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erek
[H]F Junkie
- Joined
- Dec 19, 2005
- Messages
- 10,894
Yall hookin it up, or what's going on? if i may ask that is.
"Episodic memory requires linking events in time, a function dependent on the hippocampus. In “trace” fear conditioning, animals learn to associate a neutral cue with an aversive stimulus despite their separation in time by a delay period on the order of tens of seconds. But how this temporal association forms remains unclear. Here we use 2-photon calcium imaging to track neural population dynamics over the complete time-course of learning and show that, in contrast to previous theories, the hippocampus does not generate persistent activity to bridge the time delay. Instead, learning is concomitant with broad changes in the active neural population in CA1. While neural responses were highly stochastic in time, cue identity could be reliably read out from population activity rates over longer timescales after learning. These results question the ubiquity of neural sequences during temporal association learning, and suggest that trace fear conditioning relies on mechanisms that differ from persistent activity accounts of working memory.
In addition to helping to map the circuitry involved in associative learning, these findings also provide a starting point to more deeply explore disorders involving dysfunctions in associative memory, such as panic and pos-ttraumatic stress disorder.
"While our study does not explicitly model the clinical syndromes of either of these disorders, it can be immensely informative," said Dr. Ahmed, who is also a member of the Losonczy lab at Columbia's Zuckerman Institute. "For example, it can help us to model some aspects of what may be happening in the brain when patients experience a fearful association between two events that would, to someone else, not elicit fright or panic."
The paper is titled "Hippocampal network reorganization underlies the formation of a temporal association memory.""
https://medicalxpress.com/news/2020-05-brain-link-events-memory-reveals.html
"Episodic memory requires linking events in time, a function dependent on the hippocampus. In “trace” fear conditioning, animals learn to associate a neutral cue with an aversive stimulus despite their separation in time by a delay period on the order of tens of seconds. But how this temporal association forms remains unclear. Here we use 2-photon calcium imaging to track neural population dynamics over the complete time-course of learning and show that, in contrast to previous theories, the hippocampus does not generate persistent activity to bridge the time delay. Instead, learning is concomitant with broad changes in the active neural population in CA1. While neural responses were highly stochastic in time, cue identity could be reliably read out from population activity rates over longer timescales after learning. These results question the ubiquity of neural sequences during temporal association learning, and suggest that trace fear conditioning relies on mechanisms that differ from persistent activity accounts of working memory.
In addition to helping to map the circuitry involved in associative learning, these findings also provide a starting point to more deeply explore disorders involving dysfunctions in associative memory, such as panic and pos-ttraumatic stress disorder.
"While our study does not explicitly model the clinical syndromes of either of these disorders, it can be immensely informative," said Dr. Ahmed, who is also a member of the Losonczy lab at Columbia's Zuckerman Institute. "For example, it can help us to model some aspects of what may be happening in the brain when patients experience a fearful association between two events that would, to someone else, not elicit fright or panic."
The paper is titled "Hippocampal network reorganization underlies the formation of a temporal association memory.""
https://medicalxpress.com/news/2020-05-brain-link-events-memory-reveals.html
