Table 1.

Animal studies of cognitive deficits in response to air pollution

Study (reference number)	Species	Sample Sizes	Type of Air Pollution Exposure	Control Exposure	Outcome Measures	Results
Hougaard et al., 2008 (51)	Mice (sex not reported)	Dams=11–12 Offspring 6–10 depending upon outcome measure	Gestational exposure to diesel exhaust particles (DEP) at approximately 20 mg DEP/m3 on GDs 7–19 for one hour/day.	Filtered clean air	Learning/memory in a water maze	Significantly increased latency to find escape platform in water maze on first trial of a reversal
Yokota et al., 2015 (52)	Male mice	N=15 per treatment group	Diesel exhaust particle solutions administered subcutaneously at doses of 0 or 200 ug/kg body weight on gestational days 6, 9, 12, 15 and 18	Saline administered subcutaneously	Learning/memory in a water maze; locomotor activity, passive avoidance	No effects on locomotor activity or passive avoidance; increased latency to escape in the water maze but only significant for one day (7) of a 9 day training period; significant reduction in time spent in quadrant with hidden escape platform on probe trial
Win-Shwe et al., 2008 53)	Male mice	N=6/group	Diesel exhaust nanoparticles averaging 26 nm in size delivered 5 hr/day for 5 days per week for 4 weeks with or without concurrent administration of lipoteichoic acid, a bacterial cell wall component	Filtered (HEPA filter) clean air and clean (charcoal filter) air	Water maze	Increases in latency to escape the water maze on day 1 and 2 in responses to diesel exhaust with or without LTA; increases on day 3 only for diesel exhaust with LTA; swimming speed was not affected; no differences in visible platform test; only LTA-treated mice showed deficits in the probe trial
Win-Shwe et al., 2012 (54)	Female mice	N=6 per group	Diesel exhaust nanoparticles by inhalation at a concentration of either 35.48 ug/m3 (moderate) or 122 ug/m3 (high) for 5 hr/day for five days per week for 3 months	Filtered (HEPA filter) and clean (charcoal filter) air	Water maze	Increases in escape latency only for high dose that persisted across all 4 days of training, with no effects on swimming speed; no deficits in the probe trial
Win-Shwe et al., 2012 (55)	Female mice	N=8 per group	Diesel exhaust nanoparticles by inhalation at a concentration of either 47 ug/m3 (moderate) or 129 ug/m3 (high) for 5 hr/day for five days per week for 3 months	Filtered clean air	Novel object recognition	Significant decreases in novel object discrimination index score in the high dose diesel exhaust group
Win-Shwe et al., 2014 (56)	Male mice	N=8 per group	Diesel exhaust (98 ug/m3) or diesel exhaust (114 ug/m3) with secondary organic aerosols for 5 days per week for one or three months	Filtered clean air	Novel object recognition	Decreased discrimination index score in the diesel exhaust + secondary organic aerosol group, but not diesel exhaust alone
Fonken et al., 2011 (57)	Male mice	Not specified	Concentrated ambient PM2.5 for 6 hr/day at 94 ug/m3 for 5 days per week for 10 months	Filtered air	Barnes maze for learning and memory; olfactory abilities, forelimb grip strength, inclined screen test, rotarod, locomotor activity, forced swim test, elevated plus maze	No effects on olfaction, grip strength or motor performance; PM2.5 exposure was associated with increased latency to escape and increased error counts on the Barnes maze, but only on day 2 of a 4 day test period; Increases in escape latency were increased and correct pokes decreased in the subsequent probe trial. Increased time immobile time in forced swim test, but no differences in the elevated plus maze
Allen et al., 2014 (58)	Mice of both sexes	N=8–12 per group per sex	Concentrated ambient ultrafine particle exposure ranging from 100–20 ug/m3 for 4 hr/day from postnatal days 4–7 and 10–13 (CAPS) with half also receiving exposure again to concentrated ambient ultrafine particles from postnatal days 56–50 (CAPS/CAPS), while the other half received filtered air (CAPS/Air)	Filtered air from postnatal days 4–7 and 10–13 with half also receiving filtered air again at postnatal days 56–60 (Air/Air) while the other half received concentrated ambient ultrafine particle exposure (Air/CAPS)	Fixed Interval schedule-controlled responding for food reward; novel object recognition ; locomotor activity	Postnatal only CAPS (CAPS/Air) significantly reduced Fixed Interval response rates and run rates in males, transient rate decreases in Air/CAPS males. Significant increases in fixed interval 60 sec response rates in Air/CAPS females, but reductions at fixed interval 120 sec in both CAPS/CAPS and Air/CAPS females. Reductions in percent change in time with the novel object, approaches to novel object in probe trial with CAPS/Air groups of both sexes; ambulatory locomotor activity significantly reduced in CAPS/CAPS females; reductions in horizontal activity in both Air/CAPS and CAPS/CAPS males
Allen et al., 2013 (59)	Male mice	N=7–8 per group	Concentrated ambient ultrafine particle exposure ranging from 96 ug/m3 for 4 hr/day from postnatal days 4–7 and 10–13 (CAPS) with half also receiving exposure again to concentrated ambient ultrafine particles from postnatal days 56–50 (CAPS/CAPS), while the other half received filtered air (CAPS/Air)	Filtered air from postnatal days 4–7 and 10–13 with half also receiving filtered air again at postnatal days 56–60 (Air/Air) while the other half received concentrated ambient ultrafine particle exposure (Air/CAPS)	Fixed ratio waiting for reward schedule; locomotor activity	Increases in fixed ratio overall response rates and run rates and decreased inter-response times in CAPS/Air and CAPS/CAPS groups. Increases in the number of fixed ratio resets, reductions in CAPS/CAPS group. Comparable trends towards decreased mean waiting time with CAPS/CAPS and mean longest wait time; no effects on locomotor activity
Zanchi et al., 2010 (60)	Male rats	N=12 per group	Ambient PM2.5 pollution from prenatal-weaning and to 150 days of age at a total monthly mass averaging 16.2 ug/m3	Filtered air	Novel object recognition (listed as spontaneo us non-matching to sample recognition test)	Reduced discrimination index scores in males exposed from gestation to 150 days of age, but this group also exhibited less exploration during the test session