Brain functional changes in chronic partial sleep-deprivation population by electroacupuncture at shenmen(HT7) and neiguan (PC6) acupoints: A BOLD-fMRI study

Abstract

Background

The aim of this study is to explore how electroacupuncture at the Shenmen (HT7) and Neiguan (PC6) acupoints can improve chronic partial sleep deprivation(CPSD) by regulating brain function, and to elucidate its potential neural mechanisms using resting state Blood Oxygen Level-Dependent functional magnetic resonance imaging (BOLD-fMRI).

Methods

43 CPSD participants and 48 healthy controls (HC) were recruited and underwent neuropsychological assessments before electroacupuncture. 3.0T BOLD-fMRI scans were conducted before and after receiving bilateral electroacupuncture at HT7 and PC6. Amplitude of low-frequency fluctuation (ALFF) regional homogeneity (ReHo) values and functional connectivity were analyzed between two groups before and after electroacupuncture.

Results

CPSD participants showed prolonged reaction time (RT), increased omission rate (OR), and decreased accuracy (ACC) compared to HC. Significant differences (P < 0.05) in ALFF, ReHo, and functional connectivity were observed between groups before and after electroacupuncture, particularly in the default mode network (DMN) and limbic system. ALFF in the right parahippocampal gyrus positively correlated with ACC (r = 0.637, P = 0.001) and negatively with OR (r = -0.427, P = 0.047). ReHo in the left superior frontal gyrus negatively correlated with RT (r = -0.514, P = 0.014).

Conclusion

CPSD disrupts functional brain activity, while electroacupuncture at HT7 and PC6 modulates resting-state brain function, offering neuroimaging insights into its potential mechanisms for treating emotional and cognitive impairments in CPSD.

1. Introduction

Sleep deprivation (SD), defined as a sleep duration of less than 5 h per day, occurs when an individual’s sleep fails to meet the physiological requirements for maintaining wakefulness and alertness. Sleep occupies one-third of human life and is a physiological necessity for maintaining bodily functions and health. Modern lifestyle stressors, including day-night shift work and pre-sleep electronic device usage, disrupt normal melatonin secretion patterns, contributing to SD.¹ Prolonged sleep deprivation lasting more than 72 h is termed chronic partial sleep deprivation (CPSD).² SD impairs memory, judgment, decision-making, and concentration while increasing irritability, circadian rhythm disruption, and risks of hallucinations, impulsivity, delirium, mental illness, and suicidal behavior.³ Systemically, SD elevates incidence and mortality rates for multiorgan pathologies, including neurological, cardiovascular, and gut dysbiosis-related diseases.⁴ A Canadian study estimated that insufficient sleep incurred total societal costs of $502 million (direct: $484 million; indirect: $18 million) in 2020.⁵ Thus, sleep deficiency profoundly burdens both individual health and socioeconomic systems.

Current SD management relies primarily on pharmacotherapy, which rapidly induces sleep but risks long-term dependence and adverse effects. Psychotherapeutic efficacy varies significantly across individuals. Recently, traditional Chinese medicine has gained scholarly attention as an SD intervention. Acupuncture, a cornerstone of traditional Chinese medicine, has demonstrated efficacy in treating chronic pain,⁶ depression,⁷ and drug addiction.⁸ Studies indicate acupuncture improves subjective sleep quality, though objective measures show limited statistical significance.⁹ Association rule analysis by Lu et al. identified Shenmen (HT7), Neiguan (PC6), and Sanyinjiao (SP6) as the highest-confidence acupoints for treating senile insomnia.¹⁰ Despite its potential, research on acupuncture for sleep-related conditions, particularly the combined use of Shenmen (HT7) and Neiguan (PC6) acupoints in CPSD patients, is still in its infancy, and its potential neurobiological mechanisms are worth exploring.

In contemporary neuroimaging research, BOLD-fMRI has emerged as a primary tool due to its simplicity, reproducibility, and non-invasive nature. The regional homogeneity (ReHo) and the amplitude of low-frequency fluctuations (ALFF) analysis methods, introduced by Zang et al. in 2004 and 2007, respectively, are used to assess local functional brain activity.11, 12 ALFF measures the deviation of BOLD signals from baseline amplitudes, reflecting spontaneous brain activity, while ReHo evaluates the temporal synchronization of neuronal activity within brain regions. Both methods indicate that resting-state BOLD signals are spontaneous and physiologically significant, reflecting the brain’s intrinsic functional architecture. Resting-state functional connectivity (rsFC) provides insights into the brain’s internal network organization and its changes, offering a unique perspective on normal brain function, disease mechanisms, and individual differences.

This study hypothesizes that electroacupuncture at the Shenmen (HT7) and Neiguan (PC6) acupoints has therapeutic effects on CPSD patients, and investigates the brain function regulatory mechanisms underlying their therapeutic effects using resting state BOLD-fMRI.

2. Methods

2.1. Participants

A total of 91 right-handed participants (43 CPSD and 48 healthy controls (HC)) were enrolled. HC participants were matched to CPSD participants in terms of age, sex, and education. The study protocol was approved by the Biomedical Ethics Committee of the First Affiliated Hospital of Guangdong Pharmaceutical University, and informed consent was obtained from all participants.

CPSD inclusion and exclusion criteria: (1) Intermittent sleep deprivation lasts for more than 3 days, with less than 5 h of sleep per day. (2) Pittsburgh Sleep Quality Index (PSQI) >7 points. (3) No acupuncture and moxibustion treatment within 1 month. (4) Never taken any sleep medication or neuropsychiatric medication. (5) No history of mental illness, stroke, epilepsy, head trauma, brain surgery, or cerebrovascular accident.

HC group inclusion and exclusion criteria: (1) There have been no sleep disorders in the past month, and the sleep pattern and duration are normal (≥7 h). (2) PSQI≤ 5 points. (3) No acupuncture and moxibustion treatment within 1 month. (4) Never taken any sleep medication or neuropsychiatric medication. (5) No history of mental illness, stroke, epilepsy, head trauma, brain surgery, or cerebrovascular accident.

2.2. Neuropsychological background test

Prior to the experiment, all participants completed the Montreal Cognitive Assessment (MoCA), Hamilton Anxiety Scale (HAMA), PSQI, and Epworth Sleepiness Scale (ESS). The PSQI assessed sleep quality over the past month, with higher scores indicating poorer sleep quality.

2.3. Attention network test (ANT)

The ANT, developed by Fan et al¹³., was administered using E-prime software. Participants completed 20 practice trials before the formal test to ensure familiarity with the task. Reaction time (RT), response accuracy (ACC), and omission rate (OR) were recorded.

2.4. Data acquisition method

MRI scans were performed using a 3.0T MRI system (Discovery MR750w, GE Healthcare). Resting-state BOLD-fMRI parameters included: repetition time (TR) = 1800 ms, echo time (TE) = 50 ms, field of view (FOV) = 240 mm × 240 mm, and acquisition matrix = 64 × 64. High-resolution BRAVO sequence parameters were: TR = 8.208 ms, TE = 3.22 ms, TI = 450 ms, and FOV = 240 mm × 240 mm. Each scan lasted approximately 12 min. Scans were performed before and 20 min after electroacupuncture.

2.5. Electroacupuncture procedure

Four disposable acupuncture needles (0.5 mm in diameter and 40 mm in length) were used to puncture the bilateral Shenmen (HT7) and Neiguan (PC6) acupoints. Specifically, Shenmen (HT7) is located on the ulnar side of the wrist crease, radial to the flexor carpi ulnaris tendon, near the prominence of the pisiform bone on the medial aspect of the wrist. Neiguan (PC6) is situated approximately 3 transverse finger widths proximal to the wrist crease (toward the elbow), in the depression between the palmaris longus tendon and the radial flexor carpi tendon. The insertion depth for both acupoints was approximately 10–15 mm.

An SDZ-II electronic acupuncture device was used to stimulate the bilateral Shenmen (HT7) and Neiguan (PC6) acupoints for 30 min, with an output current set at a frequency of 50 Hz and a continuous waveform. The stimulation intensity was adjusted to the maximum perceptual threshold, ensuring the absence of sharp needle pain while maintaining a continuous twitching sensation. "Deqi" (the arrival of qi) was confirmed based on participant feedback and the MASS scale.¹⁴

2.6. Data preprocessing

Data were preprocessed using DPARSFA,¹⁵ based on the MATLAB2012a (Mathworks, Natick, MA, USA) platform, including (1) Data format conversion: convert all subjects' DICOM raw files into NIFTI images. (2) Delete previous time points: remove images from the first 10 time points, due to unstable signal at the beginning of image acquisition. (3) Time correction: Reduce the differences caused by different image acquisition times. (4) Head movement correction: data with head movement exceeding 2 mm or rotation exceeding 2° will be excluded. (5) Space standardization processing: due to the significant individual differences in brain morphology and size, as well as the varying spatial positions during scanning, all subjects' data is standardized to address these issues. (6) Spatial smoothing: enhance normality for statistical purposes. (7) Removing linear drift: eliminate the linear trend caused by machine fatigue. (8) Local characteristic analysis: calculate ALFF and ReHo values for CPSD and HC groups.

2.7. Statistical analysis method

Demographic and neuropsychological data were analyzed using SPSS 22.0. For continuous variables, independent two-sample T-tests or Mann-Whitney non-parametric tests were used, according to whether they met the normal distribution and variance homogeneity. ALFF and ReHo values were compared using SPM10. Pearson’s correlation analysis was used to examine relationships between ANT results and ALFF/ReHo values in the CPSD group. Seed-based rsFC analysis was performed using xjVIEW and REST software. Seeds were chosen from regions showing pre-existing ALFF/ReHo group differences [P < 0.05] in Table 2.

Table 2.

Differences in ALFF/ReHo values within or between groups.

Brain regions	Volume (mm3)	MNI peak axis (X, Y, Z)	T	Brain regions	Volume (mm3)	MNI peak axis (X, Y, Z)	T
DifferencesofALFF/ReHo values between CPSD and HC group before acupuncture
ALFF increased region				ReHo increased region
L Inferior temporal gyrus	4401	−60,−27, −21	5.7699	L Amygdala	783	26, 3, −18	4.8060
L Supraoccipital gyrus	297	−18, −84,28	3.3867	L Posteriorcingulate gyrus	675	−6, −43, 28	5.5892
R Cuneiform leaf	378	9, −56, 44	4.8122	R Middle temporal gyrus	1323	66, −42, −3	4.3862
L Medial anteriorcingulate gyrus	405	−6, −15, 43	5.0279	L Middle temporal gyrus	1431	−57, −34, 5	4.5327
L Amygdala	513	28, 5, −16	4.0287	L Thalamus	351	−9, −13, 17	4.8124
ALFF decreased region				ReHo decreased region
R Parahippocampal gyrus	270	24, −15, −20	−5.4314	R Precuneate lobe	351	10, 56, 48	−3.3092
R Precuneate lobe	432	9, −56, 44	−6.9399	L Cuneiform leaf	675	−7, −80, 27	−4.0601
L Inferior parietal lobule	459	−44, −46, −47	−4.8491	R Glossal gyrus	1215	15, −67, −4	−3.3810
L Thalamus	837	−13, −18,15	−5.3396	L Superior frontal gyrus	486	−3, 49, 31	−4.7091
L Superior frontal gyrus	405	−7, 48, 32	−4.6129	R Middle frontal gyrus	297	8, 51, 30	−5.2516
R Angular gyrus	324	45,−60, 39	−5.0739
R Posterior cingulate gyrus	648	7, −42, 13	−4.7937
Differences of ALFF/ReHo values before and after acupuncture in the HC groups
ALFF increased region				ReHo increased region
L Precuneate lobe	486	−8, −56, 48	5.2367	L Medial superior frontal gyrus	594	−19, 35, 42	4.2070
R Thalamus	405	12, −8,8	4.6129	L Orbital middle frontal gyrus	945	3, 54, 42	4.8915
R Superior frontal gyrus	405	−19, 35, 42	4.6808	R Thalamus	324	12, −18, 8	4.9230
R Inferior frontal	351	−47, 30, 14	4.0195	R Parahippocampal gyrus	297	28, −16, −18	5.8493
R Precentral gyrus	216	40, −8, 52	5.0173
ALFF decreased region				ReHo decreased region
L Amygdala	324	−24, −1, −17	−4.6348	L Amygdala	270	−23, −1, −9	−4.0681
R Fusiform gyrus	189	33,−39,−20	−3.8256	R Inferior temporal gyrus	135	42, −15, 10	−3.5302
L Middle occipital gyrus	459	−33, −81, 16	−6.8491	R Postcentral gyrus	810	40, −25, 53	−4.1062
R Middle frontal gyrus	351	48, 9, 45	−4.6487	L Precentral gyrus	837	−9, −87, 18	−4.0735
Differences of ALFF/ReHo values before and after acupuncture in the CPSD groups
ALFF increased region				ReHo increased region
L Posterior cingulate gyrus	432	−6, −43, 25	4.1171	R Medial lateral cingulate gyrus	702	3, −21, 36	3.4974
L Precuneate lobe	432	−8, −56, 48	4.8159	L Superior frontal gyrus	837	−21, 39, 42	3.6449
R Precuneate lobe	324	13, −56, 44	5.7391	R Posterior cingulate gyrus	432	6, −42, 22	4.1171
R Cuneiform leaf	378	13, −79, 28	5.0824	L Inferior temporal gyrus	432	46, 13, 7	4.0601
L Superior frontal gyrus	486	−18, 37, 47	4.5015	L Precentral gyrus	675	−40, −6, 51	3.6902
ALFF decreased region				ReHo decreased region
L Amygdala	324	−24, −1, −17	−4.6348	L Inferior frontal gyrus	621	42, 15, 6	−5.0647
R Heschl gyrus	189	33, −39, −20	−3.8256	R Angular gyrus	594	30, 15, 6	−4.6311
R Postcentral gyrus	459	−33, −81, 16	−6.8491	L Postcentral gyrus	702	−43, −23, 49	−4.5808
L Middle occipital gyrus	351	48, 9, 45	−4.6487	L Amygdala	632	−24, −1, −17	−5.0661
				R Middle occipital gyrus	675	36, −80, 19	−4.2038

Note: two-sample t-test, cluters P < 0.05 (FDR multiple correction), V ≥ 270 mm³; MNI coordinates correspond to the maximum active voxels in each activated cluster, voxel size 3.0 mm × 3.0 mm × 3.0 mm. ALFF, the amplitude of low-frequency fluctuations; CPSD, chronic partial sleep deprivation; HC, healthy controls; L, left; MNI: Montreal Institute of Neurology Neurospace; R, right; ReHo, the regional homogeneity.

Before acupuncture, we selected three seed points (right posterior cingulate gyrus, right anterior cuneate lobe and right parahippocampal gyrus) to construct the whole brain functional connectivity in CPSD and HC groups, and compared the differences between the two groups.

Before and after acupuncture, we selected the left amygdala to construct the whole brain functional connectivity in HC groups, and compared the differences.

Before and after acupuncture, we selected the left amygdala to construct the whole brain functional connectivity in CPSD, and compared the differences.

3. Results

3.1. Behavioral results

The CPSD group exhibited significantly prolonged RT, increased OR, and decreased ACC compared to the HC group (P < 0.05) (Table 1). The total score and various scores of PSQI in the CPSD group were higher than HC group (P < 0.05). There was no statistically significant difference in Age, Gender, Education, MoCA-B, HAMA and ESS scores between the CPSD and HC groups (P > 0.05).

Table 1.

Participant demographic, clinical, and sleep characteristics.

Item	CPSD	HC	T/U/χ2	P
Age (years)	27.02±3.46	26.06±3.27	−1.496	0.135
Gender (Male/Female)	24/19	26/22	0.890	0.345
Education (years)	11.19±3.06	10.83±3.40	−0.277	0.782
MoCA-B	26.70±1.85	27.35±1.89	−1.813	0.070
PSQI total score	10.63±1.94	4.38±0.79	−8.333	0.000*
Subjective sleep quality	1.72±0.80	0.69±0.62	−5.667	0.000*
Sleep latency	1.63±0.72	0.71±0.62	−5.453	0.000*
Sleep duration	1.84±0.61	0.79±0.41	−7.104	0.000*
Habitual sleep efficiency	1.63±0.72	0.77±0.52	−5.537	0.000*
Sleep disturbances	2.09±0.72	0.77±0.59	−6.951	0.000*
Use of sleeping medication	-	-	-	-
Daytime dysfunction	1.72±0.73	0.65±0.48	−6.443	0.000*
HAMA	5.21±1.68	4.81±1.28	−1.123	0.261
ESS	6.21±1.66	5.60±1.45	−1.731	0.083
ANT test
RT (ms)	790.84±16.18	689.01±17.01	−16.03	0.037*
ACC (%)	79.74±7.85	83.22±7.57	−2.030	0.045*
OR (%)	13.93±3.71	11.87±3.38	2.765	0.007*

ACC, response accuracy; ANT, Attention Network Test; CPSD, chronic partial sleep deprivation; ESS, Epworth Sleepiness Scale; HAMA, Hamilton Anxiety Scale; HC, healthy controls; MoCA-B, Montreal Cognitive Assessment; OR, omission rate; PSQI, Pittsburgh Sleep Quality Index; RT, reaction time.

^⁎P < 0.05 is statistically significant.

3.2. ALFF and ReHo differences

Significant differences in ALFF and ReHo values were observed between the CPSD and HC groups before electroacupuncture (P < 0.05) (Table 2). Electroacupuncture induced significant changes in ALFF and ReHo values in both groups, particularly in the default mode network (DMN) and limbic system.

3.2.1. Pre-acupuncture differences in ALFF and ReHo between CPSD and HC groups

Before electroacupuncture, compared to HC, the ALFF increased regions in CPSD include: left inferior temporal gyrus, left supraoccipital gyrus, right cuneiform leaf, left medial anterior cingulate gyrus and left amygdala; the ALFF decreased regions in CPSD include: right parahippocampal gyrus, right precuneate lobe, left inferior parietal lobule, left thalamus, left superior frontal gyrus, right angular gyrus and right posterior cingulate gyrus (Fig. 1A).

Fig. 1.

Pre-acupuncture differences between CPSD and HC groups. (A) ALFF; (B) ReHo. Warmtone represents the increased while the cold tonerepresentsthe decreased. ALFF, the amplitude of low-frequency fluctuations; CPSD, chronic partial sleep deprivation; HC, healthy controls; ReHo, the regional homogeneity.

Before electroacupuncture, compared to HC, the ReHo increased regions in CPSD include: left amygdala, left posterior cingulate gyrus, right middle temporal gyrus, left middle temporal gyrus and left thalamus; the ReHo decreased regions in CPSD include: right precuneate lobe, left cuneiform leaf, right glossal gyrus, left superior frontal gyrus and right middle frontal gyrus (Fig. 1B).

3.2.2. Differences of ALFF/ ReHo values before and after acupuncture in the HC groups

After electroacupuncture, the ALFF increased regions in HC include: left precuneate lobe, right thalamus, right superior frontal gyrus, right inferior frontal and right precentral gyrus; the ALFF decreased regions in HC include: left amygdala, right fusiform gyrus, left middle occipital gyrus and right middle frontal gyrus (Fig. 2A).

Fig. 2.

Differences of values before and after acupuncture in the HC group. (A) ALFF; (B) ReHo. Warmtone represents the increased while the cold tonerepresentsthe decreased. ALFF, the amplitude of low-frequency fluctuations; CPSD, chronic partial sleep deprivation; HC, healthy controls; ReHo, the regional homogeneity.

After electroacupuncture, the ReHo increased regions in HC include: left medial superior frontal gyrus, left orbital middle frontal gyrus, right thalamus and right parahippocampal gyrus; the ReHo decreased regions in HC include: left amygdala, right inferior temporal gyrus, right postcentral gyrus and left precentral gyrus (Fig. 2B).

3.2.3. Differences of ALFF/ReHo values before and after acupuncture in the CPSD groups

After electroacupuncture, the ALFF increased regions in CPSD include: left Posterior cingulate gyrus, left precuneate lobe, right precuneate lobe, right cuneiform leaf and left superior frontal gyrus; the ALFF decreased regions in HC include: left amygdala, right heschl gyrus, right postcentral gyrus and left middle occipital gyrus (Fig. 3A).

Fig. 3.

Differences of values before and after acupuncture in the CPSD group. (A) ALFF; (B) ReHo.Warmtone represents the increased while the cold tonerepresentsthe decreased. ALFF, the amplitude of low-frequency fluctuations; CPSD, chronic partial sleep deprivation; HC, healthy controls; ReHo, the regional homogeneity.

After electroacupuncture, the ReHo increased regions in CPSD include: right medial lateral cingulate gyrus, left superior frontal gyrus, right posterior cingulate gyrus, left inferior temporal gyrus and left precentral gyrus; the ReHo decreased regions in HC include: left inferior frontal gyrus, right angular gyrus, left postcentral gyrus, left amygdala and right middle occipital gyrus (Fig. 3B).

3.3. Correlation analysis

In the CPSD group, the ALFF value of the right parahippocampal gyrus positively correlated with ACC (r = 0.637, P = 0.001) and negatively correlated with OR (r = −0.427, P = 0.047, Fig. 4A). The ReHo value of the left superior frontal gyrus negatively correlated with RT (r = −0.514, P = 0.014, Fig. 4B).

Fig. 4.

The Analysis of correlation between ANT results. (A) ALFF value of the right parahippocampal gyrus; (B) ReHo value of the right superior frontal gyrus. ACC, response accuracy; ALFF, the amplitude of low-frequency fluctuations; ANT, Attention Network Test; OR, omission rate; ReHo, the regional homogeneity.

3.4. Functional connection analysis

Significant changes in rsFC were observed in the CPSD and HC groups following electroacupuncture, particularly in the DMN and limbic system (Fig. 5, Table 3).

Fig. 5.

The effect of acupuncture on brain functional connectivity. (A) Changes before acupuncture in the CPSD group compared with the HC group; (B) Changes before and after acupuncture in the HC group; (C) Changes before and after acupuncture in the CPSD group.CPSD, chronic partial sleep deprivation; HC, healthy controls.

Table 3.

Differences of rsFC between CPSD and HC groups before acupuncture.

	ROI	Strength increase	Strength reduction
CPSD and HC groups before acupuncture	Right posterior cingulate gyrus	Left inferior temporal gyrus Right anterior cuneate lobe	Left parahippocampal gyrus Right superior frontal gyrus
	Right anterior cuneate lobe	Left inferior temporal gyrus Right superior frontal gyrus	Left superior frontal gyrus Right precentral gyrus
	Rightparahippocampal gyrus	—	Bilateral postcentral gyrus
HC group before and after acupuncture	Left amygdala	Left thalamus Right cingulate gyrus	Right superior parietal lobule Left inferior parietal lobule
CPSD group before and after acupuncture	Left amygdala	Right cuneate anterior lobe Left superior temporal gyrus	Right angular gyrus Right middle temporal gyrus

CPSD, chronic partial sleep deprivation; HC, healthy controls; rsFC, resting-state functional connectivity; ROI, Region of Interest.

3.4.1. Before acupuncture, CPSD functional connectivity changes compared with the HC

Prior to acupuncture intervention, the right posterior cingulate gyrus (PCG.R), right precuneus (Precuneus.R), and right parahippocampal gyrus (ParaHippocampal.R) were selected as seed points to establish whole-brain rsFC in both the CPSD group and the HC group.

Compared to the HC group, the CPSD group exhibited increased functional connectivity between the right posterior cingulate gyrus and both the left inferior temporal gyrus and the right precuneus, alongside decreased connectivity between the right posterior cingulate gyrus and the left parahippocampal gyrus as well as the right superior frontal gyrus.

Furthermore, enhanced functional connectivity was observed between the right precuneus and the left inferior temporal gyrus and right superior frontal gyrus, whereas connectivity with the left superior frontal gyrus and right precentral gyrus was reduced.

Additionally, the right parahippocampal gyrus showed decreased functional connectivity with the bilateral postcentral gyrus (Fig. 5A).

3.4.2. Functional connectivity changes in HC group before and after acupuncture

In the HC group, the left amygdala (Amygdala.L) was selected as a seed region to assess rsFC before and after acupuncture. Following acupuncture, increased functional connectivity was observed between the left amygdala and both the left thalamus and right cingulate gyrus, while connectivity with the right superior parietal lobule and left inferior parietal lobule was reduced (Fig. 5B).

3.4.3. Functional connectivity changes in CPSD group before and after acupuncture

In the CPSD group, the left amygdala (Amygdala.L) was also used as a seed point to evaluate whole-brain rsFC before and after acupuncture. After acupuncture, enhanced functional connectivity was detected between the left amygdala and both the right precuneus and left superior temporal gyrus, whereas connectivity with the right angular gyrus and right middle temporal gyrus was diminished (Fig. 5C).

4. Discussion

4.1. Summary of main findings

This study utilized resting-state functional magnetic resonance imaging (rs-fMRI) to investigate the neural correlates of CPSD and the neuromodulatory effects of acupuncture at Shenmen (HT7) and Neiguan (PC6). We identified significant abnormalities in regional brain activity within the DMN and limbic system in CPSD patients. Specifically, alterations in ALFF and ReHo were observed in key regions including the parahippocampal gyrus, posterior cingulate cortex, precuneus, angular gyrus, and amygdala. Following acupuncture intervention, we detected notable normalization of activity in these regions, accompanied by improved functional connectivity between the amygdala and nodes of the DMN.

4.2. Comparison with previous studies

Our results are consistent with and substantially extend the existing literature reporting DMN dysfunction in sleep-related disorders.¹⁶ Previous neuroimaging studies have consistently identified disrupted functional connectivity within the DMN in individuals with poor sleep quality, often correlating with deficits in cognition and emotion regulation.¹⁷ Specifically, research by Li et al. demonstrated abnormalities in the multi system structure and neural network connections within the brain in insomnia patients,¹⁸ which aligns with our findings of ALFF reductions in these regions. Besides, our research has found that the reduced ALFF and ReHo values in the right anterior cuneiform lobe, a pivotal region within the DMN, further underscore the likelihood of DMN dysfunction in the CPSD.

The role of the limbic system—particularly the amygdala and parahippocampal gyrus—in sleep-related emotional processing and memory has also been well established.¹⁹ For example, Wei et al. reported reduced hippocampal perfusion linked to cognitive decline in poor sleepers,²⁰ reduced functional connectivity between the amygdala, insula, striatum, and thalamus in insomnia patients,21, 22 alongside amygdala atrophy in chronic insomnia and anxiety,²³ the above studies confirms from structural and functional imaging that SD can induce dysfunction of the limbic system, which may affect the emotional regulation and memory function of subjects. For example, the CPSD group performed worse on the neural function scale evaluation compared to the healthy control group. In the ANT, the average reaction time, accuracy, and omission rate of the CPSD group were significantly reduced, and scores were higher in MoCA, HAMA, and ESS scores, although no statistical differences were observed. And the correlation analysis between ALFF and ReHo and the scores of the neurological function scale also showed statistical significance. The above research results providing parallel evidence for limbic system involvement in sleep disorders, our observation of abnormal ALFF/ReHo in similar regions further supports the involvement of limbic circuits in CPSD pathogenesis.

Notably, our study demonstrated that these neural abnormalities extend to multiple DMN and limbic system regions simultaneously, suggesting widespread network disruption rather than isolated regional dysfunction.

4.3. Clinical and scientific implications

The findings suggest that acupuncture may induce restorative neural changes in CPSD, potentially improving attention, memory, and emotional regulation through network-level modulation. Convergence of ALFF and ReHo changes within the DMN and amygdala implies that acupuncture can modulate network-level dysfunction, supporting its therapeutic potential for sleep disorders with cognitive and affective comorbidities. These insights strengthen the neurobiological basis for acupuncture in treating sleep disorders and propose rs-fMRI-derived biomarkers for treatment response evaluation.

From a clinical perspective, our study provides a neurophysiological basis for considering acupuncture as a viable intervention for CPSD, particularly for patients who cannot tolerate or prefer to avoid pharmacological treatments. The modulation of both DMN and limbic system activity suggests that acupuncture may simultaneously address both the sleep disturbances and the emotional/cognitive comorbidities that often accompany chronic sleep disorders. This dual action represents a potential advantage over conventional treatments that may target only specific symptoms.

The scientific implications of our findings are substantial. We propose that DMN and limbic system dysfunction, measured via altered activity and functional connectivity, constitutes a novel neuroimaging biomarker capable of objectively assessing treatment response and guiding therapeutic strategies for CPSD. This addresses a critical need in sleep medicine, where objective biomarkers for treatment efficacy are largely lacking. Furthermore, our findings contribute to the growing understanding of the neural mechanisms underlying acupuncture's therapeutic effects, moving beyond traditional explanations toward a systems-level understanding of its neuromodulatory actions.

Future research should explore whether these neural changes predict long-term clinical outcomes and whether different acupuncture protocols might produce differentiated effects on specific neural networks. Additionally, our findings raise the possibility that rs-fMRI could be used to identify patient subgroups most likely to respond to acupuncture treatment, potentially enabling more personalized treatment approaches for CPSD.

4.4. Strengths and limitations

Key strengths include the use of well-validated fMRI metrics and a focused analysis on predefined neural networks. However, several limitations must be acknowledged. The single-center design, small sample size, and lack of long-term follow-up constrain generalizability. The absence of a sham-acupuncture control limits causal inference. Future studies should incorporate larger cohorts, longitudinal designs, and multimodal imaging to validate and extend these results.

4.5. Conclusions and suggestions for future research

In conclusion, electroacupuncture at HT7 and PC6 can modulate aberrant brain activity in CPSD patients, particularly in the DMN and limbic system, which may underlie improvements in emotional and cognitive function. Future research should employ randomized controlled trials with sham acupuncture, longer follow-up periods, and integrate multimodal neuroimaging to elucidate sustained therapeutic mechanisms.

Funding

No funding was received for this work.

Ethical statement

This research was reviewed and approved by the institutional review board of the First Affiliated Hospital of Guangdong Pharmaceutical University (registration number2024–037). Informed consent was obtained from all participants.

Data availability

The data that support the findings of this study are not publicly available due to ethical restrictions involving human participants.

CRediT authorship contribution statement

Hui Zeng: Methodology, Software, Resources, Writing – original draft, Writing – review & editing. Ganbin Qiu: Software, Validation, Formal analysis. Chunyan Wang: Formal analysis, Investigation, Data curation. Peifan Liu: Investigation. Chunxing Liu: Investigation. Mouyuan Liu: Supervision. Xiaotong Xie: Visualization. Liheng Ma: Conceptualization, Writing – review & editing, Project administration, Funding acquisition.

Declaration of competing interest

The authors declare that they have no conflicts of interest.

Appendix A. Supplementary materials

Supplement 1. TREND checklist