Showing papers in "Neuroreport in 2008"
TL;DR: It is suggested that tDCS at 1 mA enhances working memory in a time-dependent manner for at least 30 min in healthy participants.
Abstract: The time-dependent effect of transcranial direct current stimulation (tDCS) on working memory was investigated by applying anodal stimulation over the left prefrontal cortex. This single-blind, sham-controlled crossover study recruited 15 healthy participants. A three-back verbal working-memory task was performed before, during, and 30 min after 1 mA anodal or sham tDCS. Anodal tDCS, compared with sham stimulation, significantly improved working-memory performance. Accuracy of response was significantly increased after 20 min of tDCS application, and was further enhanced after 30 min of stimulation. This effect was maintained for 30 min after the completion of stimulation. These results suggest that tDCS at 1 mA enhances working memory in a time-dependent manner for at least 30 min in healthy participants.
354 citations
TL;DR: Individual posterior posterior &agr;-band power to correlate with the individual threshold for eliciting illusory, transcranial magnetic stimulation-induced visual percepts provides direct support for an &agR;/excitability link and for baseline states of the visual brain to vary across individuals.
Abstract: Variations of oscillatory brain activity have been related to distinct functional states depending on the frequency of oscillations. In the alpha-band (about 8-14 Hz), decreased oscillatory activity is thought to reflect a state of enhanced cortical excitability, and increased activity to reflect a state of cortical idling or inhibition in which excitability is reduced, but the alpha/excitability link has not been probed directly. Here, we studied the relationship between resting oscillatory activity and visual cortex excitability across participants using electroencephalography and transcranial magnetic stimulation to the occipital pole. We found individual posterior alpha-band power to correlate with the individual threshold for eliciting illusory, transcranial magnetic stimulation-induced visual percepts. This provides direct support for an alpha/excitability link and for baseline states of the visual brain to vary across individuals.
267 citations
TL;DR: It is demonstrated that oxytocin receptor plays essential roles in the regulation of energy homeostasis with late-onset obesity with increases in abdominal fat pads and fasting plasma triglycerides in Oxtr−/− mice.
Abstract: The oxytocin receptor has been suggested to be involved in energy metabolism, such as food intake and energy consumption. Here, we demonstrate that oxytocin receptor-deficient (Oxtr -/- ) male mice exhibited late-onset obesity with increases in abdominal fat pads and fasting plasma triglycerides. Daily food intake and spontaneous motor activity of Oxtr -/- mice were not significantly different as compared with wild-type mice. In contrast, brown adipose tissue in Oxtr -/- mice contained large lipid droplets and cold-induced thermogenesis was impaired. This study demonstrates that oxytocin receptor plays essential roles in the regulation of energy homeostasis.
238 citations
TL;DR: Both region of interest-based analyses and independent component analysis identified the default mode network and there was less agreement between analytic techniques regarding age and sex effects than regardingdefault mode network structure.
Abstract: The 'default mode network' is a set of brain regions showing correlated, low-frequency activity during rest. It includes the posterior cingulate/precuneus, medial prefrontal cortex, and bilateral inferior parietal cortex. Earlier studies have characterized this network using either region of interest-based correlation analyses or data-driven techniques; however, there is some disagreement over which method is superior. We conducted both types of analysis on a large (N=40) data set and also investigated age and sex differences in the network. Both region of interest-based analyses and independent component analysis identified the default mode network. Age and sex differences were small and there was less agreement between analytic techniques regarding age and sex effects than regarding default mode network structure.
205 citations
TL;DR: This article found that anticipation of viewing rewarding stimuli (erotic pictures for 15 heterosexual men) increased financial risk taking, and that this effect was partially mediated by increases in nucleus accumbens activation.
Abstract: In functional magnetic resonance imaging research, nucleus accumbens (NAcc) activation spontaneously increases before financial risk taking. As anticipation of diverse rewards can increase NAcc activation, even incidental reward cues may influence financial risk taking. Using event-related functional magnetic resonance imaging, we predicted and found that anticipation of viewing rewarding stimuli (erotic pictures for 15 heterosexual men) increased financial risk taking, and that this effect was partially mediated by increases in NAcc activation. These results are consistent with the notion that incidental reward cues influence financial risk taking by altering anticipatory affect, and so identify a neuropsychological mechanism that may underlie effective emotional appeals in financial, marketing, and political domains.
190 citations
TL;DR: Findings demonstrate an influence of early, presumably presemantic processes on the own-race bias, which are mediated by perceptual expertise with other-race faces.
Abstract: Humans remember own-race faces more accurately than other-race faces (own-race bias). This effect is reduced by expertise with other-race faces. This study examined event-related potentials to own-race and other-race faces in a group of experts to other-race faces and a nonexpert control group. Both groups exhibited own-race recognition biases. Other-race faces elicited more negative and delayed N170 components, suggesting enhanced configural processing of own-race compared with other-race faces. Moreover, an increased P2 (approximately 210-240 ms) was observed for own-race faces. At right occipitotemporal regions of the experts only this P2 effect was found to be absent. These findings demonstrate an influence of early, presumably presemantic processes on the own-race bias, which are mediated by perceptual expertise with other-race faces.
182 citations
TL;DR: Structural magnetic resonance imaging scans showed that patients treated with lithium exhibited significantly increased volumes of the amygdala and hippocampus compared with patients who were not taking lithium, which may help to explain previous inconsistencies in the bipolar literature.
Abstract: Previous structural neuroimaging studies of bipolar disorder have reported conflicting findings in limbic structures. Medication heterogeneity of patient samples may have contributed to these inconsistencies. Using structural magnetic resonance imaging we assessed whether lithium treatment was associated with differences in amygdala and hippocampal volumes in a sample of bipolar adults. A total of 49 magnetic resonance imaging scans were collected from patients who were currently treated with or without lithium. Amygdala and hippocampal volumes were analyzed using tensor-based morphometry. Statistical between-group comparisons of deformation maps showed that patients treated with lithium exhibited significantly increased volumes of the amygdala and hippocampus compared with patients who were not taking lithium. Our findings may help to explain previous inconsistencies in the bipolar literature.
167 citations
TL;DR: Results support that disruptions in motor and attentional networks may contribute toward ADHD pathophysiology and clarify how ADHD subtype and psychiatric comorbidities affect diffusion measures.
Abstract: We used diffusion tensor imaging to investigate fractional anisotropy (FA), a measure of fiber tract integrity, in attention-deficit hyperactivity disorder (ADHD). Using a tract-based atlasing approach on six-direction diffusion tensor imaging data, we examined FA within the cingulum, corpus callosum, corticospinal tract, fornix, optic radiations, superior longitudinal fasciculus, uncinate fasciculus, and the superior and inferior occipitofrontal fasciculi in an all-male sample of 17 children and adolescents with ADHD and 16 age-matched controls. ADHD patients had significantly lower FA in the corticospinal tract (P=0.02) and the superior longitudinal fasciculus (P=0.017) compared with controls. Results support that disruptions in motor and attentional networks may contribute toward ADHD pathophysiology. Future research may clarify how ADHD subtype and psychiatric comorbidities affect diffusion measures.
164 citations
TL;DR: Using independent components analysis and region-of-interest-based functional connectivity analyses, bilateral resting state networks are demonstrated in a patient lacking all major cerebral commissures, suggesting that cortical networks in the brain can be coordinated by subcortical mechanisms.
Abstract: Split-brain patients present a unique opportunity to address controversies regarding subcortical contributions to interhemispheric coordination. We characterized residual functional connectivity in a complete commissurotomy patient by examining patterns of low-frequency BOLD functional MRI signal. Using independent components analysis and region-of-interest-based functional connectivity analyses, we demonstrate bilateral resting state networks in a patient lacking all major cerebral commissures. Compared with a control group, the patient's interhemispheric correlation scores fell within the normal range for two out of three regions examined. Thus, we provide evidence for bilateral resting state networks in a patient with complete commissurotomy. Such continued interhemispheric interaction suggests that, at least in part, cortical networks in the brain can be coordinated by subcortical mechanisms.
153 citations
TL;DR: These results are the first report of a specific decrease in fast spindles in AD, associated with learning abilities, and give further hints for a functional differentiation between slow and fast spINDles.
Abstract: Aging and Alzheimer's disease (AD) are both characterized by memory impairments and sleep changes. We investigated the potential link between these disturbances, focusing on sleep spindles, involved in memory consolidation. Two episodic memory tasks were given to young and old healthy participants, as well as to AD patients. Postlearning sleep was recorded. Sleep spindles were globally reduced in aging and AD. AD patients also exhibited a further decrease in fast spindles. Besides, mean intensity of fast spindles was positively correlated, in AD patients, with immediate recall performance. Our results are the first report of a specific decrease in fast spindles in AD, associated with learning abilities. They also give further hints for a functional differentiation between slow and fast spindles.
151 citations
TL;DR: Independent of speaker voice, emotional sentences could be differentiated from neutral sentences as early as 200 ms after sentence onset (P200), suggesting rapid emotional decoding.
Abstract: Decoding verbal and nonverbal emotional expressions is an important part of speech communication. Although various studies have tried to specify the brain regions that underlie different emotions conveyed in speech, few studies have aimed to specify the time course of emotional speech decoding. We used event-related potentials to determine when emotional speech is first differentiated from neutral speech. Participants engaged in an implicit emotional processing task (probe verification) while listening to emotional sentences spoken by a female and a male speaker. Independent of speaker voice, emotional sentences could be differentiated from neutral sentences as early as 200 ms after sentence onset (P200), suggesting rapid emotional decoding.
TL;DR: The combined data indicate that music-syntactically irregular events elicit brain activity related to emotional processes, and that, in addition to intensely pleasurable music or highly unpleasant music, single chord functions can also modulate amygdala activity.
Abstract: Numerous earlier studies have investigated the cognitive processing of musical syntax with regular and irregular chord sequences. However, irregular sequences may also be perceived as unexpected, and therefore have a diierent emotional valence than regular sequences. We provide behavioral data showing that irregular chord functions presented in chord sequence paradigms are perceived as less pleasant than regular sequences. A reanalysis of functional MRI data showed increased blood oxygen leveldependent signal changes bilaterally in the amygdala in response to music-syntactically irregular (compared with regular) chord functions.The combined data indicate that music-syntactically irregular events elicit brain activity related to emotional processes, and that, in addition to intensely pleasurable music or highly unpleasant music, single chord functions can also modulate amygdala activity. NeuroReport 19:1815^1819 � c 2008 Wolters Kluwer Health | Lippincott Williams & Wilkins.
TL;DR: Findings provide direct evidence that AQP4 is essential for the maintenance of blood–brain barrier integrity.
Abstract: To investigate the role of astroglial water channel aquaporin-4 (AQP4) in maintaining blood-brain barrier integrity, structure and permeability of the brain microvessels were investigated in adult AQP4 knockout mice. Altered ultrastructure of brain microvessels, including open tight junctions and swollen perivascular astrocytic endfeet, were frequently observed in the AQP4 null mice. Likewise, AQP4 deficiency significantly downregulated expression of glial fibrillary acidic protein in perivascular processes of astrocytes. Furthermore, the horseradish peroxidase analysis demonstrated hyperpermeability of the blood-brain barrier in AQP4 knockout mice. These findings provide direct evidence that AQP4 is essential for the maintenance of blood-brain barrier integrity.
TL;DR: The functional neuroanatomy of verbal working memory provides a statistically significant but clinically moderate contribution as a diagnostic biomarker for depression, whereas its potential as a neural predictor of clinical response requires further investigation.
Abstract: The functional neuroanatomy of verbal working memory is a potential diagnostic biomarker for depression. Twenty patients with unipolar depression and 20 healthy controls performed a variable load version (n-back) of the task. Functional MRI data were analysed with support vector machine methods. Diagnostic classification was highest at the mid-level of task difficulty (2-back) (sensitivity 65%, specificity 70%, P<0.009). Significant classification of clinical response (≥50% reduction in clinical symptom ratings) was found at the most difficult level (3-back) (sensitivity 85%, specificity 52%, P<0.003). The functional neuroanatomy of verbal working memory provides a statistically significant but clinically moderate contribution as a diagnostic biomarker for depression, whereas its potential as a neural predictor of clinical response requires further investigation.
TL;DR: Results indicate that Thy1-&agr;Syn mice display altered basal and stress-stimulated propulsive colonic motility and will be a useful model to study gut dysfunction associated with Parkinson's disease.
Abstract: The presynaptic protein alpha-synuclein (alphaSyn) has been implicated in both familial and sporadic forms of Parkinson's disease. We examined whether human alphaSyn-overexpressing mice under Thy1 promoter (Thy1-alphaSyn) display alterations of colonic function. Basal fecal output was decreased in Thy1-alphaSyn mice fed ad libitum. Fasted/refed Thy1-alphaSyn mice had a slower distal colonic transit than the wild-type mice, as monitored by 2.2-fold increase in time to expel an intracolonic bead and 2.9-fold higher colonic fecal content. By contrast, Thy1-alphaSyn mice had an increased fecal response to novelty stress and corticotropin releasing factor injected intraperipherally. These results indicate that Thy1-alphaSyn mice display altered basal and stress-stimulated propulsive colonic motility and will be a useful model to study gut dysfunction associated with Parkinson's disease.
TL;DR: Findings consolidate evidence linking MAO A to aggression and highlight subtle yet distinctive phenotypical characteristics in a novel line of mutant mice harboring a spontaneous point nonsense mutation.
Abstract: A novel line of mutant mice [monoamine oxidase A knockout (MAOAA863T KO)] harboring a spontaneous point nonsense mutation in exon 8 of the MAO A gene was serendipitously identified in a 129/SvEvTac colony. This mutation is analogous to the cause of a rare human disorder, Brunner syndrome, characterized by complete MAO A deficiency and impulsive aggressiveness. Concurrent with previous studies of MAO A KO mice generated by insertional mutagenesis (‘Tg8’), MAOAA863T KO lack MAO A enzyme activity and display enhanced aggression toward intruder mice. MAOAA863T KO, however, exhibited lower locomotor activity in a novel, inescapable open field and similar immobility during tail suspension compared with wild type, observations which differ from reports of Tg8. These findings consolidate evidence linking MAO A to aggression and highlight subtle yet distinctive phenotypical characteristics.
TL;DR: The present findings suggest that abnormal responses to negative feedback extend to samples at increased risk for depressive episodes in the absence of current symptoms.
Abstract: Major depressive disorder (MDD) is characterized by hypersensitivity to negative feedback that might involve frontocingulate dysfunction. MDD patients exhibit enhanced electrophysiological responses to negative internal (errors) and external (feedback) cues. Whether this dysfunction extends to remitted depressed (RD) individuals with a history of MDD is currently unknown. To address this issue, we examined the feedback-related negativity in RD and control participants using a probabilistic punishment learning task. Despite equivalent behavioral performance, RD participants showed larger feedback-related negativities to negative feedback relative to controls; group differences remained after accounting for residual anxiety and depressive symptoms. The present findings suggest that abnormal responses to negative feedback extend to samples at increased risk for depressive episodes in the absence of current symptoms.
TL;DR: The findings constitute the first report that pharmacological inhibition of P2X7R, possibly by acting to inhibit inflammatory reactivity, confers neuroprotection in an animal model of Alzheimer's disease brain.
Abstract: Pharmacological antagonism of the ionotropic purinergic P2X 7 R has been studied for effects on inflammatory reactivity and neuronal viability in amyloid-βΙ-42-injected rat hippocampus. Amyloid-β 1-42 -injected brains (7-day postinjection) demonstrated marked increases in P2X 7 R expression, gliosis, leakiness of blood-brain barrier and loss of hippocampal neurons. The P2X 7 R antagonist, brilliant blue G reduced levels of purinergic receptor expression, attenuated gliosis, diminished leakiness of blood-brain barrier and was neuroprotective in peptide-injected brain. Brilliant blue G also demonstrated neuroprotection and antagonism against inflammatory responses induced by the P2X 7 R agonist, 2',3'-(benzoyl-4-benzoyl)-ATP.The findings constitute the first report that pharmacological inhibition of P2X 7 R, possibly by acting to inhibit inflammatory reactivity, confers neuroprotection in an animal model of Alzheimer's disease brain.
TL;DR: The findings indicate that individual differences in temperament are an important determinant of the early neural response to threat, and demonstrate that this early bias is modulated by trait anxiety.
Abstract: We investigated the electrophysiological markers of attentional bias for threat in anxiety. Low-anxiety and high-anxiety individuals performed a spatial-cueing task, in which an emotional facial expression (angry or happy) was presented alongside a neutral expression. Results revealed that angry expressions elicited an enhanced N2pc component, but that this was true only for those reporting high levels of trait anxiety. These results confirm the early capture of spatial attention by threat-related stimuli, and demonstrate that this early bias is modulated by trait anxiety. Enhanced P1 amplitudes to targets after presentations of angry expressions were also found; however, this effect was not modulated by trait anxiety levels. Our findings indicate that individual differences in temperament are an important determinant of the early neural response to threat.
TL;DR: It is suggested that happiness/sadness emotional processing might be related to stress reduction by music, and that music specifically induces an emotional response similar to a pleasant experience or happiness.
Abstract: Neurocognitive research has the potential to identify the relevant effects of music therapy. In this study, we examined the effect of music mode (major vs. minor) on stress reduction using optical topography and an endocrinological stress marker. In salivary cortisol levels, we observed that stressful conditions such as mental fatigue (thinking and creating a response) was reduced more by major mode music than by minor mode music. We suggest that music specifically induces an emotional response similar to a pleasant experience or happiness. Moreover, we demonstrated the typical asymmetrical pattern of stress responses in upper temporal cortex areas, and suggested that happiness/sadness emotional processing might be related to stress reduction by music.
TL;DR: Findings suggest that the two corticostriatal circuits are functionally integrated, and new circuit models based on functional connectivity may need to be developed.
Abstract: Models of corticostriatal motor circuitry have focused on the role of the circuit in the hemisphere of the motor cortex providing primary control (contralateral to the movement). We used functional magnetic resonance imaging and functional connectivity analyses to study circuit function in both the controlling and noncontrolling hemispheres. During the completion of a unilateral motor task with either hand, each putamen nucleus demonstrated strong coactivation with structures in both hemispheres. The putamen in the noncontrolling hemisphere (ipsilateral to the movement) coactivated more strongly with the controlling motor cortex than with the noncontrolling cortex. These findings suggest that the two corticostriatal circuits are functionally integrated. New circuit models based on functional connectivity may need to be developed.
TL;DR: It is demonstrated that naturally occurring compounds (−)-epigallocatechin-3-gallate and curcumin suppress &bgr; amyloid-induced BACE-1 upregulation and have novel pharmacological effects that may be beneficial for Alzheimer's disease treatment.
Abstract: Beta-site APP cleaving enzyme-1 (BACE-1), is a rate-limiting enzyme for beta amyloid production. Beta amyloid induces the production of radical oxygen species and neuronal injury. Oxidative stress plays a key role in various neurological diseases such as ischemia and Alzheimer's disease. Recent studies suggest that oxidative stress induces BACE-1 protein upregulation in neuronal cells. Here, we demonstrate that naturally occurring compounds (-)-epigallocatechin-3-gallate and curcumin suppress beta amyloid-induced BACE-1 upregulation. Exposure of beta amyloid 1-42 to neuronal culture increased BACE-1 protein levels. (-)-Epigallocatechin-3-gallate or curcumin significantly attenuated beta amyloid-induced radical oxygen species production and beta-sheet structure formation. These two compounds have novel pharmacological effects that may be beneficial for Alzheimer's disease treatment.
TL;DR: Evidence is presented from two individuals suggestive that this condition, long thought to be entirely psychological in origin, actually has a neurological basis and it is proposed apotemnophilia arises from congenital dysfunction of the right superior parietal lobule and its connection with the insula.
Abstract: Apotemnophilia, a disorder that blurs the distinction between neurology and psychiatry, is characterized by the intense and longstanding desire for amputation of a specific limb. Here we present evidence from two individuals suggestive that this condition, long thought to be entirely psychological in origin, actually has a neurological basis. We found heightened skin conductance response to pinprick below the desired line of amputation. We propose apotemnophilia arises from congenital dysfunction of the right superior parietal lobule and its connection with the insula.
TL;DR: Findings support the view that at early preattentive stages of subcortical processing, neural mechanisms underlying pitch representation are shaped by particular features of the auditory stream rather than speech per se.
Abstract: Frequency-following responses were recorded from Chinese and English participants at the level of the brainstem in response to four Mandarin tonal contours presented in a speech and nonspeech context. Pitch strength analysis of these preattentive brainstem responses showed that the Chinese group exhibited stronger pitch representation than the English group regardless of context. Moreover, the Chinese group exhibited relatively more robust pitch representation of rapidly changing pitch segments. These findings support the view that at early preattentive stages of subcortical processing, neural mechanisms underlying pitch representation are shaped by particular features of the auditory stream rather than speech per se. These findings have implications for optimizing signal-processing strategies for cochlear implant design for speakers of tonal languages.
TL;DR: This study suggests two white matter pathways that may be differentially associated with reading skills in the CC splenium in dyslexic readers and typical readers.
Abstract: Inconsistent differences in the corpus callosum (CC) structure between dyslexic readers (DRs) and typical readers (TRs) have been reported. We examine differences in CC splenium microstructure and the association of splenium microstructure with reading related skills. Nine DRs and eighteen TRs completed a reading skills battery and diffusion tensor imaging (DTI). DRs had higher splenium fractional anisotropy (FA) and axial diffusivity (LA) as compared to TRs. Retrieval of orthographic information from the language lexicon was negatively associated with FA and LA within both reading groups. Phonological awareness was positively associated with splenium FA and LA in TDs but not DRs. This study suggests two white matter pathways that may be differentially associated with reading skills in the CC splenium.
TL;DR: This work focused on the relationship between self and other, and recorded ERPs during an alternative gambling task performed by two players (participant and virtual player), indicating that FRN reflects the evaluation on the basis of one's own evaluative criteria, regardless of the monetary outcome for another.
Abstract: The evaluation of whether an outcome is good or bad is reflected in feedback-related negativity (FRN), which is an event-related brain potential (ERP) component that is elicited by bad events. It is still, however, unclear how the FRN reflects the evaluation of outcomes induced by others. We focused on the relationship between self and other, and recorded ERPs during an alternative gambling task performed by two players (participant and virtual player). FRN was elicited not only by the losses of another in a cooperative situation but also by the gains of another in an antagonistic situation. These results indicate that FRN reflects the evaluation on the basis of one's own evaluative criteria, regardless of the monetary outcome for another.
TL;DR: Stress-induced activation of the dynorphin-KOR systems activates ERK1/2 MAPK signaling, and this may contribute to the behavioral responses to repeated stress exposure.
Abstract: Earlier studies identified the dynorphin-kappa opioid receptor (KOR) system as a critical mediator of dysphoria-induced aversion after repeated stress exposure, but the molecular signaling mechanisms were not fully characterized. In this study we report that repeated forced swim stress caused a significant phosphorylation of extracellular signal-regulated kinase (ERK)1/2 a mitogen-activated protein kinase (MAPK) in both the caudate and nucleus accumbens regions of the mouse striatum. Activation was blocked by the KOR antagonist, norbinaltorphimine, and absent in KOR knockout mice. In contrast to p38-MAPK activation by stress-induced dynorphin release, KOR-mediated ERK1/2 phosphorylation was not dependent on G-protein coupled receptor kinase 3 expression. These results indicate stress-induced activation of the dynorphin-KOR systems activates ERK1/2 MAPK signaling, and this may contribute to the behavioral responses to repeated stress exposure.
TL;DR: A role for microstructure in left white matter tracts for the development of mathematical skills is suggested and the findings point to the involvement of different white Matter tracts for numerical operations and mathematical reasoning.
Abstract: The role of gray matter function and structure in mathematical cognition has been well researched. Comparatively little is known about white matter microstructures associated with mathematical abilities. Diffusion tensor imaging data from 13 children (7-9 years) and two measures of their mathematical competence were collected. Relationships between children's mathematical competence and fractional anisotropy were found in two left hemisphere white matter regions. Although the superior corona radiata was found to be associated with both numerical operations and mathematical reasoning, the inferior longitudinal fasciculus was correlated with numerical operations specifically. These findings suggest a role for microstructure in left white matter tracts for the development of mathematical skills. Moreover, the findings point to the involvement of different white matter tracts for numerical operations and mathematical reasoning.
TL;DR: This study explored the brain activity related to the fast learning of object–word mappings in 14-month-old infants and observed priming effects known from earlier infant event-related potential studies that suggest infants have learned object– word mappings by four presentations.
Abstract: Between 12 and 14 months infants switch from slow to fast word learning mode. The neural processes involved in this development are largely unknown. This study explored the brain activity related to the fast learning of object-word mappings in 14-month-old infants. After four repetitions of eight object-word pairs, two priming effects known from earlier infant event-related potential studies were observed: word form priming indexed by the fronto-lateral negativity in the 200-500 ms range and semantic priming indexed by the parietal N400. These neurophysiological correlates suggest that infants have learned object-word mappings by four presentations. In a test phase applied at least 1 day later, the N400 differentiated between trained congruous and incongruous pairings, which indicates that this newly established referential knowledge has been consolidated in memory.
TL;DR: This work compared global and regional brain volumes in 17 high-functioning autistic children with 15 matched controls using voxel-based morphometry to identify significant reduction in left white matter volume and white/gray matter ratio in autism.
Abstract: Earlier studies have suggested abnormal brain volumes in autism, but inconsistencies exist. Using voxel-based morphometry, we compared global and regional brain volumes in 17 high-functioning autistic children with 15 matched controls. We identified significant reduction in left white matter volume and white/gray matter ratio in autism. Regional brain volume reductions were detected for right anterior cingulate, left superior parietal lobule white matter volumes, and right parahippocampal gyrus gray matter volume, whereas enlargements in bilateral supramarginal gyrus, right postcentral gyrus, right medial frontal gyrus, and right posterior lobe of cerebellum gray matter in autism. Our findings showed global and regional brain volumes abnormality in high-functioning autism.