Correlation of magnetic resonance images with neuropathology in acute Wernicke's encephalopathy.

We correlated serial brain MRIs with neuropathological findings in a 16-year-old female whose autopsy was consistent with Wernicke's encephalopathy (WE). Diffusion-weighted imaging, diffusion coefficients mapping and neuropathology findings were suggested vasogenic edema in the periaqueductal and peri-the-fourth ventricular areas. This is the first documented case report to make this direct comparison. The characteristic WE changes in the mammillary body was also correlated with the findings of MRI with contrast enhancement. Bilateral cortical lesions revealed by MRI were atypical and rare in WE and were not evidenced by pathological changes.

Acute Korsakoff syndrome following mammillothalamic tract infarction.

There are limited case reports of structural lesions causing Korsakoff syndrome. This report describes acute Korsakoff syndrome following localized, bilateral infarction of the mammillothalamic tracts (MTTs). Axial T2-weighted imaging revealed the lesions at the lateral wall level of the third ventricle and diffusion-weighted imaging confirmed that the left lesion was new and the right old. Korsakoff syndrome persisted 6 months after the onset. This case suggests that bilateral MTT dysfunction can lead to Korsakoff syndrome.

Causality of parenchymal and vascular changes in rats with experimental thiamine deficiency encephalopathy.

The causality of vascular and parenchymal damage to the central nervous system (CNS) was examined in rats with thiamine deficiency. Male Sprague-Dawley rats were divided into two groups; one was given a thiamine-deficient diet (TDD) and injected intraperitoneally with 10 micrograms/100 g bodyweight pyrithiamine (PT) in order to analyze morphometrically the topographical and sequential relationship between vascular and parenchymal changes and vasodilatation, and the other was given a TDD and 50 micrograms/100 g bodyweight PT in order to determine hemorrhagic sites using serial sections. Histological examination showed that spongiotic change occurred selectively in the inferior colliculus (100%) from day 19, and thereafter in the thalamus (95%), mammillary body (50%) and nuclei olivaris and vestibularis of the pons (25%), with or without hemorrhage. Simultaneously, glycogen accumulation was also observed in these regions at a frequency similar to that of hemorrhage. Ultrastructurally, however, hydropic swelling of astrocytic and neuronal processes without glycogen accumulation was observed as early as day 9 in the inferior colliculus, at which time an increase of glial fibrillary acidic protein-positive processes was also recognized. The superior colliculus was completely spared. From day 22 vasodilatation of the inferior colliculus occurred, concomitantly with bodyweight loss and neurological symptoms. Twenty-two examined hemorrhages, which occurred in the thalamus and inferior colliculus, were distributed along the arterioles or capillaries on the arterial side. In conclusion, the morphological CNS changes caused by thiamine deficiency with administration of low-dose PT in rats begin as hydropic swelling of neuronal and astrocytic processes, followed by hemorrhage and, thereafter, by vasodilation. The predilection for hemorrhage on the arterial side without parenchymal changes suggests that petechial hemorrhage is not simply secondary to parenchymal changes, but is due to hemodynamic change resulting from thiamine deficiency-induced vascular dysfunction.

Cerebral blood flow changes in limbic regions induced by unsolvable anagram tasks.

OBJECTIVE: The study addressed the question of whether unsolvable as opposed to solvable cognitive problems activate discrete neuronal systems in the human brain. METHOD: Twelve healthy humans tried to solve unsolvable anagrams. Solvable anagrams and a resting baseline after each anagram task served as control conditions in a within-subject design. Activation was measured with the equilibrium infusion method by using 15O-labeled water and positron emission tomography, with absolute quantitation of anatomically defined regional cerebral blood flow (CBF). RESULTS: Compared to rest, both anagram tasks increased activity in frontal and temporal regions. The soluble task condition increased hippocampal activation and decreased mammillary bodies activity, while unsolvable anagrams were associated with increased CBF to the mamillary bodies and amygdala and decreased hippocampal activity. CONCLUSIONS: A limbic network integrating negative emotion and cognition seems reflected in reciprocal diencephalic and limbic activation with solvable and unsolvable anagrams. Since unsolvable anagrams have been used to induce learned helplessness in humans, this finding may provide an initial step toward clarifying its neural substrate.

Cavernous malformation of the mammillary bodies: neuropsychological implications. Case report.

The authors present the first documented case of a cavernous malformation of the mammillary bodies. A 34-year-old woman presented with a 2-month history of headaches and acute memory changes. Magnetic resonance imaging studies demonstrated a retrochiasmatic interpeduncular lesion that was initially thought to be a craniopharyngioma. Operative resection confirmed the diagnosis of a cavernous malformation. This particular case is unique in its destruction of the mammillary bodies and presents further evidence of the relationship of these regions to memory. This report is also the first to document results of pre- and postoperative neuropsychological evaluations that specifically address the memory deficits created by destruction of the mammillary bodies.

[Amnesic syndrome caused by infarction in the area of the left anterior choroidal artery]. / Syndrome amnésique lors d'un infarctus du territoire de l'artère choroïdienne antérieure gauche.

A case of infarction in the left anterior choroidal artery territory presenting as a regressive amnestic syndrome, associated with the usual syndrome, is reported. This amnesia had the same characteristics as that found in the left posterior cerebral artery territory infarction. The anterior choroidal artery supplies the medial part of the temporal lobe, the amygdaloid nucleus, part of the hippocampus, uncal gyrus, and the mamillary body. Therefore, an amnestic syndrome can occur together with an infarction in the AChA territory. To our knowledge this is the first report of that occurrence.

[Comparative morpho-functional characteristics of the capillary bed of the mammillary bodies and temporal lobe of the human cerebral cortex in young and late middle-aged hypertensive patients]. / Sravnitel'naia morfofunktsional'naia kharakteristika kapilliarnogo rusla sostsevidnykh tel i kory visochnoi doli golovnogo mozga cheloveka pri gipertonicheskoi bolezni v molodom i pozhilom vozraste.

Using a morphometric technique the author has studied the regional characteristics of compensatory-adaptive reactions of the capillary bed in the mamillary bodies and cortex of the temporal lobe in hypertensive patients who has died in young and old age. It has been found that compensatory reactions of the capillary bed of the cortex fail faster than those of the mamillary bodies under the same conditions. A hypothesis is validated that this phenomenon may account for the tissue changes in the specified areas in young versus old hypertensive patients.

[Comparative characteristics of the capillary bed of the temporal lobe and the mammillary bodies of the hypothalamus in man in relation to age]. / Sravnitel'naia kharakteristika kapilliarnogo rusla kory visochnoi doli bol'shogo mozga i sostsevidnykh tel gipotalamusa cheloveka v vozrastnom aspekte.

The data have been obtained on regional differences in structure of the capillary bed in the temporal cortex of the cerebrum (TCC) and in the papillary bodies of the human thalamus (PBHT) during various age periods. The capillary diameter and nuclear volume is greater in perivascular gliocytes of the TCC than in those of the PBHT. With ageing the capillary diameter and hypertrophy of the endotheliocytic nuclei is noted to increase in both areas of the brain.

[Capillary bed of the mammillary bodies of the posterior hypothalamus in hypertension in young and old persons]. / Sostoianie kapilliarnogo rusla mamilliarnykh tel zadnego otdela gipotalamusa pri gipertonicheskoi bolezni u lits molodogo i pozhilogo vozrasta.

Young patients with essential hypertension as compared to control were shown to have an increased diameter of the ultracirculation, elevated levels of nucleic acids in the endotheliocyte nuclei with the predominance of low optical density nuclei. Elderly subjects of the respective groups showed no difference between the parameters studied.

[Ultrastructural characteristics of the cerebral capillaries of aging animals subjected to hypoxic hypoxia]. / Ul'trastrukturnaia kharakteristika kapilliarov mozga starykh zhivotnykh pri gipoksicheskoi gipoksii.

The ultrastructure of capillary walls of the mamillary bodies was studied in rats distributed in two age groups: adult (6-8-month-old) and old (28-30-month-old) animals under hypoxic hypoxia. It was found that age-related differences in the response of brain capillary walls to the injuring agent were reduced to a rapid increase in dystrophic phenomena and less conspicuous compensatory processes seen in the old animals. More profound injuries to other brain tissues adjacent to the vessels were also indicative of less efficacy of the adaptive reactions in the old animals.

[Reactive changes in the capillaries of the mammillary bodies of the brains of aging animals]. / Reaktivnye izmeneniia kapilliarov sostsevidnykh tel mozga starykh zhivotnykh.

As electron microscopic investigation of the capillary wall in the mammillary bodies has demonstrated, in old animals the number of organells in the endothelial cells decreases; discomplexion and reduction of mitochondrial crists occur, their matrix becomes cleared; myelin-like structures are formed. In pericytes pigment inclusions are accumulating. Noncellular component of the basal layer loses its regular structure and foci of hydratation appear in it. When pharmacological loadings (adrenaline, aminazine) are applied to old animals, distrophic processes in the vascular wall increase; that results in disturbance of permeability, sharp hydratation of the basal layer, edema of the tissue elements around the brain and, hence, in a more prolonged restorative period.

Blood supply of the rat hypothalamus. VI. Posterior region of the hypothalamus (nucleus hypothalamicus posterior, nuclei praemammillares, nucleus supramammilaris, mammilary body).

It was shown by the double ink-filling technique that the arteries of the rat premammillary region and mammillary body arise from the a. communicans posterior while these areas are drained by the anterior interpeduncular vein. Disregarding some minor overlaps and anastomoses, the blood supplies of the two territories are independent of each other and from the neighbouring areas of the hypothalamus, diencephalon and mesencephalon. Arteries of the premammillary region arise from the premammillary artery, except for some branches of the posterior tuberal and interpeduncular arteries. The mammillary body is supplied by three mammillary arteries (anterior, posterior and lateral). The premammillary region drains into the anterior and posterior premammillary veins. Venous blood of the mammillary body is collected by the anterior and posterior mammillary veins which end in the anterior interpeduncular vein. The circulation of individual premammillary and mammillary nuclei is described in detail.

Memory disorder in vertebrobasilar disease.

Previous workers have clearly established that the central core limbic structures of the brain are primarily concerned in the production of amnesia of the axial or mesial type. The blood supply to these structures derives primarily from the posterior cerebral circulation. This was the rationale for Benson's work on 'amnesic stroke' in patients with posterior cerebral artery occlusion. We have extended this concept to show that a similar axial amnesia, as demonstrated by a classical response on Wechsler Memory Scale testing, exists in patients with vertebrobasilar insufficiency. Relative permanency of the amnesic syndrome was demonstrated by repeat testing at may be of assistance in the diagnosis of vertebrobasilar insufficiency.