Altered structure and function in the hippocampus and medial prefrontal cortex in patients with burning mouth syndrome

Abstract

Burning mouth syndrome (BMS) is a debilitating, idiopathic chronic pain condition. For many BMS patients, burning oral pain begins in late morning and becomes more intense throughout the day, peaking by late afternoon or evening. We investigated brain gray matter volume (GMV) with voxel-based morphometry (VBM), white matter fractional anisotropy (FA) with diffusion tensor imaging (DTI), and functional connectivity in resting state functional MRI (rsfMRI) in a tightly screened, homogeneous sample of 9 female, postmenopausal/perimenopausal BMS patients and 9 matched healthy control subjects. Patients underwent 2 scanning sessions in the same day: in the morning, when ongoing pain/burning was low, and in the afternoon, when pain/burning was significantly higher. Patients had increased GMV and lower FA in the hippocampus (Hc), and decreased GMV in the medial prefrontal cortex (mPFC). rsfMRI revealed altered connectivity patterns in different states of pain/burning, with increased connectivity between mPFC (a node in the default mode network) and anterior cingulate cortex, occipital cortex, ventromedial PFC, and bilateral Hc/amygdala in the afternoon compared with the morning session. Furthermore, mPFC-Hc connectivity was higher in BMS patients than control subjects for the afternoon but not the morning session. mPFC-Hc connectivity was related to Beck depression inventory scores both between groups and between burning states within patients, suggesting that depression and anxiety partially explain pain-related brain dysfunction in BMS. Overall, we provide multiple lines of evidence supporting aberrant structure and function in the mPFC and Hc, and implicate a circuit involving the mPFC and Hc in regulating mood and depressive symptoms in BMS.

The Emotional Brain as a Predictor and Amplifier of Chronic Pain

“…TMD is associated with a decrease in striatal dopaminergic uptake (Jaaskelainen et al 2001) and with changes in gray and white matter properties of corticolimbic regions (Younger et al 2010;Moayedi et al 2012). Moreover, patients suffering from burning mouth syndrome show structural differences in the hippocampus and mPFC, as well as increased functional connectivity between frontal and limbic regions as the pain increases (Khan et al 2014). Moreover, sustained pain from postoperative dental surgery is associated with higher cerebral blood flow in the thalamus, frontal regions, and sensorimotor cortex (Newberg et al 2011).…”

The Significance of Brain Transcranial Sonography in Burning Mouth Syndrome: a Pilot Study

“…These neurotransmitters are also involved in humans and they affect depression due to close association of the brainstem raphe nuclei with dorso-caudal limbic system. In some previous studies, the authors (11,12) used transcranial ultrasonography of the brain parenchyma, thus revealing reduced raphe echogenicity in patients with major depressive disorder and, also, with suicidal tendencies. In the present study, hypoechogenicity of the midbrain raphe was found in BMS patients.…”

“…Ovi neurotransmiteri također su uključeni kod ljudi i utječu na depresiju zbog bliske povezanosti nuclei raphe s dorzo-kaudalnim limbičkim sustavom. U nekim dosadašnjim istraživanjima autori su (11,12) pokazali, koristeći se transkranijalnim ultrazvukom moždanoga parenhima, smanjenu ehogenost nuclei raphe kod pacijenata s velikim depresivnim poremećajem i suicidalnim sklonostima. U ovom istraživanju također smo ustanovili hipoehogenosti nuclei raphe kod bolesnika sa SPU-om.…”

Structural changes in the CNS of patients with hemifacial spasm

“…However, it is unclear whether these alterations in GM volume acted as a predisposing factor or a secondary effect caused by disease-related conditions. Various types of chronic pain consist of another condition that is also frequently related to personality and mood changes of the patient, specifically anxiety and depression (Burgmer et al, 2009;Seminowicz et al, 2011;As-Sanie et al, 2012;Khan et al, 2014). VBM is a method of assessing brain GM volume that has previously been applied to various chronic pain conditions (Apkarian et al, 2004;Draganski et al, 2006;May, 2008;Younger et al, 2010;As-Sanie et al, 2012;Khan et al, 2014).…”