Neural correlates of belief- and desire-reasoning in 7- and 8-year-old children: an event-related potential study

Theory of mind requires belief‐ and desire‐understanding. Event‐related brain potential (ERP) research on belief‐ and desire‐reasoning in adults found mid‐frontal activations for both desires and beliefs, and selective right‐posterior activations only for beliefs. Developmentally, children understand desires before beliefs; thus, a critical question concerns whether neural specialization for belief‐reasoning exists in childhood or develops later. Neural activity was recorded as 7‐ and 8‐year‐olds (N = 18) performed the same diverse‐desires, diverse‐beliefs, and physical control tasks used in a previous adult ERP study. Like adults, mid‐frontal scalp activations were found for belief‐ and desire‐reasoning. Moreover, analyses using correct trials alone yielded selective right‐posterior activations for belief‐reasoning. Results suggest developmental links between increasingly accurate understanding of complex mental states and neural specialization supporting this understanding.     

Neural correlates of inference-driven attention in perceptual and symbolic tasks: An event-related potential study

The inferential system anticipates the external environment by building up internal representations of its regularities. To that purpose, two sources of information are especially important and attract attentional resources: expected and unexpected events, which are useful for checking the accuracy of internal representations. In the present study, we investigated the behavioural properties and the neural mechanisms underlying the strategic allocation of attention triggered by those events. To that end, event-related potentials (ERPs) were recorded during the performance of two tasks requiring detection of predictable and unpredictable response events embedded in a visuospatial or numeric sequence. The behavioural results in the two tasks mirror each other, suggesting the recruitment of similar attentional allocation processes between the two domains. The ERPs showed partially similar effects. In both tasks, a P3a-like component signalled the capture of attention by events clashing with previous expectations, whilst a P3b-like component marked the focusing of attention on predicted events and its redistribution among all possible response events occurring after the detection of an unexpected event.     

Neural correlates of action observation and execution in 14-month-old infants: an event-related EEG desynchronization study

There is increasing interest in neurobiological methods for investigating the shared representation of action perception and production in early development. We explored the extent and regional specificity of EEG desynchronization in the infant alpha frequency range (6-9 Hz) during action observation and execution in 14-month-old infants. Desynchronization during execution was restricted to central electrode sites, while action observation was associated with a broader desynchronization across frontal, central, and parietal regions. The finding of regional specificity in the overlap between EEG responses to action execution and observation suggests that the rhythm seen in the 6-9 Hz range over central sites in infancy shares certain properties with the adult mu rhythm. The magnitude of EEG desynchronization to action perception and production appears to be smaller for infants than for adults and older children, suggesting developmental change in this measure.     

Neural correlates of subliminal and supraliminal letter processing--an event-related fMRI study

One problem of interpreting research on subconscious processing is the possibility that participants are weakly conscious of the stimuli. Here, we compared the fMRI BOLD response in healthy adults to clearly visible single letters (supraliminal presentation) with the response to letters presented in the absence of any behavioural evidence of visibility (subliminal presentation). No letter catch trials served as a control condition. Forced-choice responses did not differ from chance when letter-to-background contrast was low, whereas they were almost 100% correct when contrast was high. A comparison of fMRI BOLD signals for supraliminal and subliminal letters with the control trials revealed a signal increase in left BA 37 (fusiform gyrus). Comparison of supraliminal with subliminal letters showed a significant increase in the right inferior frontal gyrus (BA 44, partly extending to BA 9 and BA 45, as well as BA 46). Finally, a comparison of subliminal with supraliminal letters showed increases in the left middle temporal gyrus (BA 21) and the right extrastriate cortex (BA 19).     

Neural correlates of creativity in analogical reasoning

Brain-based evidence has implicated the frontal pole of the brain as important for analogical mapping. Separately, cognitive research has identified semantic distance as a key determinant of the creativity of analogical mapping (i.e., more distant analogies are generally more creative). Here, we used functional magnetic resonance imaging to assess brain activity during an analogy generation task in which we varied the semantic distance of analogical mapping (as derived quantitatively from a latent semantic analysis). Data indicated that activity within an a priori region of interest in left frontopolar cortex covaried parametrically with increasing semantic distance, even after removing effects of task difficulty. Results implicate increased recruitment of frontopolar cortex as a mechanism for integrating semantically distant information to generate solutions in creative analogical reasoning.     

Vowels in early words: an event-related potential study

Previous behavioural research suggests that infants possess phonologically detailed representations of the vowels and consonants in familiar words. These tasks examine infants' sensitivity to mispronunciations of a target label in the presence of a target and distracter image. Sensitivity to the mispronunciation may, therefore, be contaminated by the degree of mismatch between the distracter label and the heard mispronounced label. Event-related potential (ERP) studies allow investigation of infants' sensitivity to the relationship between a heard label (correct or mispronounced) and the referent alone using single picture trials. ERPs also provide information about the timing of lexico-phonological activation in infant word recognition. The current study examined 14-month-olds' sensitivity to vowel mispronunciations of familiar words using ERP data from single picture trials. Infants were presented with familiar images followed by a correct pronunciation of its label, a vowel mispronunciation or a phonologically unrelated non-word. The results support and extend previous behavioural findings that 14-month-olds are sensitive to mispronunciations of the vowels in familiar words using an ERP task. We suggest that the presence of pictorial context reinforces infants' sensitivity to mispronunciations of words, and that mispronunciation sensitivity may rely on infants accessing the cross-modal associations between word forms and their meanings.     

Conceptual integration and metaphor: an event-related potential study

Event-related brain potentials (ERPs) were recorded from 18 normal adults as they read sentences that ended with words used literally, metaphorically, or in an intermediate literal mapping condition. In the latter condition, the literal sense of the word was used in a way that prompted readers to map conceptual structure from a different domain. ERPs measured from 300 to 500 msec after the onset of the sentence-final words differed as a function of metaphoricity: Literal endings elicited the smallest N400, metaphors the largest N400, whereas literal mappings elicited an N400 of intermediate amplitude. Metaphoric endings also elicited a larger posterior positivity than did either literal or literal mapping words. Consistent with conceptual blending theory, the results suggest that the demands of conceptual integration affect the difficulty of both literal and metaphorical language.     

Response-monitoring dysfunction in schizophrenia: an event-related brain potential study

Error-monitoring abnormalities may underlie positive symptoms of schizophrenia. Response-synchronized event-related potentials during picture-word matching yielded error- and correct-response-related negativity (ERN, CRN) and positivity (Pe, Pc) and preresponse lateralized readiness potentials (LRP) from 18 schizophrenic patients and 18 controls. Both groups responded faster to matches than nonmatches, although patients were generally slower and made more errors to nonmatches. Compared with controls, patients, particularly with paranoid subtype, had smaller ERNs and larger CRNs, which were indistinguishable. LRPs showed evidence of more response conflict before errors than before correct responses in controls but not patients. Despite ERN/CRN abnormalities, post-error slowing and Pe were normal in patients, suggesting a dissociation of ERN and error awareness. Anterior cingulate and dorsolateral prefrontal cortical dysfunction in schizophrenia are implicated.     

Perspective-taking and depth of theory-of-mind reasoning in sequential-move games

Theory-of-mind (ToM) involves modeling an individual's mental states to plan one's action and to anticipate others' actions through recursive reasoning that may be myopic (with limited recursion) or predictive (with full recursion). ToM recursion was examined using a series of two-player, sequential-move matrix games with a maximum of three steps. Participants were assigned the role of Player I, controlling the initial and the last step, or of Player II, controlling the second step. Appropriate for the assigned role, participants either anticipated or planned Player II's strategy at the second step, and then determined Player I's optimal strategy at the first step. Participants more readily used predictive reasoning as Player II (i.e., planning one's own move) than as Player I (i.e., anticipating an opponent's move), although they did not differ when translating reasoning outcome about the second step to optimal action in the first step. Perspective-taking influenced likelihood of predictive reasoning, but it did not affect the rate at which participants acquired it during the experimental block. We conclude that the depth of ToM recursion (related to perspective-taking mechanisms) and rational application of belief-desire to action (instrumental rationality) constitute separate cognitive processes in ToM reasoning.     

Understanding orbitofrontal contributions to theory-of-mind reasoning: implications for autism

Autism is a lifelong developmental disorder that is associated with severe difficulties with "theory-of-mind"--the understanding that others' behaviors are motivated by internal mental states. Here, we raise the possibility that research examining the neural bases of theory-of-mind reasoning has the potential to inform researchers about the elusive functional neural impairments associated with autism. Evidence from our lab and others' suggests that theory-of-mind reasoning may be fractionated into at least two functionally and anatomically distinct neural circuits. Specifically, the ability to decode others' mental states from observable cues (such as facial expressions) may rely on contributions from the orbitofrontal/medial temporal circuit within the right hemisphere. In contrast, the ability to reason about others' mental states may rely left medial frontal regions. We conclude by reviewing evidence suggesting that the developmental roots of autism might lie in abnormal functioning of the orbitofrontal/medial temporal circuit which may, in turn, underlie the abnormal development of social-cognitive skills among individuals with autism.     

Neural correlates of infant accent discrimination: an fNIRS study

The present study investigated the neural correlates of infant discrimination of very similar linguistic varieties (Quebecois and Parisian French) using functional Near InfraRed Spectroscopy. In line with previous behavioral and electrophysiological data, there was no evidence that 3‐month‐olds discriminated the two regional accents, whereas 5‐month‐olds did, with the locus of discrimination in left anterior perisylvian regions. These neuroimaging results suggest that a developing language network relying crucially on left perisylvian cortices sustains infants’ discrimination of similar linguistic varieties within this early period of infancy.     

The neural basis of insight problem solving: an event-related potential study

The electrophysiological correlates of successful insight problem solving (Chinese logogriphs) were studied in 18 healthy subjects using high-density event-related potentials (ERPs). A new experimental paradigm (learning-testing model) was adopted in order to make subjects find a solution on their own initiative rather than receive an answer passively. Results showed that Successful guessed logogriphs elicited a more positive ERP deflection (P200-600) than did Unsuccessful guessed logogriphs in the time window from 200 to 600 ms after onset of the stimuli. Subsequently Successful logogriphs elicited a more negative ERP deflection than did Unsuccessful logogriphs in the time windows of 1500-2000 ms (N1500-2000) and 2000-2500 ms (N2000-2500). Maps of the P200-600 showed strong activity in the midline parieto-occipital scalp regions. Dipole analysis localized the generator of P200-600 in the left superior temporal gyrus and parietotemporo-occipital cortex areas. The N1500-2000 and N2000-2500 had a distinct activation over left frontal scalp regions. Dipole analysis localized the generator of the N1500-2000 in the anterior cingulate cortex (ACC) and the N2000-2500 in the posterior cingulate cortex (PCC). This result indicates that the parietotemporo-occipital cortex areas might be involved in forming rich associations in the early stage of successful logogriph solving. Then, the ACC might play an important role in the breaking mental set and the forming of novel associations. At last, "Aha" feeling might activate the PCC.     

Increased attention for computer-tailored health communications: an event-related potential study.

The authors tested whether individually tailored health communications receive more attention from the reader than nontailored health communications in a randomized, controlled trial among student volunteers (N = 24). They used objective measures of attention allocation during the message exposure. In a between-subjects design, participants had to read tailored or nontailored nutrition education messages and at the same time had to pay attention to specific odd auditory stimuli in a sequence of frequent auditory stimuli (odd ball paradigm). The amount of attention allocation was measured by recording event-related potentials (ERPs; i.e., N100 and P300 ERPs) and reaction times. For the tailored as opposed to the nontailored group, results revealed larger amplitudes for the N100 effect, smaller amplitudes for the P300 effect, and slower reaction times. Resource allocation theory and these results suggest that those in the tailored group allocated more attention resources to the nutrition message than those in the nontailored group.     

Nicotine and sensory memory in Alzheimer's disease: an event-related potential study

The auditory mismatch negativity (MMN) event-related brain potential (ERP) reflects the storage of information in acoustic sensory memory. Thirteen patients with probable Alzheimer's disease (AD), 6 receiving treatment with the cholinesterase inhibitor (ChEI) tacrine (tetrahydroaminoacridine, THA) and 7 receiving no treatment, were administered 2 mg of nicotine polacrilex and placebo. MMNs were recorded with 1- and 3-s interstimulus intervals pre- and postplacebo/nicotine administration. In nontreated patients, amplitudes were decreased from pre- to postplacebo recordings but remained stable in THA-treated patients. Comparison of pre- and postnicotine MMNs found amplitude increases with nicotine in nontreated but not THA-treated patients. MMN latencies were shortened by nicotine in both treatment groups. These exploratory findings suggest that nicotine-improved strength of acoustic sensory memory traces and speed of acoustic sensory discrimination in AD are differentially affected by chronic ChEI treatment.     

The influence of contour fragmentation on recognition memory: an event-related potential study

The present study was carried out to examine how the event-related potentials to fragmentation predict recognition success. Stimuli were abstract meaningless figures that were either complete or fragmented to various extents but still recoverable. Stimuli were first encoded as part of a symmetry discrimination task. In a subsequent recognition phase, encoded stimuli were presented complete along with never presented stimuli and participants performed an old/new discrimination task. Fragmentation stimuli elicited more negative ERPs than complete figures over the frontal, central and parietal areas between 180 and 260 ms, and over the occipito-temporal areas between 220 and 340 ms. Only this latter effect was modulated as a function of whether stimuli were recognized or not during the recognition phase of the memory test. More specifically, the effect occurred for stimuli that were later forgotten and was absent for stimuli that were later recognized. This ERP to fragmentation, the occipito-temporal N(frag), possibly reflects the brain response to encoding difficulty, and is thus predictive of recognition performance.     

Age difference in numeral recognition and calculation: an event-related potential study.

In this study, we investigated the age difference in numeral recognition and calculation in one group of school-aged children (n = 38) and one of undergraduate students (n = 26) using the event-related potential (ERP) methods. Consistent with previous reports, the age difference was significant in behavioral results. Both numeral recognition and calculation elicited a negativity peaking at about 170-280 ms (N2) and a positivity peaking at 200-470 ms (pSW) in raw ERPs, and a difference potential (dN3) between 360 and 450 ms. The difference between the two age groups indicated that more attention resources were devoted to arithmetical tasks in school-aged children, and that school-aged children and undergraduate students appear to use different strategies to solve arithmetical problems. The analysis of frontal negativity suggested that numeral recognition and mental calculation impose greater load on working memory and executive function in schoolchildren than in undergraduate students. The topography data determined that the parietal regions were responsible for arithmetical function in humans, and there was an age-related difference in the area of cerebral activation.     

Accessing word meaning in two languages: an event-related brain potential study of beginning bilinguals

Twenty-eight native-English speakers enrolled in beginning and intermediate university Spanish courses participated in a mixed language semantic categorization task in which critical words were presented in English (L1) and Spanish (L2) and repetitions of these words (within- and between-languages) were presented on subsequent trials (i.e., immediate repetition). Event-related potentials were recorded to all items allowing for comparisons of the N400 component to repetitions within- and between-languages as well as to words presented for the first time. Three important findings were observed in this sample of participants during relatively early stages of acquiring a second language. First, in the typical N400 window (300-500ms), between-language repetition (translation) produced a smaller reduction in N400 amplitude than did within-language repetition. Second, the time-course of between-language repetition effects tended to be more extended in time and differed as a function of language with L2-L1 repetitions producing larger priming effects early (during the typical N400 window) and L1-L2 repetitions producing larger priming effects later (during windows after the typical N400). Third, a greater negativity in the ERP waveforms was observed when the word on the directly preceding trial was from the other language. Within the time frame of the N400, this language switch effect arose only when the target word was Spanish and the preceding word English (i.e., L1-L2). The results are discussed within the framework of current models of bilingual lexical processing.     

Neural correlates of morphological decomposition in a morphologically rich language: an fMRI study

By employing visual lexical decision and functional MRI, we studied the neural correlates of morphological decomposition in a highly inflected language (Finnish) where most inflected noun forms elicit a consistent processing cost during word recognition. This behavioral effect could reflect suffix stripping at the visual word form level and/or subsequent meaning integration at the semantic-syntactic level. The first alternative predicts increased activation for inflected vs. monomorphemic words in the left occipitotemporal cortex while the second alternative predicts left inferior frontal gyrus and/or left posterior temporal activation increases. The results show significant activation effects in the latter areas. This provides support for the second alternative, i.e., that the morphological processing cost stems from the semantic-syntactic level.     

Neural correlates of dual task interference in rapid visual streams: an fMRI study

In rapid streams of visual stimuli, identification of a first target interferes with identification of a second target presented within the next half second (the attentional blink or AB). It has been suggested that rapid perceptual decisions under masking interference involve interactions between frontal and posterior cortex. We investigated the neural correlates of the AB using functional magnetic resonance imaging (fMRI). Twelve subjects viewed rapid streams of black letters in which were embedded two white target letters (T1 and T2) separated by either 300 or 700 ms. As expected, fewer correct T2 identifications were observed in the short-delay condition. Corresponding fMRI statistical images showed increased activation in inferotemporal and posterior parietal cortex, but also in lateral frontal cortex and cerebellum in the short-delay condition suggesting that these brain regions are associated with perceptual decisions under masking interference.