Meynert and the basal nucleus / Meynert e o núcleo basal

Meynert described the "loop of the peduncular foot" (Schlinge des Hirnschenkelfusses), and its ganglion (Ganglion der Hirnschenkelschlinge) and related them to Reil's Substantia innominata and Gratiolet's Ansa peduncularis, from which he apparently built up his findings. Koelliker renamed the ganglion with the eponymous designation Meynert'sches Basalganglion (Meynert's basal ganglion), a name which endures to the present day, and described its topographical spread in relation to neighboring structures. Meynert and Koelliker also described aspects of cell composition of the ganglion (or nucleus) with a better account of the latter. Both, together with Reil and Gratiolet, were the outstanding personalities of the 19th century who performed the pioneering studies on basal formations of the forebrain. After these works, a considerable body of research appeared in the 20th century, with a focus on Meynert's basal nucleus and related structures. The development of further knowledge about these structures revealed their great importance in the activity of the brain, as evidenced in both normal and pathological states.

Meynert descreveu a "alça do pé do pedúnculo" (Schlingedes Hirnschenkelfusses) e seu gânglio (Ganglion der Hirnschenkelschlinge), relacionando-os à Substantia innominata de Reil e à Ansa peduncularis de Gratiolet, a partir dos quais aparentemente desenvolveu seus achados. Koelliker renomeou o gânglio com a designação epônima de Meynert'sches Basalganglion (gânglio basal de Meynert), que perdura até o presente, e descreveu sua extensão topográfica em relação às estruturas vizinhas. Meynert e Koelliker descreveram também aspectos da composição celular do gânglio (ou núcleo), com um relato melhor do segundo. Ambos, juntamente com Reil e Gratiolet, foram as personalidades de destaque do século 19 que realizaram os estudos pioneiros sobre formações basais do prosencéfalo. Após esses, um número considerável de estudos apareceu no século 20, com foco no núcleo basal de Meynert e estruturas relacionadas. O desenvolvimento ulterior do saber sobre as mesmas mostraram sua grande importância na atividade cerebral, como visto em condições normais e patológicas.

Establishment of a Mouse Model of Alzheimer Dementia / 医学研究杂志

Objective To establish a Alzheimer dementia(AD) model in mice. Methods The C57BL/6 mice were lesioned with ibotenic acid in Nucleus basalis of Meynert(NBM). Behavioral tests by eight-arm radial maze were conducted 8 weeks, and immunohistochemical staining of choline acetyltransferase(ChAT), serotonin(5-HT), GAD(GABA), amyloid-?protein (AP) was conducted 12 weeks after NBM lesioning. Results In NBM lesioned mice, the ChAT-positive neurons, serotonin-positive neurons, and GAD-positive neurons in right NBM reduced, and ChAT-positive neurons reduced most evidently. At the same time, the ChAT-positive fibers in prefrontal and parietal cortices decreased significantly, serotonin-positive axons slightly, accompanied by heavily AP co-expression. On the contrary, there was no change of GAD-positive neurons in cortex. The working memory error increased significantly.Conclusion Ibotenic acid lesioning in NBM can provide as a model of AD in that it produces deafferentation of cholinergic system and recent memory disruption.

EFFECTS OF CORTICOTROPIN RELEASING FACTOR ON LEARNING AND MEMORY IN THE NUCLEUS BASALIS OF MEYNERT IN RATS / 神经解剖学杂志

The present study was performed to explore the role of corticotropin releasing factor (CRF) in the nucleus basalis of Meynert (NBM) in spatial learning and memory of rats. The latency, distance and swimming path to find the platform were measured by Morris water maze after intra-NBM injections of 0, 0.01, 0.1 and 0.4 nmol of CRF. Intra-NBM injections of 0.1 or 0.4 nmol of CRF induced significant increase of the latency for spatial learning and memory, and there were no significant changes in the swimming speed in Morris water maze test. The results suggest that CRF plays an inhibitory role in spatial learning and memory consolidation in the NBM of rats.

Reactivation of metabolically impaired neurons in Alzheimer’s disease

Several lines of evidence show that decreased metabolic rate precedes cognitive impairment in Alzheimer ’s disease (AD). Decreased neuronal metabolism contributes to neuronal atrophy and functional impairment and is thus an early occurring hallmark of AD. Factors that may contribute to a diminishment in neuronal metabolism are age, sex, APOE-ε 4 and decreased levels of sex hormones or melatonin. Several observations in postmortem brain indicate that activated neurons are better able to withstand aging and AD, a phenomenon we paraphrased as “use it or lose it”. Moreover, a number of pharmacological and non-pharmacological studies support the concept that activation of the brain has beneficial effects and may to a certain degree restore several aspects of cognition and other central functions. For instance, the circadian system of Alzheimer patients may be restimulated by exposing them to more light or transcutaneous nerve stimulation. A procedure allowing testing of the efficacy of putative stimulatory compounds such as neurotrophins and precursor cells has been developed in order to be able to culture human postmortem brain tissue.

EFFECTS OF GINSENOSIDES ON BDNF IN NUCLEUS BASALIS OF MEYNERT AND CEREBRAL CORTEX OF AGED RATS / 解剖学报

Objective To observe the age-related changes of brain-derived neurotrophic factor(BDNF) and investigate the effects of ginsenosides(GS) on BDNF in nucleus basalis of Meynert(NBM) and cerebral cortex of aged rats. Methods Twenty-four female Wistar rats were randomly divided into 3 groups: young group(3-5 months),aged groups(27 months) and GS group(27 months).GS group was fed with GS from 18 to 27 months.Immunohistochemistry and Imaging analysis were used to show the expression and distribution of BDNF in NBM and cerebral cortex of each group. Results BDNF level of aged group was much lower than that of young group in these two brain areas(P