglia in vertebrates). We found that the organization of the three thoracic ganglia was similar between the mantises and the cockroach, but not identical. The organizational structure of the thoracic ganglia suggests that the descending commands that direct the mantis toward and initiate capture of the prey may be direct signals, that transduce descending cephalic commands into motor outputs in the limbs (which are controlled by the thoracic ganglia). Each thoracic ganglion housed four groups of motor neurons located in the anterior-lateral and posterior-lateral quadrants of each ganglia. These motor neurons integrated descending cephalic input with peripheral sensory input and directed the resulting output to the limbs. Together, these complex, emergent computational processes are necessary to implement the prey identification and capture algorithms that we have exhaustively documented in our previously published research. Understanding the mantis’ underlying neural architecture is facilitating development of realistic computer models of the mantis' behavior. In turn, these models are being used in our research on assistive technology for children with visual challenges.
Cellular Organization Of The Brain And Thoracic Ganglia Of The Praying Mantis
Lobby in front of Auditorium
The praying mantis is a charismatic, predatory insect that depends on vision for prey identification. Although our lab has published extensively on the psychophysics and neurophysiology of prey recognition, little is known about the underlying neuroanatomy. We analyzed the anatomy of the brain and thoracic ganglia of several mantis species using the similarly sized cockroach, Gromphadorhina portentosa as a benchmark. Cockroaches (Blattodea) are the sister taxon to the Mantodea. Preparations included toluidine blue and horseradish peroxidase stained whole mounts, and serial sections stained for the neurotransmitters acetylcholine and GABA (gamma-aminobutyric acid). Overall, basic anatomical organization of the mantis cerebral ganglia (“brain”), and thoracic/abdominal ganglia followed the general orthopteroid bauplan but with several specializations. The latter included relatively larger optic lobes containing ommatidia in which six (of the eight) retinula cells elongated the entire length of each ommatidia. The ommatidia each contained supporting cells at their distal tips. The next more proximal optic lobe ganglion, the lamina, was densely packed with lamina monopolar cells whose axons projected through the first optic chiasm to the next more proximal ganglion called the medulla. In turn, the medulla projected to an unusual, multilayered lobula complex at the base of the optic lobe. The cerebral ganglia consisted of three pair of bilaterally symmetrical fused ganglia, the proto-, deuto-, and tritocerebal ganglia (from dorsal to ventral). The protocerebrum contained three robust, transverse axon pathways that spanned the width of the protocerebrum. The cerebral ganglia of all mantises that we examined had highly complex mushroom bodies with dense concentrations of Kenyon cells atop robust calyces. Mushroom bodies have been associated with complex sensory processing in arthropods. In addition, the center of the protocerebrum housed an elaborated central body complex with efferents displaying ACh-like immunoreactivity. Elaborated mushroom bodies and central complexes have been associated both with complex sensory processing and complex control of motor behaviors in arthropods (analogous to the roles played by the basal ganglia in vertebrates). We found that the organization of the three thoracic ganglia was similar between the mantises and the cockroach, but not identical. The organizational structure of the thoracic ganglia suggests that the descending commands that direct the mantis toward and initiate capture of the prey may be direct signals, that transduce descending cephalic commands into motor outputs in the limbs (which are controlled by the thoracic ganglia). Each thoracic ganglion housed four groups of motor neurons located in the anterior-lateral and posterior-lateral quadrants of each ganglia. These motor neurons integrated descending cephalic input with peripheral sensory input and directed the resulting output to the limbs. Together, these complex, emergent computational processes are necessary to implement the prey identification and capture algorithms that we have exhaustively documented in our previously published research. Understanding the mantis’ underlying neural architecture is facilitating development of realistic computer models of the mantis' behavior. In turn, these models are being used in our research on assistive technology for children with visual challenges.
Comments
Frederick Prete is the faculty sponsor of this poster.