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Savvateev, I.

Publications and source records attributed to Savvateev, I..

2 recordsLinked to original sources

Functional-based parcellation of the mouse prefrontal cortex for network perturbation analysis

The prefrontal cortex (PFC) is a region of the brain involved in higher-order cognitive processes such as attention, emotional regulation, and social behavior, making it a hotspot for an ongoing clinical and fundamental research. Importantly, its functionality is intricately interconnected within a wide array of functional networks encompassing multiple other brain areas. However, the delineation of distinct subdivisions within the mouse PFC and their contributions to the broader brain network function remain topics of ongoing debate. In the current study, we used resting-state functional magnetic resonance imaging (rsfMRI) from a large cohort of wildtype animals to derive the functional-connectivity (FC) based parcellation of the mouse PFC with voxel resolution. Our findings indicate the presence of FC-based clusters that deviate from the established anatomical subdivisions within the cingulate and prelimbic areas, while they align in infralimbic and orbital cortices. To further underscore the association of these FC-based clusters with distinct functional networks, we performed network-specific perturbations using chemogenetics in the identified clusters in dorsal PFC and monitor the elicited effects with fMRI (chemo-fMRI). Our recordings revealed that FC perturbations were observed only within the functional networks linked to the targeted clusters and did not spread to neighbouring anatomical areas or functional clusters. We propose that FC-based parcellation is a valuable approach for tracking the impact of external activations and confirming the precise site of activation. O_FIG O_LINKSMALLFIG WIDTH=127 HEIGHT=200 SRC="FIGDIR/small/586664v1_ufig1.gif" ALT="Figure 1"> View larger version (19K): org.highwire.dtl.DTLVardef@11d4042org.highwire.dtl.DTLVardef@165cb5forg.highwire.dtl.DTLVardef@b0a4aorg.highwire.dtl.DTLVardef@d093c9_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

Multipair phase-modulated temporal interference electrical stimulation combined with fMRI.

Temporal Interference stimulation (TIS) is a promising non-invasive brain stimulation technique exploiting frequency-shifted kHz fields to modulate oscillatory neural activity without invasive procedures. While human studies suggest TIS efficacy in targeting relatively deep brain structures, recent computational modeling and animal studies indicate potential off-target stimulations via the application of standard TIS protocols. Here, we computationally optimized TIS targeting for the prefrontal cortex (PFC) in mice. Combining in vivo electrophysiological recordings, intracellular calcium dynamics with fiber photometry, and functional MRI, we confirmed TIS-induced amplitude modulation, neuronal entrainment and hemodynamic responses in the PFC, while also identifying off-target modulations. To mitigate off-target effects, we propose a novel configuration with three electrode pairs, one of which is actively phase-shifted by 180 degrees. This cancelling field significantly enhanced TIS focality, reducing off-target effects without compromising the TIS efficacy in the target area. This work effectively addresses one of TIS most critical shortcomings and opens new avenues for research and clinical applications. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=178 SRC="FIGDIR/small/571679v2_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@b04067org.highwire.dtl.DTLVardef@154549aorg.highwire.dtl.DTLVardef@17e63c3org.highwire.dtl.DTLVardef@c7a341_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗