Seminar – Cheng-Chang Lien

Venue : Centre Broca

Cheng-Chang Lien, MD, PhD
Dean, College of Life Sciences
Chair Professor, Institute of Neuroscience
National Yang Ming Chiou Tung University, Taiwan

Invited by Eric Boué-Grabot

Title

Distinct Dorsal and Ventral Mossy Cell Dynamics Coordinate Associative Fear Learning

Abstract

The hippocampus exhibits pronounced functional specialization along its dorsal–ventral axis, yet how these domains are dynamically coordinated during emotional learning remains unresolved. Here, we identify dentate gyrus mossy cells (MCs) as a longitudinal integrative circuit linking dorsal and ventral hippocampal processing during associative fear learning. Using in vivo calcium imaging in mice undergoing auditory fear conditioning, we find that dorsal MCs preferentially encode conditioned stimulus (CS) information, whereas ventral MCs are selectively engaged by the unconditioned stimulus (US). During memory recall, dorsal MCs maintain CS-related activity, while ventral MCs display temporally coordinated activation in the absence of the US, suggesting internally driven ensemble dynamics. Causal perturbation with chemogenetic silencing or optogenetic inhibition of either population disrupts freezing behavior, indicating that both dorsal and ventral MC activity is required for fear expression. Together, these findings reveal a division of labor in which dorsal MCs represent predictive cues and ventral MCs convey aversive value, with their coordinated activity enabling the formation and expression of associative fear memory.

Biosketch

My laboratory investigates brain circuits and behavior, with a particular focus on the neural mechanisms underlying emotion and cognition within the limbic system, specifically the hippocampus and amygdala. By integrating optogenetics and chemogenetics with electrophysiology and calcium imaging, we establish causal links between specific neural circuits and behavioral outcomes. Additionally, we utilize optogenetics-assisted circuit mapping to delineate the organization of these networks. Our research highlights the critical role of GABAergic circuitry in regulating network dynamics and cognitive functions.

Publications

1. The enigmatic mossy cell of the dentate gyrus. Scharfman HE. Nat Rev Neurosci. 2016 Sep;17(9):562-75
2. Elevation of hilar mossy cell activity suppresses hippocampal excitability and avoidance behavior. Wang KY, Wu JW, Cheng JK, Chen CC, Wong WY, Averkin RG, Tamás G, Nakazawa K, Lien CC. Cell Rep. 2021 Sep 14;36(11):109702.
3. Connectivity and synaptic features of hilar mossy cells and their effects on granule cell activity along the hippocampal longitudinal axis. Abdulmajeed WI, Wang KY, Wu JW, Ajibola MI, Cheng IH, Lien CC. J Physiol. 2022 Jul;600(14):3355-3381.

• Dates
  On 30 November 2026 at 14:00