Parietal versus temporal lobe components in spatial cognition: Setting the mid‐point of a horizontal line

Recent anatomo‐clinical correlation studies have extended to the superior temporal gyrus, the right hemisphere lesion sites associated with the left unilateral spatial neglect, in addition to the traditional posterior‐inferior‐parietal localization of the responsible lesion (supramarginal gyrus, at the temporo‐parietal junction). The study aimed at teasing apart, by means of repetitive transcranial magnetic stimulation (rTMS), the contribution of the inferior parietal lobule (angular gyrus versus supramarginal gyrus) and of the superior temporal gyrus of the right hemisphere, in making judgments about the mid‐point of a horizontal line, a widely used task for detecting and investigating spatial neglect. rTMS trains at 25 Hz frequency were delivered over the inferior parietal lobule (angular gyrus and supramarginal gyrus), the superior temporal gyrus and the anterior parietal lobe of the right hemisphere, in 10 neurologically unimpaired participants, performing a line bisection judgment task. rTMS of the inferior parietal lobule at the level of the supramarginal gyrus brought about a rightward error in the bisection judgment, ipsilateral to the side of the rTMS, with stimulation over the other sites being ineffective. The neural correlates of computing the mid‐point of a horizontal segment include the right supramarginal gyrus in the inferior parietal lobule and do not extend to the angular gyrus and the superior temporal gyrus. These rTMS data in unimpaired subjects constrain the evidence from lesion studies in brain‐damaged patients, emphasizing the major role of a subset of relevant regions.     

Hemodynamic and electrophysiological connectivity in the language system: Simultaneous near-infrared spectroscopy and electrocorticography recordings during cortical stimulation

We applied near-infrared spectroscopy (NIRS) and electrocorticography (ECoG) recordings during cortical stimulation to a temporal lobe epilepsy patient who underwent subdural electrode implantation. Using NIRS, changes in blood concentrations of oxyhemoglobin (HbO(2)) and deoxyhemoglobin (HbR) during cortical stimulation of the left language areas were measured in each hemisphere. NIRS revealed that 2Hz stimulation with 5mA produced no significant hemodynamic changes in either hemisphere. By contrast, 50Hz stimulation elicited significant increases in both HbO(2) and HbR at the stimulation site. Furthermore, with 50Hz stimulation of the left superior temporal gyrus, the increases in HbO(2) and HbR were observed not only at the stimulation site but also concurrently at the left inferior frontal gyrus. This suggests the existence of functional connectivity in the language system. The present study demonstrates that simultaneous NIRS and ECoG studies during cortical stimulation allow a novel analysis of cerebral connectivity.     

Enhanced occipital and anterior cingulate activation in men but not in women during exposure to angry and fearful male faces

Blood-oxygenation-level-dependent signal was measured with functional magnetic resonance imaging in 24 healthy young subjects (12 men and 12 women) during viewing of angry, fearful, and neutral male and female face pictures. Exposure to angry male as opposed to angry female faces activated the visual cortex and the anterior cingulate gyrus significantly more in men than in women. A similar sex-differential brain activation pattern was present during exposure to fearful but not neutral faces. Previous behavioral studies indicate enhanced physiological arousal in men but not in women during exposure to angry male as opposed to female faces, and brain imaging studies have shown that the occipital cortex and the anterior cingulate gyrus are influenced by activity in the autonomic nervous system as well as by visual attention. Hence, we suggest that the elevated occipital and anterior cingulate activation in men during confrontation with other angry and fearful males may reflect enhanced vigilance in a potentially dangerous situation.     

工作记忆训练诱发的神经可塑性——基于系列fMRI实验的脑区分布递减时空模型

工作记忆训练(Working Memory Training, WMT)诱发神经可塑性, 但其具体机制尚不明晰。为探索WMT改变正常人群大脑功能的时空特性, 以“扩展的智力顶额整合理论”和“神经效率假说”为依据, 采用逐层递进的5种方法, 分6个步骤来查究近20年来正常人群WMT的37篇fMRI文献。第一步, 用叙述性综述、频数分析和卡方检验法比较脑区激活模式和脑网络功能连接在WMT前后发生的改变, 发现WMT改变了大脑的5个联合区、7个宏观区和3个子区。其中, 额上回、顶下小叶和扣带回这3个子区各自激活减弱的报道文献数量多于其激活增强的, 且这种差异分别具有统计学意义。第二步, 采用激活似然估计法对其中26篇开展元分析, 发现大脑的3个子区激活减弱水平在WMT前后的差异具有统计学意义, 即额中回(BA6和8)、额上回(BA6)和前扣带回(BA24和32)。第三步, 综合定性和定量分析结果, 提出WMT脑区分布递减时空模型, 产生5个结果和讨论。第四步, 采用非参数检验进一步追踪WMT效应的调节因素, 发现训练的任务类型和时间分别对脑区激活的影响具有统计学意义。第五步, 针对正常人群WMT诱发神经可塑性的时空特性, 得出3个结论：第一, WMT改变了正常人群相应脑区的神经活动, 表现为减弱或增强, 但减弱更加突出, 且更新和较短时间的WMT倾向于诱发较多减弱; 第二, 这些神经活动变化主要发生在额顶叶联合区, 但也包括分别以颞叶、枕叶、扣带回及纹状体为主的联合区, 在一定范围内体现了整脑功能联合。这体现了WMT诱发神经可塑性的空间特性, 且符合“扩展的智力顶额整合理论”; 第三, 额中回、额上回、顶下小叶和扣带回(尤其前扣带回)这4个子区在激活减弱水平上重点展示了WMT神经可塑性的时间特性, 且符合“神经效率假说”, 恰好体现出“聪明的大脑更懒惰”。第六步, 指出WMT诱发神经可塑性的未来研究可能关注脑可塑性中的低活跃性、辨析额中回、额上回、顶下小叶和扣带回(尤其前扣带回)这4个子区在激活减弱水平上体现的时间特性、找寻训练减弱或增强大脑活动的综合性影响因素。     

Organization of short-term verbal memory in language areas of human cortex: Evidence from electrical stimulation

Short-term verbal memory (STVM) performance was measured during electrical stimulation of human left frontal-parietal-temporal cortex, at craniotomy under local anesthesia for the treatment of medically intractable epilepsy. The areas of cortex where stimulation alters language, as measured by object naming, are separate but adjacent to the areas where stimulation alters STVM. There are differential effects of stimulation during input, storage, and output phases of STVM at different cortical sites. These suggest that cortex adjacent to the posterior language area is a site of storage of STVM, while cortex adjacent to anterior language area is involved in retrieval from STVM.     

艺术设计中创造性思维的fMRI研究：一项基于智能CAD的探索

本项工作尝试将人类思维的神经生物学基础研究与人工智能的研究成果相结合, 利用类比生成模型的原理, 开发了一个计算机辅助设计系统“多源类比人脸生成系统”, 并运用此平台开展了fMRI实验, 对人类大脑创造性思维的神经生物学机制进行了探索。实验采用open-ends模式下的“design task”和problem solving模式下的“control task”作为对照, 共采得15名健康成人被试的有效数据。数据结果显示design task与control task相比更为显著地激活了内侧前额叶、额中回、右侧颞上回、前扣带回、双侧海马、楔前叶这些脑区。综合以往研究推测, 内侧前额叶可能更多地与即兴自由创作中对自我信息的表征有关, 颞叶可能与不断产生和输出新颖性的观点有关, 边缘系统则可能主要与创造性活动中的动力驱动作用有关。总的来说, 创造性思维是多个脑区同时参与的高度分布式加工的结果。     

Articulatory/phonetic sequencing at the level of the anterior perisylvian cortex: a functional magnetic resonance imaging (fMRI) study

Damage to the anterior peri-intrasylvian cortex of the dominant hemisphere may give rise to a fairly consistent syndrome of articulatory deficits in the absence of relevant paresis of orofacial or laryngeal muscles (apraxia of speech, aphemia, or phonetic disintegration). The available clinical data are ambiguous with respect to the relevant lesion site, indicating either dysfunction of the premotor aspect of the lower precentral gyrus or the anterior insula in the depth of the Sylvian fissure. In order to further specify the functional anatomic substratum of this syndrome, functional magnetic resonance imaging (fMRI) was performed during reiteration of syllables differing in their demands on articulatory/phonetic sequencing (CV versus CCCV versus CVCVCV). Horizontal tongue movements and a polysyllabic lexical item served as control conditions. Repetition of the CV and CCCV monosyllables elicited a rather bilateral symmetric hemodynamic response at the level of the anterior and posterior bank of the central sulcus (primary sensorimotor cortex), whereas a more limited area of neural activity arose within this domain during production of lexical and nonlexical polysyllables, significantly or exclusively lateralized toward the left hemisphere. There is neurophysiological evidence that primary sensorimotor cortex mediates the "fractionation" of movements. Assuming that the polysyllables considered are organized as coarticulated higher-order units, the observed restricted and lateralized cortical activation pattern, most presumably, reflects a mode of "nonindividualized" motor control posing fewer demands on "movement fractionation." These findings may explain the clinical observation of disproportionately worse repetition of trisyllabic items as compared to monosyllables in apraxia of speech. The various test materials failed to elicit significant activation of the anterior insula. If at all, only horizontal tongue movements yielded a hemodynamic reaction extending beyond the sensorimotor cortex to premotor areas. Since limbic projections target the inferior dorsolateral frontal lobe, the enlarged region of activation during horizontal tongue movements might reflect increased attentional requirements of this task.     

不同感觉功能对抑郁的影响及其神经机制

大脑通过视觉、听觉、嗅觉、味觉和触觉等感官通道接收来自外界的信息。不同感觉功能受损涉及抑郁发生的中枢机制,而基于不同感官通道进行适当刺激以及多感官联合干预也可能发挥显著的抑郁治疗作用。笔者以症状-脑区-机制-治疗为逻辑主线,首次系统梳理了五种主要感觉障碍人群的抑郁临床症状、抑郁神经机制以及基于感觉刺激的抗抑郁治疗。结果表明,不同感觉功能障碍对抑郁相关神经机制的影响可能表征了不同的抑郁病理,涉及神经元电活动(某些神经元放电和神经环路激活等)和神经生化改变(神经可塑性和神经发生、炎症免疫和HPA轴、神经激素和神经递质等),且主要发生在边缘系统及其附近脑区,涉及岛叶、颞叶、额叶等。因此,未来研究可聚焦于机体对不同感觉信息的提取,这将为人类抑郁的病因和治疗提供新的研究视角。     

抑郁障碍和焦虑障碍治疗的神经心理机制——脑成像研究的ALE元分析

抑郁障碍和焦虑障碍是两种最常见的精神障碍。使用激活似然估计(activation likelihood estimation,ALE)元分析对抑郁和焦虑障碍患者治疗后出现的一致脑区激活改变进行评估,并考察不同条件下这一改变的差异。研究共纳入25篇文献,结果发现:(1)抑郁和焦虑障碍接受治疗后,枕下回(inferior occipital gyrus,IOG)等脑区激活增加;豆状核(lentiform nucleus)等激活减少。(2)a.心理治疗产生的脑激活改变为豆状核活动的减少;药物治疗则在于扣带回(cingulate gyrus)等活动增加,而楔前叶(precuneus)等活动减少。b.任务下成像治疗后激活增加的脑区为扣带回等,减少的脑区为楔前叶等;静息下成像,治疗后枕下回等激活增加,额内侧回(medial frontal gyrus,MFG)等激活减少。c.抑郁障碍治疗后的脑激活变化为扣带回等活动增加,楔前叶等活动减少;焦虑障碍在于前扣带回/额内侧回(anterior cingulate/MFG)活动减少。研究表明治疗会给抑郁和焦虑障碍带来一致的脑区激活改变;治疗方法、成像状态和障碍类型不同,治疗后脑区激活改变也存在差异。     

Neural correlates of viewing paintings: Evidence from a quantitative meta-analysis of functional magnetic resonance imaging data

Many studies involving functional magnetic resonance imaging (fMRI) have exposed participants to paintings under varying task demands. To isolate neural systems that are activated reliably across fMRI studies in response to viewing paintings regardless of variation in task demands, a quantitative meta-analysis of fifteen experiments using the activation likelihood estimation (ALE) method was conducted. As predicted, viewing paintings was correlated with activation in a distributed system including the occipital lobes, temporal lobe structures in the ventral stream involved in object (fusiform gyrus) and scene (parahippocampal gyrus) perception, and the anterior insula—a key structure in experience of emotion. In addition, we also observed activation in the posterior cingulate cortex bilaterally—part of the brain’s default network. These results suggest that viewing paintings engages not only systems involved in visual representation and object recognition, but also structures underlying emotions and internalized cognitions.     

Verbal reaction time patterns in aphasic adults: consideration for apraxia of speech

Verbal reaction time patterns were compared in aphasic adults presenting anterior and posterior left hemisphere lesions. Reaction Times were measured from simultaneous recording of the subjects' verbal responses and electromyographic activity from three oral-facial sites. Total Reaction Time was fractionated into Premotor Time and Motor Time components to assess latencies associated with motor speech planning and execution. The results suggested that only anterior lesions result in deficits in motor speech planning and/or execution while posterior lesion patients perform no differently than normal. The evidence supports traditional concepts regarding apraxia of speech as being associated with frontal lobe lesions.     

寻找自我:基于认知神经的观点

默认网络相关研究表明,生物进化的社会适应性建构了自我的认知神经基础,与James的自我结构相对应:主我位于后部扣带回,精神自我位于内侧前额叶,身体自我位于顶下小叶和脑岛; 并且与内侧前额叶、顶下小叶和后部扣带回之间的信息传递相关。个体在基线水平的大脑活动表明,自我是通过后部扣带回接收并调节全脑(包括表征客我的脑区)信息流,随时准备将外界满足需要有利于个体生存的资源纳入其中的神经系统。对于探讨“认识自我”这个古老的哲学问题与现代认知神经科学之间的关系有重要意义。     

Suppression of VMH-lesion-induced reactivity and aggressiveness in the rat by stimulation of lateral septum, but not medial septum or cingulate cortex

Animals made vicious with bilateral ventromedial hypothalamic lesions had bipolar electrodes implanted unilaterally in the lateral septum, medial septum, or cingulate cortex. Four days later, the animals' reactivity and aggressiveness were evaluated 5 min before, during, and 5 min after stimulation at 20 micronA (60 Hz, sine wave). Lateral septal stimulation suppressed reactivity and aggressiveness by almost 80% compared with pre- and poststimulation levels. Stimulation of neither the cingulate cortex nor the medial septum produced a change reliably different from that seen in unstimulated control animals. Further tests with stimulation of the lateral septum at the 20-micronA level showed that neither rewarding self-stimulation nor disruption of ongoing water drinking was produced. These results are congruent with evidence from lesion studies that the lateral septum normally acts to suppress reactivity and aggressiveness in the rat; they do not support previous suggestions that the medial septum is involved in the modulation of these behaviors.     

Self-referential processing of negative stimuli within the ventral anterior cingulate gyrus and right amygdala

Neural activity associated with self-referential processing of emotional stimuli was investigated using whole brain functional magnetic resonance imaging (fMRI). Fifteen healthy subjects underwent fMRI scanning while making judgments about positive and negative trait words in four conditions (self-reference, other-reference, semantic processing, and letter processing). Significant activity was observed in the right ventral anterior cingulate gyrus and the right amygdala in the negative-word/self-reference condition, and in the left amygdala in the positive-word/self-reference condition. Compared with the semantic-processing condition, the self-reference conditions showed significantly more activity in the medial prefrontal and temporal gyri, posterior cingulate gyrus, and precuneus. These results suggest that the medial prefrontal gyrus, posterior cingulate gyrus, and precuneus are associated with a self-referential processing, and the ventral anterior cingulate gyrus is involved in self-referential processing of negative emotional stimuli. The results also suggest that the amygdala is associated with self-referential processing of both positive and negative emotional stimuli.     

Neural substrates for processing task-irrelevant sad images in adolescents

Neural systems related to cognitive and emotional processing were examined in adolescents using event-related functional magnetic resonance imaging (fMRI). Ten healthy adolescents performed an emotional oddball task. Subjects detected infrequent circles (targets) within a continual stream of phase-scrambled images (standards). Sad and neutral images were intermittently presented as task-irrelevant distracters (novels). As previously shown for adults, when the adolescents responded to the task-relevant targets, activation increased in the dorsal attention-executive system including the anterior middle frontal gyrus (aMFG), dorsal anterior cingulate (ACG), posterior cingulate (PCG), insula, and supramarginal gyrus (SMG). Unlike adults, however, the adolescents exhibited strong activation to the emotional distracter images not only in the ventromedial prefrontal cortex (VmPFC), but also in the posterior middle frontal gyrus (pMFG) and in the parietal cortex. Those subjects who had stronger VmPFC activation to emotional distraction also had reduced activation in the aMFG during target detection, suggesting that emotional information may interfere with executive processing in these adolescents. In contrast, pMFG and PCG activation to emotional distracters was positively correlated with aMFG activation to targets, indicating a different role of these regions from the VmPFC. The pattern of activation to task-irrelevant emotional distraction suggests a possible immaturity of brain function in cognitive control over emotional distraction in adolescents.     

Component mechanisms underlying the processing of hierarchically organized patterns: inferences from patients with unilateral cortical lesions

Subjects identified target letters that occurred randomly at the local or global level in a divided attention task. The visual angle of the stimuli was varied. Neurologically intact controls showed a reaction time advantage for local targets which increased as visual angle increased. Patients with lesions centered in the posterior superior temporal gyrus (STG) showed a larger local advantage than controls if the lesion was on the right and a global advantage if the lesion was on the left. STG patients were no more influenced by visual angle than were controls. Control subjects also showed the usual interference of global distractors on responding to local targets. STG patients showed little evidence of interference. Control patients with lesions centered in the rostral inferior parietal lobe performed normally. The findings suggest that several component mechanisms are involved in the processing of hierarchical levels of structure, each linked to specific anatomical regions.     

Cognitive functioning after medial frontal lobe damage including the anterior cingulate cortex: a preliminary investigation

Two patients with medial frontal lobe damage involving the anterior cingulate cortex (ACC) performed a range of cognitive tasks, including tests of executive function and anterior attention. Both patients lesions extended beyond the ACC, therefore caution needs to be exerted in ascribing observed deficits to the ACC alone. Patient performance was compared with age and education matched healthy controls. Both patients showed intact intellectual, memory, and language abilities. No clear-cut abnormalities were noted in visuoperceptual functions. Speed of information processing was mildly reduced only in Patient 2 (bilateral ACC lesion). The patients demonstrated weak or impaired performance only on selective executive function tests. Performance on anterior attention tasks was satisfactory. We tentatively suggest that our findings are inconsistent with anterior attention theories of ACC function based on neuroimaging findings. We propose that the data may imply that the ACC does not have a central role in cognition. We speculate that our findings may be compatible with the view that the ACC integrates cognitive processing with autonomic functioning to guide behaviour.     

Structure and function in acquired prosopagnosia: Lessons from a series of 10 patients with brain damage

Acquired prosopagnosia varies in both behavioural manifestations and the location and extent of underlying lesions. We studied 10 patients with adult‐onset lesions on a battery of face‐processing tests. Using signal detection methods, we found that discriminative power for the familiarity of famous faces was most reduced by bilateral occipitotemporal lesions that involved the fusiform gyri, and better preserved with unilateral right‐sided lesions. Tests of perception of facial structural configuration showed severe deficits with lesions that included the right fusiform gyrus, whether unilateral or bilateral. This deficit was most consistent for eye configuration, with some patients performing normally for mouth configuration. Patients with anterior temporal lesions had better configuration perception, though at least one patient showed a more subtle failure to integrate configural data from different facial regions. Facial imagery, an index of facial memories, was severely impaired by bilateral lesions that included the right anterior temporal lobe and marginally impaired by fusiform lesions alone; unilateral right fusiform lesions tended to spare imagery for facial features. These findings suggest that (1) prosopagnosia is more severe with bilateral than unilateral lesions, indicating a minor contribution of the left hemisphere to face recognition, (2) perception of facial configuration critically involves the right fusiform gyrus and (3) access to facial memories is most disrupted by bilateral lesions that also include the right anterior temporal lobe. This supports assertions that more apperceptive variants of prosopagnosia are linked to fusiform damage, whereas more associative variants are linked to anterior temporal damage. Next, we found that behavioural indices of covert recognition correlated with measures of overt familiarity, consistent with theories that covert behaviour emerges from the output of damaged neural networks, rather than alternative pathways. Finally, to probe the face specificity of the prosopagnosic defect, we tested recognition of fruits and vegetables: While face specificity was not found in most of our patients, the data of one patient suggested that this may be possible with more focal lesions of the right fusiform gyrus.     

Aging affects both perceptual and lexical/semantic components of word stem priming: An event-related fMRI study

In this event-related fMRI study, brain activity patterns were compared in extensive groups of young (N=25) and older (N=38) adults, while they were performing a word stem completion priming task. Based on behavioral findings, we tested the hypothesis that aging affects only the lexical/semantic, but not the perceptual component of word stem priming. To this end, we distinguished between priming-related activity reductions in posterior regions involved in visual processing, and regions associated with lexical/semantic retrieval processes, i.e., left lateral temporal and left prefrontal regions. Both groups revealed significant priming-related response time reductions. However, in accordance with earlier findings, a larger priming effect was found in the group of young participants. In line with previous imaging studies, the groups showed common priming-related activity reductions in the anterior cingulate, and the left inferior prefrontal cortex extending into the anterior portion of the left superior temporal gyrus, and at lower thresholds also in the right occipital lobe. However, when directly comparing the groups, greater priming-related reductions were found for the young group in the left anterior superior temporal gyrus and the right posterior occipital lobe. These findings suggest that, converse to current psychological views, aging affects both perceptual and lexical/semantic components of repetition priming.     

Midbrain-hypothalamic interrelationships in the control of aggressive behavior

Previous studies have suggested an involvement of the midbrain ventral tegmental area in the biting attack upon a rat elicited by electrical stimulation of the lateral hypothalamus in cats. In order assess further the relationship between these two regions, 12 cats were implanted with attack-eliciting electrodes in both the lateral hypothalamus and the midbrain ventral tegmental area. Following a lesion of the midbrain attack site, attack previously elicited from hypothalamic electrodes ipsilateral to the lesion was eliminated or significantly reduced in frequency. The attack elicited from electrodes in the hypothalamus contralateral to the lesion was unaffected. Midbrain lesions made at sites from which attack was never elicited had no effect on hypothalamically elicited attack. The midbrain lesion in some cases eliminated only certain components of the total attack pattern; for example, the approach of a cat to the rat frequently remained present while the bite was absent. Additionally, it was found that the attack elicited from rostral hypothalamic electrodes was disrupted to a greater degree by a single midbrain lesion than the attack elicited from more caudal hypothalamic electrodes. These finding are discussed in terms of the neural system mediating this form of aggressive behavior in cats.