Reconstruction scheme for excitatory and inhibitory dynamics with quenched disorder: application to zebrafish imaging

Abstract

An inverse procedure is developed and tested to recover functional and structural information from global signals of brains activity. The method assumes a leaky-integrate and fire model with excitatory and inhibitory neurons, coupled via a directed network. Neurons are endowed with a heterogenous current value, which sets their associated dynamical regime. By making use of a heterogenous mean-field approximation, the method seeks to reconstructing from global activity patterns the distribution of in-coming degrees, for both excitatory and inhibitory neurons, as well as the distribution of the assigned currents. The proposed inverse scheme is first validated against synthetic data. Then, time-lapse acquisitions of a zebrafish larva recorded with a two-photon light sheet microscope are used as an input to the reconstruction algorithm. A power law distribution of the in-coming connectivity of the excitatory neurons is found. Local degree distributions are also computed by segmenting the whole brain in sub-regions traced from annotated atlas.

Two-photon all-optical electrophysiology for the dissection of larval zebrafish brain functional connectivity

“…Future efforts will be devoted to push further the volume addressable with AODs scanning, while concurrently improving the uniformity of energy delivery. Furthermore, leveraging transgenic strains that express the actuator under more selective promoters (such as vglut2 for glutamatergic and gad1b for GABAergic neurons) will undoubtedly help producing accurate inferences on network structures 76,77 , thus boosting the quest towards a comprehensive picture of zebrafish brain functional connectivity. Together, light-sheet microscopy and 3D optogenetics with AODs, along with the employment of larval zebrafish, offer a promising avenue for bridging the gap between microscale resolution and macroscale investigations, enabling the mapping of whole-brain functional connectivity at previously unattainable spatio-temporal scales.…”

Multimodal Characterization of Seizures in Zebrafish Larvae

“…The propagation of this wave-like pattern involves in a different manner diverse brain regions, with midbrain ones (namely, dorsal thalamus, optic tectum, medial tegmentum, and interpeduncular nucleus) showing the highest increase in the prominence of activity peaks. This aspect could be explained by the hub-like function exerted by larval midbrain [56][57][58]. Indeed, those hub regions have manifold incoming connections which could be responsible for tens to hundreds of action potential trains giving rise to high prominence peaks in calcium activity [59].…”

Signal propagation in complex networks

“…A whole-brain scaled model can be built from existing tools at the single-neuron level. For example, the leaky-integrate and fire (LIF) model [309,325,326] and the stochastic binary neuron model [327] are used for understanding how different components (excitatory and inhibitory neurons, synapses, and external excitatory inputs) and their interactions determine the global in-coming activity pattern. The LIF model is a classic model describing the membrane potential of neurons and well captures their nonlinearity (23).…”

“…Approaching from the network level also characterized propagation properties of the nervous system; non-random structure properties, such as power-law degree distribution [325] and a modular and hierarchical organization [327], were found in the zebrafish brain. Applied to brain-wide observation, tools of nonlinear dynamics have successfully reconstructed the organization and evolution of neural signals, and also improved the understanding of the influence of single-neuron physiology on behavior.…”