Department of Zoology

 

Neurobiology

Swidbert Ott

Royal Society Research Fellow

Email: sro21@.cam.ac.uk

Tel.: +44 (0)1223 769014

 

Mechanisms of Behavioural Plasticity in Locust Swarm Formation

My research is aimed at understanding the mechanisms that permit animals to adapt their brains, bodies and behaviour to changing environmental conditions. As a model we use the Desert Locust, Schistocerca gregaria, which undergoes an extreme and economically damaging form of such environmentally driven phenotypic plasticity.

Locust swarms are a serious threat to agriculture across Africa and Asia. These devastating outbreaks are the ultimate manifestation of the capacity of locusts to transform between a little-seen solitary phase and a brightly-coloured, swarming gregarious phase in response to changes in population density. In a recent breakthrough discovery, we found that the initial transition to gregarious behaviour is mediated by a surge of the neurochemical serotonin in the locust's nervous system. Serotonin is present in the brains of all animals, and in humans plays an important role in controlling our interactions with each other and the world. We now seek to understand how serotonin affects neurons within individuals, which in turn leads to changes in how locusts interact with each other, driving a reinterpretation of the locust genotype to yield a profoundly different phenotype.

This research problem intrinsically spans many levels of biological process and demands a broad and interdisciplinary approach. This is reflected in our research, which links multiple domains of biological organization from single genes and molecules, to changes in identified nerve cells and their connections, to behaviour and anatomy, group interactions and ecology. Accordingly we make use of a wide range of techniques including the quantitative analysis of behaviour, electrophysiology of identified neurones and circuits, laser confocal microscopy and image analysis, and biochemical and molecular analysis of neural signalling mechanisms.

Understanding the mechanisms by which locusts change phase will ultimately help develop more targeted control methods that prevent the formation of swarms and at the same time lessen the collateral damage caused by pesticides. The wider significance of our research is in gaining a deeper understanding of the mechanisms that integrate genetic and environmental information to coordinate the expression of complex phenotypes. Humans and animals share fundamental mechanisms through which changes in our environment affect the workings of our brains, the nature of our interaction with conspecifics, and ultimately who we are.

Nitric Oxide Signalling in Invertebrate Nervous Systems

I also have a long-standing research interest in nitric oxide (NO), an unusual signalling molecule with an evolutionarily conserved role in learning and memory. What sets NO apart from conventional neurotransmitters is that it is highly diffusible and may thus spread freely from its release sites. This poses the question to what extent such "volume signals" do indeed occur in the brain and to what end they are used. I have resolved long-standing uncertainties about the expression architecture of NO synthase in invertebrate nervous systems and the results implicate NO in an unexpectedly diverse array of functions. I have combined anatomical analysis of NO source and NO target neurones with models of NO diffusion, showing that signals can indeed spread freely over tens of micrometers and thus by-pass the point-to-point connectivity of synaptic networks. An exciting future extension of this will be to exploit the experimental advantages offered by invertebrate nervous systems for characterising the spatio-temporal dynamics of NO in vivo and its effects on the processing of sensory information in the nervous system.

Research Opportunities

Please contact me at any time if you are interested in joining the lab!

Postgraduate Training: PhD and MPhil Opportunities

The Postgraduate Training Programme in our Department offers excellent opportunities. If you are interested in joining us as a PhD or MPhil research student, please drop by my office (S24A) or contact me by e-mail to discuss funding options and details.

Selected publications

  • Burrows M, Rogers SM, Ott SR (2011) Epigenetic remodelling of brain, body and behaviour during phase change in locusts. Neural Systems & Circuits 1:11
  • Simões P, Ott SR, Niven JE (2011) Associative olfactory learning in the desert locust, Schistocerca gregaria. J. Exp. Biol. 214:2495–503.
  • Ott SR, Rogers SM (2010) Gregarious desert locusts have substantially larger brains with altered proportions compared with the solitarious phase. Proc. R. Soc. B 277:3087–96. [Commentary: Brain Behav. Evol. 77:3–4]
  • Munch D, Ott SR, Pfluger HJ (2010) The three dimensional distribution of NO sources in a primary mechanosensory integration centre in the locust and its implications for volume signaling. J. Comp. Neurol. 518:2903–16. [Cover Image]
  • Blackburn LM, Ott SR, Matheson T, Burrows M, Rogers SM (2010) Motor neurone responses during a postural reflex in solitarious and gregarious desert locusts. J. Insect Physiol. 56:902–10.
  • Anstey ML, Rogers SM, Ott SR, Burrows M, Simpson SJ (2009) Serotonin mediates behavioral gregarization underlying swarm formation in desert locusts. Science 323:627–30. [Cover Image; Commentaries: Science 323:594–5 and Editor’s Choice, Sci. Signal. 2:ec37].
  • Ott SR (2008) Confocal microscopy in large insect brains: zinc-formaldehyde fixation improves synapsin immunostaining and preservation of morphology in whole-mounts. J. Neurosci. Methods 172:220–30.
  • Ott SR, Philippides A, Elphick MR, O'Shea M (2007) Enhanced fidelity of diffusive nitric oxide signalling by the spatial segregation of source and target neurones in the memory centre of an insect brain. Eur. J. Neurosci. 25:181–90. [Cover Image]
  • Ott SR, Aonuma H, Newland PL, Elphick MR (2007) Nitric oxide synthase in crayfish walking leg ganglia: segmental differences in chemo-tactile centers argue against a generic role in sensory integration. J. Comp. Neurol. 501:381–99.
  • Ott SR, Delago A, Elphick MR (2004). An evolutionarily conserved mechanism for sensitization of soluble guanylyl cyclase reveals extensive nitric oxide-mediated upregulation of cyclic GMP in insect brain. Eur. J. Neurosci. 20(5): 1231–1244.
  • Philippides A, Ott SR, Husbands P, O'Shea M (2005) Modeling cooperative volume signalling in a plexus of NOS expressing neurons. J. Neurosci. 25:6520–32.
  • Korneev S, Straub V, Kemenes I, Korneeva E, Ott SR, Benjamin P, O'Shea M (2005) Timed and targeted differential regulation of NOS and antiNOS genes by reward conditioning leading to long-term memory formation. J Neurosci 25:1188–92.
  • Römer H, Hedwig B, Ott SR (2002) Contralateral inhibition as a sensory bias: the neural basis for a female preference in a synchronously calling insect. Eur J Neurosci 15:1655–62.
  • Ott SR, Jones IW, Burrows M, Elphick MR (2000) Sensory afferents and motor neurons as targets for nitric oxide in the locust. J Comp Neurol 422:521–32.
  • Ott SR, Burrows M (1998) Nitric oxide synthase in the thoracic ganglia of the locust: distribution in the neuropiles and morphology of neurones. J Comp Neurol 395:217–230.
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