Brain activity varies with modulation of dynamic pitch variance in sentence melody

Fourteen native speakers of German heard normal sentences, sentences which were either lacking dynamic pitch variation (flattened speech), or comprised of intonation contour exclusively (degraded speech). Participants were to listen carefully to the sentences and to perform a rehearsal task. Passive listening to flattened speech compared to normal speech produced strong brain responses in right cortical areas, particularly in the posterior superior temporal gyrus (pSTG). Passive listening to degraded speech compared to either normal or flattened speech particularly involved fronto-opercular and subcortical (Putamen, Caudate Nucleus) regions bilaterally. Additionally the Rolandic operculum (premotor cortex) in the right hemisphere subserved processing of neat sentence intonation. As a function of explicit rehearsing sentence intonation we found several activation foci in the left inferior frontal gyrus (Broca's area), the left inferior precentral sulcus, and the left Rolandic fissure. The data allow several suggestions: First, both flattened and degraded speech evoked differential brain responses in the pSTG, particularly in the planum temporale (PT) bilaterally indicating that this region mediates integration of slowly and rapidly changing acoustic cues during comprehension of spoken language. Second, the bilateral circuit active whilst participants receive degraded speech reflects general effort allocation. Third, the differential finding for passive perception and explicit rehearsal of intonation contour suggests a right fronto-lateral network for processing and a left fronto-lateral network for producing prosodic information. Finally, it appears that brain areas which subserve speech (frontal operculum) and premotor functions (Rolandic operculum) coincidently support the processing of intonation contour in spoken sentence comprehension.     

Recruitment of lateral rostral prefrontal cortex in spontaneous and task-related thoughts

Behavioural and neuroimaging studies suggest that spontaneous and task-related thought processes share common cognitive mechanisms and neural bases. Lateral rostral prefrontal cortex (RPFC) is a brain region that has been implicated both in spontaneous thought and in high-level cognitive control processes, such as goal/subgoal integration and the manipulation of self-generated thoughts. We therefore propose that the recruitment of lateral RPFC may follow a U-shaped function of cognitive demand: relatively high in low-demand situations conducive to the emergence of spontaneous thought, and in high-demand situations depending on processes supported by this brain region. We used functional magnetic resonance imaging to investigate brain activity while healthy participants performed two tasks, each with three levels of cognitive demands, in a block design. The frequency of task-unrelated thoughts, measured by questionnaire, was highest in the low cognitive demand condition. Low and high cognitive demand conditions were each compared to the intermediate level. Lateral RPFC and superior parietal cortex were recruited in both comparisons, with additional activations specific to each contrast. These results suggest that RPFC is involved both when (a) task demands are low, and the mind wanders, and (b) the task requires goal/subgoal integration and manipulation of self-generated thoughts.     

The role of spatial configuration in tests of working memory explored with functional neuroimaging

While the importance of the prefrontal cortex for "higher-order" cognitive functions is largely undisputed, no consensus has been reached regarding the fractionation of functions within this region. Several recent functional neuroimaging studies have suggested that the mid-ventrolateral frontal cortex may play an important role in various aspects of human memory. Thus, similar patterns of activation have been observed in this region during analogous spatial, verbal and visual span tasks. In the present study, however, activation was observed in a more dorsolateral region of the lateral frontal cortex during a modified version of the spatial span task, which differed only in the spatial configuration of the array employed. The results of a supplementary behavioral study, designed to investigate this effect further, suggest that in spatial memory tasks certain stimulus configurations may encourage subjects to adopt mnemonic strategies, which may depend upon dorsolateral, rather than ventrolateral, regions of the frontal cortex. These findings shed further light on the functional relationship between dorsal and ventral regions of the lateral frontal cortex and, more specifically, how the "executive" processes assumed to be dependent upon these regions might contribute to aspects of human memory.     

Prior cocaine exposure disrupts extinction of fear conditioning

Psychostimulant exposure has been shown to cause molecular and cellular changes in prefrontal cortex. It has been hypothesized that these drug-induced changes might affect the operation of prefrontal-limbic circuits, disrupting their normal role in controlling behavior and thereby leading to compulsive drug-seeking. To test this hypothesis, we tested cocaine-treated rats in a fear conditioning, inflation, and extinction task, known to depend on medial prefrontal cortex and amygdala. Cocaine-treated rats conditioned and inflated similar to saline controls but displayed slower extinction learning. These results support the hypothesis that control processes in the medial prefrontal cortex are impaired by cocaine exposure.     

Dissociable interference-control processes in perception and memory

Control over interference is a pervasive feature of cognitive life. Central to research on interference control has been the identification of its underlying mechanisms. Investigations have focused on processes that filter out distracting perceptual information, leading to negative priming, and processes that discard intruding memories that cause proactive interference. Theories differ regarding whether or not a single process during episodic retrieval underlies both negative priming and the resolution of proactive interference. Using functional magnetic resonance imaging, we combined both phenomena into a single paradigm and found that occipital cortex shows activation uniquely related to negative priming, whereas activation increases in left lateral prefrontal cortex are uniquely associated with proactive interference. This pattern of results contradicts theories that rely on a single process to account for both phenomena. However, results also showed common recruitment of right dorsolateral prefrontal cortex and parietal regions and therefore suggest that some control processes are shared.     

Attentional control in the aging brain: insights from an fMRI study of the stroop task

Several recent studies of aging and cognition have attributed decreases in the efficiency of working memory processes to possible declines in attentional control, the mechanism(s) by which the brain attempts to limit its processing to that of task-relevant information. Here we used fMRI measures of neural activity during performance of the color-word Stroop task to compare the neural substrates of attentional control in younger (ages: 21-27 years old) and older participants (ages: 60-75 years old) during conditions of both increased competition (incongruent and congruent neutral) and increased conflict (incongruent and congruent neutral). We found evidence of age-related decreases in the responsiveness of structures thought to support attentional control (e.g., dorsolateral prefrontal and parietal cortices), suggesting possible impairments in the implementation of attentional control in older participants. Consistent with this notion, older participants exhibited more extensive activation of ventral visual processing regions (i.e., temporal cortex) and anterior inferior prefrontal cortices, reflecting a decreased ability to inhibit the processing of task-irrelevant information. Also, the anterior cingulate cortex, a region involved in evaluatory processes at the level of response (e.g., detecting potential for error), showed age-related increases in its sensitivity to the presence of competing color information. These findings are discussed in terms of newly emerging models of attentional control in the human brain.     

高低创造性思维水平者的认知抑制能力：行为和生理的证据

本研究采用2个实验, 考察创造性思维测验得分高低者在Stroop任务干扰条件上的差异, 从行为和生理指标探讨认知抑制与创造性思维的关系, 以及时间压力对认知抑制与创造性思维关系的调节作用。实验1采用Stroop颜色命名任务。结果发现, 相比低创者, 高创者的反应时干扰效应量和正确率干扰效应量均更小。实验2采用更灵活的Stroop字义-颜色命名转换任务, 操纵不同的时间压力条件, 并记录被试完成任务时的皮肤电活动。结果发现, 高创者在有时间压力条件下的干扰效应量显著小于无时间压力条件下, 而低创者在有和无时间压力条件下的干扰效应量无显著差异; 高创者在颜色命名任务的不一致条件下的皮肤电活动变化显著高于一致条件, 而低创者在颜色命名任务的一致和不一致条件下无显著差异。研究表明：总体而言, 相比低创者, 高创者的认知抑制能力更高, 能够有效抑制优势的但不相关的反应倾向。时间压力在认知抑制与创造性思维的关系中起调节作用, 高创者面对不同任务要求能够灵活调整自身的认知抑制水平, 并表现出变化的生理唤醒水平。结果支持创造性思维的适应性认知抑制假说。     

Human topological task adapted for rats: Spatial information processes of the parietal cortex

Human research has shown that lesions of the parietal cortex disrupt spatial information processing, specifically topological information. Similar findings have been found in non-humans. It has been difficult to determine homologies between human and non-human mnemonic mechanisms for spatial information processing because methodologies and neuropathology differ. The first objective of the present study was to adapt a previously established human task for rats. The second objective was to better characterize the role of parietal cortex (PC) and dorsal hippocampus (dHPC) for topological spatial information processing. Rats had to distinguish whether a ball inside a ring or a ball outside a ring was the correct, rewarded object. After rats reached criterion on the task (>95%) they were randomly assigned to a lesion group (control, PC, and dHPC). Animals were then re-tested. Post-surgery data show that controls were 94% correct on average, dHPC rats were 89% correct on average, and PC rats were 56% correct on average. The results from the present study suggest that the parietal cortex, but not the dHPC processes topological spatial information. The present data are the first to support comparable topological spatial information processes of the parietal cortex in humans and rats.     

Updating of locations during whole-body rotations in patients with hemispatial neglect

Posterior parietal cortex lesions have been associated with both hemispatial neglect and spatialupdating deficits. Currently, the relation between these processes remains poorly understood. We tested the ability of parietal patients with neglect to update remembered target locations during passive whole-body rotations. The rotations and manual pointing responses were executed with and without vision. During the rotation, the remembered location stayed on the same side of the body midline or crossed the midline. Parietal patients generally underestimated rotations, as compared with control groups, but updated targets equally well on either side of the body midline, regardless of the amount of updating required. Once parietal patients have localized a target, they can use self-motion information to update its location, even if it passes into the region they typically neglect. This lack of contralesional updating effects contrasts with impairments in eye position updating found in previous work with parietal patients.     

Language representation in the human brain: evidence from cortical mapping

The manner in which the human brain processes grammatical-syntactic and lexical-semantic functions has been extensively debated in neurolinguistics. The discreteness and selectivity of the representation of syntactic-morphological properties in the dominant frontal cortex and the representation of the lexical-semantics in the temporo-parietal cortex have been questioned. Three right-handed adult male neurosurgical patients undergoing left craniotomy for intractable seizures were evaluated using various grammatical and semantic tasks during cortical mapping. The sampling of language tasks consisted of trials with stimulation (experimental) and without stimulation (control) from sites in the dominant fronto-temporo-parietal cortex The sampling of language implicated a larger cortical area devoted to language (syntactic-morphological and lexical-semantic) tasks. Further, a large part of the fronto-parieto-temporal cortex was involved with syntactic-morphological functions. However, only the parieto-temporal sites were implicated with the ordering of lexicon in sentence construction. These observations suggest that the representation of language in the human brain may be columnar or multilayered.     

Progress in Executive-Function Research: From Tasks to Functions to Regions to Networks

ABSTRACT— It has long been observed that damage to the frontal cortex affects a person's ability to control thought, behavior, and emotion while sometimes leaving fundamental processes such as vision, hearing, and long-term memory intact. Such observations have led theoreticians to suppose that a set of executive control functions exists, at the top of the hierarchy of mental processes. To study these executive functions and their relation to the frontal cortex and its subregions, researchers have long employed several now-classic cognitive tests in patients with brain damage. Yet until recently it has proved difficult to reliably localize the putative executive functions to discrete regions. This article illustrates how recent progress in executive-functions research has been driven by the coupling of sophisticated neuroscience techniques with advances in experimental psychology. Taking examples from recent studies, it shows how experimental tasks may be decomposed into cognitive components that can be localized to discrete—but structurally connected—brain regions. What emerges is a new ontology for executive function in terms of which cognitive components exist and of how, and when, they are recruited during task performance.     

A central circuit of the mind

The methodologies of cognitive architectures and functional magnetic resonance imaging can mutually inform each other. For example, four modules of the ACT-R (adaptive control of thought - rational) cognitive architecture have been associated with four brain regions that are active in complex tasks. Activity in a lateral inferior prefrontal region reflects retrieval of information in a declarative module; activity in a posterior parietal region reflects changes to problem representations in an imaginal module; activity in the anterior cingulate cortex reflects the updates of control information in a goal module; and activity in the caudate nucleus reflects execution of productions in a procedural module. Differential patterns of activation in such central regions can reveal the time course of different components of complex cognition.     

Neurobiologische Grundlagen psychotherapeutischer Verfahren

In the last few years the investigation of the neurobiological basis of psychotherapeutic treatments has gained importance. Therapy-associated functional changes have been studied in a number of different psychiatric diseases. It has been shown that diseases with a central role of emotions (e.g. depression, anxiety disorders, borderline personality disorder) often demonstrate dysfunctions in brain areas that are linked to emotional regulation. Psychotherapeutic interventions can lead to a kind of normalization of brain responses in these areas (e.g. amygdala, ventromedial prefrontal cortex, anterior cingulate cortex, orbitofrontal cortex). In addition, therapy-associated transformations were also demonstrated in areas which are related to attention processes and visual perception. Other studies have aimed at finding neurobiological parameters that can be used to predict a therapeutic outcome or to choose between various therapeutic strategies. For instance, in depression, the amygdala and the anterior cingulate cortex are assumed to play a major role. Altogether, knowledge on the neurobiological basis of psychotherapeutic procedures is limited. A comparatively small number of studies and several methodological problems (e.g. small sample sizes, insufficient control groups, variability of methods used) make it difficult to propose reliable statements.     

Continuous Theta Burst Transcranial Magnetic Stimulation of the Right Dorsolateral Prefrontal Cortex Impairs Inhibitory Control and Increases Alcohol Consumption

Previous research indicates that alcohol intoxication impairs inhibitory control and that the right dorsolateral prefrontal cortex (rDLPFC) is a functional brain region important for exercising control over thoughts and behaviour. At the same time, the extent to which changes in inhibitory control following initial intoxication mediate subsequent drinking behaviours has not been elucidated fully. Ascertaining the extent to which inhibitory control impairments drive alcohol consumption, we applied continuous theta burst transcranial magnetic stimulation (rDLPFC cTBS vs. control) to isolate how inhibitory control impairments (measured using the Stop-Signal task) shape ad libitum alcohol consumption in a pseudo taste test. Twenty participants (13 males) took part in a within-participants design; their age ranged between 18 and 27 years (M = 20.95, SD = 2.74). Results indicate that following rDLPFC cTBS participants’ inhibitory control was impaired, and ad libitum consumption increased. The relationship between stimulation and consumption did not appear to be mediated by inhibitory control in the present study. Overall, findings suggest that applying TMS to the rDLPFC may inhibit neural activity and increase alcohol consumption. Future research with greater power is recommended to determine the extent to which inhibitory control is the primary mechanism by which the rDLPFC exerts influence over alcohol consumption, and the degree to which other cognitive processes may play a role.     

Separating sustained from transient aspects of cognitive control during thought suppression

Cognitive theories of how people regulate their thoughts have suggested the involvement of two control processes that occur over different time courses. These cognitive accounts parallel recent neural models of executive control, which suggest that the prefrontal cortex (PFC) mediates sustained changes in the allocation of control processes, whereas the anterior cingulate cortex (ACC) relays a transient need for additional control. Combining these cognitive and neural models of control, we used recently developed analysis techniques to distinguish transient from sustained changes in brain activation while subjects attempted to suppress an unwanted thought. Results were consistent with both models: Dorsolateral PFC demonstrated sustained increases in activation during attempts at thought suppression, whereas bilateral ACC demonstrated transient increases associated with occurrences of unwanted thoughts. These data support proposals regarding the different contributions made by the PFC and ACC to executive control and provide initial neuroimaging support for dual-process models of how individuals regulate their thoughts.     

Brain areas involved in synaesthesia: a review

Despite a recent upsurge of research, much remains unknown about the neurobiological mechanisms underlying synaesthesia. By integrating results obtained so far in Magnetic Resonance Imaging (MRI) studies, this contribution sheds light on the role of particular brain regions in synaesthetic experiences. First, in accordance with its sensory nature, it seems that the sensory brain areas corresponding to the type of synaesthetic experience are activated. Synaesthetic colour experiences can activate colour regions in occipito-temporal cortex, but this is not necessarily restricted to V4. Furthermore, sensory and motor brain regions have been obtained that extend beyond the particular type of synaesthesia studied. Second, differences in experimental setup, number and type of synaesthetes tested, and method to delineate regions of interest may help explain inconsistent results obtained in the BOLD-MRI (Blood Oxygen Level Dependent functional MRI) studies. Third, an overview of obtained results shows that a network of brain areas rather than a single brain region underlies synaesthesia. Six brain regions of overlapping results emerge, these regions are in sensory and motor regions as well as 'higher level' regions in parietal and frontal lobe. We propose that these regions are related to three different cognitive processes inherently part of synaesthesia; the sensory processes, the (attentional) 'binding' processes, and cognitive control processes. Finally, we discuss how these functional and structural brain properties might relate to the development of synaesthesia. In particular, we believe this relationship is better understood by separating the question what underlies the presence of synaesthesia ('trait') from what determines particular synaesthetic associations ('type').     

Étude de l’efficience des mécanismes inhibiteurs chez des patients arabophones avec lésions frontales

Our work purpose was to study the impact of focal frontal lesions on the inhibitors processes. We used two arabophone versions of Hayling task and the Stroop task with condition of flexibility. In comparison with 13 control subjects matched by age, gender and level of education, frontal patients were (1) significantly slower in both task without been disproportionately slower in the condition needed inhibition, (2) committed significantly more errors than control subjects in the second part of Hayling task showed inhibition deficit, (3) laterality of frontal lesions had no incidence on performance, (4) individual analysis showed multiples dissociated deficits but also showed correlations between scores of rapidity, flexibility and inhibition. In conclusion, among all of performances, scores of errors in the Stroop and the Hayling tasks seemed to be the more sensitive to the frontal damage. Patients with the lowest performance in both inhibition tasks were those who presented lesions involving both the medial and lateral frontal cortex, the anterior cingulated cortex and/or orbitofrontal cortex.     

Prefrontal brain activity predicts temporally extended decision-making behavior

Although functional neuroimaging studies of human decision-making processes are increasingly common, most of the research in this area has relied on passive tasks that generate little individual variability. Relatively little attention has been paid to the ability of brain activity to predict overt behavior. Using functional magnetic resonance imaging (fMRI), we investigated the neural mechanisms underlying behavior during a dynamic decision task that required subjects to select smaller, short-term monetary payoffs in order to receive larger, long-term gains. The number of trials over which the longterm gains accrued was manipulated experimentally (2 versus 12). Event-related neural activity in right lateral prefrontal cortex, a region associated with high-level cognitive processing, selectively predicted choice behavior in both conditions, whereas insular cortex responded to fluctuations in amount of reward but did not predict choice behavior. These results demonstrate the utility of a functional neuroimaging approach in behavioral psychology, showing that (a) highly circumscribed brain regions are capable of predicting complex choice behavior, and (b) fMRI has the ability to dissociate the contributions of different neural mechanisms to particular behavioral tasks.     

Neurocognitive mechanisms of cognitive control: the role of prefrontal cortex in action selection, response inhibition, performance monitoring, and reward-based learning

Convergent evidence highlights the differential contributions of various regions of the prefrontal cortex in the service of cognitive control, but little is understood about how the brain determines and communicates the need to recruit cognitive control, and how such signals instigate the implementation of appropriate performance adjustments. Here we review recent progress from cognitive neuroscience in examining some of the main constituent processes of cognitive control as involved in dynamic decision making: goal-directed action selection, response activation and inhibition, performance monitoring, and reward-based learning. Medial frontal cortex is found to be involved in performance monitoring: evaluating outcome vis-a-vis expectancy, and detecting performance errors or conflicting response tendencies. Lateral and orbitofrontal divisions of prefrontal cortex are involved in subsequently implementing appropriate adjustments.     

Individual differences in delay discounting: relation to intelligence, working memory, and anterior prefrontal cortex

Lower delay discounting (better self-control) is linked to higher intelligence, but the basis of this relation is uncertain. To investigate the potential role of working memory (WM) processes, we assessed delay discounting, intelligence (g), WM (span tasks, 3-back task), and WM-related neural activity (using functional magnetic resonance imaging) in 103 healthy adults. Delay discounting was negatively correlated with g and WM. WM explained no variance in delay discounting beyond that explained by g, which suggests that processes through which WM relates to delay discounting are shared by g. WM-related neural activity in left anterior prefrontal cortex (Brodmann's area 10) covaried with g, r= .26, and delay discounting, r=-.40, and partially mediated the relation between g and delay discounting. Overall, the results suggest that delay discounting is associated with intelligence in part because of processes instantiated in anterior prefrontal cortex, a region known to support the integration of diverse information.