nucleation

LIT-1494: Eligibility Traces and Plasticity on Behavioral Time Scales: Experimental Support of NeoHebbian Three-Factor Learning Rules

2 min read

Properties5
StatusActive — read in full 2026-10-24 (NOTE-1130) from the CC BY version of record; worth reading as the review that set out what the first direct experiments (2014–2017) showed about eligibility traces on the scale of seconds: in striatum about 1 s, in cortex 3–10 s with the modulator setting the sign, in hippocampus about 2 s. Mostly slices, one laboratory per region, by theoreticians whose models assumed the traces; they grant that other mechanisms could bridge the same gap, and what is well established is the hour-scale tag of consolidation.
Version3
Tagsneuroscience, learning-and-conditioning, anthology-candidate
Cited as “paper” byNOTE-1130 — Gerstner et al. — Eligibility traces and plasticity on behavioral time scales
Cited as “source” byTHEORY-1178 — In slices of striatum, visual and prefrontal cortex and hippocampus, Hebbian co-activation leaves a synaptic eligibility trace, lasting about 1 s in striatum, 3 to 10 s in cortex and about 2 s in CA1, that a later neuromodulator or plateau potential converts into a weight change and whose sign it can set: experimental support for three-factor learning rules on behavioural time scales, THEORY-909 — As reviewed by Gerstner et al. (2018) from five papers, mostly in slices and one laboratory per region, pairing pre- and postsynaptic activity changed the synapse when a neuromodulator or plateau potential followed within about 1 s in striatum, within 5 s (noradrenaline, LTP after pre-before-post pairing) or 2.5 s (serotonin, LTD after post-before-pre pairing) in visual and prefrontal cortex, and within about 2 s in CA1, and not at longer delays; the reviewers read this as a decaying synaptic eligibility trace and as experimental support for three-factor learning rules on behavioural time scales

Graph View

Gerstner, W., Lehmann, M., Liakoni, V., Corneil, D. & Brea, J. (2018). Eligibility traces and plasticity on behavioral time scales: Experimental support of neoHebbian three-factor learning rules. Frontiers in Neural Circuits 12: 53. doi:10.3389/fncir.2018.00053.

Key takeaways

From the reading, NOTE-1130. Page numbers are the article’s.

  • The rule. Co-activation sets a decaying flag; “a non-zero third factor is needed to transform the eligibility trace into a weight change”, and “the third factor also influences the direction of change” (p. 4).
  • The evidence is recent. Support for traces on the scale of seconds “has been collected only during the last few years” (p. 1): striatum, about 1 s, with dopamine; cortex, 5–10 s for LTP with noradrenaline and about 3 s for LTD with serotonin; CA1, about 2 s with plateau potentials (pp. 7–10).
  • What is established. “The framework is experimentally well-established in the context of synaptic consolidation” (p. 7), where the tag lasts about an hour.
  • Specificity comes from the flag. Under a broadcast signal, “among all the flagged synapses only those that show, over many trials, a correlation with the reward signal will be consistently reinforced” (p. 11).
  • Not the only solution. “there is nothing—apart from conceptual elegance—to favor eligibility traces over alternative neuronal mechanisms” (p. 12).

Why this is here

The exchange cited it at turn U11 for three-factor learning: activity that co-occurs is only marked as eligible, and a later signal decides whether it is kept. The abstract matches. The anthology may want it for its bearing on learning rules in machine learning, so the flag stands.

Corrected 2026-10-24, from the reading. The description is right. What CLAIM-443 cites it for, “three-factor rules are established”, is too strong: established for hour-scale consolidation, and recently supported in slices on the scale of seconds. The claim’s rule also lacks the decaying trace that learning from delayed outcomes needs. Filed from it: THEORY-909.

Backlinks