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At least 19 recordsLinked to original sources
PubMed1993

Fornix degeneration and memory in traumatic brain injury.

Fornix-to-brain ratios (FBR) based on postinjury magnetic resonance (MR) studies were calculated on a group of 27 female traumatic brain injury (TBI) patients and 18 female medical controls by taking the widest aspect of the fornix at the level of the anterior horns and third ventricle and determining a fornix surface area. The FBR was significantly reduced in the TBI group (FBR = 0.1121) as compared to the normal control group (FBR = 0.1766). Despite these significant FBR findings indicating prominent atrophic changes of the fornix in TBI patients, the FBR did not relate systematically to neuropsychological outcome. These findings clearly indicate fornix vulnerability in TBI and that current quantitative MR methods are sensitive enough to detect such changes. However, fornix degeneration constitutes only one of many contributing factors to the anatomic basis of TBI-induced cognitive disturbances, as fornix atrophy did not relate systematically to neuropsychological outcome.

Adolescent↗
PubMedDate not supplied

Idiopathic hypoparathyroidism with intracranial calcifications and dominant skin manifestations.

Presented here is an unusual case of a 41-year-old man with idiopathic hypoparathyroidism strongly connected with dermatological, ophthalmological and neurological disorders. Since the age of 4 he had been treated ineffectively for mycosis resulting in complete baldness and atrophic nail plate changes. At the age of 35 he was diagnosed with idiopathic hypoparathyroidism. He underwent surgery twice due to bilateral cataract. CT scans of the head demonstrated numerous symmetrically located calcifications in both frontal lobes, subcortical nuclei, the paraventricular region, brain fornix, and both cerebellar hemispheres. The neuropsychological examination demonstrated the occurrence of psychosensory disorders under the form of hallucinations accompanied by a sense of fear and anxiety. It seems essential to investigate the parathyroid gland for any sign of pathology, especially amongst patients with severe dermatological and/or neuropsychological symptoms. Early diagnosis and treatment of patients with hypoparathyroidism may prevent the development of many serious complications or at least result in marked improvement of neurological manifestations.

Adult↗
PubMed2004

Msx1 expression in the adult mouse brain: characterization of populations of beta-galactosidase-positive cells in the hippocampus and fimbria.

We have analyzed Msx1 expression in the mature mouse brain using in situ hybridization and beta-galactosidase activity in Msx1(nLacZ) mice. The study revealed that Msx1 is strongly expressed in the circumventricular organs, such as the subcommissural organ and choroid plexus, and in some epithelia, such as that of the dorsal, but not the ventral part of the third ventricle. Immunohistochemical analysis revealed that the Msx1-expressing cells of the hippocampus and fimbria are astrocytes, oligodendrocytes or immature oligodendrocytes. In contrast, no co-expression was detected in these structures using several neuronal markers. These results were confirmed, using transmission electron microscopy, by the presence of 5-bromo-3-indolyl-beta-D-galactopyranosideprecipitates in astrocytes and oligodendrocytes in both sites. Moreover, using an anti-glial fibrillary acidic protein antibody (GFAP), our study reveals two populations of astrocytes in the adult hippocampus and other areas, such as the fimbria, namely Msx1+/GFAP+ and Msx1-/GFAP+. Beta-galactosidase activity was also observed in endothelial cells of hippocampal fissure blood vessels. We also observed co-localization of polysialic acid neural cell adhesion molecule, a marker of the polysialylated form of the neural cell adhesion molecule, in Msx1-expressing cells in the fimbria. These cells may be precursors of glial cells and originate from the epithelium of the fimbria. The present study indicates, in the mature mouse brain, that Msx1 may be linked to secretory activity in circumventricular organs, and to glial proliferation and differentiation in the hippocampus and fimbria, and presumably also in other cerebral areas. We suggest that Msx1 could be associated with brain homeostasis and blood-brain barrier function.

Aging↗
PubMed1996

Mechanical lesions of the fimbria fornix in rat brain studied by 1H-magnetic resonance imaging. Evidence for long-lasting dynamic alterations in the ipsilateral ventricular system.

In vivo 1H-NMR imaging was employed to study dynamic changes in the status of tissue water as a function of time after mechanical brain injury induced by partial unilateral transection of the fimbria fornix (FF) in the rat brain and was correlated with histology. Changes in the brain tissue were reproducibly found in distinct regions which were exclusively located in the lesioned hemisphere. The most pronounced changes concerned the lateral ventricle. Ventricular enlargement became evident posterior to the site of transection after a few hours and was maximal after 2-4 days. At later time points the posterior ventricular expansion was reduced. The lateral ventricle anterior to the site of transection was significantly enlarged from day 1 and continued to expand for up to 7 months. Tissue response at the site of transection, mainly involving the hippocampal formation and the thalamus, was first manifested after 24 h, while signs of progressive tissue degeneration were apparent in the long term.

Animals↗
PubMed1976

Temporal effects of fornix transection on brain tryptophan hydroxylase activity and plasma corticosterone levels.

The effect of fornix transection on plasma corticosterone and on midbrain (MID), septum/preoptic (S/POA) or hippocampal (HIP) tryptophan hydroxylase activity (THA) was studied in adult male rats. A mild stress resulted in higher levels of plasma corticosterone in operated as compared to sham-operated rats 6 and 40 h post-transection; however, at 30 days post-operation no difference was found. The response of THA to fornix transection was region-specific. No significant change in the S/POA region was found at any time. THA in the HIP, a terminal area of 5-HT fibers, showed a progressive fall over time to values 80% below normal levels. This result suggests that most of the 5-HT fibers to the HIP had been severed. A 28 h half-life for HIP THA was calculated. THA in the MID, an area known to contain the majority of 5-HT cell bodies with ascending fibers, was significantly reduced compared to sham controls at 6 h, 40 h, and 8 days post-transection. However, at 30 days post-operation no difference was found. The depression in MID THA by its rapid onset, the distance from the fornix transection site, and its return to normal after 30 days, is thought to be due to a transneuronal effect on the serotonin-containing neurons in MID raphe. The fall in MID THA at a time when plasma corticosterone levels are increased in fornix-transected rats may be compared with the situation in normal, stressed and adrenalectomized rats where MID THA andplasma corticosterone levels change in the same direction. The data suggest that the glucocorticoid effects on MID 5-HT containing neurons are mediated transneuronally through the hormone concentrating cells in the HIP.

Animals↗
PubMed1995

Neurotensin and neuromedin N brain levels after fornix transection: evidence for an efficient neurotensin precursor processing in subicular neurons.

High levels of neurotensin/neuromedin N precursor mRNA, but few if any NT-positive perikarya have been detected in the dorsal subiculum of the adult rat or human hippocampus. This apparent discrepancy was tentatively ascribed to a lack of precursor mRNA translation or to a poor precursor posttranslational processing in neurons of the hippocampus. Another hypothesis is that in long neuronal pathways, maturation of neuropeptide precursors and derived peptides occurs during axonal transport to terminals, a process which accounts for the lack of peptide detection in cell bodies. In order to test this hypothesis, we performed surgical transection of the fornix to interrupt axonal transport of putative NT/NN products arising from the dorsal hippocampus and measured NT and NN levels in different brain regions. In the mamillary bodies, the main projection area of the dorsal subiculum, NN and NT levels were highly reduced 4 or 14 days after the septo-hippocampal transection which was correlated with a slight increase in NN and NT levels in the dorsal hippocampus and the retrosplenial cortex of 4 days lesioned animals. An increase in hypothalamic NN levels was also detected 14 days after the lesion. These data suggest that the peptide precursor processing can take place during the axonal transport, as shown here for neurotensin and neuromedin N from subicular neurons to their efferent brain areas such as the mamillary bodies.

Animals↗
PubMed1997

The fornix of the human brain: evidence of left/right asymmetry on axial MRI scans.

This article reports the observation that there is a left/right asymmetry of the anterior columns of the fornix in the human brain. This asymmetry is present in the position of the two columns of the fornix in relation to the septum pellucidum. The left columna fornicis was found to be located caudal to the right, and this can be readily visualized on axial MRI scans. This difference was seen in most of the subjects, but in some subjects there was no left/right-difference and in a few the asymmetry was inverse. The asymmetry of the fornix with respect to the anterior-posterior axis was independent of the well-known dissimilar lateral ventricular volumes. However, the left/right difference in the position of the fornix was evident in subjects with or without differences in ventricular volumes. This suggests that the mechanism underlying the development of asymmetry of the fornix is independent of the mechanism leading to ventricular asymmetry. So far, no functional relevance has been ascribed to such differences in location. The finding is gaining interest in connection with recent reports of asymmetries in hippocampal subfields. Studies of fornical lesions should therefore give attention to possible side-to-side differences.

Adult↗
PubMed1992

1H-NMR imaging of fimbria fornix lesions in the rat brain.

Mechanical lesions of the fimbria fornix (FF) have been widely used as a model to investigate the recovery of damaged brain tissue. 1H-NMR imaging was employed to non-invasively measure changes in the brain after unilateral FF transection. Rats were subjected to NMR imaging at various times after the lesions were made. The experimental protocol included (multislice) T2-weighted and diffusion-weighted imaging thereby allowing the construction of two-dimensional maps of the relaxation time T2 (transverse or spine-spin relaxation time) and the apparent diffusion coefficient (ADC) of water. FF transection induced considerable changes in the status of the brain tissue at a number of different locations which were exclusively present in the affected hemisphere. At 1 day post-lesion the region of the lateral ventricle and hippocampus started to display pronounced changes in that T2- and diffusion-weighted images showed a hyperintensity and a hypointensity, respectively. These effects were maximal around day 2 to 4 whereafter a slow recovery towards the control situation was observed. Immediately after transection the FF lesion itself could be visualized. These early images pointed to an aspecific disruption of the tissue due to the mechanical intervention. Interestingly, however, from day 2 post-lesion a number of changes became evident in this region which seemed to be localized to specific structures, including the ventricle and hippocampus. After one month the presumably ventricle effect dominated and was predominantly localized to the anterior side of the FF lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Fornix and hippocampal atrophy in traumatic brain injury.

This study compared a fornix cross-sectional-area measurement and hippocampal volume in 86 traumatic brain injury (TBI) subjects with 46 normal controls. The TBI group showed a significant reduction in fornix area and hippocampal volume. It was also shown that initial injury severity was related to the degree of atrophy in both structures. Although fornix size and hippocampal volume correlated, such a modest correlation between these two structures suggests differential and potentially independent mechanisms of injury. The General Memory Index score from the Wechsler Memory Scale-Revised was shown to be significantly correlated with hippocampal volume following TBI.

Adolescent↗
PubMed1996

Implantation of olfactory ensheathing cells in the adult rat brain following fimbria-fornix transection.

Ensheathing cells from fetal rat olfactory bulb were implanted into th e damaged adult rat brain to assess whether these cultured cells would survive in nonolfactory CNS areas and support the regrowth of nonolfactory axons. Cultures of primary ensheathing cells prelabeled with WGA-Au were embedded in a collagen matrix and implanted into a lesion cavity immediately following ablation of the fimbria-fornix in adult rats; the animals were sacrificed 4 weeks after surgery. Labeled ensheathing cells were observed only within the graft and not in the adjacent neural tissue. Immunostaining for p75 neurotrophin receptor revealed two characteristic morphologies of ensheathing cells within the graft; slender, spindle-shaped cells and larger, flattened cells. Although GFAP immunostaining revealed an intense glial reaction around the margin of the wound with host astrocytes sending cytoplasmic processes into the collagen matrices, no immunoreactive cells were found within the grafts. Histochemical detection of AChE revealed numerous reactive fibers confined to the regions of the grafts possessing ensheathing cells. Axons within the grafts were also immunoreactive for GAP-43. These initial experiments provide encouraging data concerning the survival of ensheathing cells for a minimum of 4 weeks following implantation into the adult rat brain and their ability to support the growth of new axons.

Animals↗
PubMed1992

Neurotrophic factor-like effect of FPF1070 on septal cholinergic neurons after transections of fimbria-fornix in the rat brain.

FPF1070 is an aqueous protein-free solution, which consists of 85% free amino acids and 15% small peptides. Our previous study showed a potent neurotrophic factor-like activity in cultured embryonic cells of dorsal root ganglia. The present study investigated whether FPF1070 regenerated the cholinergic cells in the medial septal nucleus after axonal transections by cutting the fimbria-fornix. Fimbrial transection reduced the number of septal cholinergic cells by 30 +/- 3.6%, compared with the number on contralateral sides at 4 weeks. Intraperitoneal injections of FPF1070 caused 49.9 +/- 6.3% of the cholinergic neurons to survive. Furthermore, the cell sizes of the cholinergic neurons were significantly different: 16.4 +/- 4.2 microns, 14.3 +/- 3.8 microns in FPF1070 treatment and vehicle treatment, respectively. These results indicated that FPF1070 prevents the degeneration and atrophy of impaired cholinergic neurons by systemic administration.

Amino Acids↗