Functional magnetic resonance imaging of human cognitive processes

Functional magnetic resonance imaging (fMRI) is now widely accepted as a tool for analyzing human brain function. Since the realization of fMRI in the early 1990s, numerous reports have been published. In this paper, we present three studies. The first examined syntactic processing of Japanese sentences and the results prove that Broca's area is involved in the use of grammar. The second study compared binocular with monocular stereopsis. There were significant activations in the right inferior parietal lobe. The third study concerned the encoding and retrieval processes underlying face recognition. It revealed activations mainly in the right prefrontal areas, which is contrary to the hemispheric encoding and retrieval asymmetry (HERA) theory. fMRI will continue to play an important role in the analysis of human brain function.     

Frontal Lobe Function and Pain in the Elderly

We review the literature on pain and aging and conclude that evidence supports a hypothesis that right frontal cortex contributes to the mediation of the chronic pain experience in elderly persons with chronic pain syndromes. Evidence for the right frontal pain hypothesis comes from clinical, neurocognitive, and neuroimaging studies, which implicate right inferior and orbitofrontal cortex in (1) the persistent pain experience, (2) negative emotional states, (3) retrieval of negative emotional and autobiographical memories, (4) regulation of autonomic arousal, and (5) regulation of attentional and pain functions of the anterior cingulate region. Right frontal dysfunction is also implicated in the effects of cognitive aging. If right frontal neurocognitive systems are affected in cognitively impaired elderly, and if (by hypothesis) the right frontal cortex also plays a major role in the experience of chronic pain, then cognitively impaired elderly with right frontal dysfunction should be protected to some extent from persistent pain syndromes. Available evidence supports this proposition.     

Is a sigh “just a sigh”? Sighs as emotional signals and responses to a difficult task

Sighing and the interpretation of sighs in everyday life seem never to have been the subject of psychological research. A questionnaire study of sighing showed that people associate sighing mainly with negative, low-intensity and deactivated emotional states. A second study investigated self/other differences in the interpretation of sighs in four hypothetical situations, revealing that sighs in other people are primarily perceived as signs of sadness, whereas own sighs are more often believed to express a state of "giving up" something or somebody. In a third experimental study participants worked on difficult (insoluble) puzzles, which generated many futile solution attempts, often accompanied by sighs. It is concluded that sighs are often unintentional expressions of an activity, plan or desire that has to be discarded, creating a pause before it can be replaced by a novel initiative.     

Asymmetries in the processing of emotionally valenced words

Earlier research has shown a valence dependent encoding asymmetry of emotional words (e.g., Pratto & John, 1991; White, 1996; Stenberg, Wiking & Dahl, 1998). To further study this asymmetry, two word detection experiments were performed based on the following hypothesis: when there is a more thoroughly processing of the valence, in this case a valence categorisation, there will be, in a subsequent task, prolonged latencies for negative words, compared to positive words. The result gave significantly prolonged response latencies for negative words compared to positive ones in the subsequent detection task when using an affective orienting task, something not found using a non-affective orienting task. The results support the Mobilization-Minimization hypothesis (Taylor, 1991), according to which negative events and stimuli occupy more cognitive resources, but with some limitation: the affective asymmetry, with prolonged latencies for negative words, occurs only when there is a deepened encoding of the affective component of the words.     

Functional brain activation differences in stuttering identified with a rapid fMRI sequence

The purpose of this study was to investigate whether brain activity related to the presence of stuttering can be identified with rapid functional MRI (fMRI) sequences that involved overt and covert speech processing tasks. The long-term goal is to develop sensitive fMRI approaches with developmentally appropriate tasks to identify deviant speech motor and auditory brain activity in children who stutter closer to the age at which recovery from stuttering is documented. Rapid sequences may be preferred for individuals or populations who do not tolerate long scanning sessions. In this report, we document the application of a picture naming and phoneme monitoring task in 3 min fMRI sequences with adults who stutter (AWS). If relevant brain differences are found in AWS with these approaches that conform to previous reports, then these approaches can be extended to younger populations. Pairwise contrasts of brain BOLD activity between AWS and normally fluent adults indicated the AWS showed higher BOLD activity in the right inferior frontal gyrus (IFG), right temporal lobe and sensorimotor cortices during picture naming and higher activity in the right IFG during phoneme monitoring. The right lateralized pattern of BOLD activity together with higher activity in sensorimotor cortices is consistent with previous reports, which indicates rapid fMRI sequences can be considered for investigating stuttering in younger participants.Educational objectives: The reader will learn about and be able to describe the: (1) use of functional MRI to study persistent developmental stuttering; (2) differences in brain activation between persons who stutter and normally fluent speakers; and (3) potential benefit of time efficient fMRI sequences combined with a range of speech processing tasks for investigating stuttering in younger populations.     

Cognitive control of a simple mental image in patients with obsessive--compulsive disorder

The nature of obsessions has led researchers to try to determine if the main problem in obsessive-compulsive disorder (OCD) is impaired inhibitory control. Previous studies report that the effort to suppress is one of the factors that increase the frequency of obsessive thoughts. Based on these results and those of the present study that suggest inferior parietal lobe (IPL) abnormality in OCD and findings of a recent study that reported the importance of the right posterior parietal cortex in cognitive control of a simple mental image, the present cognitive control paradigm study aimed to determine whether there is a difference in brain dynamics between OCD patients and non-obsessive controls while performing tasks that necessitate cognitive control of a simple mental image, and whether the right posterior parietal region is one of the regions in which a difference in activity between the OCD patients and controls would be observed. Functional brain imaging was performed while the participants attempted to suppress, imagine, or manipulate a mental image. The general linear model showed that there was a main effect of group and main effect of task. Accordingly, in all contrasts (suppression minus free-imagination, erasing minus free-imagination, and imagination minus free-imagination), the right IPL, right posterior cingulate cortex, and right superior frontal gyrus activity were lower in the OCD patients than in the healthy controls. These results and the observed correlations between activity levels, and symptom and subjective performance scores are discussed. In conclusion, the results of the present study and those of previous studies suggest that the main problem in OCD might be difficulty activating the right frontoparietal networks during tasks that require cognitive control, which might result in the intrusiveness of obsessive thoughts.     

The relation between electroencephalogram asymmetry and attention biases to threat at baseline and under stress

Electroencephalogram (EEG) asymmetry in the alpha frequency band has been implicated in emotion processing and broad approach-withdrawal motivation systems. Questions remain regarding the cognitive mechanisms that may help elucidate the observed links between EEG asymmetry and patterns of socioemotional functioning. The current study observed frontal EEG asymmetry patterns at rest and under social threat among young adults (N = 45, M = 21.1 years). Asymmetries were, in turn, associated with performance on an emotion-face dot-probe attention bias task. Attention biases to threat have been implicated as potential causal mechanisms in anxiety and social withdrawal. Frontal EEG asymmetry at baseline did not predict attention bias patterns to angry or happy faces. However, increases in right frontal alpha asymmetry from baseline to the stressful speech condition were associated with vigilance to angry faces and avoidance of happy faces. The findings may reflect individual differences in the pattern of response (approach or withdrawal) with the introduction of a mild stressor. Comparison analyses with frontal beta asymmetry and parietal alpha asymmetry did not find similar patterns. Thus, the data may reflect the unique role of frontal regions, particularly the dorsolateral prefrontal cortex, in cognitive control and threat detection, coupled with ruminative processes associated with alpha activity.     

The neural basis of updating: Distinguishing substitution processes from other concurrent processes

Sörqvist, P. & Sætrevik, B. (2010). The neural basis of updating: Distinguishing substitution processes from other concurrent processes. Scandinavian Journal of Psychology, 51, 357–362. Most previous studies of updating processes have not been able to contrast processes of substituting items in memory with other concurrent processes. In the present investigation, we used a new task called “number updating” and an fMRI protocol to contrast the activation of trials that require item substitution (adding a new item to the working memory representation and suppressing an old item) with trials that involve no substitution (discarding the new item). Trials that require item substitution activated the dorsolateral prefrontal cortex, the posterior medial frontal cortex and the parietal lobes, areas typically seen activated for working memory tasks in general. Trials that do not require substitution activated the anterior medial frontal cortex. Studies examining executive functions have associated this area with cognitive conflict, and may represent suppression of the substitution processes.     

Hemispheric specialization for emotional word processing is a function of SSRI responsiveness

Vulnerability to depression and non-response to Selective Serotonin Reuptake Inhibitors (SSRIs) are associated with specific neurophysiological characteristics including greater right hemisphere (RH) relative to left hemisphere (LH) activity. The present study investigated the relationship between hemispheric specialization and processing of emotional words using a divided visual field paradigm administered to never-depressed and previously-depressed individuals, who were subdivided into SSRI responders and non-responders. SSRI responders and never-depressed participants were similar in their left hemispheric lateralization for evaluating emotional words. In contrast, SSRI non-responders showed a relative shift towards RH processing of negative words, and a strong bias toward negative evaluation of words presented to the RH. The results are discussed within the context of a biological-cognitive model of vulnerability to depression.     

The role of experience in web-building spiders (Araneidae)

A typical feature of vertical orb-webs is the ‘top/bottom’ asymmetry, where the lower web region is larger than the upper web region. This asymmetry may improve prey capture success, because, sitting in the hub of the web, a spider can reach prey entangled below the hub faster than prey entangled in the area above the hub. While web asymmetry is known to vary intraspecifically, we tested if this variation also exists at the individual level and whether it is the result of experience, using two orb-web spider species, Argiope keyserlingi and Larinioides sclopetarius. The results reveal that experienced web-building spiders constructed more asymmetric webs than conspecifics deprived of any prior building experience over a period of several months. Experienced individuals invested more silk material into the web region below the hub, which covered a larger area. Moreover, web asymmetry was also influenced by previous prey capture experiences, as spiders increased the lower region of the web if it intercepted the most prey over a period of 6 days. Consequently, spiders may be able to use long-term web-building experience as well as short-term prey capture experience to build better traps. In contrast to previous views of spiders, experience can contribute to intraspecific as well as to individual variations in web design. Received: 1 March 1999 / Accepted after revision: 18 August 1999