Deeper dive into all publications

Interplay between resource dynamics, network structure and spatial propagation of transient explosive synchronization in an adaptively coupled mouse brain network model

Question:Epileptic seizures are considered a dynamic disease of brain networks, representing a complex interplay between the organization of brain networks and the dynamics of metabolic resources. This interplay shapes how seizures initiate and spread in the brain. How do the structure of brain networks and the dynamics of resource allocation influence the generation and propagation of seizures?

Impact: Understanding seizure dynamics at the whole-brain level is crucial for controlling abnormal hypersynchronous activity. Currently, complete brain coverage recordings are lacking in both patients and animal models. In this study, we investigate seizure dynamics at whole brain level in silico. Moreover, our results support existing studies that suggest the cortico-thalamic initiation of generalized seizures, with regions primarily in the cortex initiating the seizures.

Avinash Ranjan, Saurabh R. Gandhi

Network Neuroscience

Fractional order modified Treves model: Simulation and Learning

Question:Can fractional order models capture the long first spike latency and downward adaptation of neurons in the Treves model?

Impact: We show that a fractional order modified Treves model can capture both of these features simultaneously, which was not previously observed in simple neuron models.

Y Vats, M Mehra, D Oelz, SR Gandhi

ICFDA (2023)

A survey of neurophysiological differentiation across mouse visual brain areas and timescales

Question:We previously showed that spevtral differentiation can identify specific brain areas that might be more involved in subjective perception. How does this metric, spectral differentation, depend on the timescale of observation, or change from one brain region to another?

Impact: We used the Allen Brain Observatory Visul Coding Neuropixels dataset to analyze the spectral differentiation of activity of ~50,000 neurons. We found that differentiation of single neurons is maximized at a timescale of ~100 ms, similar to the timescales of conscious perception; and the differentiation of activity of the entire visual cortex most faithfully reflects ‘conscious perception’ compared to individual areas in the visual cortex.

SR Gandhi, WGP Mayner, W Marshall, YN Billeh, C Bennett, SD Gale, C Mochizuki, JH Siegle, S Olsen, G Tononi, C Koch, A Arkhipov

Frontiers in Computational Neuroscience (2023)

Measuring stimulus-evoked neurophysiological differentiation in distinct populations of neurons in mouse visual cortex

Question:Decoding is an extrinsic approach - the experimenter knows what is shown to the subject, and then asks- activity in what brain region can predict what was shown? But what is shown can be very different from what was consciously perceived by the subject. Can a new metric (spectral differentiation) predict what was consciously seen by the subject?

Impact: While decoding neural responses from any of the observed visual areas in mice can predict what was shown to the mouse, spectral differentiation in only specific visual areas (AL, AM) and layers (L2/3) is increased for ethologically ‘meaningful’ compared to ‘meaningless’ stimuli. Could it possibly be predicting what the mouse actually saw, not just what it was shown?

WGP Mayner, W Marshall, YN Billeh, SR Gandhi, S Caldejon, A Cho, F Griffin, N Hancock, S Lambert, EK Lee, JA Luviano, K Mace, C Nayan, TV Nguyen, K North, S Seid, A Williford, C Cirelli, PA Groblewski, J Lecoq, G Tononi, C Koch, A Arkhipov

ENEURO.0280-21.2021 9 (1) (2022)

Influence of claustrum on cortex varies by area, layer, and cell type

Question:The claustrum, a centrally connected brain region, has been hypothetized to be involved in consciousness. How does the cortex respond to optogenetic stimulation of the mouse claustrum?

Impact: We found that unlike a few similar recent studies that suggest claustrum stimulation uniformly inhibits the cortex, claustrum stimulation can actually lead to a wide variety of responses in the cortex, depending on the cortical area and cell types observed. We characterized these responses in depth in this manuscript.

EG McBride, SR Gandhi, JR Kuyat, DR Ollerenshaw, A Arkhipov, C Koch, SR Olsen

Neuron (2022)

See further context here

Cooperation mitigates diversity loss in a spatially expanding microbial population

Question:The qualitative differences in the dynamics of pulled and pushed waves (2016 PNAS paper) has a tremendous impact on how the populations evolve, especially how they lose genetic diversity. Can we measure this impact under the well controlled conditions in the lab?

Impact: We demonstrate that pushed waves lose genetic diversity over 100x slower than pulled waves! This demonstrates a seriously large fitness advantage to populations that grow cooperatively compared to competitively.

SR Gandhi, KS Korolev, J Gore

PNAS 116 (47) 23582-23587 (2019)

See commentary by Mark Lewis.

Range expansions transition from pulled to pushed waves as growth becomes more cooperative in an experimental microbial population

Question:Can we predictably vary the local dynamics of a real biological population to obtain different types of emergent global dynamics in a controlled manner? I studied the eco-evolutionary dynamics in a spatially expanding yeast population.

Impact: We demonstrated the existence of long-predicted pulled and pushed waves in a real biological population in a quantitative manner for the first time.

SR Gandhi, EA Yurtsev, KS Korolev, J Gore

PNAS 113, 6922–6927 (2016)

See commentary by Mark Lewis.