Regional cerebral blood flow and stroke index after left carotid artery ligation in the conscious gerbil

We measured the regional cerebral blood flow in both hemispheres of Mongolian gerbil subjected to permanent left caratoid artery ligation, using [³H]nicotine as the tracer. At 1,3 and 6 h post-ligation, neurological signs were recorded and a stroke index score was tallied for each animal.In conscious control gerbils, mean cerebral blood flow on the left side was1.10 ± 0.08 (S.E.M.) ml·g⁻¹·min⁻¹ at the cerebral cortex0.58 ± 0.02 at the hippocampus and0.69 ± 0.04 at the diencephalon. Animals with a stroke index score exceeding 10 were considered symptomatic. We noted a close relationship between regional cerebral blood flow and the stroke index score. In symptomatic animals, regional cerebral blood flow in the ischemic hemisphere at 1,3 and 6 post-ligation was less than 0.21 ml·g⁻¹·min⁻¹ at the cortex and diencephalon, and less than 0.09 ml·g⁻¹min⁻¹ at the hippocampus.We suggest that unilaterally ligated gerbils manifesting a stroke index score greater than 10 represent a good experimental model for the study of ischemia.     

Regional cerebral blood flow in various types of brain tumor

Regional cerebral blood flow (rCBF) was measured in 23 patients with brain tumors using the ¹³³Xe intra-carotid injection method and a 254 channel gamma camera. The glioblastomas (4) and astrocytomas (4) all showed hyperemia in the tumor and tumor-near region. This was also seen in several meningiomas (4 of 7 cases) in which most of the tumor itself did not receive any isotope. Brain metastases (6) usually had a low flow in the tumor and tumor-near region. The glioblastomas tended to show markedly bending ¹³³Xe wash-out curves pointing to pronounced heterogeneity of blood flow. Most of the flow maps, regardless of the tumor types, showed widespread abnormalities of rCBF not only in the tumor region but also in the region remote from the tumor.
It is concluded that measurement of rCBF cannot yield accurate differential diagnostic information, but that the widespread derangement of the brain tissue function can be revealed even in the case of fairly small size tumors.     

应用近红外光技术观察经穴刺激对局部脑血流量的影响（英文）

目的:观察针刺孔最、三阴交、足三里对人脑血氧水平的影响,探讨应用近红外光成像技术(NIRS)测定针刺与它的关联性。方法:采用半随机(测试顺序随机)方法,临床试验①:18名成年人予以伪针刺百会。临床试验②:54名成年人分为3组(18人/组)分别予以针刺孔最、三阴交、足三里。于针刺前后分别实行语言流畅性课题测试,并应用NIRS测试大脑皮层血氧浓度变化。结果:临床试验①伪针刺组针刺百会前脑血氧浓度水平变化的积分值的平均值为10.8 mMcm·s,针刺后为9.2 mMcm·s。针刺后脑血氧浓度水平未出现明显差异。临床试验②:孔最组针刺前脑血氧浓度水平变化的积分值的平均值为18.1 mMcm·s,针刺后为8.6 mMcm·s。针刺后脑血氧浓度水平出现了有意义的减少(P=0.001)。三阴交组针刺前脑血氧浓度水平变化的积分值的平均值为16.1 mMcm·s,针刺后为17.4 mMcm·s。针刺后脑血氧浓度水平略见增加趋势,但差异无统计学意义。足三里组针刺前脑血氧浓度水平变化的积分值的平均值为13.8 mMcm·s,针刺后为10.1 mMcm·s。针刺后脑血氧浓度水平略见减少趋势,但差异无统计学意义。结论:针刺孔最使前头部脑血氧浓度水平减少,针刺足三里使前头部脑血氧浓度水平有减少趋势。针刺三阴交使前头部脑血氧浓度水平有增加趋势。     

The cognitive functions of the caudate nucleus

The basal ganglia as a whole are broadly responsible for sensorimotor coordination, including response selection and initiation. However, it has become increasingly clear that regions of the basal ganglia are functionally delineated along corticostriatal lines, and that a modular conception of the respective functions of various nuclei is useful. Here we examine the specific role of the caudate nucleus, and in particular, how this differs from that of the putamen. This review considers converging evidence from multiple domains including anatomical studies of corticostriatal circuitry, neuroimaging studies of healthy volunteers, patient studies of performance deficits on a variety of cognitive tests, and animal studies of behavioural control. We conclude that the caudate nucleus contributes to behaviour through the excitation of correct action schemas and the selection of appropriate sub-goals based on an evaluation of action-outcomes; both processes fundamental to successful goal-directed action. This is in contrast to the putamen, which appears to subserve cognitive functions more limited to stimulus-response, or habit, learning. This modular conception of the striatum is consistent with hierarchical models of cortico-striatal function through which adaptive behaviour towards significant goals can be identified (motivation; ventral striatum), planned (cognition; caudate) and implemented (sensorimotor coordination; putamen) effectively.     

Cerebral blood flow changes in man by wake-promoting drug, modafinil: a randomized double blind study

To investigate the effects of a wake‐promoting drug, modafinil on regional cerebral blood flow (rCBF) in healthy volunteers, we performed ^99mTc‐ethylcysteinate dimer single photon emission computed tomography (SPECT) before and after modafinil or placebo administration. Twenty‐one healthy subjects received single doses of 400 mg modafinil or placebo in a double blind randomized crossover study design. Administrations of modafinil or placebo in a subject were separated by a 2‐week washout. Brain SPECT was performed twice before and 3 h after modafinil or placebo administration. For statistical parametric mapping analysis, all SPECT images were spatially normalized to the standard SPECT template and then smoothed using a 12‐mm full width at half‐maximum Gaussian kernel. The paired t‐test was used to compare pre‐ versus post‐modafinil and pre‐ versus post‐placebo SPECT images. Differences in rCBF between post‐modafinil and post‐placebo conditions were also tested. Modafinil decreased Epworth and Stanford sleepiness scales whereas placebo did not. The post‐modafinil condition was associated with increased rCBF in bilateral thalami and dorsal pons, whereas the post‐placebo condition showed increased rCBF in a smaller area of the dorsal pons when compared with the drug naïve baseline condition. Compared with the post‐placebo condition, the post‐modafinil condition showed higher rCBF in bilateral frontopolar, orbitofrontal, superior frontal, middle frontal gyri, short insular gyri, left cingulate gyrus, left middle/inferior temporal gyri, left parahippocampal gyrus, and left pons. In healthy volunteers, modafinil increased wakefulness and rCBF in the arousal‐related systems and in brain areas related to emotion and executive function.     

The neurobiology of depression in later-life: clinical, neuropsychological, neuroimaging and pathophysiological features

As the population ages, the economic and societal impacts of neurodegenerative and neuropsychiatric disorders are expected to rise sharply. Like dementia, late-life depressive disorders are common and are linked to increased disability, high healthcare utilisation, cognitive decline and premature mortality. Considerable heterogeneity in the clinical presentation of major depression across the life cycle may reflect unique pathophysiological pathways to illness; differentiating those with earlier onset who have grown older (early-onset depression), from those with illness onset after the age of 50 or 60 years (late-onset depression). The last two decades have witnessed significant advances in our understanding of the neurobiology of early- and late-onset depression, and has shown that disturbances of fronto-subcortical functioning are implicated. New biomedical models extend well beyond perturbations of traditional monoamine systems to include altered neurotrophins, endocrinologic and immunologic system dysfunction, inflammatory processes and gene expression alterations. This more recent research has highlighted that a range of illness-specific, neurodegenerative and vascular factors appear to contribute to the various phenotypic presentations. This review highlights the major features of late-life depression, with specific reference to its associated aetiological, clinical, cognitive, neuroimaging, neuropathological, inflammatory and genetic correlates. Data examining the efficacy of pharmacological, non-pharmacological and novel treatments for depression are discussed. Ultimately, future research must aim to evaluate whether basic biomedical knowledge can be successfully translated into enhanced health outcomes via the implementation of early intervention paradigms.     

高血压脑出血后局部脑血流与皮层下失语变化的相关性研究

目的 研究皮层下失语与局部脑血流（ｒＣＢＦ）变化的关系。方法 对５１例优势侧高血压脑出血患行语言功能评定和单光子发计算机断层显像（ＳＰＥＣＴ）ｒＣＢＦ检查,并进行视觉分析和半定量分析。结果 （１）发病时皮层下ｒＣＢＦ的下降在失语组明显低于非失语组。（２）运动性失语组在额叶、Ｂｒｏｃａ区缺血明显,感觉性失语组则在颞叶、Ｗｅｒｎｉｃｋｅ区ｒＣＢＦ最低。（３）失语伴随皮层缺血的改善而好转,皮层下失语与皮层的ｒＣＢＦ的动态变化有显相关性,结论 Ｂｒｏｃａ区、Ｗｅｒｎｉｃｋｅ区的ｒＣＢＦ下降与皮层下失语密切相关,可有效地改善高血压脑出血患皮层的ｒＣＢＦ下降,并改善皮层下失语的预后。     

Improvements in both psychosis and motor signs in Parkinson's disease, and changes in regional cerebral blood flow after electroconvulsive therapy

Purpose

Psychotic symptoms in Parkinson's disease (PD) are relatively common and, in addition to creating a disturbance in patients' daily lives, have consistently been shown to be associated with poor outcome. The use of anti-PD medications has been the most widely identified risk factor for PD psychosis (PDP). However, the pathophysiology of PDP remains unclear. Although the efficacy of electroconvulsive therapy (ECT) for PD had been pointed out, only one study has demonstrated the effectiveness of ECT on both psychotic symptoms and motor symptoms. The aim of this study was to examine the acute effectiveness of ECT on PD and to identify the brain areas associated with PDP.

Methods

The study was conducted at Juntendo University Hospital in Tokyo. Eight patients with L-DOPA- or dopamine (DA) agonist-induced PDP, who were resistant to quetiapine treatment, were enrolled. Severity of PD was evaluated using the Hoehn and Yahr stage. Psychotic symptoms were evaluated using multiple measures from the Scale for the Assessment of Positive Symptoms (SAPS). Technetium-99m ethyl cysteinate dimer single photon emission computed tomography (99mTc ECD SPECT) was used to assess regional cerebral blood flow (rCBF) before and after a course of ECT. A voxel-by-voxel group analysis was performed using Statistical Parametric Mapping (SPM5).

Results

Our study clearly demonstrated that PDP was significantly less severe after ECT than before ECT, as indicated by change in mean SAPS total domain score (t = 7.2, P = 0.0002). Furthermore, the patients showed significant improvement in Hoehn and Yahr stage after ECT (t = 11.7, P < 0.0001). A further notable observation was significant increase in rCBF in the right middle frontal gyrus after ECT.

Conclusion

We conclude that a course of ECT produced notable improvements not only in PDP but also in the severity of PD. The findings of change in rCBF suggest implications for dysfunction in the middle frontal region for patients with PDP.     

Electro-acupuncture protects against hypoxic–ischemic brain-damaged immature rat via hydrogen sulfide as a possible mediator

We investigated whether hydrogen sulfide (H₂S) may be a mediator of electro-acupuncture (EA) stimulation treatment for hypoxic–ischemic brain-damage (HIBD). We studied a HIBD 7-day-old rat model with 4 types of treatments: (1) 14 sessions of EA; (2) hydroxylamine (HA), an inhibitor of cystathionine-β-synthase (CBS), the key enzyme of H₂S generation; (3) both EA and HA; or (4) no treatment. Sham-treated rats with or without EA were also studied. Regional cerebral blood flow (rCBF) was monitored before, during and after EA at different periods of treatment (d1, 7 and 14 sessions). We evaluated motor function, H₂S levels and CBS expression in the cerebral cortex and prepared cerebral pathomorphological images after 14 sessions of treatment. EA stimulation could increase local blood circulation and improve motor function in HIBD rats. HIBD significantly increased H₂S levels of brain tissue as compared with sham treatment, and EA treatment could decrease the H₂S generation. Rats with HIBD receiving both EA and HA therapy showed greatly recovered motor function and brain morphology. H₂S might be a mediator of EA treatment of HIBD in rats.     

Activation in the Ipsilateral Posterior Parietal Cortex during Tool Use: A PET Study

The basis of perceptual assimilation of tool and hand has been considered to be in modification of body schemata, for which integration of multimodal sensory information about our body parts is required. Using positron emission tomography and H(2)(15)O, we aimed to identify brain regions that change their neural activity in association with changes in neural processing of visual and/or somatosensory information when humans use a simple tool. Normal subjects were instructed to manipulate a small graspable object with a pair of tongs or with the fingers of their right or left hand. The only site activated during manipulation with the tool, compared with the fingers, with the right hand was the lateral edge of the right intraparietal sulcus (IPS). During manipulation using the left hand with the tool, compared with using the fingers, an area in the middle part of the left IPS was activated. Areas in the contralateral hemisphere were activated during both the tool-use and the finger-use tasks compared to the control task, but there was no statistically significant difference between the tool-use and the finger-use tasks. Therefore, the results suggest that the ipsilateral posterior parietal cortex was recruited during the tool-use tasks to integrate visuosomatosensory information.