Neural Basis of Elementary Behavior in Stick Insects: (10 Studies of Brain Function)

This monograph represents the current status of neuro- ethological research on the diurnal behavior of the stick in- sect, Carausius morosus. The growing profusion of inter- related studies, many of which are published only in German, makes an overview of this field increasingly difficult. Many stick insect results contribute to general problems like con- trol of catalepsy, control of walking, program-dependent reactions and control of joint position. For this reason I decided to compile and synthesize the results that are pre- sently available even though the analyses are far from con- cluded. In addition to both published and unpublished results of the group in Kaiserslautern (Bassler, Cruse, Ebner, Graham, Pfluger, Storrer, as well as doctoral and masters students), I have drawn upon the literature which had ap- peared as of summer 1981. This includes above all the work of Godden and of Wendler and his colleagues in Cologne. A summary of the anatomical and physiological background, necessary for an understanding of these investigations, is provided in an appendix (Chap. 6). Methodological details must be obtained from the original publications. Figures for which no source is given are from my own studies. I intend to update this monograph on an annual basis. Requests for these supplements should be directed to me in Kaiserslautern. I would like to express my appreciation to all members of the group in Kaiserslautern for their constructive discussions, their unflagging cooperation, and their permission to include hitherto unpublished results.

Table of Contents:
1 Introduction.- 1.1 Statement of the Problem.- 1.2 The Experimental Animal and Its Behavior.- 1.3 Experimental Strategy.- 2 Behavioral Components of Twig Mimesis - Experiments on the Femur-Tibia Joint.- 2.1 Twig Mimesis and Its Components.- 2.2 Control of the State of Activity.- 2.3 Thanatosis.- 2.4 Catalepsy (Flexibilitas Cerea).- 2.4.1 Description and Definition of Catalepsy.- 2.4.2 Catalepsy in the Femur-Tibia Joint as a Characteristic of a Feedback Control Loop.- 2.5 Rocking.- 2.5.1 Description of Rocking.- 2.5.2 Possible Origins of Rocking Movements.- 2.5.3 Frequency Response of the Open Femur-Tibia Control Loop.- 2.5.4 Rocking After Ablation of Sense Organs - Definition of Central Oscillator and Program.- 2.5.5 Further Support for a Central Oscillator.- 2.6 The Femur-Tibia Control Loop.- 2.6.1 Force Measurements on the Extensor and Flexor Muscles of the Tibia.- 2.6.2 Simulation of the Control System Based on the Results of Muscle Force Measurements.- 2.6.3 Gain Control.- 2.6.4 Influence of Other Sense Organs on the Input-Output Relationships of the Control Loop.- 2.7 Evolution of Catalepsy and Rocking.- 2.7.1 The Femur-Tibia Control Loop in Schistocerca.- 2.7.2 Femur-Tibia Control Loop, Catalepsy and Rocking in Extatosoma tiaratum and Cuniculina impigra.- 2.7.3 Hypotheses on the Evolution of Catalepsy and Rocking.- 2.8 Neural Basis of the Femur-Tibia Control Loop.- 2.8.1 The Motor Neurons of the Extensor Tibiae Muscle.- 2.8.2 The Responses of FETi and SETi to Stimulation of the Femoral Chordotonal Organ.- 2.8.3 Alterations of the FETi and SETi Membrane Potential in Cuniculina.- 2.8.4 Neuronal Equivalents of the Elements of Control-Loop Simulation.- 2.9 Significance of Systems Theory (Cybernetic) Methods for the Strategy Used Here.- 2.10 Arousal.- 3 Other Behaviors of the Stationary Animal.- 3.1 Claw Flexing.- 3.2 Active Movements of the Femur-Tibia Joint in Restrained Animals.- 3.2.1 Quantitative Description of the Movement.- 3.2.2 Stimulation of the Chordotonal Organ in the Active Animal.- 3.2.3 Reflex Reversal, Program-Dependent Reaction.- 3.3 Control of the Coxa-Trochanter Joint.- 3.4 Control of the Subcoxal Joint.- 3.4.1 Description of the Response.- 3.4.2 The Motor Neurons of the Retractor Coxae Muscle.- 3.4.3 Response of the Retractor Coxae Motor Neurons to Movement of the Joint.- 3.5 Leg Raising by the Standing Animal.- 3.6 Height Control by a Standing Animal.- 4 Walking.- 4.1 Introduction.- 4.2 Control of a Single Leg.- 4.2.1 Description of the Walking Movement of a Single Leg.- 4.2.1.1 Free-Moving Animals.- 4.2.1.2 Adults Walking on a Treadwheel.- 4.2.1.3 Animals on a Mercury Substrate.- 4.2.2 Description of the Torques in Single Leg Joints During Stance Phase.- 4.2.3 Motor Neuron Activity During a Normal Step.- 4.2.4 Afferent Influences on the Walking Movement of a Single Leg.- 4.2.4.1 Femoral Chordotonal Organ.- 4.2.4.2 Campaniform Sensilla on the Trochanter.- 4.2.4.3 Position Receptors on the Subcoxal Joint.- 4.2.5 Motor Output During Prolongation of a Phase.- 4.2.5.1 Remaining in Stance Phase.- 4.2.5.2 Remaining in Swing Phase (Saluting).- 4.2.5.3 Conclusions.- 4.2.6 Structure and Localization of the Walking Program.- 4.2.6.1 Ablation of the Periphery.- 4.2.6.2 Unspecific Stimulation of Sense Organs.- 4.2.6.3 Stimulation of Single Receptor Organs.- 4.2.6.4 Elimination of Higher Centers.- 4.2.6.5 Conclusions.- 4.2.7 Responses to Irregularities of the Walking Surface.- 4.2.7.1 Control of Femur-Tibia Joint Position During Walking.- 4.2.7.2 Load Increase.- 4.2.7.3 Obstacles During the Swing Phase.- 4.2.7.4 Control of Segment Height.- 4.2.8 Model for the Control of a Single Leg.- 4.3 Interactions Between Legs that Do Not.- Influence Timing.- 4.3.1 Hindleg "Aims" at Tarsus of Middle Leg.- 4.3.2 Treading-on-Tarsus (TOT) Reflex.- 4.3.3 Increased Loading.- 4.3.4 Influence of Searching Movements on the Other Legs.- 4.3.5 Control of Body Height During Walking.- 4.3.6 Amputation of Single Legs.- 4.4 Coordination.- 4.4.1 Description of Leg Coordination - Gaits.- 4.4.1.1 Nymph Walking.- 4.4.1.2 Free Walking Adults.- 4.4.1.3 Adult Walking on a Treadwheel.- 4.4.1.4 Walking on a Mercury Surface.- 4.4.1.5 Dependence of Coordination on the Resistance.- 4.4.2 Coordination After Surgical Intervention.- 4.4.3 Coordination Models.- 4.5 Walking Backwards.- 5 Orientation.- 5.1 Gravity Orientation.- 5.1.1 Description of Behavior.- 5.1.2 Receptors Involved in Behavior.- 5.1.3 Processing of Proprioceptive Input.- 5.2 Light Orientation.- 5.2.1 The Carausius Eye.- 5.2.2 Photomenotaxis.- 5.2.3 Optomotor Response - Color Vision.- 5.2.4 Orientation to Visual Patterns.- 5.3 Idiothetic Orientation.- 6 Anatomy of the Muscles, Nerves, and Sense Organs of the Carausius Thorax.- 6.1 Anatomy of the Thorax and the Legs.- 6.1.1 Skeletal Components and Joints.- 6.1.2 Musculature.- 6.1.3 Nervous System.- 6.2 Anatomy and Physiology of the Sense Organs of the Legs.- 6.2.1 Coxa.- 6.2.2 Trochanter.- 6.2.3 Femur.- 6.2.4 Tibia.- 6.2.5 Tarsus.- 6.3 Motor Innervation of the Leg Muscles.- 6.3.1 Retractor Coxae.- 6.3.2 Depressor Trochanteris.- 6.3.3 Extensor Tibiae.- 6.3.4 Flexor Tibiae.- 6.3.5 Retractor Unguis.- References.