Rbm8a regulates neurogenesis and reduces Alzheimer's disease-associated pathology in the dentate gyrus of 5×FAD mice

Alzheimer’s disease is a prevalent and debilitating neurodegenerative condition that profoundly affects a patient’s daily functioning with progressive cognitive decline,which can be partly attributed to impaired hippocampal neurogenesis.Neurogenesis in the hippocampal dentate gyrus is likely to persist throughout life but declines with aging,especially in Alzheimer’s disease.Recent evidence indicated that RNA-binding protein 8A(Rbm8a)promotes the proliferation of neural progenitor cells,with lower expression levels observed in Alzheimer’s disease patients compared with healthy people.This study investigated the hypothesis that Rbm8a overexpression may enhance neurogenesis by promoting the proliferation of neural progenitor cells to improve memory impairment in Alzheimer’s disease.Therefore,Rbm8a overexpression was induced in the dentate gyrus of 5×FAD mice to validate this hypothesis.Elevated Rbm8a levels in the dentate gyrus triggered neurogenesis and abated pathological phenotypes(such as plaque formation,gliosis reaction,and dystrophic neurites),leading to ameliorated memory performance in 5×FAD mice.RNA sequencing data further substantiated these findings,showing the enrichment of differentially expressed genes involved in biological processes including neurogenesis,cell proliferation,and amyloid protein formation.In conclusion,overexpressing Rbm8a in the dentate gyrus of 5×FAD mouse brains improved cognitive function by ameliorating amyloid-beta-associated pathological phenotypes and enhancing neurogenesis.

Effects of Oestrogen on Ischemia-induced Neurogenesis in the Dentate Gyrus of Rats

To study the effects of oestrogcn on ischemia-induced neurogenesis in the hippocampal dentate gyms, thirty-two adult male rats were randomly divided into four groups： the control surgery group with eestrogen administration （SE）, the control surgery group with normal saline administration （SN）, the middle cerebral artery occlusion （MCAO） group with oestrogen administration （ME） and the MCAO group with normal saline administration （MN）. The MCAO rats were occluded for 90 rain by an intraluminal filament and then recirculated. After 1, 3, 12, 24 and 28 h of MCAO, the rats of the four groups were killed to investigate the infarct volume, apoptosis and neurogenesis. The cerebral infarct volume in the ME group was significantly smaller than that of the MN group （P 〈 0.05）. No significant cell loss was seen in the dentate gyms. Cerebral ischemia led to increased neurogenosis, which is independent of cell death in the ipsilateral dentate gyrus（P 〈 0.05）. BrdU-pesitive cells in the ipsilateral dentate gyms of the ME group were significantly increased when compared with those of the MN group（P 〈 0.05）. In the SE group, BrdU-positive cells in both the ipsilateral and contralateral dentate gyms, were increased when compared with those of the SN group （ P 〈 0.05 ）. We concluded that ocstregen plays an important role in neurogenesis, which is independent of ischemia-induced by MCAO in the hippocampal dentate gyms of rats.

Increased activation of the caudate nucleus and parahippocampal gyrus in Parkinson's disease patients with dysphagia after repetitive transcranial magnetic stimulation:a case-control study

Repetitive transcranial magnetic stimulation(r TMS)has been shown to effectively improve impaired swallowing in Parkinson's disease(PD)patients with dysphagia.However,little is known about how r TMS affects the corresponding brain regions in this patient group.In this casecontrol study,we examined data from 38 PD patients with dysphagia who received treatment at Beijing Rehabilitation Medicine Academy,Capital Medical University.The patients received high-frequency r TMS of the motor cortex once per day for 10 successive days.Changes in brain activation were compared via functional magnetic resonance imaging in PD patients with dysphagia and healthy controls.The results revealed that before treatment,PD patients with dysphagia showed greater activation in the precentral gyrus,supplementary motor area,and cerebellum compared with healthy controls,and this enhanced activation was weakened after treatment.Furthermore,before treatment,PD patients with dysphagia exhibited decreased activation in the parahippocampal gyrus,caudate nucleus,and left thalamus compared with healthy controls,and this activation increased after treatment.In addition,PD patients with dysphagia reported improved subjective swallowing sensations after r TMS.These findings suggest that swallowing function in PD patients with dysphagia improved after r TMS of the motor cortex.This may have been due to enhanced activation of the caudate nucleus and parahippocampal gyrus.The study protocol was approved by the Ethics Committee of Beijing Rehabilitation Hospital of Capital Medical University(approval No.2018 bkky017)on March 6,2018 and was registered with Chinese Clinical Trial Registry(registration No.Chi CTR 1800017207)on July 18,2018.

No changes in densities of cannabinoid receptors in the superior temporal gyrus in schizophrenia

Objective In recent years,abnormal changes in the endocannabinoid system have been found in schizophrenia. The superior temporal gyrus（STG）is strongly implicated in the pathophysiology of schizophrenia,particularly with regards to auditory hallucinations.In this study,we investigated the binding density of cannabinoid CB1 receptors in the STG of schizophrenia patients compared to control subjects.Methods Quantitative autoradiography was used to investigate the binding densities of[^3H]SR141716A（a selective antagonist）and[^3H]CP-55940（an agonist）to the CB1 receptors in the STG.Post-mortem brain tissue was obtained from the NSW Tissue Resource Centre（Australia）.Results Contrasting to previous findings in the alterations of CB1 receptor densities in the prefrontal,anterior and posterior cingulate cortex of schizophrenia,which were suggested to be associated to impairment of cognition function,no significant difference was found between the schizophrenia and control cases in both[^3H]SR141716A and[^3H]CP-55940 binding. Conclusion We suggest that CB1 receptors in the STG are not involved in the pathology of schizophrenia and the auditory hallucination symptom of this disease.

Study of the hippocampus and the anterior cingulate gyrus by proton MR spectroscopy in patients with post-traumatic stress disorder

Objective:To explore the characteristics of metabolic changes in patients with post-traumatic stress disorder through 1H-MRS in neuroanatomical circuit comparing with age-matches controls.Methods:Fifty patients with post-traumatic stress disorder and SO gender-and agematched normal controls were involved.The neurochemical abnormalities including the levels of choline(Cho)/ creatine(Cr) and N-acetylaspartate(NAA)/Cr were measured respectively in hippocampus and the anterior cingulate gyrus with three-dimension 1H-proton specrroscopy(3D 1H-MRS).Results:The values of NAA/Cr ratios in hippocampus and the anterior cingulate gyrus were significant lower in patients with post-traumatic stress disorder(1.71±0.32,left l.58±0.29, right 1.55±0.31) than that in controls(2.24±0.41,left 1.98±0.27,right 2.02±0.36)(P【0.05).but the values of Cho/Cr in hippocampus(left 1.64±0.23,right 1.66±0.34) were no significant with that of controls(left 1.48±0.29,right 1.54±0.38).Values of Cho/Cr in cingulate gyrus were significant higher in post-traumatic stress disorder patients(I.88±0.44) than that in controls(1.37.±0.32) (P【0.05).Conclusions:The results indicate some special neurochemical and histological structure changes in post-traumatic stress disorder patients,which might occurre earlier in anterior cingulate gyrusthe than in hippocampus.

Tooth loss inhibits neurogenesis in the dentate gyrus of adult mice

Tooth loss has been shown to affect learning and memory in mice and increases the risk of Alz- heimer＇s disease. The dentate gyrus is strongly associated with cognitive function. This study hypothesized that tooth loss affects neurons in the dentate gyrus. Adult male mice were randomly assigned to either the tooth loss group or normal control group. In the tooth loss group, the left maxillary and mandibular molars were extracted. Normal control mice did not receive any intervention. Immunofluorescence staining revealed that the density and absorbance of double- cortinand neuronal nuclear antigen-positive cells were lower in the tooth loss group than in the normal control group. These data suggest that tooth loss may inhibit neurogenesis in the dentate gyrus of adult mice.

N-methyl-D-aspartate receptor subunit 1 regulates neurogenesis in the hippocampal dentate gyrus of schizophrenia-like mice

N-methyl-D-aspartate receptor hypofunction is the basis of pathophysiology in schizophrenia. Blocking the N-methyl-D-aspartate receptor impairs learning and memory abilities and induces pathological changes in the brain. Previous studies have paid little attention to the role of the N-methyl-D-aspartate receptor subunit 1 (NR1) in neurogenesis in the hippocampus of schizophrenia. A mouse model of schizophrenia was established by intraperitoneal injection of 0.6 mg/kg MK-801, once a day, for 14 days. In N-methyl-D-aspartate-treated mice, N-methyl-D-aspartate was administered by intracerebroventricular injection in schizophrenia mice on day 15. The number of NR1-, Ki67- or BrdU-immunoreactive cells in the dentate gyrus was measured by immunofluorescence staining. Our data showed the number of NR1-immunoreactive cells increased along with the decreasing numbers of BrdU- and Ki67-immunoreactive cells in the schizophrenia groups compared with the control group. N-methyl-D-aspartate could reverse the above changes. These results indicated that NR1 can regulate neurogenesis in the hippocampal dentate gyrus of schizophrenia mice, supporting NR1 as a promising therapeutic target in the treatment of schizophrenia. This study was approved by the Experimental Animal Ethics Committee of the Ningxia Medical University, China (approval No. 2014-014) on March 6, 2014.

Effects of CXCR7-neutralizing antibody on neurogenesis in the hippocampal dentate gyrus and cognitive function in the chronic phase of cerebral ischemia

Stromal cell-derived factor-1 and its receptor CXCR4 are essential regulators of the neurogenesis that occurs in the adult hippocampal dentate gyrus.However,the effects of CXCR7,a new atypical receptor of stromal cell-derived factor-1,on hippocampal neurogenesis after a stroke remain largely unknown.Our study is the first to investigate the effect of a CXCR7-neutralizing antibody on neurogenesis in the dentate gyrus and the associated recovery of cognitive function of rats in the chronic stage of cerebral ischemia.The rats were randomly divided into sham,sham+anti-CXCR7,ischemia and ischemia+anti-CXCR7 groups.Endothelin-1 was injected in the ipsilateral motor cortex and striatum to induce focal cerebral ischemia.Sham group rats were injected with saline instead of endothelin-1 via intracranial injection.Both sham and ischemic rats were treated with intraventricular infusions of CXCR7-neutralizing antibodies for 6 days 1 week after surgery.Immunofluorescence staining with doublecortin,a marker for neuronal precursors,was performed to assess the neurogenesis in the dentate gyrus.We found that anti-CXCR7 antibody infusion enhanced the proliferation and dendritic development of doublecortin-labeled cells in the dentate gyrus in both ischemic and sham-operated rats.Spatial learning and memory functions were assessed by Morris water maze tests 30-32 days after ischemia.CXCR7-neutralizing antibody treatment significantly reduced the escape latency of the spatial navigation trial and increased the time spent in the target quadrant of spatial probe trial in animals that received ischemic insult,but not in sham operated rats.These results suggest that CXCR7-neutralizing antibody enhances the neurogenesis in the dentate gyrus and improves the cognitive function after cerebral ischemia in rats.All animal experimental protocols and procedures were approved by the Institutional Animal Care and Use Committee of China Medical University(CMU16089 R)on December 8,2016.

A comparison of the spontaneous firing patterns between principal cells and fast spiking interneurons from dentate gyrus in waking guinea pigs

Objective To explore the possible mechanisms that cause the dentate gyrus （DG） neurons to play different roles in information coding. Methods In vivo extracellular single unit recording was performed on 22 waking female guinea pigs, which were positioned in a sound-attenuated recording chamber without any muscular relaxants. The spontaneous firing patterns of the DG neurons were detected and compared. Results There were two different electrophysiologi- cal populations in the DG of guinea pigs, principal cells （PCs） and fast spiking interneurons （INs）. Of the PCs, 1.3% discharged regularly, 48.1% irregularly and 50.6% in bursts ; in contrast, of the INs units, 64.1% discharged regularly, 2.6% irregularly and 33.3% in bursts. The spontaneous firing patterns of PCs were significantly different from those of INs （P 〈0.01 ）. In addition, the differences of several interspike interval （ISI） parameters also have been observed： （1） the ISI coefficients of variation of PCs （3.39 ± 3.56） were significantly higher than those of INs （1.08 ± 0.46） （P 〈0.01） ; （2） the ISI asymmetric indexes of PCs （0. 047±0. 059） were significantly lower than those of INs （0.569±0. 238） （P 〈 0.01 ）. Conclusion In the DG, the spontaneous firing patterns of PCs were significantly different from those of INs. The former were prone to fire in bursts, the latter were prone to fire regularly. The different roles in information coding between PCs and INs might be caused by their different firing patterns.

The effect of Jujuboside A on the evoked field potentials of Granule cells in dentate gyrus

Jujuboside A (JuA) is a main component of Jujubogenin extracted from the seeds of Ziziphus. The authors have not seen any report on JuA's direct effect on the neurons of the central nervous system. This study aimed to assess the effect of JuA on paired pulse responses of dentate gyrus granule cells in urethane anaesthetized rats, used intracerebroventricular (i.c.v.) JuA to mimic in vitro bath conditions in vivo. Paired pulse stimuli with 80ms interpulse interval were used to stimulate the perforant pathway. Evoked responses were recorded in the dentate gyrus cell layer after i.c.v. administration of 0.9% normal saline or JuA. In the first responses, the slopes of excitatory postsynaptic potential (EPSP1) and the amplitudes of population spike (PS1) decreased significantly after administration of JuA while the PS1 latencies increased significantly. In the second responses, the EPSP2 slopes and PS2 latencies were changed similarly to those of the first ones, but PS2 amplitudes increased. The results showed that JuA may have some inhibitory effect on the granule cell excitability mediated by presynaptic mechanism but may have little effect on the excitability mediated by postsynaptic mechanism since the second evoked N methyl D aspartic mediating paired pulse facilitation is a postsynaptic mechanism.

Estimation of the density of neural,glial,and endothelial lineage cells in the adult mouse dentate gyrus

The dentate gyrus subregion of the mammalian hippocampus is an adult neural stem cell niche and site of lifelong neurogenesis.Hypotheses regarding the role of adult-born neuron synaptic integration in hippocampal circuit function are framed by robust estimations of adultborn versus pre/perinatally-born neuron number.In contrast,the non-neurogenic functions of adult neural stem cells and their immediate progeny,such as secretion of bioactive growth factors and expression of extracellular matrix-modifying proteins,lack similar framing due to few estimates of their number versus other prominent secretory cells.Here,we apply immunohistochemical methods to estimate cell density of neural stem/progenitor cells versus other major classes of glial and endothelial cell types that are potentially secretory in the dentate gyrus of adult mice.Of the cell types quantified,we found that GFAP^(+)SOX2^(+)stellate astrocytes were the most numerous,followed by CD31^(+)endothelia,GFAP-SOX2^(+)intermediate progenitors,Olig2^(+)oligodendrocytes,Iba1+microglia,and GFAP^(+)SOX2^(+)radial glia-like neural stem cells.We did not observe any significant sex differences in density of any cell population.Notably,neural stem/progenitor cells were present at a similar density as several cell types known to have potent functional roles via their secretome.These findings may be useful for refining hypotheses regarding the contributions of these cell types to regulating hippocampal function and their potential therapeutic uses.All experimental protocols were approved by the Ohio State University Institutional Animal Care and Use Committee(protocol#2016A00000068)on July 14,2016.

Cognitive impairment after traumatic brain injury is associated with reduced long-term depression of excitatory postsynaptic potential in the rat hippocampal dentate gyrus

Traumatic brain injury can cause loss of neuronal tissue, remote symptomatic epilepsy, and cognitive deficits. However, the mechanisms underlying the effects of traumatic brain injury are not yet clear. Hippocampal excitability is strongly correlated with cognitive dysfunction and remote symptomatic epilepsy. In this study, we examined the relationship between traumatic brain injury-induced neuronal loss and subsequent hippocampal regional excitability. We used hydraulic percussion to generate a rat model of traumatic brain injury. At 7 days after injury, the mean modified neurological severity score was 9.5, suggesting that the neurological function of the rats was remarkably impaired. Electrophysiology and immunocytochemical staining revealed increases in the slope of excitatory postsynaptic potentials and long-term depression（indicating weakened long-term inhibition）, and the numbers of cholecystokinin and parvalbumin immunoreactive cells were clearly reduced in the rat hippocampal dentate gyrus. These results indicate that interneuronal loss and changes in excitability occurred in the hippocampal dentate gyrus. Thus, traumatic brain injury-induced loss of interneurons appears to be associated with reduced long-term depression in the hippocampal dentate gyrus.

Bumetanide promotes neural precursor cell regeneration and dendritic development in the hippocampal dentate gyrus in the chronic stage of cerebral ischemia

Bumetanide has been shown to lessen cerebral edema and reduce the infarct area in the acute stage of cerebral ischemia. Few studies focus on the effects of bumetanide on neuroprotection and neurogenesis in the chronic stage of cerebral ischemia. We established a rat model of cerebral ischemia by injecting endothelin-1 in the left cortical motor area and left corpus striatum. Seven days later, bumetanide 200 μg/kg/day was injected into the lateral ventricle for 21 consecutive days with a mini-osmotic pump. Results demonstrated that the number of neuroblasts cells and the total length of dendrites increased, escape latency reduced, and the number of platform crossings increased in the rat hippocampal dentate gyrus in the chronic stage of cerebral ischemia. These findings suggest that bumetanide promoted neural precursor cell regeneration, dendritic development and the recovery of cognitive function, and protected brain tissue in the chronic stage of ischemia.

Effects of butternut squash extract on dentate gyrus cell proliferation and spatial learning in male adult rats

Previous studies reported that some plants, including butternut squash, exert positive effects on the brain. However, few studies have examined the effects of butternut squash on learning, memory, and neurogenesis. This study studied the effects of butternut squash extract on spatial learning and cell proliferation in the dentate gyrus of healthy male rats. Thirty-five male Wistar rats were intraperitoneally injected with 0, 50, 100, 200 and 400 mg/kg butternut squash extract once daily for 2 months. After the last administration, rat＇s spatial memory was studied using the Morris water maze. Finally, rats were sacrificed and hippocampal sections were prepared for light microscopy and bromodeoxyuridine immunohistochemistry studies. The results revealed that escape latency and swim distance decreased in all treatment groups compared with the control rats, and that the number of bromodeoxyuridine-positive cells in the dentate gyrus was significantly increased in the treatment groups compared with the controls. These findings suggest that butternut squash extract improves the learning and memory abilities of male rats, and increases the proliferation of dentate gyrus cells.

Long-term administration of scopolamine interferes with nerve cell proliferation, differentiation and migration in adult mouse hippocampal dentate gyrus, but it does not induce cell death

Long-term administration of scopolamine, a muscarinic receptor antagonist, can inhibit the survival of newly generated cells, but its effect on the proliferation, differentiation and migration of nerve cells in the adult mouse hippocampal dentate gyrus remain poorly understood. In this study, we used immunohistochemistry and western blot methods to weekly detect the biological behaviors of nerve cells in the hippocampal dentate gyrus of adult mice that received intraperito- neal administration of scopolamine for 4 weeks. Expression of neuronal nuclear antigen （NeuN; a neuronal marker） and Fluoro-]ade B （a marker for the localization of neuronal degeneration） was also detected. After scopolamine treatment, mouse hippocampal neurons did not die, and Ki-67 （a marker for proliferating cells）-immunoreactive cells were reduced in number and reac hed the lowest level at 4 weeks. Doublecortin （DCX; a marker for newly generated neurons）-im- munoreactive cells were gradually shortened in length and reduced in number with time. After scopolamine treatment for 4 weeks, nearly all of the 5-bromo-2＇-deoxyuridine （BrdU）-labeled newly generated cells were located in the subgranular zone of the dentate gyrus, but they did not migrate into the granule cell layer. Few mature BrdU/NeuN double-labeled cells were seen in the subgranular zone of the dentate gyrus. These findings suggest that long-term administration of scopolamine interferes with the proliferation, differentiation and migration of nerve cells in the adult mouse hippocampal dentate gyrus, but it does not induce cell death.

Apoptosis and autophagy control cell proliferation in the dentate gyrus following hippocampal lesion

Brain injuries often result in the promotion of cell proliferation in the hippocampal dentate gyrus（DG）,but the number of newborn cells declines with time.However,the cause of this decline remains poorly understood.Elucidation of the fate of these newborn cells will further the understanding of the pathological process and treatment of brain injury.In the present study,the number of newborn cells was quantitatively analyzed using an unbiased stereological method following hippocampal lesion by kainic acid,in combination with detection of apoptosis and autophagy.Results revealed that hippocampal lesion resulted in a significantly increased number of 5-bromo-2-deoxyuridine（BrdU）-positive cells in the DG,which subsequently decreased with time.BrdU/cleaved caspase-3 double-labeled cells were detected in the granular cell layer and hilus of DG.However,expressions of LC3-11,Beclin 1,and p53 were upregulated,and pro-caspase-3 and Bcl-2 were downregulated.Results indicated that hippocampal lesion in adult rats resulted in significant cell proliferation in the DG,which subsequently reduced with time.In addition,results suggested that apoptosis and autophagic processes could regulate cell proliferation in the DG following hippocampal lesion.

Neurons in the hippocampal CA1 region,but not the dentate gyrus,are susceptible to oxidative stress in rats with streptozotocin-induced type 1 diabetes

In this study, we investigated the effects of streptozotocin-induced type 1 diabetes on antioxi- dant-like protein-1 immunoreactivity, protein carbonyl levels, and malondialdehyde formation, a marker for lipid peroxidation, in the hippocampus. For this study, streptozotocin （75 mg/kg） was intraperitoneally injected into adult rats to induce type 1 diabetes. The three experimental pa- rameters were determined at 2, 3, 4 weeks after streptozotocin treatment. Fasting blood glucose levels significantly increased by 20.7-21.9 mM after streptozotocin treatment. The number of antioxidant-like protein-1 immunoreactive neurons significantly decreased in the hippocampal CA1 region, but not the dentate gyrus, 3 weeks after streptozotocin treatment compared to the control group. Malondialdehyde and protein carbonyl levels, which are modified by oxidative stress, significantly increased with a peak at 3 weeks after malondialdehyde treatment, and then decreased 4 weeks after malondialdehyde treatment. These results suggest that neurons in the hippocampal CA1 region, but not the dentate gyrus, are susceptible to oxidative stress 3 weeks after malondialdehyde treatment.

Effects of bone morphogenetic protein-4 on spatial memory and cholinergic expression in the dentate gyrus after fornix-fimbria transection in rats

BACKGROUND： Previous experiments have confirmed bone morphogenetic proteins （BMPs） upregulate cholinergic expression in neurons isolated from the embryonic rat hippocampus and cerebral cortex. Therefore, BMPs could be useful for treating Alzheimer＇s disease and other neurodegenerative diseases. OBJECTIVE： BMP-4 was infused into the hippocampal dentate gyrus of fomix-fimbria transected rats to test the effects of BMP-4 on cholinergic expression in dentate gyrus neurons, and to observe changes in spatial memory behavior. DESIGN： A randomized controlled animal experiment. SETTING： Department of Neurosurgery and Laboratory for Cell Biology, Institute of Geriatrics, General Hospital of Chinese PLA. MATERIALS： Twenty-seven healthy adult male Sprague Dawley （SD） rats, weighing 250-300 g, were provided by the Laboratory Animal Center of the General Hospital of Chinese PLA. Reagents： BMP-4 （B-2680, Sigma Company） and choline acetyl transferase （CHAT） antibody （AB5042, Chemicon Company） were used in this study. Equipments： a rat stereotaxic instrument （type： SN-2N, Narushige Group, Japan） and Image-prog-plus image analysis software （Media Cybernetics company, USA） were used in this study. The protocol was carried out in accordance with ethical guidelines for the use and care of animals. METHODS： This experiment was performed in the Institute of Geriatrics, General Hospital of Chinese PLA between July 2004 and March 2005. Rats were randomly divided into 4 groups： Alzheimer＇s disease group （n = 7）, normal control group （n = 5）, BMP-4-Alzheimer＇s disease group （n = 8）, and model group （n = 7）. In the Alzheimer＇s disease group, the left hippocampal fomix-fimbria of rats was transected to mimic Alzheimer＇s disease symptoms. In the BMP-4-Alzheimer＇s disease group, 1 μt L BMP-4 （10 mg/L） was perfused into the left dentate gyrus with a microinjector at 1 μ L/min. In the model group, 1 μ L saline was perfused into the same position by the same method. Twenty-eight days after injection, Morris water maze test was performed in all rats to test spatial memory. Time-to-platform and swim-path length were recorded. Immunohistochemical staining of cholinergic neurons was performed on brain sections containing dentate gyrus. The area covered by ChAT-positive cells was analyzed using an Image-prog-plus image analysis software. MAIN OUTCOME MEASURES： Area covered by ChAT-positive cells in the dentate gyrus. Time-to-platform and swim path-length. RESULTS： Twenty-seven rats were included in the final analysis. In the Alzheimer＇s disease group, the area covered by ChAT-positive cells was significantly smaller compared with the normal control group （F = 76.03, P 〈 0.01）. The area covered by ChAT-positive cells was significantly larger in the BMP-4- Alzheimer＇s disease group than in the model group （F = 35.17, P 〈 0.05）, but significantly smaller than in the normal control group （F = 40.17, P 〈 0.05）. Time-to-platform and swim-path length were significantly longer in the Alzheimer＇s disease group than in the normal control group （F =24.62 and 631.58, respectively, both P 〈 0.05）. Time-to-platform and swim-path length were significantly shorter in the BMP4-Alzheimer＇s disease group compared with the model group （F= 22.06 and 606.89, respectively P 〈 0.05）. CONCLUSION： Injection of BMP-4 into the dentate gyrus of Alzheimer＇s disease model rats alleviates central cholinergic system injury and concomitantly improves spatial memory.

Visual processing of word and image in the fusiform gyrus

BACKGROUND： The role of the left midfusiform gyrus as a target for visual word processing has been a topic of discussion. Numerous studies have utilized alphabetic writing for subject matter. However, few have addressed visual processing of Chinese characters in the left midfusiform gyrus. OBJECTIVE： To verify visual processing of Chinese characters and images in the left midfusiform gyrus using functional magnetic resonance imaging. DESIGN, TIME AND SETTING： A blocked design paradigm study. Experiments were performed at the Room of Magnetic Resonance, Guangdong Provincial Second People＇s Hospital, China from May to June 2009. PARTICIPANTS： A total of eight undergraduate students were recruited from Guangzhou University of China, comprising two females and six males, aged 20-23 years. The subjects were right-handed which was determined by a Chinese standard questionnaire. None of the subjects had a history of psychoneurosis, familial disease, color blindness, or color weakness. METHODS： A total of eight undergraduates were enrolled as subjects. Picture-naming and verb generation tasks were employed through the use of functional magnetic resonance imaging. Analysis of Functional Neurolmages software was used to process the data. MAIN OUTCOME MEASURES： Visual processing of Chinese characters and images in the left midfusiform gyrus was measured. RESULTS： Picture-naming and verb generation tasks were shown to significantly activate the bilateral midfusiform gyrus. Activation occurred in the visual word form area of the left midfusiform gyrus. CONCLUSION： The left midfusiform gyrus plays a general role in visual processing of Chinese characters and images.