Author Year Animal model Specimen; gender Stimulation parameters Main findings Stimulation electrode Reference electrode Anesthesia rtDCS Polarity Position Stimulation intensity (mA) Size (cm2 ) Stimulation duration (min) Current density (A/m2 ) Position Area (cm2 ) Nekhendzy et al. [97 ] 2004 Inflammatory nociception model Sprague Dawley rats; males 31 c-tDCS Frontal cortex 2.25 N/A 45 N/A Bimastoid N/A Y Y (8 days) ↓ Nociceptive response (effects lasted up to 50 min poststimulation) Taib et al. [98 ] 2009 Left hemicerebellectomy Wistar rats; males 9 a-tDCS Right or left motor cortex 0.4 0.071 20 56.3 Supraorbital region 0.0064 N/A Y ↑ T corticomuscular response amplitudes Kim et al. [99 ] 2010 MCAO Sprague Dawley rats; both genders 61 c-tDCS vs. a-tDCS Left primary motor cortex (M1) 0.1 0.785 30 N/A Trunk 9 Y Y (2 weeks) Neuroprotection over white matter and ischemic size ↓ (a-tDCS) ↑ Motor function Jiang et al. [95 ] 2012 MCAO Sprague Dawley rats; both genders 90 a-tDCS and c-tDCS Motor cortex 0.1 0.785 30 1.27 Trunk 9 Y Y (daily, for 3, 7, or 14 days postlesion) ↑ Motor function (7 and 14 days poststroke) Yoon et al. [56 ] 2012 MCAO Sprague Dawley rats; males 30 a-tDCS Left primary motor cortex (M1) 0.2 N/A 20 28.2 Anterior chest 48.0 Y Y (5 days stimulation 1 week vs. 1 day postischemia) ↑ Motor function and Barnes maze performance (a-tDCS applied 1 week after ischemic injury) ↑ MAP-2 and GAP-43 expression around the perilesional area (a-tDCS applied 1 week postischemic injury) Laste et al. [100 ] 2012 CFA injection/chronic inflammation induction Wistar rats; males 18 a-tDCS Parietal cortex 0.5 1.5 (ECG electrode) 20 33.4 Supraorbital area 1.5 (ECG electrode) N Y (8 days) Significant differences in nociceptive response (immediately after and 24 h poststimulation) Adachi et al. [101 ] 2012 CRS Wistar rats; males 48 a-tDCS Parietal cortex 0.5 1.5 (ECG electrode) 20 3.3 Supraorbital area 1.5 (ECG electrode) N Y (8 days) ↓ Nociceptive response in chronic stress conditionhippocampus Peruzzotti-Jametti et al. [60 ] 2013 MCAO C57BL/6 mice; males 137 c-tDCS vs. a-tDCS Left parietal cortex 0.25 0.0144 40 55 Ventral thorax 5.2 N/A N (single session) ↑ Infarct volume and ↑ BBB leakage (a-tDCS ipsilesional hemisphere) Cortical Glu activity ↓, functional ↑ and ischemic damage ↓ (c-tDCS ipsilesional hemisphere) Notturno et al. [102 ] 2014 MCAO Sprague Dawley rats; both genders 53 c-tDCS Left motor cortex 0.2 0.07 120 28.6 Ventral thorax 10.5 Y N (single session) Ischemia volume ↓ Lu et al. [103 ] 2015 MPTP injection C57bl mice; males 36 a-tDCS Left frontal cortex 0.2 0.035 10 57 Between shoulders 9 N/A Y (daily for 3 weeks) ↑ Motor coordination (until 21 days poststimulation) Spezia Adachi et al. [104 ] 2015 Restraint stress model Wistar rats; males 78 a-tDCS Parietal cortex (midline) 0.5 1.5 (ECG electrode) 20 N/A Supraorbital area 1.5 (ECG electrode) N Y (daily for 8 days) ↓ Stress-induced nociceptive response Yoon et al. [31 ] 2016 Lateral fluid percussion method Sprague Dawley rats; males 36 a-tDCS Hippocampus 0.2 0.0225 20 28.2 Chest 48 (corset) Y Y (daily for 5 days) ↑ Perilesional area BDNF expression (tDCS 2 weeks post-TBI) ↑ Choline/creatinine ratios (tDCS 1 week post-TBI) Motor performance recovery (2 weeks of tDCS) Leffa et al. [33 ] 2016 SHR SHR rats and WKT rats; males 48 a-tDCS Frontal cortex 0.5 1.5 20 33.4 Between ears 1.5 N Y (8 consecutive days) ↑ DA levels in STR in both rat strains and in the hippocampus following tDCS treatment in WKY Liu et al. [105 ] 2016 PTI Sprague Dawley rats; N/A 58 c-tDCS Right S1FL 2 N/A 20 20.37 Venter N/A N/A N (single session) Ischemia expansion inhibition (c-tDCS immediately postischemia induction) Braun et al. [106 ] 2016 MCAO Wistar rats; males 41 c-tDCS vs. a-tDCS Left primary motor cortex (M1) 0.5 0.035 15 N/A Ventral thorax N/A Y Y (10-day stimulation; 5 days with 2-day interval) Gait recovery at day 16 poststroke (both polarities) Cioato et al. [107 ] 2016 Sciatic nerve chronic constriction Wistar rats; males 84 a-tDCS and c-tDCS Parietal cortex (bicephalic) 0.5 1.5 (ECG electrode) 20 N/A Supraorbital area 1.5 (ECG electrode) N Y (8 days) Nociceptive relieve (for up to 7 days poststimulation) Filho et al. [108 ] 2016 Partial sciatic nerve compression Wistar rats; males 144 a-tDCS Parietal cortex 0.5 1.5 (ECG electrode) 20 N/A Supraorbital area 1.5 (ECG electrode) N Y (8 days) ↓ BDNF expression (48 h poststimulation) Moreira et al. [109 ] 2016 Pain and menopause (ovariectomised animals) Wistar rats; females 45 C-tDCS Parietal cortex 0.5 1.5 (ECG electrode) 20 N/A Supraorbital area 1.5 (ECG electrode) N Y (8 days) ↓ Hypothalamic BDNF levels and T serum BDNF in ovariectomised animals Dimov et al. [87 ] 2016 N/A Wistar rats; males 25 c-tDCS Left primary motor cortex (M1) 0.25 0.0227 15 N/A Ventral thorax N/A N N (single session) Bilateral ↓ Egr-1 expression in the PAG Spinal ENK immunoreactivity ↓ in the DHSC Liu et al. [110 ] 2017 PTI Sprague Dawley rats; males 58 c-tDCS S1FL 2 N/A 20 N/A 3 mm lateral to lambda N/A N/A N (single session) Prevention of ischemia injury expansion during hyperacute phase of ischemia (c-tDCS+PSS) Kim & Han [111 ] 2017 Modified Tang’s method [128] Sprague Dawley rats; N/A 31 a-tDCS Left motor cortex 0.2 1 30 0.26 Ventral thorax 9 Y N Early recovery of consciousness and MEP and SEP prolonged latency (tDCS applied right after TBI) Winkler et al. [112 ] 2017 Striatal 6-OHDA injection Sprague Dawley rats; females 24 a-tDCS and c-tDCS Left motor cortex N/A 0.16 20 8 Chest 3 N Y (daily for 14 days) Graft survival, striatal dopaminergic reinnervation and motor recovery (a-tDCS) de Souza et al. [113 ] 2017 PSNL Swiss mice; males N/A a-tDCS and c-tDCS Parietal cortex (bicephalic) 0.5 N/A (EEG electrode) 5; 10; 15; 20 N/A Supraorbital area N/A (EEG electrode) N N (single session) Antiallodynic effect (seen 4 h poststimulation of 15 min and 20 min) Leffa et al. [46 ] 2018 ADHD SHR and WKY rats; males 30 a-tDCS (bicephalic) Frontal cortex (supraorbital area) 0.5 1.5 (ECG electrode) 20 33.3 Neck 1.5 (ECG electrode) N/A Y (8 days) ↓ Inflammatory cytokines and reversion of long-term memory deficits in SHR rats Paciello et al. [114 ] 2018 NIHL Wistar rats; males 124 a-tDCS Temporal lobe (auditory cortex) 0.35 0.0625 20 56 Ventral thorax 12 N Y (2 days) ↑ Dendritic spines density (layer 2/3 pyramidal neurons of the auditory cortex) ↑ BDNF and synaptophysin expression in auditory cortex (24 h poststimulation) Fregni et al. [115 ] 2018 N/A Wistar rats; males 32 N/A N/A (bicephalic) N/A N/A 20 N/A N/A N/A N/A Y (8 days) tDCS prior to stress exposure prevented thermal hyperalgesia Lee et al. [116 ] 2019 MPTP injection C57bl mice; male 60 a-tDCS Primary motor cortex (M1) N/A N/A 30 N/A Between shoulders N/A N/A Y (daily for 5 days) ↑ Motor coordination Rescue of MTPT-induced mitochondrial dysfunction (Ç ATP and GDH and $ Drp1 levels) Callai et al. [117 ] 2019 CCI-ION Wistar rats, males 151 a-tDCS Parietal cortex (bicephalic) 0.5 1.5 (ECG electrode) 20 N/A Supraorbital area 1.5 (ECG electrode) N Y (8 days) ↓ Mechanical hyperalgesia ↓ TNF-a expression (7 days poststimulation) ↓ IL-10 (7 days poststimulation) ↓ LDH serum levels Scarabelot et al. [118 ] 2019 CFA injection/chronic inflammation induction Sprague Dawley rats; males 104 a-tDCS Parietal cortex (bicephalic) 0.5 1.5 (ECG electrode) 20 N/A Supraorbital area 1.5 (ECG electrode) N/A Y (8 days) ↓ Thermal and mechanical hyperalgesia ↑ IL-6 (in brainstem 24 h poststimulation) ↓ IL-10 (7 days poststimulation) Normalization of BDNF levels (24 h poststimulation)
