Circuit mechanisms underlying multisensory integration in the superior colliculus

behaviours and spatially directed actions. Individual SC neurons respond to multiple sensory modalities, and the interaction between these inputs can generate complex multisensory response properties.

While local circuit mechanisms contribute to multisensory processing within the SC, long-range cortical inputs have been proposed to play a critical role in shaping nonlinear multisensory integration. However, the precise organisation of cortical and subcortical inputs onto functionally defined SC neuronal populations remains poorly understood. In particular, it is unknown how the anatomical organisation of inputs relates to the emergence of specific multisensory computations at the level of individual cell types. We hypothesise that distinct functional populations of SC neurons receive specific combinations of cortical and subcortical inputs that generate specialised representations of spatially aligned audiovisual information.

Using a custom-built hemispheric stimulation system, spatially coincident visual and auditory stimuli will be presented from multiple locations to probe multisensory responses under controlled behavioural conditions. Combining two- and three-photon calcium imaging will enable the functional mapping of visual, auditory, and multisensory neuronal populations across the SC. To uncover the circuit architecture underlying these functional responses, this project will use Barcoded Rabies In Situ Connectomics (BRISC), a high-throughput approach for mapping neural connectivity across the mouse brain, developed by Petr Znamenskiy’s lab. By combining functional imaging with large-scale connectivity reconstruction, this work will determine layer- and cell-type-specific connectivity rules and identify the long-range cortical and subcortical inputs that target distinct SC neuronal populations. Once we understood the circuitry underlying multisensory integration, we hope to use related approaches to elucidate the circuitry underlying sensorimotor transformations.

Together, these approaches will reveal how circuit organisation gives rise to multisensory representations in the SC. By linking functional responses, anatomical connectivity, and genetic identity, this project will establish how specific neuronal populations integrate information from different sensory modalities and may identify molecular markers associated with multisensory processing. Understanding the circuit principles underlying multisensory integration will provide fundamental insight into how the brain combines information from the environment to guide behaviour.

Candidate background

The successful candidate will either come from a degree in Neuroscience / Molecular Biology with a strong background and interest in mathematics / data science approaches.

Alternatively, the successful candidate will come from a degree in Bioengineering, Computational Biology and have a strong background, interest in and enthusiasm for experimental neuroscience / neurophysiology.

Extensive quantitative, analytical ability will be essential and experience in computer programming (ideally Python or Matlab) and enthusiasm for advanced data analysis approaches will be highly advantageous.

The lab is highly collaborative and ability and enthusiasm to work and communicate in a team is essential. Previous work with animals and experience in in vivo recordings or spatial transcriptomics is desirable but not essential as this can be part of the training programme.

Lab-specific question

Please describe any experience you have that might help you to interrogate the functional architecture of the brain.

Funding Notes

Successful applicants will be awarded a non-taxable annual stipend of £27,715 plus payment of university tuition fees. Students of all nationalities are eligible to apply.

References

1. Bianchini, G., Razafindrahaba, I., Moglie, M.J., Konstantinou, G., Cano-Ferrer, X., Imbert, A. and Iacaruso, M.F. (2025) Functional specialisation of multisensory temporal integration in the mouse superior colliculus. Nature Communications 16: 9615. PubMed abstract
2. Becalick, A., Blot, A., Strom, M. and Znamenskiy, P. (2025) Preprint: Barcoded Rabies In Situ Connectomics for high-throughput reconstruction of neural circuits. Available at: bioRxiv https://www.biorxiv.org/content/10.1101/2025.07.16.665048v1.full.pdf
3. Egea-Weiss, A., Turner-Bridger, B., Viduolyte, A., Marianelli, E., Znamenskiy, P. and Iacaruso, M.F. (2025) Preprint: Topographic alignment of auditory inputs to the visual cortex. Available at: bioRxiv https://www.biorxiv.org/content/10.1101/2025.07.29.667237v1.full.pdf
4. Alvarado, J.C., Stanford, T.R., Vaughan, J.W. and Stein, B.E. (2007) Cortex mediates multisensory but not unisensory integration in superior colliculus. Journal of Neuroscience 27: 12775–12786. PubMed abstract
5. Basso, M.A. and May, P.J. (2017) Circuits for Action and Cognition: A View from the Superior Colliculus. Annual Review of Vision Science 3: 197–226. PubMed abstract