Memory and Cognition-Related Neuroplasticity Enhancement by Transcranial Direct Current Stimulation in Rodents: A Systematic Review

Table 1

Effect of transcranial direct current stimulation on memory and learning of healthy animals.

Author

Year

Animal model

Specimen; gender

Stimulation parameters

Main findings

Stimulation electrode

Reference electrode

Anesthesia

rtDCS

Polarity

Position

Stimulation intensity (mA)

Size (m^2)

Stimulation duration (min)

Current density (A/m^2)

Position

Area (cm^2)

Dockery et al. [42]

2011

NDM

Long-Evans rats; males

41

a-tDCS vs. c-tDCS

Frontal cortex (left or right hemisphere)

0.2

0.035

30

57.1

Back

10.5

N

Y (3 days)

↑ Visuospatial working memory (c-tDCS)

de Souza Custódio et al. [29]

2013

NDM

Wistar rats; males

23

a-tDCS

Left mPFC

0.4

0.25

11

N/A

Neck

1

N

Y (5 days)

↑ Spatial working memory (1 h, 4 h, and 10 h poststimulation)

Faraji et al. [96]

2013

NDM

Long-Evans rats; males

24

a-tDCS

Somatosensory cortex (bilateral)

0.065

N/A

10

N/A

Back of skull

N/A

N

Y

↑ Cortical neural density; ↑ Motor learning (a-tDCS applied bilaterally or into paw preferred to reaching contralateral hemisphere)

Podda et al. [40]

2016

NDM

C57BL/6 mice; males

16

a-tDCS vs. c-tDCS

Left parietal cortex (dorsal to hippocampal formation)

0.35

0.06

20

N/A

Ventral thorax

5.2

N

N (single session)

↑ Spatial learning and memory (a-tDCS; benefits observable one week after); ↑ BDNF expressions in the hippocampus; CREB/CBP pathway activation

Manteghi et al. [36]

2017

NDM

NMRI mice; males

64

a-tDCS

Right frontal cortex

0.2

0.04

20

N/A

Chest

9.5

N/A

N (single session)

↓ Freezing time % and ↑ latency to the freezing (tDCS following 0.1 mg/kg ACPA injection)

Nasehi et al. [37]

2017

NDM

NMRI mice; males

128

a-tDCS vs. c-tDCS

Right frontal cortex

0.2

0.04

20

N/A

Ventral thorax

9.5

N

Y (2 sessions)

↑ Fear memory retrieval/freezing time (a-tDCS and propranolol injection before conditioning)

Nasehi et al. [38]

2017

NDM

NMRI mice; males

128

a-tDCS vs. c-tDCS

Left frontal cortex

0.2

0.04

20

N/A

Ventral thorax

9.5

N

Y (2 sessions)

↑ Contextual fear memory acquisition (a-tDCS before pre- or posttraining)

Abbasi et al. [39]

2017

NDM

NMRI mice; males

41

a-tDCS vs. c-tDCS

Left PFC

0.2

0.04

20 or 30

N/A

Chest

9.5

N

N (single session)

↓ Contextual and cued fear memory

Martins et al. [97]

2019

NDM

Male Wistar rats; males

50

a-tDCS

Left mPFC

0.4

N/A

13

N/A

N/A

N/A

N/A

Y (5 days)

↑ Spatial working memory; ↑ GAP-43 (extinct by AMPAR antagonist PRP)

Yu et al. [41]

2019

NDM

Sprague Dawley rats; males

224

a-tDCS

SC dorsal to the hippocampus

0.25

0.25

30

N/A

Anterior chest

N/A (EEG electrode)

Y

N (single session)

↑ Memory (passive avoidance memory retention); ↑ LTP in CA1 hippocampus (blocked by TrkB antagonist); ↑ BDNF in CA1 hippocampus

Abbreviations: rtDCS: repetitive transcranial direct current stimulation; a-tDCS: anodal transcranial direct current stimulation; c-tDCS: cathodal transcranial direct current stimulation; SC: stereotaxic coordinates; C57BL/6: mouse strain; NMRI: Naval Medical Research Institute outbred mice; NBM: no disease model; SHR: spontaneous hypertensive rats; WKY: Wistar Kyoto rats; PFC: prefrontal cortex; mPFC: medial prefrontal cortex; ITC: inferotemporal cortex; CAI: comu ammonis 1 region in the hippocampus; PRP: perampanel; ACPA: anticitrullinated protein antibody (selective cannabinoid CBI receptor agonist); AMPAR: α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor; Trk: tropomyosin receptor kinase receptor; CREB/CBP: cAMP response element binding protein; BDNF: brain-derived neurotrophic factor; GAP-43: growth-associated protein 43; LTP: long-term potentiation; EEG: electroencephalography; A/m²: ampere per square meter; mA: milliampere; cm²: square centimeter; mm: millimeter; h: hour; min: minute; vs.: versus; Y: yes; N: no; N/A: not available.