Research(-> home)

Welcome to the Laboratory of

Crustacean 
Neurobiology 
& Behavior

Overview

Research in my lab investigates the neural basis of animal behavior:

We are interested in identifying and examining neural circuitry that underlies aggression and social hierarchy formation as well as decision-making and behavioral choice.

We use crayfish as our primary animal model because they display easily quantifiable behavioral patterns, and they feature a nervous system of tractable complexity that is accessible for neurophysiological and neuropharmacological studies.

Most social animals compete aggressively for resources such as food, shelter and mates. The early stages of an encounter between well-matched crayfish are marked by an aggressive escalation that can include strikes, aggressive posture, grappling with claws, and bouts of offensive tail-flips (Herberholz et al. 2001, Edwards & Herberholz 2005). At some point, fighting in crayfish is interrupted by an abrupt change in the agonistic behavior of one animal as it switches from aggressive to submissive behaviors. This switch marks the change in the dominance status of the animals and identifies the new subordinates (Herberholz et al. 2001). Dominant and subordinate crayfish then show clear differences in their behavior. The dominant animal displays a dominant posture, initiates approaches and attacks, constructs a shelter and claims first access to most resources, while the subordinate displays a submissive posture, retreats and escapes from the dominant, and is left to claim unwanted resources (Herberholz et al. 2001, Edwards et al. 2003, Herberholz et al. 2003, Song et al. 2006, Herberholz et al. 2007). In our attempt to understand the behavioral mechanisms underlying social dominance, we use video analysis to identify aggressive and submissive behaviors that are expressed during agonistic interactions in pairs and groups of crayfish. We combine this with non-invasive electrophysiology, intracellular electrophysiology and neuropharmacology to investigate the neural circuitry that promotes dominant and subordinate status.

When attacked by a natural predator (e.g., dragonfly nymphs), juvenile crayfish produce three different forms of escape tail-flips controlled by as many neural circuits (Herberholz et al. 2004a). Two of the tail-flips are mediated by giant neurons (medial giant and lateral giant) that evoke stereotyped, reflexive escape responses away from the stimulus. One is mediated by non-giant circuitry that produces tail-flips of less stereotyped forms with longer response latencies. The neural circuits that control the tail-flip behavior are only partially understood (Herberholz et al. 2002, Antonsen et al. 2005).We are interested in how the different escape circuits integrate sensory signals and how they interact with each other to produce effective behavioral outputs. 

We are also interested in decisions-making processes that take place in the nervous system and lead to adaptive behavioral choices. By combining video- and electrophysiological recordings, we can measure behavioral and neural responses to simulated predatory attacks. We expose juvenile crayfish to moving shadows while the animals are searching for food. In response to approaching shadows, each crayfish produces one of two discrete behavioral outputs: it either tail-flips backwards by rapid flexion of its abdomen or it immediately stops forward locomotion (Liden & Herberholz 2008).

We are currently investigating how external conditions (e.g., changes in stimulus properties) and internal conditions (e.g., behavioral, motivational, and developmental state) affect the decisions that lead to discrete behavioral choices. 
By using a non-invasive technique to record neural activity (Herberholz et al. 2001, Herberholz et al. 2004a), we are also able to identify the underlying neural circuitry that controls the tail-flips produced in response to shadows. The different components of the circuitry are accessible for intracellular electrophysiology, and the effects of neuromodulators can be tested.

To identify discrete patterns of neural activity that are correlated with status-related behaviors and decision-making, we use manganese-enhanced Magnetic Resonance Imaging (MEMRI). Manganese, a paramagnetic contrast agent and calcium analog, can highlight active brain areas. Preliminary experiments with live crayfish have shown that they are well suited for MEMRI studies because they have no blood-brain barrier and can easily be restrained within the imaging apparatus. Crayfish tolerate long imaging sessions in high magnetic fields, and they can be placed in small imaging coils which results in images of very high spatial resolution. We have previously demonstrated the feasibility of MEMRI for identification and reconstruction of neural structures in crayfish; thus, manganese can be used as a contrast agent for crayfish neural tissue (Herberholz et al. 2004b). We are currently investigating the applicability of MEMRI for measurements of neural activity and identification of active neural pathways.

1. Liden W.H. and Herberholz J. (2008) Behavioral and neural responses of juvenile crayfish to moving shadows. The Journal of Experimental Biology 211: 1355-1361.
2. Herberholz J., C. McCurdy and D.H. Edwards (2007) Direct benefits of social dominance in juvenile crayfish. The Biological Bulletin 213: 21-27.
3. Herberholz J. (2007) The neural basis of communication in crustaceans. In: Evolutionary ecology of social and sexual systems: crustaceans as model organisms, J. E. Duffy and M. Thiel (eds). Oxford University Press: 71-89.
4. Song C.-K., J. Herberholz and D.H. Edwards (2006) The effects of social experience on the behavioral response to unexpected touch in crayfish. The Journal of Experimental Biology 209: 1355-1363.
5. Edwards D.H. and J. Herberholz (2005) Crustacean models of aggression. In: The Biology of Aggression, R. J. Nelson (ed). Oxford University Press: 38-61
6. Antonsen B.L., J. Herberholz and D.H. Edwards (2005) The retrograde spread of synaptic potentials and recruitment of presynaptic inputs. The Journal of Neuroscience 25 (12): 3086-3094
7. Herberholz J., C.J. Mims, X. Zhang, X. Hu and D.H. Edwards (2004) Anatomy of a live invertebrate revealed by manganese-enhanced Magnetic Resonance Imaging. The Journal of Experimental Biology 207: 4543-4550
8. Herberholz J., M.M. Sen and D.H. Edwards (2004) Escape behavior and escape circuit activation in juvenile crayfish during prey-predator interactions. The Journal of Experimental Biology 207: 1855-1863
9. Edwards D.H., F.A. Issa and J. Herberholz (2003) The neural basis of dominance hierarchy formation in crayfish. Microscopy Research and Technique 60: 369-376
10. Herberholz J., M.M. Sen and D.H. Edwards (2003) Parallel changes in agonistic and non-agonistic behaviors during dominance hierarchy formation in crayfish. The Journal of Comparative Physiology A 189: 321-325
11. Herberholz J., B.L. Antonsen and D.H. Edwards (2002) A lateral excitatory network in the escape circuit of crayfish. The Journal of Neuroscience 22 (20): 9078-9085 
12. Drummond J., F.A. Issa, C.K. Song, J. Herberholz, S.R. Yeh and D.H. Edwards (2002) Neural mechanisms of dominance hierarchies in crayfish. In: The Crustacean Nervous System, K. Wiese (ed).  Springer Verlag, Berlin: 124-135
13. Herberholz, J. and B. Schmitz (2001) Signaling via water currents in behavioral interactions of snapping shrimp (Alpheus heterochaelis). The Biological Bulletin 201 (1): 6-16
14. Herberholz J., F.A. Issa and D.H. Edwards (2001) Patterns of neural circuit activation and behavior during dominance hierarchy formation in freely behaving crayfish. The Journal of Neuroscience 21 (8): 2759-2767
15. Edwards D.H., B.L. Antonsen and J. Herberholz (2001) Network, neuronal and biochemical computations in the escape circuit of crayfish. In: Proceedings of the Eleventh Yale Workshop on Adaptive and Learning Systems, K. S. Narendra (ed). Center for Systems Science, Yale University, New Haven: 225-232
16. Herberholz J. and B. Schmitz (1999) Flow visualisation and high speed video analysis of water jets in the snapping shrimp (Alpheus heterochaelis). The Journal of Comparative Physiology A 185: 41-49
17. Herberholz J. and B. Schmitz (1998) Role of mechanosensory stimuli in intraspecific agonistic encounters in the snapping shrimp (Alpheus heterochaelis). The Biological Bulletin 195 (2): 156-167
18. Schmitz B. and J. Herberholz (1998) Snapping behaviour in intraspecific agonistic encounters in the snapping shrimp (Alpheus heterochaelis). The Journal of Biosciences 23 (5): 623-632
    

     click here for a complete list of publications including theses and abstracts (pdf) 

Undergraduate Research Assistant for Spring 2008 - position filled

PSYC 479-Special Research Problems in Psychology (1-3 credits). Prerequisites: Completion of nine credits in Psychology, a 3.0 GPA in Psychology and a 2.8 GPA overall. The student also needs a completed contract signed by the faculty sponsor and a departmental permission stamp. Course 
Research and data collection under individual faculty supervision, leading to a written research report.

1. What is the nature of the project?
Crayfish form stable dominance hierarchies through aggressive interactions. The winners of these fights dominate the losers and control access to valuable resources. This (continuative) project measures the effects of an intruder crayfish on established social dominance relationships in an environment that is unfamiliar to the animals.

2. What are the specific duties of the research assistant?
Animal care, behavioral experiments, digital video recordings and (elaborate) data analysis.

3. What form of written report will be required of the student? (Requirement for PSYC479 credit)
Brief written summary of experimental results in scientific format.

4. What are the faculty member's plans for meeting with the student?
Several times each week in the laboratory.

5. What will be the required readings for the student?
Scientific publications related to the research topic.

6. What are the start & end dates?
Spring semester 2008.

7. Are there any special skills or hours required?
Minimum of 8 hours per week (min. of 4 h/day); basic science background and strong motivation to work with crayfish.

8. Compensation?  (1-3 credits of PSYC479 is customary)
Up to three credits.