Age-related differences in the brain areas outside the classical language areas among adults using category decision task

Older adults perform much like younger adults on language. This similar level of performance, however, may come about through different underlying brain processes. In the present study, we evaluated age-related differences in the brain areas outside the typical language areas among adults using a category decision task. Our results showed that similar activation patterns were found in classical language processing areas across the three age groups although regional lateralization indices in Broca’s and Wernicke’s areas decreased with age. The greatest differences, however, among the three groups were found primarily in the brain areas not associated with core language functioning including the hippocampus, middle frontal gyrus, ventromedial frontal cortex, medial superior parietal cortex and posterior cingulate cortex. Therefore, the non-classical language areas may exhibit an age-related difference between three age groups while the subjects show a similar activation pattern in the core, primary language processing during a semantic decision task.     

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.     

Perception of suffering and compassion experience: brain gender disparities

Compassion is considered a moral emotion related to the perception of suffering in others, and resulting in a motivation to alleviate the afflicted party. We compared brain correlates of compassion-evoking images in women and men. BOLD functional images of 24 healthy volunteers (twelve women and twelve men; age=27±2.5 y.o.) were acquired in a 3T magnetic resonance scanner while subjects viewed pictures of human suffering previously verified to elicit compassion and indicated their compassionate experience by finger movements. Functional analysis revealed that while women manifested activation in areas involved in basic emotional, empathic, and moral processes, such as basal regions and cingulate and frontal cortices, activation in men was restricted mainly to the occipital cortex and parahippocampal gyrus. These findings suggest that compassion and its moral elements constitute gender-relative subjective phenomena emerging from differently evolved neural mechanisms and socially learned features possibly related to nurturing skills.     

Sex differences in functional brain activation during a lexical visual field task

Functional MRI was used to investigate sex differences in brain activation during a paradigm similar to a lexical-decision task. Six males and 6 females performed two runs of the lexical visual field task (i.e., deciding which visual field a word compared with a pseudoword was presented to). A sex difference was noted behaviorally: The reaction time data showed males had a marginal right visual field advantage and women a left visual field advantage. Imaging results showed that men had a strongly left-lateralized pattern of activation, e.g., inferior frontal and fusiform gyrus, while women showed a more symmetrical pattern in language related areas with greater right-frontal and right-middle-temporal activation. The data show evidence of task-specific sex differences in the cerebral organization of language processing.     

Brain activation while forming memories of fearful and neutral faces in women and men

Event-related functional MRI (fMRI) was used to assess brain activity during encoding of fearful and neutral faces in 12 women and 12 men. In a subsequent memory analysis, the authors separated successful from unsuccessful encoding of both types of faces, based on whether they were remembered or forgotten in a later recognition memory test. Overall, women and men recruited overlapping neural circuitries. Both sexes activated right-sided medial-temporal regions during successful encoding of fearful faces. Successful encoding of neutral faces was associated with left-sided lateral prefrontal and right-sided superior frontal activation in both sexes. In women, relatively greater encoding related activity for neutral faces was seen in the superior parietal and parahippocampal cortices. By contrast, men activated the left and right superior/middle frontal cortex more than women during successful encoding of the same neutral faces. These findings suggest that women and men use similar neural networks to encode facial information, with only subtle sex differences observed for neutral faces.     

An fMRI study of sex differences in regional activation to a verbal and a spatial task

Sex differences in cognitive performance have been documented, women performing better on some phonological tasks and men on spatial tasks. An earlier fMRI study suggested sex differences in distributed brain activation during phonological processing, with bilateral activation seen in women while men showed primarily left-lateralized activation. This blood oxygen level-dependent fMRI study examined sex differences (14 men, 13 women) in activation for a spatial task (judgment of line orientation) compared to a verbal-reasoning task (analogies) that does not typically show sex differences. Task difficulty was manipulated. Hypothesized ROI-based analysis documented the expected left-lateralized changes for the verbal task in the inferior parietal and planum temporal regions in both men and women, but only men showed right-lateralized increase for the spatial task in these regions. Image-based analysis revealed a distributed network of cortical regions activated by the tasks, which consisted of the lateral frontal, medial frontal, mid-temporal, occipitoparietal, and occipital regions. The activation was more left lateralized for the verbal and more right for the spatial tasks, but men also showed some left activation for the spatial task, which was not seen in women. Increased task difficulty produced more distributed activation for the verbal and more circumscribed activation for the spatial task. The results suggest that failure to activate the appropriate hemisphere in regions directly involved in task performance may explain certain sex differences in performance. They also extend, for a spatial task, the principle that bilateral activation in a distributed cognitive system underlies sex differences in performance.     

Distinct brain systems underlie the processing of valence and arousal of affective pictures

Valence and arousal are thought to be the primary dimensions of human emotion. However, the degree to which valence and arousal interact in determining brain responses to emotional pictures is still elusive. This functional MRI study aimed to delineate neural systems responding to valence and arousal, and their interaction. We measured neural activation in healthy females (N = 23) to affective pictures using a 2 (Valence) × 2 (Arousal) design. Results show that arousal was preferentially processed by middle temporal gyrus, hippocampus and ventrolateral prefrontal cortex. Regions responding to negative valence included visual and lateral prefrontal regions, positive valence activated middle temporal and orbitofrontal areas. Importantly, distinct arousal-by-valence interactions were present in anterior insula (negative pictures), and in occipital cortex, parahippocampal gyrus and posterior cingulate (positive pictures). These data demonstrate that the brain not only differentiates between valence and arousal but also responds to specific combinations of these two, thereby highlighting the sophisticated nature of emotion processing in (female) human subjects.     

Brain correlates of aesthetic expertise: a parametric fMRI study

Several studies have demonstrated that acquired expertise influences aesthetic judgments. In this paradigm we used functional magnetic resonance imaging (fMRI) to study aesthetic judgments of visually presented architectural stimuli and control-stimuli (faces) for a group of architects and a group of non-architects. This design allowed us to test whether level of expertise modulates neural activity in brain areas associated with either perceptual processing, memory, or reward processing. We show that experts and non-experts recruit bilateral medial orbitofrontal cortex (OFC) and subcallosal cingulate gyrus differentially during aesthetic judgment, even in the absence of behavioural aesthetic rating differences between experts and non-experts. By contrast, activity in nucleus accumbens (NAcc) exhibits a differential response profile compared to OFC and subcallosal cingulate gyrus, suggesting a dissociable role between these regions in the reward processing of expertise. Finally, categorical responses (irrespective of aesthetic ratings) resulted in expertise effects in memory-related areas such as hippocampus and precuneus. These results highlight the fact that expertise not only modulates cognitive processing, but also modulates the response in reward related brain areas.     

Lateralized Changes in Regional Cerebral Blood Flow during Performance of Verbal and Facial Recognition Tasks: Correlations with Performance and “Effort”

Functional neuroimaging has been used to investigate neural substrates of mnemonic processes, and cerebral blood flow (CBF) measures have been sensitive to activation with memory tasks. Studies of memory with two-dimensional¹³³Xenon clearance techniques found that word and face recognition tasks produced contralateral CBF changes in mid-temporal cortical regions. This study replicated the activation paradigm, expanding to the three-dimensional resolution of positron emission tomography (PET). Word and face recognition, and a control baseline task were administered to 19 healthy right-handed volunteers (11 men, 8 women) during successive 10 min PET¹⁵O-water measures of CBF. Quantitative CBF rates were calculated with the arterial input function and the equilibrium model. Redistributions of blood flow were compared across tasks using both absolute and relative (region/whole brain) CBF.Replicating the¹³³Xenon clearance findings, CBF was “appropriately” lateralized during task performance (left–right for words > left–right for faces) in the mid-temporal region. Contrary to predictions, the recognition tasks did not activate expected mesolimbic or prefrontal areas. The task-induced CBF changes also correlated with performance. Bilateral CBF in mid-temporal and parahippocampal gyrus regions of interest correlated with the ability to correctly identify word targets (sensitivity). Left-lateralized CBF in the amygdala and hippocampus correlated with better word sensitivity as well as specificity (ability to correctly reject foils). Complementally, right-lateralized CBF in the parahippocampal gyrus correlated with better face specificity performance. In addition, left-lateralized CBF in the amygdala and right-lateralized CBF in the parahippocampal gyrus and hippocampus correlated with “mental effort” indices (task performance relative to basal ability) for word and face memory tasks, respectively. Thus, whereas this recognition task showed the expected lateralized increase in the mid-temporal region and not in frontal and limbic areas, lateralized activation in some of these areas was associated with better performance. Exploratory analyses on other regions showed lateralized changes in one additional temporal region, the occipital-temporal, and several limbic regions.     

Distinct brain systems underlie the processing of valence and arousal of affective pictures

Valence and arousal are thought to be the primary dimensions of human emotion. However, the degree to which valence and arousal interact in determining brain responses to emotional pictures is still elusive. This functional MRI study aimed to delineate neural systems responding to valence and arousal, and their interaction. We measured neural activation in healthy females (N = 23) to affective pictures using a 2 (Valence) × 2 (Arousal) design. Results show that arousal was preferentially processed by middle temporal gyrus, hippocampus and ventrolateral prefrontal cortex. Regions responding to negative valence included visual and lateral prefrontal regions, positive valence activated middle temporal and orbitofrontal areas. Importantly, distinct arousal-by-valence interactions were present in anterior insula (negative pictures), and in occipital cortex, parahippocampal gyrus and posterior cingulate (positive pictures). These data demonstrate that the brain not only differentiates between valence and arousal but also responds to specific combinations of these two, thereby highlighting the sophisticated nature of emotion processing in (female) human subjects.     

认知重评和表达抑制情绪调节策略的脑网络分析：来自EEG和ERP的证据

本文旨在对认知重评和表达抑制两种常用情绪调节策略的自发脑网络特征及认知神经活动进行深入探讨。研究采集36名在校大学生的静息态和任务态脑电数据, 经过源定位和图论分析发现节点效率与两种情绪调节显著相关的脑区, 以及脑区之间的功能连接。研究结果表明, 在使用认知重评进行情绪调节时会激活前额叶皮质、前扣带回、顶叶、海马旁回和枕叶等多个脑区, 在使用表达抑制进行情绪调节时会激活前额叶皮质、顶叶、海马旁回、枕叶、颞叶和脑岛等多个脑区。因此, 这些脑区的节点效率或功能连接强度可能成为评估个体使用认知重评和表达抑制调节情绪效果的指标。     

Sex differences in semantic language processing: a functional MRI study

Predictions based on two models of sex differences in cerebral organization of language were compared by examining fMRI patterns of 10 females and 9 males during a semantic processing task. Both groups displayed activation of left inferior frontal gyrus (IFG), left superior temporal gyrus (STG), and cingulate. Females, but not males, showed bilateral IFG and STG activation. Further analyses revealed females had less diffuse left activation and greater right posterior temporal and insula region activation than males. Results support both an interhemispheric and an intrahemispheric model of sex differences in language, suggesting that the models may not be mutually exclusive.     

Direct comparison of episodic encoding and retrieval of words: an event-related fMRI study

Functional magnetic resonance imaging (fMRI) was used to compare directly episodic encoding and retrieval. During encoding, subjects studied visually presented words and reported via keypress whether each word represented a pleasant or unpleasant concept (intentional, deep encoding). During the retrieval phase, subjects indicated (via keypress) whether visually presented words had previously been studied. No reliable differences were found during the recognition phase for words that had been previously studied and those that had not been studied. Areas preferentially active during encoding (relative to retrieval) included left superior frontal cortex, medial frontal cortex, left superior temporal cortex, posterior cingulate, left parahippocampal gyrus, and left inferior frontal gyrus. Regions more active in retrieval than encoding included bilateral inferior parietal cortex, bilateral precuneus, right frontal polar cortex, right dorsolateral prefrontal cortex, and right inferior frontal/insular cortex.     

Direct Comparison of Episodic Encoding and Retrieval of Words: An Event-related fMRI Study

Functional magnetic resonance imaging (fMRI) was used to compare directly episodic encoding and retrieval. During encoding, subjects studied visually presented words and reported via keypress whether each word represented a pleasant or unpleasant concept (intentional, deep encoding). During the retrieval phase, subjects indicated (via keypress) whether visually presented words had previously been studied. No reliable differences were found during the recognition phase for words that had been previously studied and those that had not been studied. Areas preferentially active during encoding (relative to retrieval) included left superior frontal cortex, medial frontal cortex, left superior temporal cortex, posterior cingulate, left parahippocampal gyrus, and left inferior frontal gyrus. Regions more active in retrieval than encoding included bilateral inferior parietal cortex, bilateral precuneus, right frontal polar cortex, right dorsolateral prefrontal cortex, and right inferior frontal/insular cortex.     

Brain activation during episodic memory retrieval: sex differences

Behavioral studies have shown a tendency for women to outperform men on episodic memory tasks. Here, data from a series of positron emission tomography (PET) studies were analyzed to examine sex differences in brain activity associated with episodic memory retrieval (yes/no recognition). A total of 17 women and 17 men were included in the analyses. The strongest effect of the design was a retrieval-related increase in activity, involving right prefrontal and anterior cingulate regions, that was common to women and men. In addition, a significant task-by-sex interaction effect was observed which involved a distributed set of brain regions, including several frontal areas. These results suggest that while the neural correlate of episodic memory retrieval is largely the same for men and women, some differences do exist. Possible explanations for the observed differences are discussed, and it is concluded that biological and experiential factors jointly contribute to sex differences in brain activity.     

Spatial and temporal episodic memory retrieval recruit dissociable functional networks in the human brain

Imaging, electrophysiological studies, and lesion work have shown that the medial temporal lobe (MTL) is important for episodic memory; however, it is unclear whether different MTL regions support the spatial, temporal, and item elements of episodic memory. In this study we used fMRI to examine retrieval performance emphasizing different aspects of episodic memory in the context of a spatial navigation paradigm. Subjects played a taxi-driver game ("yellowcab"), in which they freely searched for passengers and delivered them to specific landmark stores. Subjects then underwent fMRI scanning as they retrieved landmarks, spatial, and temporal associations from their navigational experience in three separate runs. Consistent with previous findings on item memory, perirhinal cortex activated most strongly during landmark retrieval compared with spatial or temporal source information retrieval. Both hippocampus and parahippocampal cortex activated significantly during retrieval of landmarks, spatial associations, and temporal order. We found, however, a significant dissociation between hippocampal and parahippocampal cortex activations, with spatial retrieval leading to greater parahippocampal activation compared with hippocampus and temporal order retrieval leading to greater hippocampal activation compared with parahippocampal cortex. Our results, coupled with previous findings, demonstrate that the hippocampus and parahippocampal cortex are preferentially recruited during temporal order and spatial association retrieval--key components of episodic "source" memory.     

“啊哈！”和“哈哈！”：顿悟与幽默的脑认知成分比较

作为人类智能的高级表现形式, 顿悟和幽默存在诸多共同之处。从认知和情感组成上看, 顿悟的非连续性、突发性、重构和惊讶, 对应于幽默的失谐、失谐探测、失谐消解和愉悦, 两者存在表征机制的重叠。神经机制的研究发现, 顿悟和幽默的心理事件都伴随着400 ms左右的额中央区负波(N400)以及前扣带回、顶颞叶联合区和前额叶等脑区的活动; 同时顿悟和幽默在P300成分以及海马、右侧前部颞上回等脑区活动上存在差异。未来可借鉴幽默的认知和情感成份的脑成像研究范式, 进一步探明顿悟过程的认知和情感组成。     

Age-Related Changes in Neural Activation During Working Memory Performance

Changes in frontal lobe functions are a typical part of aging of the brain. There are age-related declines in working memory performance, a skill requiring frontal lobe activation. This study examined neural activation, using [15 O] water positron emission tomography (PET) methodology, during performance on two verbal working memory tasks in younger and older participants. The results demonstrated the typical areas of activation associated with working memory performance (e.g., dorsolateral prefrontal cortex and inferior parietal cortex) in both groups. However, the younger participants utilized the right dorsolateral prefrontal cortex and anterior cingulate gyrus significantly more than the older participants. In turn, the older participants used the left dorsolateral prefrontal cortex significantly more than the younger participants and maintained material-specific lateralization in their pattern of activation. These findings are consistent with a previous report of different age-related patterns of frontal activation during working memory.     

用药动作线索诱发海洛因戒断者的镜像神经活动:一项fMRI研究

相关线索能够诱发药物依赖者的心理渴求,而健康人不会对相关线索产生心理渴求。15名海洛因成瘾者和12名没有任何物质滥用的健康被试参与实验,收集了他们在观看相关线索与对照线索时的脑神经活动。结果发现,药物线索能够诱发戒断者更多脑区的活动,包括扣带回和楔前叶。两组被试在对照动作线索刺激诱发作用下,其颞叶、顶叶均出现了较为一致的活动。在用药动作线索诱发作用下,戒断组双侧颞中回、双侧顶下小叶、左侧顶上小叶和右侧额下回显示出显著活动,并且与对照动作线索激活脑区一致;健康组被试除枕叶-颞叶联合区外,没有出现显著的脑区活动。以上结果表明,用药动作线索诱发了海洛因戒断者颞中回、顶下小叶、额下回等镜像神经系统的活动,这些脑区对不同类型的相关线索十分敏感,它们可能通过对用药动作的心理模拟,参与了用药动作线索的快速自动化加工。     

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。