Table 1.

Characteristics of animal studies with information on the effect of NBM DBS on behavioral cognitive outcomes.

No	Author, year	Species, strain, sex	Age	Comparisons	Bilateral/unilateral stimulation (right/left)	Stimulation parameter	Behavioral task	Stimulation timing	Stimulation duration
I. Sham vs NBM stimulation (rodent study)
1	Montero-Pastor et al. 200111	Rats, Wistar, male	92.8 (SEM = 0.66) days old	Sham vs stimulation	Unilateral (right)	Intermittent stimulation (500 ms with electrical pulses and 500 ms without electrical pulses), 100 Hz, 500 µs, 60–90 µA	Two-way active avoidance paradigm	Immediately after acquisition training	20 min
2	Montero-Pastor et al. 200412	Rats, Wistar, male	97.63 (SD = 5.52) days old	Sham vs stimulation	Unilateral (right)	Intermittent stimulation (500 ms with electrical pulses and 500 ms without electrical pulses), 100 Hz, 500 µs, 100 µA	Two-way active avoidance paradigm	Immediately before (a) or after (b) acquisition training, or before 24-h-retention assessment (c)	30–45 min
3	Boix-Trelis et al. 200615	Rats, Wistar, male	98.23 (SEM = 0.78) days old	Sham vs stimulation	Unilateral (left/right)*	Intermittent stimulation (500 ms with electrical pulses and 500 ms without electrical pulses), 100 Hz, 500 µs, 100 µA	Relational odor-association task—the social transmission of food preference (STFP)	Before acquisition training	20 min
4	Reed et al. 201116	Rats	N/A	Sham vs stimulation	Unilateral (right)	Intermittent stimulation (electrical pulses was synchronized to the cue presentation), 20 pulses at 100 Hz, 100 µs, 120–200 µA, biphasic	Tone discrimination task	During acquisition training	3 h/day for 20 days
5	Lee et al. 201613	Rats, Sprague–Dawley, male	6 weeks old	NBM-intact vs NBM lesioned vs NBM-lesioned + electrode implant vs NBM-lesioned + stimulation	Unilateral (right)	120 Hz, 90 μs, 1 V	Morris water maze	Before acquisition training	1 h/day; 7 days in total
6	Huang et al. 201814	C57/BL6-Tg APP/P1 transgenic mice, Wild type WT C57BL/6 mice, male	4, 6, 9, 12 months old	Control non-surgical mice, sham stimulation, stimulation	Unilateral (left)	Continuous stimulation, (10/50/100/130) Hz, 90 μs, 1 A	Morris water maze	Before acquisition training	60 min per day for 30 days; 60 min per day for 7, 14, 21, 28 days; 60 min per day for 21 days
II. Unsynchronized vs synchronized stimulation (rodent study)
7	McLin III et al. 200217	Rats, Wistar, male	N/A	Synchronized vs unsynchronized stimulation	Unilateral (right)	100 Hz bipolar, pulse width is unknown, 50–100 μA, 200 ms train duration	Classical conditioning**	During acquisition training	N/A
8	Weinberger et al. 200620	Rats, Sprague–Dawley, male	115 (SD = 33) days old	Weak amplitude + unsychronized vs weak amplitude + synchronized stimulation; moderate amplitude + unsynchronized vs moderate + synchronized	Unilateral (right)	bipolar, 100 Hz, 200 µs, 65.7 ± 9.0 µA (moderate)/46.7 ± 12.1µA (weak), 200 ms train duration, biphasic pulses	Classical conditioning**		1–3 training sessions, ~ 4 h per session
9	Miasnikov et al. 200619	Rats, Sprague–dawley, male	110 ± 24 days	Synchronized vs unsynchronized stimulation	Unilateral (right)	bipolar, 100 Hz, 200 µs, ~ 66 µA, 200 ms train duration, biphasic pulses	Classical conditioning**		1 training session, ~ 4 h per session
10	Miasnikov et al. 200922	Rats, Sprague–Dawley, male	112 (SD = 24) days old	Synchronized vs unsynchronized stimulation	Unilateral (right)	bipolar, 100 Hz, 200 µs, ~ 66 µA, 200 ms train duration, biphasic pulses	Classical conditioning**		1 training sessions, ~ 4 h per session
11	Weinberger et al. 200918	Rats, Sprague–Dawley, male	N/A	Synchronized vs unsynchronized stimulation	Unilateral (right)	bipolar, 100 Hz, 200 µs, ~ 66 µA, 200 ms train duration, biphasic pulses	Classical conditioning**		3 training sessions, ~ 4 h per session
12	Miasnikov et al. 201121	Rats, Sprague–Dawley	92 (SD = 7) days	Synchronized vs unsynchronized stimulation	Unilateral (right)	bipolar, 100 Hz, 200 µs, ~ 66 µA, 200 ms train duration, biphasic pulses	Classical conditioning**		3 training sessions, ~ 4 h per session
III. Single-group, repeated-measures study with non-human primates & rodents
13	Miasnikov et al. 2008a25	Rats, Sprague–Dawley, male	104 (SD = 17) days old	Before vs after stimulation	Unilateral (right)	100 Hz, 200 µs, 66 µA, 200 ms train duration, biphasic pulses	Classical conditioning**	During cognitive assessment	1 training sessions, ~ 4 h per session
14	Miasnikov et al. 200826	Rats, Sprague–Dawley, male	N/A	Before vs after stimulation	Unilateral (right)	100 Hz, 200 µs, 66 µA, 200 ms train duration, biphasic pulses	Classical conditioning**		1 training sessions, ~ 4 h per session
15	Avila & Lin 201427	Rats, Long-Evans, male	3–6 months	Stimulation vs no stimulation	Bilateral	100 µs, 11 pulses with 10 ms interstimulus interval, 16–48 µA, biphasic pulses	Auditory-cued discrimination task		N/A
16	Mayse et al. 201528	Rats, Long-Evans, male	6 months	Stimulation vs no stimulation	Bilateral	1–3 pulses at 100 Hz, 24–48 µA, 100 µs, biphasic pulses	Stop no-reward task		N/A
17	Liu et al. 201723	Rhesus monkey (M. mulata)	6 years old	Continuous vs intermittent vs no stimulation	Bilateral	Continuous stimulation, 80 Hz, 100 μs, 200 uA, biphasic pulses; Intermittent stimulation (20-s ON, 40-s OFF), 60 Hz, 100 μs, 200 μA, biphasic pulses	Delayed match-to-sample task		N/A
18	Liu et al. 201824	Rhesus monkey (M. mulata), male	6 years old	Intermittent vs no stimulation	Bilateral	Intermittent stimulation (20-s ON, 40-s OFF), 60 Hz, 100 us, 200 μA, biphasic pulses	Continuous performance task		N/A
19	Koulousakis et al. 202029	Tg APP/P1 transgenic rats, male	18 months	Continuous vs intermittent vs no stimulation	Bilateral	Intermittent stimulation (20-s ON, 40-s OFF), positive monophasic pulses, 100 µs, 200 µA, 60 Hz; continuous stimulation, 20 Hz	Modified Barnes maze task		N/A

N/A data is not available. *left or right NBM, the number within the group was made. **sound of 8-kHz tone as the conditioned stimulus, NBM stimulation as the unconditioned stimulus, and respiratory change index as the conditioned response balance.