New Approach to PTSD Treatment

A new study led by Siqiong June Liu, PhD, has found that cerebellar inhibitory interneurons are essential for fear memory, a type of emotional memory formation. Inhibitory interneurons within the cerebellar circuitry act as gatekeepers and control the output of the cerebellar cortex. The formation of fear memory requires the activity of these interneurons. 

“While synaptic plasticity is considered the basis of learning and memory, modifications of the intrinsic excitability of neurons can amplify the output of neuronal circuits and consequently change behavior,” notes Dr. Liu. “In the cerebellum, we find that silencing molecular layer interneurons completely abolishes fear memory, revealing their critical role in memory consolidation.”

The research team found that fear conditioning suppresses hyperpolarization-activated cyclic nucleotide-gated (HCN) channels and enhances cerebellar interneuron excitability. HCN currents are similar to pacemakers in the brain because they help regulate rhythmic activity and communication between brain cells. HCN loss is driven by a learning-induced decrease in endocannabinoid levels. When the activity of these neurons is suppressed, experimental animals do not remember the experience a few hours after learning.

“Our study reveals that activity in cerebellar interneurons drives fear memory formation via a learning-specific increase in intrinsic excitability,” Liu concludes. “This highlights the importance of moving beyond traditional synaptic plasticity-focused investigations of memory formation and suggests a novel therapeutic approach for the treatment of PTSD.”

Sources:

Kathryn Lynn Carzoli, Georgios Kogias, Jessica Fawcett-Patel, Siqiong June Liu. Cerebellar interneurons control fear memory consolidation via learning-induced HCN plasticity. Cell Reports, 2023; 42 (9): 113057 DOI: 10.1016/j.celrep.2023.113057

Louisiana State University Health Sciences Center. “Potential new approach to PTSD treatment.” ScienceDaily. ScienceDaily, 13 September 2023. <www.sciencedaily.com/releases/2023/09/230913122754.htm>.

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