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We performed a functional magnetic resonance imaging study to elucidate the process involved in the transformation of the format types of action descriptions between stimuli and representations. We independently manipulated the format types of both stimuli (visual action [Vi] vs. verbal [Ve] stimulus) and internal representations (Vi vs. Ve representation) and set four types of experimental tasks. Each participant was required to generate a Vi or Ve representation after being presented with a Vi or Ve stimulus, according to each task. Increased activity in the left inferior frontal gyrus (IFG) (Brodmann areas 44 and 45) was found in the transformation contrast: ([Vi stimulus and Ve representation] + [Ve stimulus and Vi representation]) > ([Vi stimulus and Vi representation] + [Ve stimulus and Ve representation]). This result suggests that the left IFG is involved with the transformation process and has the function of generating an internal representation in a format different from that of externally presented stimuli. • We used verbal and visual action stimuli (sentences and pictures). • Participants were asked to generate verbal and visual representations. • Left IFG was active in transforming the types between stimuli and representations. • We discuss the role of the left IFG on the transformation process. [ABSTRACT FROM AUTHOR]

Sensorimotor synchronization (SMS) requires aligning motor actions to external events and represents a core part of both musical and dance performances. In the current study, to isolate the brain mechanisms involved in synchronizing finger tapping with a musical beat, we compared SMS to pure self-paced finger tapping and listen-only conditions at different tempi. We analyzed EEG data using frequency domain steady-state evoked potentials (SSEPs) to identify sustained electrophysiological brain activity during repetitive tasks. Behavioral results revealed different timing modes between SMS and self-paced finger tapping, associated with distinct scalp topographies, thus suggesting different underlying brain sources. After subtraction of the listen-only brain activity, SMS was compared to self-paced finger tapping. Resulting source estimations showed stronger activation of the left inferior frontal gyrus during SMS, and stronger activation of the bilateral inferior parietal lobule during self-paced finger tapping. These results point to the left inferior frontal gyrus as a pivot for perception-action coupling. We discuss our findings in the context of the ongoing debate about SSEPs interpretation given the variety of brain events contributing to SSEPs and similar EEG frequency responses. [ABSTRACT FROM AUTHOR]

We previously reported speaking-related activity changes associated with assisted recovery induced by a fluency shaping therapy program and unassisted recovery from developmental stuttering (Kell et al., Brain 2009). While assisted recovery re-lateralized activity to the left hemisphere, unassisted recovery was specifically associated with the activation of the left BA 47/12 in the lateral orbitofrontal cortex. These findings suggested plastic changes in speaking-related functional connectivity between left hemispheric speech network nodes. We reanalyzed these data involving 13 stuttering men before and after fluency shaping, 13 men who recovered spontaneously from their stuttering, and 13 male control participants, and examined functional connectivity during overt vs. covert reading by means of psychophysiological interactions computed across left cortical regions involved in articulation control. Persistent stuttering was associated with reduced auditory-motor coupling and enhanced integration of somatosensory feedback between the supramarginal gyrus and the prefrontal cortex. Assisted recovery reduced this hyper-connectivity and increased functional connectivity between the articulatory motor cortex and the auditory feedback processing anterior superior temporal gyrus. In spontaneous recovery, both auditory-motor coupling and integration of somatosensory feedback were normalized. In addition, activity in the left orbitofrontal cortex and superior cerebellum appeared uncoupled from the rest of the speech production network. These data suggest that therapy and spontaneous recovery normalizes the left hemispheric speaking-related activity via an improvement of auditory-motor mapping. By contrast, long-lasting unassisted recovery from stuttering is additionally supported by a functional isolation of the superior cerebellum from the rest of the speech production network, through the pivotal left BA 47/12. [ABSTRACT FROM AUTHOR]

Recent research suggests that attributing human movement to ambiguous and static Rorschach stimuli (M responses) is associated with EEG mu suppression, and that disrupting the left inferior gyrus (LIFG; a putative area implicated in mirroring activity) decreases the tendency to see human movement when exposed to the Rorschach ambiguous stimuli. The current study aimed to test whether disrupting the LIFG via repetitive transcranial stimulation (rTMS) would decrease both the number of human movement attributions and EEG mu suppression. Each participant was exposed to the Rorschach stimuli twice, i.e., during a baseline condition (without rTMS but with EEG recording) and soon after rTMS (TMS condition with EEG recording). Experimental group ( N  = 15) was stimulated over the LIFG, while the control group ( N  = 13) was stimulated over the Vertex. As expected, disrupting the LIFG but not Vertex, decreased the number of M attributions provided by the participants exposed to the Rorschach stimuli, with a significant interaction effect. Unexpectedly, however, rTMS did not significantly influence EEG mu suppression. [ABSTRACT FROM AUTHOR]

Suicide is a serious public health problem. In this study, we investigated functional brain changes to novel visual stimuli of suicidal means, DNA methylation status, and the relationship between the two markers. 14 suicidal attempt patients (SAs) and 22 healthy controls were included. Pictures of facial expressions and suicidal means were shown to subjects during fMRI scanning. 11 CpG sites within transcription factor binding site of CACNA1C gene were selected. In knives (K) vs. natural landscape (NL) condition, left middle frontal gyrus (Brodmann's area, BA 6 and 46) and left inferior frontal gyrus (BA 9) were shown to be significantly higher brain activation in the SAs than the controls (p<0.001). DNA methylation percentages of CpG site 4 (p=0.005) and 6 (p=0.037) were found to be related to the SAs. In the SAs, methylation degree of site 4 and site 6 was positively correlated with signal intensity of K vs. NL condition in left thalamus. The degree of site 4 was positively correlated with signal intensity in left middle and inferior frontal gyri in SAs. The possibility that these findings might be involved in the neurobiology of suicidal behavior is suggested. [ABSTRACT FROM AUTHOR]

Tics in Gilles de la Tourette syndrome (GTS) resemble fragments of normal motor behaviour but appear in an intrusive, repetitive and context-inappropriate manner. Although tics can be voluntarily inhibited on demand , the neural correlates of this process remain unclear. 14 GTS adults without relevant comorbidities participated in this study. First, tic severity and voluntary tic inhibitory capacity were evaluated outside the scanner. Second, patients were examined with resting state functional magnetic resonance imaging (RS-fMRI) in two states, free ticcing and voluntary tic inhibition. Local synchronization of spontaneous fMRI-signal was analysed with regional homogeneity (ReHo) and differences between both states (free ticcing

Abstract: Genetic studies found the A allele of the single nucleotide polymorphism rs1006737 in the CACNA1C gene, which encodes for the alpha 1C subunit of the voltage-dependent, L-type calcium ion channel Cav1.2, to be overrepresented in patients with major depressive disorder (MDD). Altered prefrontal brain functioning and impaired semantic verbal fluency (SVF) are robust findings in these patients. A recent functional magnetic resonance imaging (fMRI) study found the A allele to be associated with poorer performance and increased left inferior frontal gyrus (IFG) activation during SVF tasks in healthy subjects. In the present study, we investigated the effects of rs1006737 on neural processing during SVF in MDD. In response to semantic category cues, 40 patients with MDD and 40 matched controls overtly generated words while brain activity was measured with fMRI. As revealed by whole brain analyses, genotype significantly affected brain activity in patients. Compared to patients with GG genotype, patients with A allele demonstrated increased task-related activation in the left middle/inferior frontal gyrus and the bilateral cerebellum. Patients with A allele also showed enhanced functional coupling between left middle/inferior and right superior/middle frontal gyri. No differential effects of genotype on SVF performance or brain activation were found between diagnostic groups. The current data provide further evidence for an impact of rs1006737 on the left IFG and demonstrate that genetic variation in CACNA1C modulates neural responses in patients with MDD. The observed functional alterations in prefrontal and cerebellar areas might represent a mechanism by which rs1006737 influences susceptibility to MDD. [Copyright &y& Elsevier]

Abstract: In this fMRI study we investigate the neural correlates of information structure integration during sentence comprehension in Dutch. We looked into how prosodic cues (pitch accents) that signal the information status of constituents to the listener (new information) are combined with other types of information during the unification process. The difficulty of unifying the prosodic cues into overall sentence meaning was manipulated by constructing sentences in which the pitch accent did (focus-accent agreement), and sentences in which the pitch accent did not (focus-accent disagreement) match the expectations for focus constituents of the sentence. In case of a mismatch, the load on unification processes increases. Our results show two anatomically distinct effects of focus-accent disagreement, one located in the posterior left inferior frontal gyrus (LIFG, BA6/44), and one in the more anterior-ventral LIFG (BA 47/45). Our results confirm that information structure is taken into account during unification, and imply an important role for the LIFG in unification processes, in line with previous fMRI studies. [Copyright &y& Elsevier]

Abstract: In two experiments, we combined a semantic blocked naming paradigm with anodal transcranial direct current stimulation (tDCS) to shed light on the neural correlates of the semantic interference (SI) effect. In particular, prior to the naming task, anodal tDCS was applied over the left superior temporal gyrus (STG, Experiment 1) or the left inferior frontal gyrus (IFG, Experiment 2) to enhance cortical excitability in these regions. In both experiments, participants were tested in two sessions in which either real or sham tDCS was delivered. We found that anodal tDCS over the left STG significantly increased the SI effect, whereas anodal tDCS over the left IFG led to a reduction of the SI effect. Overall, our data confirm the existence of a distributed cortical network involved in lexical retrieval and show that both the left IFG and the left STG play a causal role in this process. In particular, the left IFG is likely to be critical in resolving the conflict between competitor lexical representations, while the left STG seems to be the neural locus of the lexical representational system, where competition among different lexical representations occurs. [Copyright &y& Elsevier]

Abstract: Figurative speech (e.g., proverb, irony, metaphor, and idiom) has been reported to be particularly sensitive to measurement of abstract thinking in patients who suffer from impaired abstraction and language abilities. Metaphor processing was investigated with fMRI in adults with moderate to severe post-acute traumatic brain injury (TBI) and healthy age-matched controls using a valence-judgment task. We hypothesized that TBI patients would display decreased activation of the left inferior frontal gyrus (LIFG), which is considered central to semantic memory retrieval and abstract thought, in comparison with healthy controls. We also predicted that decreased activation in TBI individuals would correlate with their behavioral response times. A whole-brain analysis across the two participant groups revealed that patients did not strongly engage frontal and temporal regions related to semantic processing for novel metaphor comprehension, whereas control participants exhibited more intensive and concentrated activation within frontal and temporal areas. A region of interest (ROI) analysis verified that the LIFG was underactivated in TBI patients compared to controls across all conditions. TBI patients’ impaired abstraction of novel stimuli may stem from reduced prefrontal control of semantic memory as well as disrupted interconnectivity of prefrontal cortex with other regions. [Copyright &y& Elsevier]

Abstract: Although predictive inference in reading has been extensively investigated with behavioral paradigms, little is known about its neural substrates. Manipulating the likelihood that a particular event can be predicted from the content of a preceding three-sentence story, the present functional MRI study showed that the left inferior frontal gyrus (LIFG) and the right lingual gyrus were involved in predictive inference generation. It is suggested that the LIFG was responsible for the construction of predictive inference and the right lingual gyrus for integrating the constructed inference into a coherent text representation. Combined with previous research, the results provide brain imaging evidence consistent with predictions from the Schmalhofer et al. model (Discourse Processes, 33, 105-13, 2002) which intends to unify predictive inference and bridging inference in a single theoretical framework. [Copyright &y& Elsevier]

Abstract: Recent research suggests that the left inferior frontal gyrus (LIFG) plays a role in selecting semantic information from among competing alternatives. A key question remains as to whether the LIFG is engaged by the selection of semantic information only or by increased semantic competition in and of itself, especially when such competition is implicit in nature. Ambiguous words presented in a lexical context provide a means of examining whether the LIFG is recruited under conditions when contextual cues constrain selection to only the meaning appropriate to the context (e.g., coin-mint-money) or under conditions of increased competition when contextual cues do not allow for the resolution to a particular meaning (e.g., candy-mint-money). In this event-related fMRI study, an implicit task was used in which subjects made lexical (i.e., word/nonword) decisions on the third stimulus of auditorily presented triplets in conditions where the lexical context either promoted resolution toward a particular ambiguous word meaning or enhanced the competition among ambiguous word meanings. LIFG activation was observed when the context allowed for the resolution of competition and hence the selection of one meaning (e.g., coin-mint-money) but failed to emerge when competition between the meanings of an ambiguous word was unresolved by the context (e.g., candy-mint-money). In the latter case, there was a pattern of reduced activation in frontal, temporal and parietal areas. These findings demonstrate that selection or resolution of competition as opposed to increased semantic competition alone engages the LIFG. Moreover, they extend previous work in showing that the LIFG is recruited even in cases where the selection of meaning takes place implicitly. [Copyright &y& Elsevier]

Abstract: To test the hypothesis of a participation of inner speech in self-referential activity we reviewed 59 studies measuring brain activity during processing of self-information in the following self-domains: agency, self-recognition, emotions, personality traits, autobiographical memory, preference judgments, and REST. The left inferior frontal gyrus (LIFG) has been shown to sustain inner speech use. We calculated the percentage of studies reporting LIFG activity for each self-dimension. 55.9% of all studies reviewed identified LIFG (and presumably inner speech) activity during self-awareness tasks. Furthermore, the LIFG was more frequently recruited during conceptual tasks (e.g., emotions, traits) than during perceptual tasks (e.g., agency, self-recognition). This supports the view of a relative involvement of inner speech in self-reflective processes. [Copyright &y& Elsevier]

Abstract: The neural mechanisms underlying the syntactic processing of sentence comprehension in Korean (L1) and English (L2) by late bilinguals were investigated using functional MRI. The Korean native speakers were asked to read sentences with different levels of syntactic complexity in L1 and L2 and respond to comprehension questions concerning the sentences. The syntactic complexity was varied using a center-embedded sentence “The director that the maid introduced ignored the farmer” or a conjoined sentence “The maid introduced the director and ignored the farmer”. It was found that the major areas involved in sentence processing such as the left inferior frontal gyrus (IFG), bilateral inferior parietal gyrus, and occipital lobe including cuneus, and lingual gyrus were commonly activated during the processing of both L1 and L2. However, the pattern of activation was different for L1 and L2 in the left IFG. The amount of activation was greater for embedded sentences than for conjoined sentences in L1 while no difference was found in L2. These results suggest that the cortical areas involved with syntactic processing in L1 and L2 are shared, but that the underlying neural mechanisms are different. The findings of the present study are discussed in comparison with Hasegawa et al.’s (Hasegawa, M., Carpenter, P.A., Just, M.A., 2002. An fMRI study of bilingual sentence comprehension and workload. NeuroImage 15, 647–660.) and Yokoyama et al.’s (Yokoyama, S., Okamoto, H., Miyamoto, T., Yoshimoto, K., Kim, J., Iwata, K., Jeong, H., Uchida, S., Ikuta, N., Sassa, Y., Nakamura, W., Horie, K., Sato, S., Kawashima, R., 2006. Cortical activation in the processing of passive sentences in L1 and L2: An fMRI study. NeuroImage 30, 570–579.) studies which also found common areas of activation but different patterns of activation during the processing of L1 and L2. [Copyright &y& Elsevier]

Abstract: It has long been known that storage of information in working memory suffers as a function of proactive interference. Here we review the results of experiments using approaches from cognitive neuroscience to reveal a pattern of brain activity that is a signature of proactive interference. Many of these results derive from a single paradigm that requires one to resolve interference from a previous experimental trial. The importance of activation in left inferior frontal cortex is shown repeatedly using this task and other tasks. We review a number of models that might account for the behavioral and imaging findings about proactive interference, raising questions about the adequacy of these models. [Copyright &y& Elsevier]

The left inferior frontal gyms (LIFG, BA 44,45,47) has been associated with linguistic processing (from sentence- to syllable-parsing) as well as action analysis. We hypothesize that the function of the LIFG may be the monitoring of action, a function well adapted to agent deixis (verbal pointing at the agent of an action). The aim of this fMRI study was therefore to test the hypothesis that the LIFG is involved during the production of agent deixis. We performed an experiment, whereby three kinds of deictic sentences were pronounced, involving prosodic focus, syntactic extraction and prosodic focus with syntactic extraction. A common pattern of activation was found for the three deixis conditions in the LIFO (BA 45 and/or 47), the left insula and the bilateral premotor (BA 6) cortex. Prosodic deixis additionally activated the left anterior cingulate gyms (BA 24, 32), the left supramarginal gyms (LSMG, BA 40) and Wernicke's area (BA 22). Our results suggest that the LIFG is involved during agent deixis, through either prosody or syntax, and that the LSMG and Wernicke's area are additionally required in prosody-driven deixis. [ABSTRACT FROM AUTHOR]