Novelty and Dopaminergic Modulation of Memory Persistence: A Tale of Two Systems. Issue 2 (February 2019)

• Record Type: Journal Article
• Authors: Duszkiewicz, Adrian J.; McNamara, Colin G.; Takeuchi, Tomonori; Genzel, Lisa
• Is Part Of: Trends in neurosciences. Volume 42:Issue 2(2019)
• Page Start: 102
• Page End: 114
• Publication Date: 2019-02
• Subjects: dopamine -- novelty -- memory consolidation -- hippocampus -- episodic memory -- semantic memory; Neurology -- Periodicals; Neurophysiology -- Periodicals; Neurobiology -- Periodicals; 612.8
• DOI: 10.1016/j.tins.2018.10.002
• Languages: English
• ISSNs: 0166-2236

Abstract

Abstract : Adaptation to the ever-changing world is critical for survival, and our brains are particularly tuned to remember events that differ from previous experiences. Novel experiences induce dopamine release in the hippocampus, a process which promotes memory persistence. While axons from the ventral tegmental area (VTA) were generally thought to be the exclusive source of hippocampal dopamine, recent studies have demonstrated that noradrenergic neurons in the locus coeruleus (LC) corelease noradrenaline and dopamine in the hippocampus and that their dopamine release boosts memory retention as well. In this opinion article, we propose that the projections originating from the VTA and the LC belong to two distinct systems that enhance memory of novel events. Novel experiences that share some commonality with past ones ('common novelty') activate the VTA and promote semantic memory formation via systems memory consolidation. By contrast, experiences that bear only a minimal relationship to past experiences ('distinct novelty') activate the LC to trigger strong initial memory consolidation in the hippocampus, resulting in vivid and long-lasting episodic memories. Highlights: Novelty induces dopamine release in the hippocampus, triggering memory consolidation to boost memory persistence. Two dopaminergic systems (the ventral tegmental area- and locus coeruleus-hippocampus systems) can stabilise memory through novelty-induced dopamine release in the hippocampus. Novel experiences can be viewed as a spectrum, from experiences that, while clearly novel, share some commonality with past experiences ('common novelty'), to more fundamentally distinct experiences that bear minimal relationships to past experiences ('distinct novelty'). We propose that events characterised by 'common novelty' boost memory retention via activation of the ventral tegmental area-hippocampus system, resulting in initial consolidation followed by systems consolidation to create neocortical, semantic, long-term memories. We further propose that events characterised by 'distinct novelty' lead to the boost of detailed hippocampal, episodic, long-term memory via activation of the locus coeruleus-hippocampus system through strong upregulation of the synaptic tagging and capture mechanism.