首次发病且未用药的成年早发和晚发抑郁症患者脑功能连接差异研究

目的比较成年早发抑郁症(EOD)和成年晚发抑郁症(LOD)患者默认网络(DMN)内部功能连接的差异,探究不同发病年龄的抑郁症患者是否有不同的发病机制。方法选取在昆明医科大学第一附属医院精神科门诊或住院的EOD患者(n=58)和LOD患者(n=62)为研究对象,同期招募年轻健康对照组(n=60)和年老健康对照组(n=52)。对受试者进行静息态功能磁共振扫描,选择左侧楔前叶为种子点,计算该种子点与全脑的功能连接,并比较各组间该种子点的功能连接差异。结果四组之间功能连接具有差异的脑区涉及双侧额叶、颞叶、基底节、枕叶、顶叶及小脑等脑区。EOD组左侧楔前叶与左侧小脑Crus1区、左侧小脑IX区、左侧颞中回、右侧楔前叶、右侧前扣带回、右侧额中回、右侧角回、右侧脑岛、右侧内侧额上回、右侧颞中回的功能连接均高于年轻健康对照组(Z=3. 752 4～5. 867 8,P均0. 05);而左侧楔前叶与左侧额中回、左侧中央旁小叶、右侧缘上回、右侧额上回、右侧颞下回、右侧中央后回、右侧中央前回、右侧枕上回的功能连接均低于年轻健康对照组(Z=-5. 007 6～-3. 797 7,P均0. 05)。LOD组左侧楔前叶与左侧小脑Crus2区、左侧尾状核、左侧颞下回、左侧小脑Crus1区、左侧角回、左侧额中回、右侧额中回、右侧角回、右侧眶额部额中回的功能连接均高于年老健康对照组(Z=4. 122 8～6. 579 4,P均0. 05);与左侧海马旁回、左侧额上回、右侧枕中回、右侧中央前回、右侧内侧额上回、右侧锯状回、右侧颞下回、右侧中央旁小叶、右侧梭状回、右侧后扣带回的功能连接均低于年老健康对照组(Z=-5. 884 0～-3. 617 2,P均0. 05)。EOD组左侧楔前叶与左侧锯状回、左侧小脑IV-VI区、左侧小脑Crus2区的功能连接比LOD组高(Z=4. 087 7、3. 937 4、3. 672 1,P均0. 05);EOD组左侧楔前叶与右侧额中回、右侧眶额部额下回、右侧额上回的功能连接比LOD组低(Z=-4. 274 8、-3. 956 8、-4. 724 3、-3. 663 2,P均0. 05)。结论 DMN内部功能连接增高及额顶网络功能连接降低可能与EOD的发病机制相关,而DMN前部功能连接增高和后部功能连接降低可能与LOD的发病机制相关,不同发病年龄的成年抑郁症患者可能有不同的发病机制。     

Abnormal baseline brain activity in low-grade hepatic encephalopathy: a resting-state fMRI study

Resting-state functional magnetic resonance imaging (fMRI) has been used to detect the alterations of spontaneous neuronal activity in various neuropsychiatric diseases, but rarely in low-grade hepatic encephalopathy (HE), a common neuropsychiatric complication of liver cirrhosis. We conducted a resting-state fMRI in 19 healthy controls, 18 cirrhotic patients without HE, and 22 cirrhotic patients with low-grade HE. The amplitude of low-frequency fluctuations (ALFF) of fMRI signal was computed to measure the spontaneous neuronal activity. Several regions showing significant ALFF differences among three groups were the precuneus, occipital lobe, left frontal lobe and anterior/middle cingulate cortex, and left cerebellum posterior lobe. Compared to controls or patients without HE, patients with low-grade HE showed decreased ALFF in the precuneus and adjacent cuneus, visual cortex, and left cerebellum posterior lobe. Compared to controls, patients with low-grade HE showed higher ALFF in both cortical and subcortical regions, including the right middle cingulate gyrus, and left anterior/middle cingulate gyrus, inferior frontal gyrus, insula lobe, parahippocampal gyrus, middle temporal gyrus and lentiform nucleus; compared to patients without HE, patients with low-grade HE showed higher ALFF in the left medial frontal gyrus and anterior cingulate gyrus, bilateral superior frontal gyrus, and right middle frontal gyrus. Moreover, correlations between ALFF changes and poor neurocognitive performances were found in patients with low-grade HE. These results suggested the existence of aberrant brain activity at the baseline state in low-grade HE, which may be implicated in the neurological pathophysiology underlying HE.     

Sex and performance level effects on brain activation during a verbal fluency task: A functional magnetic resonance imaging study

Neuroimaging studies investigating the neural correlates of verbal fluency (VF) focused on sex differences without taking into account behavioural variation. Nevertheless, group differences in this verbal ability might account for neurocognitive differences elicited between men and women. The aim of this study was to test sex and performance level effects and the combination of these on cerebral activation. Four samples of 11 healthy students (N = 44) selected on the basis of sex and contrasted VF scores, high fluency (HF) versus low fluency (LF), performed a covert phonological VF task during scans. Within- and between-group analyses were conducted. Consistent with previous studies, for each sample, the whole-group analysis reported activation in the inferior frontal gyrus (IFG), insula, anterior cingulate cortex (ACC), medial frontal gyrus (mFG), superior (SPL) and inferior parietal lobules (IPL), inferior visual areas, cerebellum, thalamus and basal ganglia. Between-group analyses showed an interaction between sexes and performances in the right precuneus, left ACC, right IFG and left dorsolateral prefrontal cortex (dlPFC). HF men showed more activation than LF ones in the right precuneus and left dlPFC. LF men showed more activation in the right IFG than HF ones and LF women elicited more activation in the left ACC than HF ones. A sex main effect was found regardless of performance in the left inferior temporal gyrus (ITG), cerebellum, anterior and posterior cingulate cortexes and in the right superior frontal gyrus (SFG) and dlPFC, lingual gyrus and ACC, with men eliciting significantly greater activations than women. A performance main effect was found for the left ACC and the left cerebellum regardless of sex. LF subjects had stronger activations than HF ones in the ACC whereas HF subjects showed stronger activations in the cerebellum. Activity in three discrete subregions of the ACC is related to sex, performance and their interaction, respectively. Our findings emphasize the need to consider sex and performance level in functional imaging studies of VF.     

Morphometric Brain Abnormalities in Schizophrenia in a Population-Based Sample: Relationship to Duration of Illness

Biased recruitment and sample selection may cause variability in neuroimaging studies. Epidemiologically principled population-based magnetic resonance imaging (MRI) studies of schizophrenia are very rare. We gathered structural MRI data on 154 subjects from the Northern Finland 1966 Birth Cohort, aged 33–35 (100 controls, 54 schizophrenia patients). Regional differences in density of gray matter, white matter, and cerebrospinal fluid (CSF) were identified between groups using nonparametric statistical analysis, and the relationship of the regional differences to duration of illness was explored. Gray matter reductions were found bilaterally in the cerebellum, thalamus, basal ganglia, middle frontal gyrus, inferior frontal gyrus, precentral gyrus, insula, superior temporal gyrus, fusiform gyrus, parahippocampal gyrus, cuneus, and lingual gyrus; in the left posterior cingulate, superior frontal gyrus, transverse temporal gyrus, and precuneus; and in the right postcentral gyrus. Gray matter excesses were observed bilaterally in the basal ganglia, anterior cingulate, and medial orbitofrontal cortices. There were white matter deficits in an extensive network including inter- and intrahemispheric tracts bilaterally in the frontal, temporal, parietal, and occipital lobes, subcortical structures, cerebellum, and brain stem. CSF excesses were found bilaterally in the lateral ventricles, third ventricle, interhemispheric, and left Sylvian fissure. We replicated the previous findings of structural brain abnormalities in schizophrenia on a general population level. Gray and white matter deficits were associated with duration of illness suggesting either that developmental brain deficits relate to an earlier age of onset or that brain abnormalities in schizophrenia are progressive in nature.     

Common cortical and subcortical targets of the dorsolateral prefrontal and posterior parietal cortices in the rhesus monkey: evidence for a distributed neural network subserving spatially guided behavior

Common efferent projections of the dorsolateral prefrontal cortex and posterior parietal cortex were examined in 3 rhesus monkeys by placing injections of tritiated amino acids and HRP in frontal and parietal cortices, respectively, of the same hemisphere. Terminal labeling originating from both frontal and parietal injection sites was found to be in apposition in 15 ipsilateral cortical areas: the supplementary motor cortex, the dorsal premotor cortex, the ventral premotor cortex, the anterior arcuate cortex (including the frontal eye fields), the orbitofrontal cortex, the anterior and posterior cingulate cortices, the frontoparietal operculum, the insular cortex, the medial parietal cortex, the superior temporal cortex, the parahippocampal gyrus, the presubiculum, the caudomedial lobule, and the medial prestriate cortex. Convergent terminal labeling was observed in the contralateral hemisphere as well, most prominently in the principal sulcal cortex, the superior arcuate cortex, and the superior temporal cortex. In certain common target areas, as for example the cingulate cortices, frontal and parietal efferents terminate in an array of interdigitating columns, an arrangement much like that observed for callosal and associational projections to the principal sulcus (Goldman-Rakic and Schwartz, 1982). In other areas, frontal and parietal terminals exhibit a laminar complementarity: in the depths of the superior temporal sulcus, prefrontal terminals are densely distributed within laminae I, III, and V, whereas parietal terminals occupy mainly laminae IV and VI directly below the prefrontal bands. Subcortical structures also receive apposing or overlapping projections from both prefrontal and parietal cortices. The dorsolateral prefrontal and posterior parietal cortices project to adjacent, longitudinal domains of the neostriatum, as has been described previously (Selemon and Goldman-Rakic, 1985); these projections are also found in close apposition in the claustrum, the amygdala, the caudomedial lobule, and throughout the anterior medial, medial dorsal, lateral dorsal, and medial pulvinar nuclei of the thalamus. In the brain stem, both areas of association cortex project to the intermediate layers of the superior colliculus and to the midline reticular formation of the pons.(ABSTRACT TRUNCATED AT 400 WORDS)     

Serotonin modulation of cerebral glucose metabolism measured with positron emission tomography (PET) in human subjects

To develop a method to measure the dynamic response of the serotonin system in vivo, the effects of intravenously administered citalopram (the most selective of the serotonin reuptake inhibitors) on cerebral glucose metabolism were evaluated. Cerebral glucose metabolism was measured with positron emission tomography (PET) in 14 normal subjects scanned after administration of saline placebo and citalopram administered on 2 separate days. Citalopram administration resulted in a decrease in metabolism in the right anterior cingulate gyrus (BA 24/32), right superior (BA 9) and right middle frontal gyrus (BA 6), right parietal cortex (precuneus), right superior occipital gyrus, left thalamus, and right cerebellum. Increased metabolism was observed in the left superior temporal gyrus and left occipital cortex. Alterations in metabolism by acute citalopram administration involved the heteromodal association cortices that also show metabolic alterations in patients with geriatric depression and overlap with the regions affected by antidepressant treatment. Future studies will evaluate how the acute metabolic response to citalopram relates to the metabolic response after chronic treatment in patients with geriatric depression.     

长期海洛因依赖者前额叶功能连接的变化

以前额叶为种子点,利用静息态fMRI进行全脑时域相关的功能连接分析,观察长期海洛因成瘾者前额叶功能连接的变化。结果发现相比于正常对照,以左侧前额叶为种子点进行功能连接分析,海洛因成瘾者左侧前额叶与左侧海马、右侧前扣带回、左侧额中回、右侧额中回、右侧楔前叶功能连接明显降低;以右侧前额叶为种子点进行功能连接分析,海洛因成瘾者右侧前额叶与左侧眶额叶、左侧额中回功能连接明显降低。提示长期海洛因成瘾者前额叶与相关脑区的功能连接减弱,可能与海洛因成瘾的维持与戒断后复吸相关。     

颞叶内侧癫癎海马功能连接的功能磁共振成像研究

目的研究颞叶内侧癫癎患者右侧海马与全脑,尤其是默认网络功能连接的关系,探讨颞叶内侧癫癎患者默认网络异常的机制及其形成的颞叶癫癎网络。方法23例颞叶内侧癫癎患者,采用静息功能连接的功能磁共振成像,选择右侧海马作为兴趣区,获得正常对照组和颞叶内侧癫癎组受试者的脑功能连接激活图,观察其右侧海马与全脑的功能连接。结果正常对照组受试者默认网络包括海马、后扣带回和（或）楔前叶、前扣带回和（或）前额叶内侧、角回及前颞叶。颞叶内侧癫癎组患者右侧海马与默认网络的正向功能连接明显减弱,与右侧额下回、颞上回及第一运动感觉皮质下部的正向功能连接增强;与前额叶背侧、顶间沟及第一运动感觉皮质上部的负向功能连接减弱。结论在颞叶内侧癫癎患者功能连接网络中,默认网络及部分正向功能连接网络受损,提示患者存在广泛的、与海马相关的生理功能丧失;与右侧额下回、颞上回及第一感觉运动皮质下部的功能连接增强则可能与颞叶癫癎网络有关。     

Effects of incidental and intentional feature binding on recognition: a behavioural and PET activation study.

Using Positron Emission Tomography (PET), we investigated cerebral regions associated with the episodic recognition of words alone and words bound to contextual colours. Two modes of colour encoding were tested: incidental and intentional word-to-colour binding. Word-only recognition was associated with brain activation in a lexico-semantic left middle temporal region and in the cerebellum following an incidental colour encoding, and with brain activation in the left posterior middle frontal gyrus, right anterior cingulate and right inferior frontal gyrus following an intentional encoding. Recognition of bound features was associated with activation in left prefrontal and superior parietal regions following an incidental colour encoding, and with preferential right prefrontal cortex activation following an intentional colour encoding. Our results are in line with the hypothesis of a parietal involvement in context processing, and prefrontal areas in monitoring retrieval processes. Our results also support the hypothesis of a 'cortical asymmetry for reflective activity' (CARA).     

Reduced cerebral glucose metabolism in patients at risk for Alzheimer's disease

While significantly reduced glucose metabolism in fronto-temporo-parietal and cingulate cortices has been demonstrated in Alzheimer's disease (AD) compared with controls, cerebral glucose metabolism in patients with mild cognitive impairment who subsequently develop AD is less well-defined. In the present study we measured cerebral glucose metabolism by positron emission tomography (PET) with (18)F-2-fluoro-2-deoxy-D-glucose in 14 patients with aging-associated cognitive decline (AACD), 44 patients with AD, and 14 healthy control subjects at baseline. The AACD patients were clinically followed up, and conversion to AD was determined. Compared with controls, AACD patients had significantly reduced glucose metabolism in the right precuneus, posterior cingulate, right angular gyrus, and bilateral middle temporal cortices, while the respective deficits were more pronounced in AD patients and also involved the frontal cortices. AACD patients who subsequently converted to AD (AACD-converters) showed more extended metabolic changes which also involved the frontal and temporal cortices, right cingulate gyrus, right thalamus, and bilateral precuneus.     

年轻人与老年人简单乘法运算之功能磁共振成像研究

目的应用fMRI技术探讨中国青年和老年人群在简单运算任务下脑激活模式及其与行为学之间的关系。方法分别对青年组(19例)和老年组(20例)健康志愿者进行对照任务和简单运算任务下的fMRI检查。结果两组受试者受教育程度(P=0.125)、智力水平(P=0.921),以及完成对照任务(P=0.142)和简单乘法运算任务(P=0.880)之正确率差异无统计学意义,但老年组受试者完成对照任务(P=0.000)和简单乘法运算任务(P=0.005)反应时间明显延长。青年组受试者在任务刺激下可激活右侧缘上回并向顶内沟和颞中上回后部延伸,中央前回和运动前区、前额叶,左侧缘上回并向颞上回后部和角回延伸,顶内沟区域、颞中下回,内侧后扣带回、楔前叶、辅助运动区、海马沟、海马旁回及前额叶内侧;老年组受试者则分别激活右侧缘上回和顶下区域并向颞中上回后部延伸,中央前回和运动前区、前额叶,左侧缘上回和角回并向顶下延伸,中央前回和运动前区、岛叶及前额叶,内侧后扣带回和中央旁小叶、前扣带回及前额叶内侧;两组受试者共激活脑区包括顶下区域、楔前叶、中央前后回和额顶叶网络,以及颞叶、海马旁回、钩回、屏状核和后扣带回等皮质下结构。结论数学事实提取相关网络的主要成分受年龄影响较小,老年人群的任务激活脑区主要向任务相关顶区集中。     

反社会人格障碍男性青年大脑白质异常改变： 证据来自于基于体素脑形态测量学的DARTEL分析

SPM8 DARTEL工具包对3D脑结构成像数据对男性青年反社会人格障碍者和正常组的大脑白质结构进行基于体素的形态学分析（VBM）。结果显示,与正常对照者比较,反社会人格障碍者主要表现为双侧前额叶、右岛叶、中央前回,左右颞上回、右中央后回、右侧顶下小叶、右侧楔前叶、右枕中叶、右海马旁回及双侧扣带回等多个脑区白质体积密度增加,左颞中叶、右小脑的白质体积密度减小。相关分析显示,额内侧回的白质体积密度增加与反社会行为的评分(PDQ)有正相关。提示反社会人格障碍者存在多个脑区的白质形态学明显异常,这些异常可能与其反社会行为有关。     

Recovery from wernicke's aphasia: A positron emission tomographic study

Changes in the organization of the brain after recovery from aphasia were investigated by measuring increases in regional cerebral blood flow (rCBF) during repetition of pseudowords and during verb generation. Six right-handed patients who had recovered from Wernicke's aphasia caused by an infarction destroying the left posterior perisylvian language zone were compared with 6 healthy, right-handed volunteers. In the control subjects, strong rCBF increases were found in the left hemisphere in the posterior part of the superior and middle temporal gyrus (Wernicke's area), and during the generation task in lateral prefrontal cortex (LPFC) and in inferior frontal gyrus (Broca's area). There were some weak right hemisphere increases in superior temporal gyrus and inferior premotor cortex. In the patients, rCBF increases were preserved in the frontal areas. There was clear right hemisphere activation in superior temporal gyrus and inferior premotor and lateral prefrontal cortices, homotopic to the left hemisphere language zones. Increased left frontal and right perisylvian activity in patients with persisting destruction of Wernicke's area emphasizes redistribution of activity within the framework of a preexisting, parallel processing and bilateral network as the central mechanism in functional reorganization of the language system after stroke.     

Object identification and lexical/semantic access in children: a functional magnetic resonance imaging study of word-picture matching

Theoretical models for lexical access to visual objects have been based mainly on adult data. To investigate the developmental aspects of object recognition and lexical access in children, a large-scale functional MRI (fMRI) study was performed in 283 normal children ages 5-18 using a word-picture matching paradigm in which children would match an aurally presented noun to one of two pictures (line drawings). Using group Independent Component Analysis (ICA), six task-related components were detected, including (a) the posterior superior temporal gyrus bilaterally; (b) the fusiform, inferior temporal, and middle occipital gyri bilaterally; (c) the dorsal aspect of the inferior frontal gyrus bilaterally, the left precuneus, the left superior/middle temporal gyrus, and the anterior cingulate; (d) the right medial fusiform gyrus; (e) a left-lateralized component including the inferior/middle frontal, middle temporal, medial frontal, and angular gyri, as well as the thalamus and the posterior cingulate; and (f) the ventral/anterior aspect of the inferior frontal gyrus bilaterally. Increased activation associated with age was seen in the components (b) and (d) (ventral visual pathway) for object recognition, and (c) and (f) likely associated with semantic maintenance and response selection. Increased activation associated with task performance was seen in components (b) and (d) (ventral visual pathway) while decreased activation associated with task performance was seen in component (f) (ventral/anterior inferior frontal gyrus). The results corroborate the continued development of the ventral visual pathway throughout the developmental period.     

抑郁症患者情绪图片刺激早期低频脑磁图研究

目的：探讨抑郁症患者给予视觉情绪图片刺激早期0～100ms、100～200ms、200～300ms3个时段8～30Hz的神经磁场激活特征。方法：8例抑郁症患者及12例健康右利手对照者,在给予国际情绪图片库（IAPS）正性、中性、负性情绪图片刺激同时记录脑磁图信号,使用SPM8b软件进行数据分析：设两样本t检验P〈0.01（未校正）和K值≥10个体素范围为差异有统计学意义。结果：与对照组相比,抑郁组在正性情绪图片刺激下,100～200ms内的左侧额下回,右侧的终板旁回、额内侧回、海马回激活增强。在中性情绪图片刺激下,抑郁组在0～100ms的右侧豆状核、岛叶、额上回,左内侧额叶,100～200ms内的右侧岛叶、豆状核壳核及屏状核,左侧额下回、额上回、颞上回,200～300ms内的右侧岛叶、豆状核、尾状核体激活增强。负性情绪图片刺激下抑郁组在0～100ms内的右侧颞上回、岛叶、尾状核头部、额中下回激活增强,100～200ms内的右侧额中回、尾状核体,200～300ms内右额下回激活增强。此外还比较一致的发现抑郁组在楔前叶、后扣带回等顶叶脑区激活降低。结论：抑郁个体起注意调节功能的顶叶脑区如楔前叶功能不足,对视觉皮质向前部脑区情绪信息颞叶底部传递通路抑制不足,腹侧前额皮质、岛叶过度的激活,可能是抑郁症的一个发病基础。     

不同亚型轻度认知障碍患者静息态脑功能局部一致性研究

目的探讨遗忘型和非遗忘型轻度认知障碍(mild cognition impairment,MCI)患者局部自发脑活动特点。方法纳入遗忘型MCI(amnesicMCI,aMCI)患者25例,非遗忘型MCI(non-amnesticMCI,naMCI)患者21例和正常对照(normal control,NC)15名进行静息态功能磁共振扫描,通过计算每个给定体素与其最邻近26个体素时间序列的相似性获得全脑局部一致性(regional homogeneity,ReHo)图,比较三组被试全脑ReHo差异。结果 aMCI组右侧额叶ReHo值低于NC组,左侧颞中回和左侧小脑ReHo值高于NC组(P0.05,Alphasim校正);naMCI组前扣带回和右侧额中回ReHo值低于NC组,右侧海马旁回、右侧颞中回和右侧楔前叶ReHo值高于NC组(P0.05,Alphasim校正);aMCI左侧前额叶和左侧颞中回ReHo值高于naMCI组,右侧小脑ReHo值低于naMCI组(P0.05,Alphasim校正)。结论 aMCI和naMCI患者左侧前额叶、左侧颞中回及右侧小脑自发脑功能活动存在差异,这为区别aMCI和naMCI两者脑功能活动特点提供了初步影像学依据。     

Putative Tests of Frontal Lobe Function: A PET-Study of Brain Activation During Stroop's Test and Verbal Fluency

Stroop's test and the Verbal Fluency test are commonly argued to be measures of the integrity of the prefrontal cortex. This assumption has only to some degree been confirmed by lesion studies. In the present study, Positron Emission Tomography (PET) with H 2 15 O was used to further validate Stroop's test and the Verbal Fluency as measures of frontal lobe function; both tests were implemented as activation paradigms during scanning of normal middleaged individuals. Stroop interference was found to activate the left anterior cingulate cortex, the supplementary motor cortex, thalamus, and the cerebellum. Although the prominent anterior cingulate activation is in the frontal lobe, it is not prefrontal. Verbal Fluency activated the left inferior frontal cortex and the left dorsolateral prefrontal cortex, the supplementary motor cortex, the anterior cingulate cortex and the cerebellum. These results bring this latter test closer to being a specific test of prefrontal function.     

Putative tests of frontal lobe function: a PET-study of brain activation during Stroop's Test and verbal fluency

Stroop's test and the Verbal Fluency test are commonly argued to be measures of the integrity of the prefrontal cortex. This assumption has only to some degree been confirmed by lesion studies. In the present study, Positron Emission Tomography (PET) with H(2)(15)O was used to further validate Stroop's test and the Verbal Fluency as measures of frontal lobe function; both tests were implemented as activation paradigms during scanning of normal middleaged individuals. Stroop interference was found to activate the left anterior cingulate cortex, the supplementary motor cortex, thalamus, and the cerebellum. Although the prominent anterior cingulate activation is in the frontal lobe, it is not prefrontal. Verbal Fluency activated the left inferior frontal cortex and the left dorsolateral prefrontal cortex, the supplementary motor cortex, the anterior cingulate cortex and the cerebellum. These results bring this latter test closer to being a specific test of prefrontal function.     

An fMRI investigation of detection of semantic incongruities in autistic spectrum conditions

The aim of this study was to investigate differences in the brain's haemodynamic response to semantically incongruent and congruent sentences in adults with an autistic spectrum condition (ASC) and a typically developing Control group. We used functional magnetic resonance imaging to measure regional variations in neural activity during detection of semantic incongruities within written sentences. Whilst the 12 controls showed a pattern of activity extending from posterior cingulate cortices bilaterally and the left occipitotemporal region to the left superior and inferior temporal lobes, right anterior cingulate and right inferior frontal gyrus, the 12 participants with an ASC presented a more spatially restricted activation pattern, including the left inferior frontal gyrus, left anterior cingulate cortex and right middle frontal gyrus. These results are coherent with the hypothesis that impaired integration of multiple neural networks in people with an ASC is related to previous observations that this group have difficulties in the use of context to predict the final word of sentences.     

Functional neuroanatomy of sustained attention in schizophrenia: contribution of parietal cortices

Deficits in sustained attention have been frequently described in schizophrenia. The neuroanatomical basis reported previously have included altered levels of activation in cingulate and prefrontal cortex, but the contribution of further regions remains unclear. We explored the full neuroanatomy underlying the sustained attentional deficits observed in naïve schizophrenics compared with controls. Participants included 10 controls and 11 patients. The experimental design included rest, auditory stimulation using clicks, and two counting tasks. Subjects were instructed to mentally count the clicks, and then to count forward at the same frequency they heard previously when listening to the clicks. Relative cerebral blood flow (relCBF) was measured by means of PET ¹⁵O‐water. Differences were observed between both groups at superior temporal cortex, superior parietal gyrus, and cerebellum during tasks requiring listening. During all counting conditions, additionally to supplementary motor area (SMA), dorsolateral prefrontal cortex (DLPCF), precentral gyrus, cingulate, cerebellum, and inferior parietal (IP) gyrus, patients engaged other frontal structures including inferior, medial, and superior frontal areas. When counting with no auditory stimulation (C; requires components of working memory and time estimation), significant differences were observed in the level of activation of frontal and IP regions. Our naïve patients presented abnormal activation of auditory associative pathways. They failed to activate prefrontal and parietal regions at a similar level during tasks requiring increased cognitive effort, and they required a higher activation of inferior frontal regions to properly respond to cognitive demands. Hum. Brain Mapping 17:116–130, 2002. © 2002 Wiley‐Liss, Inc.