Dynamic Changes of Functional Pain Connectome in Women with Primary Dysmenorrhea.

Primary dysmenorrhea (PDM) is the most prevalent gynecological problem. Many key brain systems are engaged in pain processing. In light of dynamic communication within and between systems (or networks) in shaping pain experience and behavior, the intra-regional functional connectivity (FC) in the hub regions of the systems may be altered and the functional interactions in terms of inter-regional FCs among the networks may be reorganized to cope with the repeated stress of menstrual pain in PDM. Forty-six otherwise healthy PDM subjects and 49 age-matched, healthy female control subjects were enrolled. Intra- and inter-regional FC were assessed using regional homogeneity (ReHo) and ReHo-seeded FC analyses, respectively. PDM women exhibited a trait-related ReHo reduction in the ventromedial prefrontal cortex, part of the default mode network (DMN), during the periovulatory phase. The trait-related hypoconnectivity of DMN-salience network and hyperconnectivity of DMN-executive control network across the menstrual cycle featured a dynamic transition from affective processing of pain salience to cognitive modulation. The altered DMN-sensorimotor network may be an ongoing representation of cumulative menstrual pain. The findings indicate that women with long-term PDM may develop adaptive neuroplasticity and functional reorganization with a network shift from affective processing of salience to the cognitive modulation of pain.

Changes in functional connectivity of pain modulatory systems in women with primary dysmenorrhea.

Menstrual pain is the most prevalent gynecological complaint, and is usually without organic cause (termed primary dysmenorrhea, PDM). The high comorbidity in the later life of PDM with many functional pain disorders (associated with central dysfunction of pain inhibition, eg, fibromyalgia) suggests possible maladaptive functionality of pain modulatory systems already occurred in young PDM women, making them vulnerable to functional pain disorders. Periaqueductal gray (PAG) matter functions as a critical hub in the neuraxis of pain modulatory systems; therefore, we investigated the functional connectivity of PAG in PDM. Forty-six PDM subjects and 49 controls received resting-state functional magnetic resonance imaging during menstruation and periovulatory phases. The PAG of PDM subjects exhibited adaptive/reactive hyperconnectivity with the sensorimotor cortex during painful menstruation, whereas it exhibited maladaptive hypoconnectivity with the dorsolateral prefrontal cortex and default mode network (involving the ventromedial prefrontal cortex, posterior cingulate cortex, or posterior parietal cortex) during menstruation or periovulatory phase. We propose that the maladaptive descending pain modulatory systems in PDM may underpin the central susceptibility to subsequent development of various functional disorders later in life. This hypothesis is corroborated by the growing body of evidence that hypoconnectivity between PAG and default mode network is a coterminal to many functional pain disorders.

Reduced functional connectivity between salience and visual networks in migraine with aura.

BACKGROUND: Migraine with visual aura (MA) is associated with distinct visual disturbances preceding migraine attacks, but shares other visual deficits in between attacks with migraine without aura (MO). Here, we seek to determine if abnormalities specific to interictal MA patients exist in functional brain connectivity of intrinsic cognitive networks. In particular, these networks are involved in top-down modulation of visual processing. METHODS: Using resting-state functional magnetic resonance imaging, whole-brain functional connectivity maps were derived from seeds placed in the anterior insula and the middle frontal gyrus, key nodes of the salience and dorsal attention networks, respectively. Twenty-six interictal MA patients were compared with 26 matched MO patients and 26 healthy matched controls. RESULTS: The major findings were: connectivity between the anterior insula and occipital areas, including area V3A, was reduced in MA but not in MO. Connectivity changes between the anterior insula and occipital areas further correlated with the headache severity in MA only. CONCLUSIONS: The unique pattern of connectivity changes found in interictal MA patients involved area V3A, an area previously implicated in aura generation. Hypoconnectivity to this and other occipital regions may either represent a compensatory response to occipital dysfunctions or predispose MA patients to the development of aura.