FocusStack and StimServer

New, open-source toolboxes for visual stimulation and analysis of two-photon imaging data

1st December, 2014
Multiple-trial GCAMP6m calcium responses to a natural movie stimulus.

Two-photon calcium imaging of neuronal responses is an increasingly accessible technology for probing population responses in cortex at single cell resolution, and with reasonable and improving temporal resolution. However, analysis of two-photon data is usually performed using ad-hoc solutions. To date, no publicly available software exists for straightforward analysis of stimulus-triggered two-photon imaging experiments, while incorporating information about stimulus triggers. In addition, the increasing data rates of two-photon acquisition systems imply increasing cost of computing hardware required for in-memory analysis.

Pattern motion responses in mouse visual cortex

Model-based analysis of cortical responses

8th August, 2015

Example imaging region in mouse V1

Example imaging region in mouse V1

Green: OGB labelling of neurons. Red: Sulforhodamine labelling of astrocytes. Scale: 50um.

In visual cortex, information about features such as edges or textures with particular orientations must be integrated to recognize a visual scene or object. In principle, the architecture of rodent cortex would enable local circuits to integrate sensory information — however, whether feature integration occurs in rodent primary sensory areas has not been examined directly. Our results show that a broad range of pattern integration already takes place at the level of V1.

How connectivity rules affect cortical behaviour

Analytical examination of eigenvalue spectra

24th April, 2015
An example eigenvalue spectrum for a sparse network.

How does the behaviour and stability of a neuronal network depend on the connectivity rules used to build it? A common approach is to build many stochastic instances of a network, tweak the parameters, simulate and analyse, and then try to derive an impression about stability. We instead used an analytical approach, to directly relate connectivity rules and parameters to bounds on stability.