Atmospheric methane levels increased over geological formations in Northern Siberia following a heat wave in 2020, suggesting that permafrost thaw releases methane from reservoirs.
Image credit: Wikimedia Commons.
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Contributed by Michael M. Merzenich
Article Figures & SI
Figures
- Figure 1
Schematic drawing of a trial. A trial began with an orienting response, the animal breaking an infrared beam in front of its nose. Two to six standard tones were then repeated. After the tones changed to the target frequency, which was higher than the standard frequency, the animal could remove its head from the beam to receive a fruit-juice reward.
- Figure 2
(A) (Upper) The sum of all responses sampled from the array as a function of frequency and intensity in the first week of behavioral training. (Lower) Responses in the last week. The black bars indicate the range of frequencies and intensities used as targets in the behavior. (Left) Animal one; (Right) animal two. (B) The sum of all responses to different frequencies at the trained intensity. At the end of training, every standard frequency response was lower than the response to at least 10 of the next 12 higher frequencies. Each of the eight plots is individually normalized to its maximum and minimum response. Standard frequencies are indicated by thin vertical lines.
- Figure 3
Changes in threshold and selectivity with time. (A) Thresholds vs. time are shown on the top for animal one. Selectivity of target and nontarget ranges are shown on the bottom. (B) Animal two. Targets were presented in frequency ranges symbolized with a circle and star. Nontarget ranges are symbolized by an X. In all cases, significant differences emerged between the target and nontarget frequency ranges.
- Figure 4
Daily changes across the breakpoint in animal two for the upper frequency range. Circles show average response to the target frequency range. Xs show the daily response to the standards. Stars show the responses to frequencies not used in the behavior. All physiological responses are derived immediately before the corresponding behavioral sessions. The animal first achieved performance above chance before day 0 recordings.
Tables
- Table 1
t test results for Fig. 3t statistics and associated probabilities for significant changes are shown
Week Animal one Animal two t-stat P t-stat-1 P-1 t-stat-2 P-2 0 — — — — — — 1 — — 4.53 0.00002 — — 2 2.756 0.005 10.8 0 5.45 3e-7 3 — — 5.01 2e-6 — — 4 2.666 0.008 6.77 8e-10 — — 5 5.03 5e-7 10.8 0 3.14 0.002 6 6.44 1e-10 -
t-stat-1 is the statistic for the upper target frequency range for animal two, and t-stat-2 is the statistic for the lower target frequency range.
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Neural correlates of instrumental learning in primary auditory cortex
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