UPCOMING

Nicolas Guyon, PhD student in the CarlenLab will defend his thesis May 21 2021 at 14.00!

Place: Eva & Georg Klein hall, Biomedicum + zoom

Opponent: Kathleen Cho, UCSF, CA, USA.

Committee:

Victoria Puig Velasco, Mar Institute for Medical Research Barcelona, Spain.

Paolo Medini, Umeå University, Umeå, Sweden

Rochellys Diaz Heijtz, Karolinska Institutet, Stockholm, Sweden

2x Guyon N et al are out!

Network asynchrony underlying increased broadband gamma power

Nicolas Guyon, Leonardo Rakauskas Zacharias, Eliezyer Fermino de Oliveira, Hoseok Kim, João Pereira Leite, Cleiton Lopes-Aguiar and Marie Carlén

Journal of Neuroscience 16 February 2021, JN-RM-2250-20. LINK

Brain oscillations are fundamental to the coordination of neuronal activity across neurons and structures. Gamma oscillations (30-80 Hz) have received particular attention through their association with perceptual and cognitive processes. Synchronous activity of inhibitory PV interneurons generates cortical gamma oscillation, but, paradoxically, PV neuron deficiency is associated with increases in gamma oscillations. We here reconcile this conundrum and show how deficient PV inhibition can lead to increased and asynchronous excitatory firing, contaminating the LFP and manifesting as increased gamma power. Thus, increased gamma power does not always reflect a genuine rhythm. Further, we show that ketamine-induced gamma increases are caused by separate network mechanisms.

Adult trkB signaling in pavalbumin interneurons is essential to prefrontal network dynamics

Nicolas Guyon, Leonardo Rakauskas Zacharias, Josina Anna van Lunteren, Jana Immenschuh, Janos Fuzik, Antje Märtin, Yang Xuan, Misha Zilberter, Hoseok Kim, Konstantinos Meletis, Cleiton Lopes-Aguiar and Marie Carlén

Journal of Neuroscience 16 February 2021, JN-RM-1848-20. LINK

BDNF/trkB signaling promotes the maturation of inhibitory PV interneurons – neurons central to local cortical dynamics, gamma rhythms, and cognition. Here, we used a novel viral approach for reduced BDNF/trkB signaling in PV interneurons in the mPFC to establish the role of BDNF/trkB signaling in adult prefrontal network activities. Reduced BDNF/trkB signaling caused pronounced morphological alterations, reduced PV inhibition, and deficient prefrontal network dynamics. The altered network activity appeared to manifest across stimuli and brain states and was associated with aberrant LFP activities and increased aggression. The results demonstrate that adult BDNF/trkB signaling is essential to PV inhibition and prefrontal circuit function and directly links BDNF/trkB signaling to network integrity in the adult brain.