Unilaterally Disrupted Structural and Functional Connectivity of The Fronto-Iimbic System In Idiopathic Hypogonadotropic Hypogonadism

Background: Idiopathic hypogonadotropic hypogonadism (IHH) is rare and can either be associated with normal or defective olfactory sensation, classified as normosmic IHH (nIHH) or Kallmann’s syndrome (KS), respectively. We do not yet understand the central processing pathways in the olfactory system, especially regarding these disorders. We aimed to compare the resting-state structural and functional connectivity (FC) of olfactory neural pathways in patients with nIHH and KS.Methods: A total of 50 males were studied: 13 nIHH patients, 12 KS patients, and 25 healthy controls (HCs). All subjects underwent diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI) scans. Structural and functional connectivity data analyses were then performed.Results: The results indicated that fractional anisotropy (FA) was significantly decreased in the right uncinate fasciculus (UF) in the KS group. The olfactory cortex FC values of the right gyrus rectus and orbitofrontal cortex (OFC) in the KS group were decreased compared with those in the HC group and increased compared with those in the nIHH group (nIHH< KS <HC). Moreover, there were significant negative correlations between right UF FA and olfactory cortex FC to both the gyrus rectus and OFC within the nIHH and HC groups.Conclusion: We have reported significant structural and functional disruptions unilaterally at the right junction of the fronto-limbic system in KS patients. The results may indicate that a specific structural-functional asymmetry exists in the olfactory cortex pathways in KS patients.

Ginkgo Biloba Extract Is Comparable With Donepezil in Improving Functional Recovery in Alzheimer’s Disease: Results From a Multilevel Characterized Study Based on Clinical Features and Resting-State Functional Magnetic Resonance Imaging

Background: Ginkgo biloba extract (GBE) and donepezil have been reported to be effective in patients with Alzheimer’s disease (AD). Nonetheless, how these drugs impact spontaneous brain activities and how they consequently improve functional recovery are currently unclear.Objectives: This study was to explore the efficacy of GBE vs. donepezil and their add-on efficacy on functional recovery and the adaption of spontaneous brain activities following pharmacologic treatment in patients with AD.Methods: Patients with AD were enrolled and assigned to the GBE group (n = 50), the donepezil group (n = 50), or the combined group (n = 50). Neuropsychological assessments, including minimum mental state examination (MMSE), Alzheimer’s disease assessment scale-cognition (ADAS-Cog), instrumental activity of daily living (IADL), geriatric depression scale (GDS), neuropsychiatric inventory (NPI), and quality of life in Alzheimer’s disease (QOL-AD), were conducted at baseline, 1 month, 3 months, and 6 months. Resting-state functional magnetic resonance imaging (rs-fMRI) was collected to compare the amplitude of low-frequency fluctuation (ALFF), percent amplitude of fluctuation (PerAF), regional homogeneity (ReHo), and degree centrality (DC) at baseline and 6 months.Results: No major significant differences were detected in all comparisons between groups across all follow-up time points. For intragroup comparison, MMSE and ADAS-Cog scores differed significantly across all follow-ups in three groups. The combined group showed significant improvement of GDS scores between baseline and 6 months (p = 0.007). The GBE group (p = 0.044) and donepezil group (p = 0.012) demonstrated significant improvement of NPI scores between baseline and 6 months. Significant correlations were observed between IADL and ALFF in the right gyrus rectus (p = 0.03) and in the left superior cerebellum gyrus (p = 0.01), between GDS and ALFF in the right middle temporal gyrus (p = 0.01), between NPI and PerAF in the left fusiform gyrus (p = 0.03), and between MMSE and ReHo in right superior frontal gyrus (p = 0.04).Conclusion: GBE was comparable with donepezil in the improvement of functional recovery in patients with AD while the combined application of GBE and donepezil seems unnecessary. GBE-mediated improvement of functional recovery was characterized by decreased ALFF values in the right gyrus rectus and decreased PerAF values in the left fusiform gyrus. These featured variations of imaging metrics in specific brain regions may serve as biomarkers in the monitoring of the therapeutic efficacy of GBE.

Investigating morphological changes in the brain in relation to etiology and duration of olfactory dysfunction with voxel-based morphometry

Olfactory loss (OL) affects up to 20% of the general population and is related to changes in olfaction-related brain regions. This study investigated the effect of etiology and duration of OL on gray matter volume (GMV) of these regions in 257 patients. Voxel-based morphometry was applied to measure GMV in brain regions of interest to test the effects of etiology and duration on regional GMV and the relation between olfactory function and regional GMV. Etiology of OL had a significant effect on GMV in clusters representing the gyrus rectus and orbitofrontal cortex (OFC), bilaterally. Patients with congenital anosmia had reduced GMV in the gyrus rectus and an increased OFC volume compared to patients with acquired OL. There was a significant association between volume of the left OFC and olfactory function. This implies that changes in GMV in patients with acquired OL are mainly reflected in the OFC and depend on olfactory function. Morphology of olfactory areas in the brain therefore seems to relate to olfactory function and the subsequent degree of exposure to olfactory input in patients with acquired OL. Differences in GMV in congenital anosmia are most likely due to the fact that patients were never able to smell.

Ventromedial prefrontal area 14 provides opposing regulation of threat and reward-elicited responses in the common marmoset

The ventromedial prefrontal cortex (vmPFC) is a key brain structure implicated in mood and anxiety disorders, based primarily on evidence from correlational neuroimaging studies. Composed of a number of brain regions with distinct architecture and connectivity, dissecting its functional heterogeneity will provide key insights into the symptomatology of these disorders. Focusing on area 14, lying on the medial and orbital surfaces of the gyrus rectus, this study addresses a key question of causality. Do changes in area 14 activity induce changes in threat- and reward-elicited responses within the nonhuman primate, the common marmoset, similar to that seen in mood and anxiety disorders? Area 14 overactivation was found to induce heightened responsivity to uncertain, low-imminence threat while blunting cardiovascular and behavioral anticipatory arousal to high-value food reward. Conversely, inactivation enhanced the arousal to high-value reward cues while dampening the acquisition of cardiovascular and behavioral responses to a Pavlovian threat cue. Basal cardiovascular activity, including heart rate variability and sympathovagal balance, which are dysfunctional in mood and anxiety disorders, are insensitive to alterations in area 14 activity as is the extinction of conditioned threat responses. The distinct pattern of dysregulation compared to neighboring region area 25 highlights the heterogeneity of function within vmPFC and reveals how the effects of area 14 overactivation on positive and negative reactivity mirror symptoms of anhedonia and anxiety that are so often comorbid in mood disorders.

Spontaneous improvement of secondary empty sella syndrome due to re-expansion of an intrasellar cyst: A case report

Background: In patients with secondary empty sella syndrome (ESS), optic nerve herniation into the sella turcica is caused by shrinkage of the mass lesion at the sella turcica, resulting in visual disturbance. ESS is often surgically treated using chiasmapexy. Here, we report the first case of spontaneous improvement in a patient with ESS. Case Description: A 69-year-old woman presented with a month-long history of visual disturbance in the right eye, poor visual acuity, and quadrantanopia in her upper temporal visual field. Magnetic resonance (MR) imaging showed herniation of her right optic nerve and gyrus rectus into the sella turcica. The visual disturbance gradually improved, and the patient’s vision became almost normal after a month without any treatment. On repeated MR imaging, it was observed that the herniation of the right optic nerve and gyrus rectus disappeared due to an intrasellar cyst re-expansion. The secondary ESS caused by the shrinkage of the intrasellar cyst resulted in the visual disturbance and re-expansion of the cyst resulted in spontaneous improvement of symptoms. The visual disturbance did not recur for a year. Conclusion: Patients with secondary ESS without severe symptoms may be followed up conservatively. However, surgical treatment should be applied if symptoms deteriorate or do not improve.

Congenital Herniation of the Gyrus Rectus Resulting in Compressive Optic Neuropathy

We report a 34-year-old male with a previously uninvestigated lifelong blindness of the right eye from compressive optic neuropathy secondary to congenital herniation of the gyrus rectus (HGR). His past medical history was otherwise unremarkable, with no history of prior head or ocular trauma. On examination, he had no light perception in the right eye, right relative afferent pupillary defect (RAPD), and primary optic atrophy. His left eye had normal visual acuity, color vision, and a healthy optic disc. There was a sensory exotropia in the right eye; however, extraocular movements were intact and the remainder of his neurological exam was normal. MRI revealed compression of the prechiasmatic right optic nerve from HGR and atrophy of the right optic nerve and optic chiasm (Figures 1 and 2), without any parenchymal mass lesions. There were no signal abnormalities in the optic nerves or the chiasm.

Partial Gyrus Rectus Resection as a Technique to Improve the Exposure to the Anterior Communicating Artery Complex through the Junctional Triangle: A Quantitative Study

Objective The junctional triangle, formed by the distal A1 anterior cerebral artery (ACA) segment, the proximal A2 ACA segment, and the medial surface of gyrus rectus (GR), is a corridor of access to superiorly and posteriorly projecting anterior communicating artery (AComA) aneurysms that is widened by GR retraction or resection. Exposure of the AComA complex through the junctional triangle after GR resection has not been previously quantitatively evaluated. Design GR resection extent and increase in artery exposure through the junctional triangle were assessed in this study. Setting This study was conducted in the laboratory with a pterional approach, exposing the AComA complex. Participants Ten sides of five cadaveric heads were considered. Main Outcome Measures Exposure extent of ipsilateral and contralateral A1, A2, and AComA and accessibility of branches coming off the AComA complex were measured before and after GR resection. The GR was resected until sufficient bilateral A2 and contralateral A1 exposures were achieved. GR resection span was measured. Results The mean (standard deviation) resected span of GR was 7 ± 3.9 mm. After GR resection, the exposed span of the ipsilateral A2 increased from 2 ± 0.7 mm to 4 ± 1.1 mm (p = 0.001); contralateral A2 exposure increased from 3 ± 1.5 mm to 4 ± 1.1 mm (p = 0.03). Contralateral recurrent artery of Heubner (RAH) and orbitofrontal artery were accessible in five and eight specimens, respectively, before GR resection and in all 10 after resection. Conclusion GR resection improves exposure of bilateral A2 segments through the junctional triangle. Exposure improvement is greater for the ipsilateral A2 than contralateral A2. The junctional triangle concept is enhanced by partial GR resection during surgery for superior and posterior AComA aneurysms.

Lower limb weakness with gyrus rectus hematoma: an unusual presentation of paraclinoid aneurysm; a case report with review of literature

Lower limb weakness is usually a feature of ruptured anterior communicating (ACom) aneurysms due to spasm of the anterior cerebral arteries. Paraclinoid aneurysms, in addition to other cardinal features of subarachnoid haemorrhage (SAH), usually present with headache and visual field defects due to compression of the optic pathway. We report a case of left paraclinoid aneurysm presenting with right lower limb weakness and gyrus rectus hematoma without SAH. The aneurysm was long, passing beneath the optic nerve to emerge in the inter-optic cistern, leading to such atypical presentation. The aneurysm was clipped successfully after drilling the clinoid. As per our knowledge, such a clinical presentation of paraclinoid aneurysm has not been reported in the literature till date.