Brian Mulloney

Brian Mulloney

Position Title
Distinguished Research Professor

Unit
Department of Neurobiology, Physiology and Behavior

1155 Life Sciences
Bio

Profile Introduction

Neural control of locomotion; pattern-generation and circuit dynamics; neural basis of decision-making; computational neuroscience

Research Interests

I am interested in how an animal's nervous system produces the overt behaviors that we observe. My research concentrates on how the central nervous system of arthropods, particularly crayfish, works. The behaviors of these animals are complex, but their nervous systems have a structural elegance that makes the challenge of understanding these behaviors in cellular terms achievable. In answering questions about the neural basis of behaviors in these animals, we also provide probable explanations of complex behaviors in other animals, including vertebrates.

Some time ago, we began to analyze the central mechanisms that cause the swimmerets of crayfish to produce coordinated cycles of power-strokes and return-strokes whenever the animal swims forward. We demonstrated that each limb has its own module of neurons that can operate independently. This means that the normal coordination of movements of different limbs is imposed on these modules by a separate circuit of coordinating interneurons, and that we can study the organization of a module and of the coordinating circuit as separate problems.

My strategy is to combine electrophysiological experiments with computational analysis of the hypotheses these experiments generate. We have identified a small set of nonspiking local interneurons that are key components of each module. We have developed a minimal cellular model of the organization of a module, and are starting to test it experimentally. We have also described three types of intersegmental coordinating interneurons that are necessary and sufficient for normal intersegmental coordination, and described how these interneurons respond to changes in excitation of the system. We have developed a cellular model of the circuit formed by these interneurons. This model has dynamics similar to the dynamics of the real system, and that predicts the connections these interneurons make within their target modules.

Neural control of locomotion; pattern-generation and circuit dynamics; neural basis of decision-making; computational neuroscience

Grad Group Affiliations

  • Neuroscience

Labs

  • 1155 LSA
    • People in the Mulloney Lab: Michael Wright, Cynthia Weller and Brian Mulloney

Honors and Awards

  • Fellow of the Japan Society for Promotion of Science (1995)
  • Councillor of the International Society for Neuroethology (1992-1998)
  • Alexander v. Humboldt Research Fellowship
  • A.P. Sloan Foundation Research Fellow
  • Fellow of AAAS

    Professional Societies

    • Society for Neuroscience
    • International Society for Neuroethology
    • AAAS (Fellow)
    • American Physiological Society
    • Organization for Computational Neurosciences

    Degrees

    • 1963 BS (Zoology and Chemistry) McGill University
    • 1967 MA (Zoology) University of California, Berkeley
    • 1969 PhD (Zoology) University of California, Berkeley

    Publications

    Weller, C.A., T.M. Hochhaus, T.M. Wright Jr., and B. Mulloney (2015) A classic improved: Minor tweaks yield major benefits in crayfish slow-flexor preparations. J. Undergrad. Neurosci. Edu. 13: A74-A80.

    Zhang C, RD Guy, B Mulloney, Q Zhang, and TJ Lewis (2014) The neural mechanism of optimal limb coordination in crustacean swimming. Proc. Nat. Acad. Sci. 111:13840-13845.

    Mulloney B, CR Smarandache-Wellmann, C Weller, WM Hall, and RA DiCaprio (2014) Proprioceptive feeback modulates coordinating information in a system of segmentally-distributed microcircuits. J Neurophysiol 112:2799-2809.

    Smarandache-Wellmann CR, Weller C, and Mulloney B.(2014) Mechanisms of coordination in distributed neural circuits: Decoding and integration of coordinating information. J.Neurosci. 34: 793-803.

    Smarandache-Wellmann CR, C Weller, TM Wright Jr. and B Mulloney (2013) Five types of non-spiking interneurons in the local pattern-generating circuits of the crayfish swimmeret system. J Neurophysiol. 110:344-357

    Mulloney B and CR Smarandache-Wellmann (2012) Neurobiology of the crustacean swimmeret system. Prog.Neurobiol. 96:242-267.

    Mulloney, B and CR Smarandache (2010) Fifty years of CPGs: two neuroethological papers that shaped the course of neuroscience. Frontiers in Behavioral Neuroscience 4 (45): 1-8.

    Smarandache, C.R., W.M. Hall, and B. Mulloney (2009) Coordination of rhythmic motor activity by gradients of synaptic strength in a neural circuit that couples modular neural oscillators. J Neurosci. 29: 9351-9360.

    Tschuluun N, WM Hall, and B. mulloney (2009) State-changes in the swimmeret system: a neural circuit that drives locomotion. J. Exp. Biol. 212:3605-3611.

    Hedrick, AV, M Hisada, and B Mulloney (2007) Tama-kugel: Hardware and software for measuring direction, distance, and velocity of locomotion by insects. J. Neurosci. Methods 164: 86-92.

    Mulloney B and WM Hall (2007) Not by spikes alone: Responses of coordinating neurons and the swimmeret system to local differences in excitation. J Neurophysiol 97:436-450.

    Mulloney B and Hall WM (2007) Local and intersegmental interactions of coordinating neurons and local circuits in the swimmeret system. J Neurophysiol. 98: 405-413.

    Mulloney B, Harness PI, Hall WM (2006) Bursts of information: coordinating interneurons encode multiple parameters of a periodic motor pattern. J Neurophysiol 95:850-861.

    Mulloney B (2005) A method to measure the strength of multi-unit bursts of action-potentials. J Neurosci Meth 146:98-105.

    Mulloney B (2003) During fictive locomotion, graded synaptic currents drive bursts of impulses in swimmeret motor neurons. J. Neurosci. 23:5953-5962.

    Mulloney B and WM Hall (2003) Local commissural interneurons integrate information from intersegmental coordinating interneurons. J. Comp. Neurol. 466: 366-376.

    Jones SR, B Mulloney, TJ Kapper, and N Kopell (2003) Coordination of cellular pattern-generating circuits that control limb movements: The sources of stable differences in intersegmental phase. J. Neurosci. 23: 3457-3468.

    Mulloney B, N Tschuluun, and WM Hall (2003) Architectonics of crayfish ganglia. Microscopy Res. and Tech. 60: 253-265.

    Tschuluun N, WM Hall, and B Mulloney (2001) Limb movements during locomotion: Tests of a model of an intersegmental coordinating circuit. J Neurosci 21: 7859-7869

    Nakagawa H, and B Mulloney (2001) Local specifications of relative strengths of synapses between different abdominal stretch-receptor axons and their common target neurons. J. Neurosci. 21:1645-1655

    Mulloney, B and WM Hall (2000) Functional organization of crayfish abdominal ganglia: III. Swimmeret motor neurons. J. Comp. Neurol. 419: 233-243

    Namba, H. and B. Mulloney (1999) Coordination of limb movements: Three types of intersegmental interneurons in the swimmeret system, and their responses to changes in excitation. J Neurophysiol. 81:2437-2450

    Skinner FK and B Mulloney (1998) Intersegmental coordination of limb movements during locomotion: mathematical models predict circuits that drive swimmeret beating. J Neurosci. 18:3831-3842

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