References | Main focus | Impairment | Animal model | Stimulation protocol | Stimulation time frame |
---|---|---|---|---|---|
Yoon et al. [159] | Effects of anodal tDCS on behavioral and spatial memory in early stage TBI | Behavioral and spatial memory | 36 male Sprague–Dawley rats, lateral FPI (moderate TBI), anesthetized during tDCS | Anodal tDCS, 0.2 mA, (2.82 mA/cm2 current density), for 20 min | Once per day, for 5 days, starting 1 or 2 weeks post-injury |
Kim and Han [160] | Effects of anodal tDCS on neuroplasticity | Motor and sensory cortical excitability | 31 male Sprague–Dawley rats (postnatal day 42), weight drop (175 g from 30 cm, 3 consecutive times, repetitive mild TBI), anesthetized during all procedures and evaluations | Anodal tDCS, 0.2 mA (0.255 mA/cm2 current density), for 30 min | Once, directly after TBI |
Bragina et al. [161] | Perfusion and tissue oxygenation after anodal tDCS, motor and cognitive neurologic outcome | mCBF and tissue oxygenation, motor function | 40 mice, CCI (5Â m/s, 2Â mm from cortical surface, mild to moderate TBI), awake during tDCS | Repetitive anodal tDCS, 0.1Â mA, for 15Â min | Over 4Â weeks, for 4 consecutive days at 3-day intervals, starting 1 or 3Â weeks post-injury |
Yu et al. [162] | Effects of tDCS and ECS on motor and cognitive recovery, brain plasticity, spatial learning and memory | Motor and cognitive function | 30 male Sprague–Dawley rats, weight drop (moderate TBI), awake during tDCS | Anodal tDCS, 0.1 mA, 50 Hz, 200 µs pulses, for 30 min | Once per day from days 3 to 28 after electrode positioning |
Martens et al. [165] | Cathodal tDCS in the treatment of psychiatric-like symptoms after TBI | Impulsivity and attention | 20 male Long-Evans rats, bilateral, frontal CCI (severe TBI), anesthetized during tDCS | Cathodal tDCS, 800 µA (0.708 mA/cm2), 10 min | Once per day for 7 days (2 h before testing), starting 6 weeks post-injury |
Bragina et al. [164] | Effects of anodal tDCS on cerebrovascular reactivity and mCBF regulation | Cerebrovascular reactivity and mCBF | 20 mice, CCI (5Â m/s, 2Â mm from cortical surface, mild to moderate TBI), awake during tDCS | Anodal tDCS, 0.1Â mA, for 15Â min | Once, 3Â weeks post-injury |
Park et al. [163] | Anodal tDCS to improve motor function after repetitive mild TBI | Motor function | 65 male Sprague–Dawley rats, weight drop (175 g from 30 cm, once daily for 3 days, repetitive mTBI), anesthetized during tDCS | Anodal tDCS, 0.2 mA (0.255 mA/cm2), for 30 min | Once, 24 h after last induction of mTBI |
References | Stimulus location | Tests | Acquired parameters | Persistent effects | Main findings |
---|---|---|---|---|---|
Yoon et al. [159] | Anode over perilesional area, cathode on chest | RRT, Barnes maze test, brain MRI, MRS, immunohistochemical analysis | Behavioral ability, spatial memory, lesion volume, brain edema, metabolites, BDNF expression | Beneficial effects visible 1Â weeks after stimulation, no sustained effects after 3Â weeks | tDCS increases recovery of spatial and memory functions when applied 2Â weeks post injury, only improves spatial memory when applied 1Â week post-injury |
Kim and Han [160] | Anode around left motor cortex, counter electrode on thorax | MEP and SEP test, brain MRI, immunohistochemical analysis | Recovery of righting reflex, MEP latency and amplitude, SEP latency and amplitude, brain volumetric changes, GFAP expression | Immunohistochemistry performed 12Â days after stimulation, showed no significant improvements | Single anodal tDCS after rmTBI induces early recovery of consciousness, increases modulation of cortical excitability and promotes transient motor recovery |
Bragina et al. [161] | Anode near craniotomy, counter electrode on thorax | Custom-made LSCI, two-photon LSM, RRT, passive avoidance test, Y-maze test, Nissl staining | Regional and microvascular cerebral blood flow, motor deficits, learning, spatial and working memory | Preserved improvement in learning and motor abilities 1Â week after stimulation was ended | Anodal tDCS increases brain microvascular blood flow and tissue oxygenation in TBI and sham mouse brain and could contribute to neurologic improvement |
Yu et al. [162] | Anode above lesion, cathode at trunk | Rehabilitation training (SPRT, RRT, Y-maze), neurological examination, histology, immunohistochemistry | Success rate of SPRT and Y-maze tests, average rates of RRT, lesion assessments, c-Fos expression | Not investigated | ES with rehabilitation training for TBI rats is effective for motor recovery and brain plasticity, ECS induces faster behavioral and cognitive improvements than tDCS |
Martens et al. [165] | Cathode near bregma, anode between scapulae | Five-choice serial reaction time task, analysis of brain slices to verify injury severity | Motor impulsivity, attention, relationship between magnitude of impairment and recovery | No lingering effects observed, disappeared after stimulation stopped | Relationship between magnitude of impulsive deficit and degree of tDCS-recovery, the most severely impaired subjects benefit the most from neuromodulation |
Bragina et al. [164] | Anode near craniotomy, cathode on thorax | Two-photon LSM (before and after stimulation), cerebrovascular reactivity test (hypercapnia) | mCBF (arteriolar diameter), brain tissue oxygen flow (NADH autofluorescence) | Not investigated | Anodal tDCS restores cerebrovascular reactivity of parenchymal arterioles and regulation of mCBF, could contribute to neurologic improvement |
Park et al. [163] | Anode over left M1 area, cathode on trunk | Brain MRI, histology, MEP evaluation (via TMS and needle electrodes), foot-fault test, rotarod test | Damage evaluation after repetitive mTBI, MEP amplitude and latency, motor coordination, sensorimotor function, balance alterations | Not investigated | Anodal tDCS at the M1 area after repetitive mTBI could improve MEP amplitude, balance control, postural orientation and motor endurance by activating the CST |