Influences of Combined Traffic Noise on the Ability of Learning and Memory in Mice

Influences of Combined Traffic Noise on the Ability of Learning and Memory in Mice Di Qin

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Influences of Combined Traffic Noise on the Ability of Learning and Memory in Mice 2018 Noise & Health 10.4103/nah.nah_27_17 Di2018-influences-of-combined-traffic-noise-on-the Di2018-influences-of-combined-traffic-noise-on-the.txt, the project's staged copy 3ffc28f56cd62b5fe94c6ead511ca6ca7ce0a7ea not-redistributable medicine

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0 spans located by searching the stored text for the quote's exact words, allowing any whitespace between them Mice exposed for six weeks to recorded combined highway and high-speed-railway noise, assessed by water-maze learning and hippocampal neurotransmitters. Quotation withheld because this record is not cleared for redistribution. mechanism Quotation withheld because this record is not cleared for redistribution. traffic-noise effects on spatial learning and memory Quotation withheld because this record is not cleared for redistribution. behavioural-experiment behavioural-experiment Quotation withheld because this record is not cleared for redistribution. mechanisms A low-dose stressor breaks homeostasis and triggers a compensatory response that overshoots the inhibition, producing facilitation early on. Quotation withheld because this record is not cleared for redistribution. mechanisms With continued exposure the compensatory response is exhausted, so the inhibitory effect of the noise comes to dominate. Quotation withheld because this record is not cleared for redistribution. mechanisms Glutamate acting on hippocampal NMDA receptors admits calcium and thereby changes synaptic plasticity, which is the substrate of learning and memory. Quotation withheld because this record is not cleared for redistribution. mechanisms The behavioural swing is mediated by the hippocampal glutamate level, which is raised by short exposure and lowered by long exposure. Quotation withheld because this record is not cleared for redistribution. The direction of the effect reverses with exposure duration, which the paper identifies as hormesis - excitation at low dose, inhibition at high Quotation withheld because this record is not cleared for redistribution. Dose for noise is not the level but the level multiplied by the duration, which is why the same decibel figure sits on both sides of the curve Quotation withheld because this record is not cleared for redistribution. The reversal is attributed to a compensatory response that outruns the insult at first and is then exhausted Quotation withheld because this record is not cleared for redistribution. The behavioural reversal is tracked by glutamate, which rises early and falls late while GABA stays flat Quotation withheld because this record is not cleared for redistribution. Glutamate has its own inverted-U: more release aids learning until excitotoxicity sets in Quotation withheld because this record is not cleared for redistribution. Combined road and rail noise is not the sum of its parts - the two sources differ in continuity, peak level and low-frequency content Quotation withheld because this record is not cleared for redistribution. The extrapolation from mice to human cognitive ability is explicitly only a speculation awaiting human testing. what this limits: the human relevance of the whole study: THIS SPECULATION NEEDS TO BE VERIFIED BY ADDITIONAL COGNITIVE BEHAVIOR TESTS IN HUMANS EXPOSED TO 70 dB(A) CTN Quotation withheld because this record is not cleared for redistribution. The compensatory-response account of the biphasic effect is inferred rather than measured. what this limits: the mechanistic account of the biphasic effect: IT WAS SPECULATED THAT THE COMPENSATORY RESPONSE WAS GREATER THAN THE INHIBITORY RESPONSE Quotation withheld because this record is not cleared for redistribution. Ten mice per group per batch, with the key contrasts significant in only some batches what this limits: every group comparison: EACH BATCH (N = 20) CONSISTED OF TWO GROUPS ... THE EXPERIMENTAL GROUP (N = 10) AND THE CONTROL GROUP (N = 10) Quotation withheld because this record is not cleared for redistribution. Batches are separate groups of animals rather than repeated measures, so the time course is between-subjects what this limits: the time course specifically: batches are separate groups of animals, so the comparison across durations is between-subjects rather than repeated Quotation withheld because this record is not cleared for redistribution. All animals were male, so nothing here speaks to sex differences what this limits: any claim about the population: A TOTAL OF 80 HEALTHY MALE ICR MICE - all male, so nothing here speaks to sex differences Quotation withheld because this record is not cleared for redistribution. Only one sound level was tested, so the dose-response curve is traced through duration alone what this limits: the dose-response reading: only one sound level was tested, so the curve is traced through EXPOSURE DURATION alone Quotation withheld because this record is not cleared for redistribution. The mechanism is inferred from a speculation about compensation rather than measured duplicate of: limitations[1] · what this limits: the same scope as limitations[1] - the compensation account is speculated, not measured Quotation withheld because this record is not cleared for redistribution. The human literature the study is motivated by is itself inconsistent, and the paper attributes that to uncontrolled personal and social factors what this limits: the human literature this is motivated by: THE RESULTS OF EPIDEMIOLOGICAL SURVEY WERE ALSO INFLUENCED BY THE PERSONAL FACTORS OF PARTICIPANTS (E.G., AGE, EDUCATIONAL LEVEL, AND PHYSICAL CONDITION) - the disagreement it aims to resolve is attributed to confounding Quotation withheld because this record is not cleared for redistribution. the hormesis biphasic dose-response model, with noise dose defined by analogy to an ingested toxicant dose (sound level times duration) Quotation withheld because this record is not cleared for redistribution. a control group of ten mice per batch held at a background level of no more than 35 dB(A), against 70 +/- 1.5 dB(A) for the exposed group, and never given the combined traffic noise eliminates: that the auditory and physiological changes follow from handling, captivity or elapsed time rather than from the traffic-noise exposure · outcome (stated by the tagger, no quotation): absent-stated-about-other · would have ruled out, had it been run: handling, caging and the passage of the 42 days as the explanation of the learning and neurotransmitter differences - the control animals live the same 42 days in the same room and differ only in the noise Quotation withheld because this record is not cleared for redistribution. short-term exposure short-term exposure Quotation withheld because this record is not cleared for redistribution. long-term exposure long-term exposure Quotation withheld because this record is not cleared for redistribution. ability of learning ability of learning Quotation withheld because this record is not cleared for redistribution. Mg 2+ → synaptic plasticity THE MECHANISM THE SPAN ACTUALLY DESCRIBES, between terms it actually names: magnesium blocked the calcium channel, was removed, and the resulting calcium influx induced the change of synaptic plasticity. A three-step chain, and no edge type carries a chain - each link would have to be asserted separately, losing the ordering that is the content. Quotation withheld because this record is not cleared for redistribution. the effect of 70 dB(A) noise - after SHORT exposure (6-10 days): learning and memory IMPROVE Quotation withheld because this record is not cleared for redistribution. the effect of 70 dB(A) noise - after LONG exposure (26-40 days): learning and memory DECLINE, at the same sound level Quotation withheld because this record is not cleared for redistribution. dose - as sound level: the 70 dB(A) figure, which is what gets reported and compared across studies Quotation withheld because this record is not cleared for redistribution. dose - as level times duration: the quantity that actually determines the sign of the effect Quotation withheld because this record is not cleared for redistribution. glutamate - below the toxic threshold: more release, better learning Quotation withheld because this record is not cleared for redistribution. glutamate - above it: excitotoxic, and learning declines with the same transmitter that improved it Quotation withheld because this record is not cleared for redistribution. phenomenon: traffic-noise effects on spatial learning and memory a second reading reaching the same value. Recorded: traffic-noise effects on spatial learning and memory — note: a second reading reaching the same value from a different sentence. Not applied - a person decides. Quotation withheld because this record is not cleared for redistribution. builds-on → hormesis, the biphasic low-dose-excitation / high-dose-inhibition dose-effect model in toxicology (refs 22-26) Quotation withheld because this record is not cleared for redistribution. replicates → the epidemiological surveys of Haines (ref 8) and Kempen (ref 9) showing declining cognitive ability in children after long-term aircraft or road traffic noise Quotation withheld because this record is not cleared for redistribution. extends → Calabrese's overcompensation account of hormesis Quotation withheld because this record is not cleared for redistribution. critiques → previous animal noise studies that used white noise, narrow band noise or pure tones instead of real environmental noise Quotation withheld because this record is not cleared for redistribution. supports → Di et al. on combined road-rail noise being more annoying than a single dominant source at the same level Quotation withheld because this record is not cleared for redistribution. overcompensation —causes→ hormesis overcompensation hormesis strength of the relation: 0.9 Quotation withheld because this record is not cleared for redistribution. GABA —distinct-from→ Glu GABA Glu strength of the relation: 1 Quotation withheld because this record is not cleared for redistribution. GABA —causes→ NMDA GABA NMDA strength of the relation: 0.9 Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but GABA 'COULD strengthen the blocking effect of Mg2+ on the NMDA receptor'; 'causes NMDA' drops the blocking and is hedged. Quotation withheld because this record is not cleared for redistribution. Glu —causes→ excitatory toxic effect Glu excitatory toxic effect status: the paper's own words: could · strength of the relation: 1 · note: direction corrected 2026-08-20 by the project: the quote puts 'Glu' on the causing side. The edge previously read excitatory toxic effect --causes--> Glu, which is the reverse of its own sentence. Nothing else on the row changed; the quote, weight and anchor are untouched. Quotation withheld because this record is not cleared for redistribution. Morris water maze —operationalised-as→ latencies Morris water maze latencies strength of the relation: 1 Audit 2026-09-28: DOUBTFUL - read against its span and kept, but latencies are the water-maze measure; operationalised-as is loose. Quotation withheld because this record is not cleared for redistribution. combined traffic noise —operationalised-as→ day–night equivalent continuous A-weighted sound pressure level combined traffic noise day–night equivalent continuous A-weighted sound pressure level strength of the relation: 1 Quotation withheld because this record is not cleared for redistribution. short-term exposure —causes→ ability of learning short-term exposure ability of learning holds when: 6-10 days of exposure to 70 dB(A) combined traffic noise · direction on the measure: increases · strength of the relation: 1 · note: ONE OF A PAIR: the SAME exposure carries the OPPOSITE sign at longer durations. Neither edge is the paper's finding alone - the finding is that the sign flips. Quotation withheld because this record is not cleared for redistribution. long-term exposure —causes→ ability of learning long-term exposure ability of learning holds when: 26-30 and 36-40 days of exposure · direction on the measure: reduces · strength of the relation: 1 · note: ONE OF A PAIR: see the short-term edge, which carries the opposite sign on the same measure. Quotation withheld because this record is not cleared for redistribution. ANOVA ANOVA Quotation withheld because this record is not cleared for redistribution. t-test t-test Quotation withheld because this record is not cleared for redistribution. standard error of the mean standard error of the mean Quotation withheld because this record is not cleared for redistribution. statistical-significance statistical-significance Quotation withheld because this record is not cleared for redistribution. linear regression linear regression Quotation withheld because this record is not cleared for redistribution. Six to ten days of exposure to 70 dB(A) combined traffic noise improved learning and memory in mice. Quotation withheld because this record is not cleared for redistribution. Longer exposure reversed the effect, degrading learning and memory. Quotation withheld because this record is not cleared for redistribution. Learning rate was significantly higher in exposed mice than in controls in the first batch (6-10 days). Quotation withheld because this record is not cleared for redistribution. Time in the target quadrant was significantly higher in exposed mice than in controls in the first batch (6-10 days). Quotation withheld because this record is not cleared for redistribution. Glutamate rose after short (6-10 day) exposure and fell after long exposure. Quotation withheld because this record is not cleared for redistribution. Hippocampal GABA was unchanged by noise exposure at every time point. Quotation withheld because this record is not cleared for redistribution. The authors rule out excessive glutamate release causing an excitotoxic effect on hippocampal neurons. Quotation withheld because this record is not cleared for redistribution. The biphasic time course of the noise effect matches the hormesis dose-response pattern. Quotation withheld because this record is not cleared for redistribution. short exposure to 70 dB(A) combined traffic noise improved water-maze learning and memory Quotation withheld because this record is not cleared for redistribution. long exposure at the same level degraded them Quotation withheld because this record is not cleared for redistribution. in the intermediate batch (16-20 days) learning rate was similar to controls Quotation withheld because this record is not cleared for redistribution. glutamate was higher in exposed mice than in controls in the first batch Quotation withheld because this record is not cleared for redistribution. GABA did not differ between groups in any batch Quotation withheld because this record is not cleared for redistribution. the human literature already disagrees about noise and cognition, including one study where 71 dB(A) road noise IMPROVED children's episodic memory Quotation withheld because this record is not cleared for redistribution. hormesis hormesis Quotation withheld because this record is not cleared for redistribution. learning rate learning rate Quotation withheld because this record is not cleared for redistribution. hidden platform test hidden platform test Quotation withheld because this record is not cleared for redistribution. probe trail test probe trail test Quotation withheld because this record is not cleared for redistribution. combined traffic noise (CTN) combined traffic noise (CTN) Quotation withheld because this record is not cleared for redistribution. hormesis hormesis Quotation withheld because this record is not cleared for redistribution. exposure dose of noise exposure dose of noise Quotation withheld because this record is not cleared for redistribution. GABA GABA Quotation withheld because this record is not cleared for redistribution. Glu Glu Quotation withheld because this record is not cleared for redistribution. percentage of time spent in the target quadrant percentage of time spent in the target quadrant Quotation withheld because this record is not cleared for redistribution. percentages of time spent in a target quadrant percentages of time spent in a target quadrant Quotation withheld because this record is not cleared for redistribution. 70 ± 1.5 dB(A) — day-night equivalent sound pressure level of the combined traffic noise played to the experimental group Quotation withheld because this record is not cleared for redistribution. 35 dB(A) — background noise level, i.e. the exposure of the control group Quotation withheld because this record is not cleared for redistribution. 80 — total number of male ICR mice used, split into four batches Quotation withheld because this record is not cleared for redistribution. n = 20 (n = 10 and n = 10) — mice per batch, split evenly into experimental and control groups Quotation withheld because this record is not cleared for redistribution. 42 days — duration of continuous noise exposure for the experimental group after a 7-day adaptation Quotation withheld because this record is not cleared for redistribution. 5 and 15 μmol/g — normal hippocampal glutamate range against which the measured values were judged non-toxic Quotation withheld because this record is not cleared for redistribution. 2092 pcu/h — highway traffic flux used to reconstruct the combined traffic noise stimulus Quotation withheld because this record is not cleared for redistribution. 90 s — maximum trial duration in the Morris water maze hidden platform test Quotation withheld because this record is not cleared for redistribution. 70 dB(A) — the single exposure level, which produces opposite effects at different durations Quotation withheld because this record is not cleared for redistribution. 80 healthy male ICR mice — the whole sample, in four batches of twenty Quotation withheld because this record is not cleared for redistribution. 42 days — total exposure period across which the four batches were tested Quotation withheld because this record is not cleared for redistribution. 71 dB(A) — the level at which an earlier human study found IMPROVED episodic memory - one decibel above this study's exposure Quotation withheld because this record is not cleared for redistribution. 63.5 dB — the level above which combined road-rail noise becomes more annoying than a single dominant source Quotation withheld because this record is not cleared for redistribution. 2092 pcu/h — the highway traffic flux used to reconstruct the combined exposure Quotation withheld because this record is not cleared for redistribution.

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