At the core of reasoning: Dissociating deductive and non‐deductive load

In recent years, neuroimaging methods have been used to investigate how the human mind carries out deductive reasoning. According to some, the neural substrate of language is integral to deductive reasoning. According to others, deductive reasoning is supported by a language‐independent distributed network including left frontopolar and frontomedial cortices. However, it has been suggested that activity in these frontal regions might instead reflect non‐deductive factors such as working memory load and general cognitive difficulty. To address this issue, 20 healthy volunteers participated in an fMRI experiment in which they evaluated matched simple and complex deductive and non‐deductive arguments in a 2 × 2 design. The contrast of complex versus simple deductive trials resulted in a pattern of activation closely matching previous work, including frontopolar and frontomedial “core” areas of deduction as well as other “cognitive support” areas in frontoparietal cortices. Conversely, the contrast of complex and simple non‐deductive trials resulted in a pattern of activation that does not include any of the aforementioned “core” areas. Direct comparison of the load effect across deductive and non‐deductive trials further supports the view that activity in the regions previously interpreted as “core” to deductive reasoning cannot merely reflect non‐deductive load, but instead might reflect processes specific to the deductive calculus. Finally, consistent with previous reports, the classical language areas in left inferior frontal gyrus and posterior temporal cortex do not appear to participate in deductive inference beyond their role in encoding stimuli presented in linguistic format.     

The neural substrates of mindfulness: An fMRI investigation

“Mindfulness” is a capacity for heightened present-moment awareness that we all possess to a greater or lesser extent. Enhancing this capacity through training has been shown to alleviate stress and promote physical and mental well-being. As a consequence, interest in mindfulness is growing and so is the need to better understand it. This study employed functional magnetic resonance imaging (fMRI) to identify the brain regions involved in state mindfulness and to shed light on its mechanisms of action. Significant signal decreases were observed during mindfulness meditation in midline cortical structures associated with interoception, including bilateral anterior insula, left ventral anterior cingulate cortex, right medial prefrontal cortex, and bilateral precuneus. Significant signal increase was noted in the right posterior cingulate cortex. These findings lend support to the theory that mindfulness achieves its positive outcomes through a process of disidentification.     

Neurocognitive basis of deductive reasoning in children varies with parental education

The neurocognitive basis of elementary academic skills varies with parental socioeconomic status (SES). Little is known, however, about SES‐related differences underlying higher‐order cognitive skills that are critical for school success, such as reasoning. Here we used fMRI to examine how the neurocognitive basis of deductive reasoning varies as a function of parental education in school‐aged children. Higher parental education was associated with greater reliance on the left inferior frontal gyrus when solving set‐inclusion problems, consistent with other work suggesting that these problems might more heavily rely on verbal systems in the brain. In addition, children who are at the lower end of the parental education continuum, but have higher nonverbal skills relied on right parietal areas to a greater degree than their peers for solving set‐inclusion problems. Finally, lower parental education children with higher verbal or nonverbal skill engaged dorsolateral prefrontal regions to a greater degree for set‐inclusion and linear‐order relations than their peers. These findings suggest that children with lower parental education rely on spatial and cognitive control mechanisms to achieve parity with their peers with parents who have more education. Better understanding variability in the neurocognitive networks that children recruit as a function of their parental factors might benefit future individualized interventions that best match children''s characteristics.     

Brain correlates of discourse processing: an fMRI investigation of irony and conventional metaphor comprehension

Higher levels of discourse processing evoke patterns of cognition and brain activation that extend beyond the literal comprehension of sentences. We used fMRI to examine brain activation patterns while 16 healthy participants read brief three-sentence stories that concluded with either a literal, metaphoric, or ironic sentence. The fMRI images acquired during the reading of the critical sentence revealed a selective response of the brain to the two types of nonliteral utterances. Metaphoric utterances resulted in significantly higher levels of activation in the left inferior frontal gyrus and in bilateral inferior temporal cortex than the literal and ironic utterances. Ironic statements resulted in significantly higher activation levels than literal statements in the right superior and middle temporal gyri, with metaphoric statements resulting in intermediate levels in these regions. The findings show differential hemispheric sensitivity to these aspects of figurative language, and are relevant to models of the functional cortical architecture of language processing in connected discourse.     

The neural substrate of analogical reasoning: an fMRI study

This study investigated the anatomical substrate of analogical reasoning using functional magnetic resonance imaging. In the study, subjects performed a verbal analogy task (e.g., soldier is to army as drummer is to band) and, to control for activation caused by purely semantic access, a semantic judgment task. Significant activation differences between the verbal analogy and the semantic judgment task were found bilaterally in the prefrontal cortex (right BA 11/BA 47 and left BA45), the fusiform gyrus, and the basal ganglia; left lateralized in the postero-superior temporal gyrus (BA 22) and the (para) hippocampal region; and right lateralized in the anterior cingulate. The role of these areas in analogical reasoning is discussed.     

The influence of emotional distraction on verbal working memory: an fMRI investigation comparing individuals with schizophrenia and healthy adults

The ability to maintain information over short periods of time (i.e., working memory) is critically important in a variety of cognitive functions including language, planning, and decision-making. Recent functional Magnetic Resonance Imaging (fMRI) research with healthy adults has shown that brain activations evoked during the delay interval of working memory tasks can be reduced by the presentation of distracting emotional events, suggesting that emotional events may take working-memory processes momentarily offline. Both executive function and emotional processing are disrupted in schizophrenia, and here we sought to elucidate the effect of emotional distraction upon brain activity in schizophrenic and healthy adults performing a verbal working memory task. During the delay period between the memoranda and memory probe items, emotional and neutral distractors differentially influenced brain activity in these groups. In healthy adults, the hemodynamic response from posterior cingulate, orbital frontal cortex, and the parietal lobe strongly differentiated emotional from neutral distractors. In striking contrast, schizophrenic adults showed no significant differences in brain activation when processing emotional and neutral distractors. Moreover, the influence of emotional distractors extended into the memory probe period in healthy, but not schizophrenic, adults. The results suggest that although emotional items are highly salient for healthy adults, emotional items are no more distracting than neutral ones to individuals with schizophrenia.     

The implementation of verbal instructions: an fMRI study

In everyday life, our actions are often guided by verbal instructions. Usually, we can implement such instructions immediately without trial and error learning. This raises the fundamental question how verbal instructions are transformed into efficient motor behavior. The aim of this study was to gain deeper insights into the implementation of verbal instructions both on a neural and a cognitive level. To this end, we devised an fMRI experiment in which participants were required to permanently implement new stimulus-response (S-R) mappings and object-color (O-C) mappings. This enabled us to test whether there are brain areas that are specific to the implementation of newly instructed S-R mappings or whether newly instructed rules are represented independently from the specific content. Furthermore, we could test which brain areas are involved in the processing of S-R mappings when compared with O-C mappings. Our results suggest that only one brain area, the left inferior frontal junction (IFJ), was sensitive to the novelty of instructions regardless of whether these instructions conveyed S-R or O-C mappings. Furthermore, our results show that instructions conveying S-R mapping involve a network of brain areas, including pre-PMd, M1, and IPS that was not sensitive to the novelty of the instructions. Therefore, we conclude that the implementation of verbal instructions results from an interplay of a brain areas that represent novel rulelike information in domain general terms and brain areas that are specific to S-R rules.     

Neuroimaging of the functional and structural networks underlying visuospatial vs. linguistic reasoning in high-functioning autism

High-functioning individuals with autism have been found to favor visuospatial processing in the face of typically poor language abilities. We aimed to examine the neurobiological basis of this difference using functional magnetic resonance imaging and diffusion tensor imaging. We compared 12 children with high functioning autism (HFA) to 12 age- and IQ-matched typically developing controls (CTRL) on a pictorial reasoning paradigm under three conditions: V, requiring visuospatial processing; S, requiring language (i.e., semantic) processing; and V+S, a hybrid condition in which language use could facilitate visuospatial transformations. Activated areas in the brain were chosen as endpoints for probabilistic diffusion tractography to examine tract integrity (FA) within the structural network underlying the activation patterns. The two groups showed similar networks, with linguistic processing activating inferior frontal, superior and middle temporal, ventral visual, and temporo-parietal areas, whereas visuospatial processing activated occipital and inferior parietal cortices. However, HFA appeared to activate occipito-parietal and ventral temporal areas, whereas CTRL relied more on frontal and temporal language regions. The increased reliance on visuospatial abilities in HFA was supported by intact connections between the inferior parietal and the ventral temporal ROIs. In contrast, the inferior frontal region showed reduced connectivity to ventral temporal and middle temporal areas in this group, reflecting impaired activation of frontal language areas in autism. The HFA group's engagement of posterior brain regions along with its weak connections to frontal language areas suggest support for a reliance on visual mediation in autism, even in tasks of higher cognition.     

The neural underpinnings of intergroup social cognition: an fMRI meta-analysis

Roughly 20 years of functional magnetic resonance imaging (fMRI) studies have investigated the neural correlates underlying engagement in social cognition (e.g. empathy and emotion perception) about targets spanning various social categories (e.g. race and gender). Yet, findings from individual studies remain mixed. In the present quantitative functional neuroimaging meta-analysis, we summarized across 50 fMRI studies of social cognition to identify consistent differences in neural activation as a function of whether the target of social cognition was an in-group or out-group member. We investigated if such differences varied according to a specific social category (i.e. race) and specific social cognitive processes (i.e. empathy and emotion perception). We found that social cognition about in-group members was more reliably related to activity in brain regions associated with mentalizing (e.g. dorsomedial prefrontal cortex), whereas social cognition about out-group members was more reliably related to activity in regions associated with exogenous attention and salience (e.g. anterior insula). These findings replicated for studies specifically focused on the social category of race, and we further found intergroup differences in neural activation during empathy and emotion perception tasks. These results help shed light on the neural mechanisms underlying social cognition across group lines.     

fMRI investigation of speed-accuracy strategy switching

Switching between rapid and accurate responses is an important aspect of decision-making. However, the brain mechanisms important to smoothly change the speed-accuracy strategy remain mostly unclear. This issue was addressed here by using functional magnetic resonance imaging (fMRI). On each trial, right-handed healthy participants had to stress speed or accuracy in performing a color discrimination task on a target stimulus according to the instructions given by an initial cue. Participants were capable of trading speed for accuracy and vice versa. Analyses of cue-related fMRI activations revealed a significant recruitment of left middle frontal gyrus and right cerebellum when switching from speed to accuracy. The left superior parietal lobule was activated in the same switching condition but only after the target onset. The anterior cingulate cortex was more recruited, also after target presentation, when speed had to be maintained from one trial to the next. These results are interpreted within a theoretical framework that attributes a role in criterion-setting to the left lateral prefrontal cortex, perceptual evidence accumulation to the superior parietal lobule, and action energization to the anterior cingulate cortex, extending previous findings to the domain of speed-accuracy tradeoff regulations.     

The other face of the other-race effect: an fMRI investigation of the other-race face categorization advantage

The present study was the first to use the functional magnetic resonance imaging (fMRI) methodology to investigate the neural correlates of race categorization of own- and other-race faces. We found that Chinese participants categorized the race of Caucasian faces more accurately and faster than that of Chinese faces, replicating the robust effect of the other-race categorization advantage. Regions of interest (ROI) analyses revealed greater neural activations when participants were categorizing own-race faces than other-race faces in the bilateral ventral occipito-temporal cortex (VOT) such as the fusiform face areas (FFAs) and the occipital face areas (OFAs). Within the left FFA, there was also a significant negative correlation between the behavioral difference of own- and other-race face categorization accuracy and the activation difference between categorizing own- and other-race faces. Whole brain analyses showed that categorizing own-race faces induced greater activations in the right medial frontal cortex (MFC) and right inferior frontal gyrus (IFG) than categorizing other-race faces. Psychophysiological interaction (PPI) analyses revealed that the frontal cortical regions interacted more strongly with the posterior VOT during the categorization of own-race faces than that of other-race faces. Overall, our findings suggest that relative to the categorization of other-race faces, more cortical resources are engaged during the categorization of own-race faces with which we have a higher level of processing expertise. This increased involvement of cortical neural sources perhaps serves to provide more in-depth processing of own-race faces (such as individuation), which in turn paradoxically results in the behavioral other-race categorization advantage.     

Neural representation of verb meaning: an fMRI study

The neural basis for verb comprehension has proven elusive, in part because of the limited range of verb categories that have been assessed. In the present study, 16 healthy young adults were probed for the meaning associated with verbs of MOTION and verbs of COGNITION. We observed distinct patterns of activation for each verb subcategory: MOTION verbs are associated with recruitment of left ventral temporal-occipital cortex, bilateral prefrontal cortex and caudate, whereas COGNITION verbs are associated with left posterolateral temporal activation. These findings are consistent with the claim that the neural representations of verb subcategories are distinct. Although the "sensory-motor" hypothesis may play a role in explaining activation associated with MOTION verbs, the left posterolateral temporal distribution of cortical activation associated with COGNITION verbs cannot be easily explained by the "sensory-motor" hypothesis. We suggest that left posterolateral temporal activation supports aspects of lexical semantic processing concerned with the neural representation of propositional knowledge contributing to COGNITION verbs.     

Material specific lateralization of medial temporal lobe function: An fMRI investigation

The theory of material specific lateralization of memory function posits that left and right MTL regions are asymmetrically involved in mnemonic processing of verbal and nonverbal material respectively. Lesion and functional imaging (fMRI) studies provide robust evidence for a left MTL asymmetry in the verbal memory domain. Evidence for a right MTL/nonverbal asymmetry is not as robust. A handful of fMRI studies have investigated this issue but have generally utilised nonverbal stimuli which are amenable to semantic elaboration. This fMRI study aimed to investigate the neural correlates of recognition memory processing in 20 healthy young adults (mean age = 26 years) for verbal stimuli and nonverbal stimuli that were specifically designed to minimize verbalisation. Analyses revealed that the neural correlates of recognition memory processing for verbal and nonverbal stimuli were differentiable and asymmetrically recruited the left and right MTL respectively. The right perirhinal cortex and hippocampus were preferentially involved in successful recognition memory of items devoid of semantic information. In contrast, the left anterior hippocampus was preferentially involved in successful recognition memory of stimuli which contained semantic meaning. These results suggest that the left MTL is preferentially involved in mnemonic processing of verbal/semantic information. In contrast, the right MTL is preferentially involved in visual/non‐semantic mnemonic processing. We propose that during development, the left MTL becomes specialised for verbal mnemonic processing due to its proximity with left lateralised cortical language processing areas while visual/non‐semantic mnemonic processing gets ‘crowded out’ to become predominantly, but not completely, the domain of the right MTL. Hum Brain Mapp 37:933–941, 2016. © 2015 Wiley Periodicals, Inc .     

Neural basis of prosopagnosia: an fMRI study

Brain imaging research has identified at least two regions in human extrastriate cortex responding selectively to faces. One of these is located in the mid-fusiform gyrus (FFA), the other in the inferior occipital gyrus (IOG). We studied activation of these areas using fMRI in three individuals with severely impaired face recognition (one pure developmental and two childhood prosopagnosics). None of the subjects showed the normal pattern of higher fMRI activity to faces than to objects in the FFA and IOG or elsewhere. Moreover, in two of the patients, faces and objects produced similar activations in the regions corresponding to where the FFA and IOG are found in normal subjects. Our study casts light on the important role of FFA and IOG in the network of areas involved in face recognition, and indicates limits of brain plasticity.     

Investigating emotion with music: an fMRI study

The present study used pleasant and unpleasant music to evoke emotion and functional magnetic resonance imaging (fMRI) to determine neural correlates of emotion processing. Unpleasant (permanently dissonant) music contrasted with pleasant (consonant) music showed activations of amygdala, hippocampus, parahippocampal gyrus, and temporal poles. These structures have previously been implicated in the emotional processing of stimuli with (negative) emotional valence; the present data show that a cerebral network comprising these structures can be activated during the perception of auditory (musical) information. Pleasant (contrasted to unpleasant) music showed activations of the inferior frontal gyrus (IFG, inferior Brodmann's area (BA) 44, BA 45, and BA 46), the anterior superior insula, the ventral striatum, Heschl's gyrus, and the Rolandic operculum. IFG activations appear to reflect processes of music-syntactic analysis and working memory operations. Activations of Rolandic opercular areas possibly reflect the activation of mirror-function mechanisms during the perception of the pleasant tunes. Rolandic operculum, anterior superior insula, and ventral striatum may form a motor-related circuitry that serves the formation of (premotor) representations for vocal sound production during the perception of pleasant auditory information. In all of the mentioned structures, except the hippocampus, activations increased over time during the presentation of the musical stimuli, indicating that the effects of emotion processing have temporal dynamics; the temporal dynamics of emotion have so far mainly been neglected in the functional imaging literature.     

High-resolution fMRI investigation of the medial temporal lobe

The medial temporal lobe (MTL) is critical for declarative memory formation. Several theories of MTL function propose functional distinctions between the different structures of the MTL, namely the hippocampus and the surrounding cortical areas. Furthermore, computational models and electrophysiological studies in animals suggest distinctions between the subregions of the hippocampus itself. Standard fMRI resolution is not sufficiently fine to resolve activity on the scale of hippocampal subregions. Several approaches to scanning the MTL at high resolutions have been made, however there are limitations to these approaches, namely difficulty in conducting group-level analyses. We demonstrate here techniques for scanning the MTL at high resolution and analyzing the high-resolution fMRI data at the group level. To address the issue of cross-participant alignment, we employ the ROI-LDDMM alignment technique, which is demonstrated to result in smaller alignment errors when compared with several other common normalization techniques. Finally, we demonstrate that the pattern of activation obtained in the high-resolution functional data is similar to that obtained at lower resolution, although the spatial extent is smaller and the percent signal change is greater. This difference in the pattern of activation may be due to less partial volume sampling in the high-resolution data, resulting in more accentuated regions of activation.     

The self across the senses: an fMRI study of self-face and self-voice recognition

There is evidence that the right hemisphere is involved in processing self-related stimuli. Previous brain imaging research has found a network of right-lateralized brain regions that preferentially respond to seeing one''s own face rather than a familiar other. Given that the self is an abstract multimodal concept, we tested whether these brain regions would also discriminate the sound of one''s own voice compared to a friend''s voice. Participants were shown photographs of their own face and friend''s face, and also listened to recordings of their own voice and a friend''s voice during fMRI scanning. Consistent with previous studies, seeing one''s own face activated regions in the inferior frontal gyrus (IFG), inferior parietal lobe and inferior occipital cortex in the right hemisphere. In addition, listening to one''s voice also showed increased activity in the right IFG. These data suggest that the right IFG is concerned with processing self-related stimuli across multiple sensory modalities and that it may contribute to an abstract self-representation.     

Neural correlates of sensory preconditioning: A preliminary fMRI investigation

Sensory preconditioning (SPC; also known as behaviorally silent learning) consists of a combination of two neutral stimuli, none of which elicits an unconditional response. After one of them is later paired with an unconditional stimulus (US), the other neutral stimulus also yields a conditional response although it has never been paired with the US. In this study, an event‐related functional magnetic resonance imaging (fMRI) paradigm was used to specify brain regions involved in SPC. The results demonstrated that SPC was associated with significant changes in activity of several regions, notably, the left amygdala, the left hippocampus, the bilateral thalamus, the bilateral medial globus pallidus, the bilateral cerebellum, the bilateral premotor cortex, and the bilateral middle frontal gyrus. This is a first effort to use fMRI to examine the effects of SPC on brain activation. Our data suggest that there is a distributed network of structures involved in SPC including both cortical and subcortical regions, therefore add to our understanding of the neural mechanisms underlying the ability to associative learning. Hum Brain Mapp 35:1297–1304, 2014. © 2013 Wiley Periodicals, Inc.     

Language lateralization in female patients with schizophrenia: an fMRI study

Gender differences in schizophrenia are among the most consistently reported findings in schizophrenia research. However, the biological substrate underlying these gender differences is still largely unknown. Differences in language lateralization between men and women may underlie some gender differences in schizophrenia.

In previous functional imaging studies, language lateralization was found to be decreased in male schizophrenia patients as compared to healthy males, which was due to enhanced language activation of the right hemisphere as compared to the healthy males. It could be hypothesized that decreased language lateralization in schizophrenia is gender specific, i.e. decreased lateralization in male patients and normal lateralization in female patients.

To test this hypothesis, language activation was measured in 12 right-handed female patients with schizophrenia and 12 healthy females, and compared to findings in 12 male patients and 12 male controls of an earlier study.

Language lateralization was significantly lower in the female patients (0.44) as compared to the female controls (0.75), which was due to increased activation of the right-sided language areas (patients: 19 voxels; controls: 8 voxels), while left hemisphere activation was similar in patients and controls. When these data are compared to the male patients and controls, both patient groups had lower lateralization than their healthy counterparts, but there was no difference between male and female patients. In both sexes, decreased lateralization resulted from increased right hemispheric language activation, which suggests a failure to inhibit nondominant language areas in schizophrenia. These findings indicate that lower language lateralization in women is not likely to underlie gender differences in schizophrenia.