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The antidepressant effects of ventromedial prefrontal cortex stimulation is associated with neural activation in the medial part of the subthalamic nucleus

Lim LW, Janssen ML, Kocabicak E, Temel Y

Behav Brain Res, 2015 Feb 15;279:17-21.
PMID: 25446757 DOI: 10.1016/j.bbr.2014.11.008

The nucleus accumbens (NAc), ventromedial prefrontal cortex (vmPFC), and cingulate gyrus (Cg) are key regions in the control of mood-related behaviors. Electrical stimulation of these areas induces antidepressant-like effects in both patients and animal models. Another structure whose limbic connections are receiving more interest in the context of mood-related behaviors is the medial part of the subthalamic nucleus (STN). Here, we tested the hypothesis that the mood-related effects of NAc, vmPFC, and Cg are accompanied by changes in the neural activity of the STN. We performed high-frequency stimulation (HFS) of the NAc, vmPFC, and Cg. Animals were behaviorally tested for hedonia and forced swim immobility; and the cellular activities in the different parts of the STN were assessed by means of c-Fos immunoreactivity (c-Fos-ir). Our results showed that HFS of the NAc and vmPFC, but not Cg reduced anhedonic-like and forced swim immobility behaviors. Interestingly, there was a significant increase of c-Fos-ir in the medial STN with HFS of the vmPFC, but not the NAc and Cg as compared to the sham. Correlation analysis showed that the medial STN is associated with the antidepressant-like behaviors in vmPFC HFS animals. No behavioral correlation was found with respect to behavioral outcome and activity in the lateral STN. In conclusion, HFS of the vmPFC induced profound antidepressant-like effects with enhanced neural activity in the medial part of the STN.

Matched MeSH terms: Prefrontal Cortex/physiopathology*
Fulltext Cortical haemodynamic response measured by functional near infrared spectroscopy during a verbal fluency task in patients with major depression and borderline personality disorder

Husain SF, Tang TB, Yu R, Tam WW, Tran B, Quek TT, et al.

EBioMedicine, 2020 Jan;51:102586.
PMID: 31877417 DOI: 10.1016/j.ebiom.2019.11.047

BACKGROUND: Functional near infrared spectroscopy (fNIRS) provides a direct and quantitative assessment of cortical haemodynamic function during a cognitive task. This functional neuroimaging modality may be used to elucidate the pathophysiology of psychiatric disorders, and identify neurophysiological differences between co-occurring psychiatric disorders. However, fNIRS research on borderline personality disorder (BPD) has been limited. Hence, this study aimed to compare cerebral haemodynamic function in healthy controls (HC), patients with major depressive disorder (MDD) and patients with BPD.
METHODS: fNIRS signals during a verbal fluency task designed for clinical assessment was recorded for all participants. Demographics, clinical history and symptom severity were also noted.
FINDINGS: Compared to HCs (n = 31), both patient groups (MDD, n = 31; BPD, n = 31) displayed diminished haemodynamic response in the frontal, temporal and parietal cortices. Moreover, haemodynamic response in the right frontal cortex is markedly lower in patients with MDD compared to patients with BPD.
INTERPRETATION: Normal cortical function in patients with BPD is disrupted, but not as extensively as in patients with MDD. These results provide further neurophysiological evidence for the distinction of patients with MDD from patients with BPD.

Matched MeSH terms: Prefrontal Cortex/physiopathology*
Fulltext Relationships between dietary nutrients intake and lipid levels with functional MRI dorsolateral prefrontal cortex activation

Lau H, Shahar S, Mohamad M, Rajab NF, Yahya HM, Din NC, et al.

Clin Interv Aging, 2019;14:43-51.
PMID: 30613138 DOI: 10.2147/CIA.S183425

Background: Dorsolateral prefrontal cortex (DLPFC) is a key node in the cognitive control network that supports working memory. DLPFC dysfunction is related to cognitive impairment. It has been suggested that dietary components and high-density lipoprotein cholesterol (HDL-C) play a vital role in brain health and cognitive function.
Purpose: This study aimed to investigate the relationships between dietary nutrient intake and lipid levels with functional MRI (fMRI) brain activation in DLPFC among older adults with mild cognitive impairment.
Participants and methods: A total of 15 community-dwelling older adults with mild cognitive impairment, aged ≥60 years, participated in this cross-sectional study at selected senior citizen clubs in Klang Valley, Malaysia. The 7-day recall Diet History Questionnaire was used to assess participants' dietary nutrient intake. Fasting blood samples were also collected for lipid profile assessment. All participants performed N-back (0- and 1-back) working memory tasks during fMRI scanning. DLPFC (Brodmann's areas 9 and 46, and inferior, middle, and superior frontal gyrus) was identified as a region of interest for analysis.
Results: Positive associations were observed between dietary intake of energy, protein, cholesterol, vitamins B6 and B12, potassium, iron, phosphorus, magnesium, and HDL-C with DLPFC activation (P<0.05). Multivariate analysis showed that vitamin B6 intake, β=0.505, t (14)=3.29, P=0.023, and Digit Symbol score, β=0.413, t (14)=2.89, P=0.045; R2=0.748, were positively related to DLPFC activation.
Conclusion: Increased vitamin B6 intake and cognitive processing speed were related to greater activation in the DLPFC region, which was responsible for working memory, executive function, attention, planning, and decision making. Further studies are needed to elucidate the mechanisms underlying the association.

Matched MeSH terms: Prefrontal Cortex/physiopathology
Fulltext Validating a functional near-infrared spectroscopy diagnostic paradigm for Major Depressive Disorder

Husain SF, Yu R, Tang TB, Tam WW, Tran B, Quek TT, et al.

Sci Rep, 2020 06 16;10(1):9740.
PMID: 32546704 DOI: 10.1038/s41598-020-66784-2

Reduced haemodynamic response in the frontotemporal cortices of patients with major depressive disorder (MDD) has been demonstrated using functional near-infrared spectroscopy (fNIRS). Most notably, changes in cortical oxy-haemoglobin during a Japanese phonetic fluency task can differentiate psychiatric patients from healthy controls (HC). However, this paradigm has not been validated in the English language. Therefore, the present work aimed to distinguish patients with MDD from HCs, using haemodynamic response measured during an English letter fluency task. One hundred and five HCs and 105 patients with MDD took part in this study. NIRS signals during the verbal fluency task (VFT) was acquired using a 52-channel system, and changes in oxy-haemoglobin in the frontal and temporal regions were quantified. Depression severity, psychosocial functioning, pharmacotherapy and psychiatric history were noted. Patients with MDD had smaller changes in oxy-haemoglobin in the frontal and temporal cortices than HCs. In both regions of interest, oxy-haemoglobin was not associated with any of the clinical variables studied. 75.2% and 76.5% of patients with MDD were correctly classified using frontal and temporal region oxy-haemoglobin, respectively. Haemodynamic response measured by fNIRS during an English letter fluency task is a promising biomarker for MDD.

Matched MeSH terms: Prefrontal Cortex/physiopathology
Hypersexuality As a Neuropsychiatric Disorder: The Neurobiology and Treatment Options

Asiff M, Sidi H, Masiran R, Kumar J, Das S, Hatta NH, et al.

Curr Drug Targets, 2018;19(12):1391-1401.
PMID: 28325146 DOI: 10.2174/1389450118666170321144931

Hypersexuality refers to abnormally increased or extreme involvement in any sexual activity. It is clinically challenging, presents trans-diagnostically and there is extensive medical literature addressing the nosology, pathogenesis and neuropsychiatric aspects in this clinical syndrome. Classification includes deviant behaviours, diagnosable entities related to impulsivity, and obsessional phenomena. Some clinicians view an increase in sexual desire as 'normal' i.e. psychodynamic theorists consider it as egodefensive at times alleviating unconscious anxiety rooted in intrapsychic conflicts. We highlight hypersexuality as multi-dimensional involving an increase in sexual activity that is associated with distress and functional impairment. The aetiology of hypersexuality is multi-factorial with differential diagnoses that include major psychiatric disorders (e.g. bipolar disorder), adverse effects of treatments (e.g. levodopatreatment), substance-induced disorders (e.g. amphetamine substance use), neuropathological disorders (e.g. frontal lobe syndrome), among others. Numerous neurotransmitters are implicated in its pathogenesis, with dopamine and noradrenaline playing a crucial role in the neural reward pathways and emotionally- regulated limbic system neural circuits. The management of hypersexuality is determined by the principle of de causa effectu evanescent, if the causes are treated, the effect may disappear. We aim to review the role of pharmacological agents causing hypersexuality and centrally acting agents treating the associated underlying medical conditions. Bio-psycho-social determinants are pivotal in embracing the understanding and guiding management of this complex and multi-determined clinical syndrome.

Matched MeSH terms: Prefrontal Cortex/physiopathology
Fulltext Negative correlation of cortical thickness with the severity and duration of abdominal pain in Asian women with irritable bowel syndrome

Chua CS, Bai CH, Shiao CY, Hsu CY, Cheng CW, Yang KC, et al.

PLoS One, 2017;12(8):e0183960.
PMID: 28859146 DOI: 10.1371/journal.pone.0183960

BACKGROUND & AIMS: Irritable bowel syndrome (IBS) manifests as chronic abdominal pain. One pathophysiological theory states that the brain-gut axis is responsible for pain control in the intestine. Although several studies have discussed the structural changes in the brain of IBS patients, most of these studies have been conducted in Western populations. Different cultures and sexes experience different pain sensations and have different pain responses. Accordingly, we aimed to identify the specific changes in the cortical thickness of Asian women with IBS and to compare these data to those of non-Asian women with IBS.
METHODS: Thirty Asian female IBS patients (IBS group) and 39 healthy individuals (control group) were included in this study. Brain structural magnetic resonance imaging was performed. We used FreeSurfer to analyze the differences in the cortical thickness and their correlations with patient characteristics.
RESULTS: The left cuneus, left rostral middle frontal cortex, left supramarginal cortex, right caudal anterior cingulate cortex, and bilateral insula exhibited cortical thinning in the IBS group compared with those in the controls. Furthermore, the brain cortical thickness correlated negatively the severity as well as duration of abdominal pain.
CONCLUSIONS: Some of our findings differ from those of Western studies. In our study, all of the significant brain regions in the IBS group exhibited cortical thinning compared with those in the controls. The differences in cortical thickness between the IBS patients and controls may provide useful information to facilitate regulating abdominal pain in IBS patients. These findings offer insights into the association of different cultures and sexes with differences in cortical thinning in patients with IBS.

Matched MeSH terms: Prefrontal Cortex/physiopathology