Overview
Which changes first during stimulus omission — the local field potential, or spiking?
Primary population-level result
A larger fraction of high-frequency LFP responses (beta, low gamma, high gamma) are temporally resolved than low-frequency responses (theta, alpha), and this replicates across sessions: median HIGH−LOW difference +7.27 percentage points, exact exhaustive sign-flip permutation p = 8.39e-05 (262,144 assignments enumerated, n = 21 sessions, 18 non-zero), Holm p = 1.7e-04. replicated across sessions
What the corpus contains
| Quantity | Value | Scope |
|---|---|---|
| Eligible single units | 4,130 | SPK, all sessions |
| Omission responses detected | 637 | a response exists |
| Omission latencies resolved | 187 | estimators agree |
| Resolved units with a stimulus reference | 139 | ΔT defined |
| Median resolved Tom | 190 ms | IQR 120–250 ms |
| LFP area×frequency cells | 1,820 | all sessions |
| LFP cells resolved | 114 | 6.3% of cells |
The three session-level tests, and their three different answers
The session is the inferential unit. Units within a session and area×frequency cells within a session are not independent, so pooled counts below are labelled descriptive.
| Test | n | median | p (sign-flip) | Standing |
|---|---|---|---|---|
| LFP high−low frequency, fraction resolved | 21 | +7.27 pp | 8.39e-05 | replicated |
| SPK increase-vs-decrease timing | 7 | -60 ms | 0.875 | not replicated |
| SPK omission−stimulus shift | 11 | +20 ms | 0.0527 | not significant |
Three outcomes from the same test procedure. The third is insufficient session-level evidence, not an established null: at n = 11 sessions the smallest attainable exact p is bounded away from zero. The pooled unit-level tendency (104/139 = 74.8% of units with ΔT > 0) is descriptive and is weighted by unit count, not by session.
Held, deliberately
No common-axis LFP-vs-SPK figure. It is withheld pending a scientifically appropriate LFP representation: the LFP side must be interval- and censoring-based, not a cloud of points, because beta latencies are strongly left-censored (see LFP).
No area-latency hierarchy claim. Area and subject are partially confounded; no area was recorded in all subjects. Pooled area medians are descriptive only (see Coverage).
No LFP→SPK causal or directional claim. Nothing in 6A tests direction.