Somatostatin peptide signaling dampens cortical circuits and promotes exploratory behavior

Brockway, D. F.; Moyer, J. B.; Aloimonos, C. M.; Clarity, T.; Griffith, K. R.; Smith, G. C.; Dao, N. C.; Hossain, M. S.; Drew, P. J.; Gordon, J. A.; Kupferschmidt, D. A.; Crowley, N. A.

doi:10.1101/2022.07.18.499817

bioRxiv · 10.1101/2022.07.18.499817

Somatostatin peptide signaling dampens cortical circuits and promotes exploratory behavior

Brockway, D. F.·Moyer, J. B.·Aloimonos, C. M.·Clarity, T.·Griffith, K. R.·Smith, G. C.·Dao, N. C.·Hossain, M. S.·Drew, P. J.·Gordon, J. A.·Kupferschmidt, D. A.·Crowley, N. A.

View original source ↗Export metadata ↓

Abstract

Somatostatin (SST) neurons in the prelimbic (PL) cortex mediate a variety of behavioral states. However, little is known about the actions of somatostatin peptide signaling in shaping cortical functioning and behavior. Here, we sought to characterize the unique physiological and behavioral roles of the SST peptide in the PL cortex. We employed a combination of ex vivo pharmacologic and optogenetic electrophysiology, in vivo calcium monitoring, and in vivo peptide pharmacology to explore the role of SST neuron and peptide signaling in the mouse PL cortex. Whole-cell slice electrophysiology was conducted in pyramidal and GABAergic neurons in the PL cortex of C57BL/6J and SST-IRES-Cre male and female mice to characterize the pharmacological mechanism of SST signaling. Fiber photometry of GCaMP6f fluorescent calcium signals from SST neurons was conducted to characterize the activity profile of SST neurons during exploration of an elevated plus maze (EPM) and open field test (OFT). We further used local delivery of both a broad SST receptor (SSTR) agonist and antagonist into bilateral PL cortex to test causal effects of SST administration and receptor blockade on these same exploratory behaviors. SSTR activation broadly hyperpolarized layer 2/3 pyramidal neurons in the PL cortex in both male and female mice ex vivo, an effect that was recapitulated with optogenetic stimulation of SST neurons, through both monosynaptic and polysynaptic GABA neuron-mediated mechanisms of action. This hyperpolarization was blocked by pre-application of the SSTR antagonist cyclo-somatostatin (cyclo-SST) and was non-reversible. SST neurons in PL were activated during EPM and OFT exploration, indicating task-related recruitment of these neurons. Lastly, in line with this exploration-related activity profile, SSTR agonist administration directly into the PL enhanced open arm exploration in the EPM, while in vivo administration of an antagonist had no effect. Together, this work describes a broad ability for SST peptide signaling to modulate microcircuits within the prefrontal cortex and related exploratory behaviors.

Source connections

Published article ↗

Explore related subjects

neuroscience Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Brockway, D. F., Moyer, J. B., Aloimonos, C. M., Clarity, T., Griffith, K. R., Smith, G. C., Dao, N. C., Hossain, M. S., Drew, P. J., Gordon, J. A., Kupferschmidt, D. A., Crowley, N. A.. 2022-07-20. Somatostatin peptide signaling dampens cortical circuits and promotes exploratory behavior. https://doi.org/10.1101/2022.07.18.499817

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Exploring subacute effects of a DMT and harmine meditation retreat on the brain's control energy landscape

Modeling the brain as a controllable structural network allows the estimation of the control energy (CE) required to reach functional states, where low-CE states are more accessible. Psychedelics are thought to acutely flatten the brain's CE landscape, broadening the repertoire of reachable states, but whether this reorganization persists into the subacute ``afterglow" window is largely unknown. This exploratory study uses rs-fMRI from a randomized, double-blind, placebo-controlled trial (N = 39; 19 verum [N,N-dimethyltryptamine (DMT) + harmine, Ayahuasca-inspired formulation], 20 placebo) scanned before and after a three-day meditation retreat. We compute CE on a group human connectome project (HCP) structural connectome under two approaches that emphasize long and short timescale dynamics. Globally, we found no systematic shift in the distribution of CE between transitions, however mean CE increased in both groups at the long timescale approach. Surviving network effects emerge when a network's intrinsic timescale matches the stabilization regime. In the long timescale regime, the central executive network (CEN) showed an increase in post-retreat CE within the verum group that survived Benjamini-Hochberg False Discovery Rate (FDR-BH) correction. Although CE and functional connectivity are distinct, this higher CEN cost may relate to the reduced within-network connectivity previously reported subacutely after psilocybin. The default mode network (DMN) also showed a post-retreat CE increase in both groups, but neither change survived FDR correction. In the short timescale approach, the visual network (VN) showed a FDR-BH CE decrease within the verum group, consistent with reduced dynamical demand in a region acutely engaged by DMT. To examine whether changes were concentrated in less accessible states, we additionally analyzed rare brain states, defined by the top decile of information content. This analysis revealed a modest session x condition interaction in the long timescale approach. Overall, the two timescale lenses surface different network effects, that align with cortical timescale hierarchies. These findings point to network- and timescale-specific, rather than global, CE changes in the afterglow window, though effects are small and heterogeneous and require confirmation in larger samples. Characterizing whether and where psychedelic effects persist into the subacute window is relevant to psychedelic-assisted therapy, including safety, therapeutic timing, and durability of drug effects. More broadly, considering cortical timescale hierarchies may help identify network-specific CE changes that might be less apparent when networks are evaluated under a single dynamical timescale.

neuroscience↗

bioRxiv2026

Advanced meditation stabilizes cortical dynamics through inhibitory gain control linked to absorptive depth

Advanced meditation can shift conscious experience from ordinary body- and world-centered awareness toward absorption, detachment and dissociation-like states, yet the neural mechanisms that stabilize these immersive states remain unclear. We studied 18 long-term meditators during eyes-open rest and Rajyoga meditation, a practice in which practitioners reduce bodily identification while enhancing inner self-awareness. We combined multidimensional neural approach including frontal EEG spectral power, temporal non-stationarity and corticothalamic neural-field modeling, because these measures probe underlying complementary levels of the brain state transition: the strength of neural activity, its temporal stability, and the circuit level inhibition-excitation gain mechanisms. This framework is especially relevant to meditation because oscillatory, temporal organization may distinguish stable meditative states, and corticothalamic dynamics are closely linked to arousal and conscious state regulation. We correlated meditation induced neural changes with subjective ratings of absorption and dissociation. Compared with rest, meditation was associated with higher beta1, beta2 and gamma power, with no change in the slower bands (delta, theta and alpha), and with lower beta-band temporal non-stationarity, indicating a more stable expression of fast cortical dynamics. Fitting the corticothalamic model to the EEG spectra showed stronger cortical inhibitory gain and lower effective intracortical gain, placing meditation in an inhibition-dominant regime, with lower gain in the loop between excitatory and inhibitory neurons within the cortex. During meditation, these model estimates were related to subjective absorption and showed trend level links with dissociation. Together, these findings suggest that Rajyoga meditation stabilizes cortical dynamics through inhibitory gain control, linking absorption (deep and steady attention on the meditation) to dissociation-like self-detachment.

neuroscience↗

bioRxiv2026

CoReg, tracking-based motion compensation for in vivo calcium imaging

In vivo calcium imaging enables the observation of neural activity with high spatial and temporal resolution. However, recordings are frequently affected by motion artifacts caused by animal movement, physiological processes, tissue drift, or instability of the imaging setup. These artifacts make signal extraction harder and reduce the consistency of downstream analyses. Current registration methods can correct rigid and non-rigid motion, but often estimate motion from individual frames or image patches and make limited use of temporal information. In addition, activity-driven fluorescence changes can make it difficult to distinguish changes in image appearance from actual motion. Here, we treat motion correction in calcium imaging as a point tracking problem and introduce CoReg, an open-source Python- based software tool with a graphical user interface. We benchmark CoReg against established registration methods using fluorescence imaging datasets from multiple species. CoReg performs competitively with or better than existing approaches across several settings. We further show that its performance is robust to the choice of tracked points, making the method straightforward to apply. CoReg includes implementations of both our method and the evaluated established methods. Our results show that tracking-based registration provides a simple and reliable approach for motion correction in vivo calcium imaging.

neuroscience↗