Activation In Left Fusiform Gyrus Research Articles

Cross-cultural comparison of the neural correlates of true and false memory retrieval

ABSTRACT Prior work has shown Americans have higher levels of memory specificity than East Asians. Neuroimaging studies have not investigated mechanisms that account for cultural differences at retrieval. In this study, we use fMRI to assess whether mnemonic discrimination, distinguishing novel from previously encountered stimuli, accounts for cultural differences in memory. Fifty-five American and 55 Taiwanese young adults completed an object recognition paradigm testing discrimination of old targets, similar lures and novel foils. Mnemonic discrimination was tested by comparing discrimination of similar lures from studied targets, and results showed the relationship between activity in right fusiform gyrus and behavioural discrimination between target and lure objects differed across cultural groups. Parametric modulation analyses of activity during lure correct rejections also indicated that groups differed in left superior parietal cortex response to variations in lure similarity. Additional analyses of old vs. new activity indicated that Americans and Taiwanese differ in the neural activity supporting general object recognition in the hippocampus, left inferior frontal gyrus and middle frontal gyrus. Results are juxtaposed against comparisons of the regions activated in common across the two cultures. Overall, Americans and Taiwanese differ in the extent to which they recruit visual processing and attention modulating brain regions.

Emotion processing in youths with conduct problems: an fMRI meta-analysis

Functional magnetic resonance imaging (fMRI) studies consistently indicate differences in emotion processing in youth with conduct problems. However, no prior meta-analysis has investigated emotion-specific responses associated with conduct problems. This meta-analysis aimed to generate an up-to-date assessment of socio-affective neural responding among youths with conduct problems. A systematic literature search was conducted in youths (ages 10–21) with conduct problems. Task-specific seed-based d mapping analyses examined responses to threatening images, fearful and angry facial expressions, and empathic pain stimuli from 23 fMRI studies, which included 606 youths with conduct problems and 459 comparison youths. Whole-brain analyses revealed youths with conduct problems relative to typically developing youths, when viewing angry facial expressions, had reduced activity in left supplementary motor area and superior frontal gyrus. Additional region of interest analyses of responses to negative images and fearful facial expressions showed reduced activation in right amygdala across youths with conduct problems. Youths with callous-unemotional traits also exhibited reduced activation in left fusiform gyrus, superior parietal gyrus, and middle temporal gyrus when viewing fearful facial expressions. Consistent with the behavioral profile of conduct problems, these findings suggest the most consistent dysfunction is found in regions associated with empathic responding and social learning, including the amygdala and temporal cortex. Youth with callous-unemotional traits also show reduced activation in the fusiform gyrus, consistent with reduced attention or facial processing. These findings highlight the potential role of empathic responding, social learning, and facial processing along with the associated brain regions as potential targets for interventions.

Naming fMRI predicts the effect of temporal lobe resection on language decline.

ObjectiveTo develop language functional MRI (fMRI) methods that accurately predict postsurgical naming decline in temporal lobe epilepsy (TLE).MethodsForty‐six patients with TLE (25 left) and 19 controls underwent two overt fMRI paradigms (auditory naming and picture naming, both with active baseline conditions) and one covert task (verbal fluency). Clinical naming performance was assessed preoperatively and 4 months following anterior temporal lobe resection. Preoperative fMRI activations were correlated with postoperative naming decline. Individual laterality indices (LI) were calculated for temporal (auditory and picture naming) and frontal regions (verbal fluency) and were considered as predictors of naming decline in multiple regression models, along with other clinical variables (age at onset of seizures, preoperative naming scores, hippocampal volume, age).ResultsIn left TLE patients, activation of the left posterior inferior temporal gyrus during auditory naming and activation of left fusiform gyrus during picture naming were related to greater postoperative naming decline. Activation LI were the best individual predictors of naming decline in a multivariate regression model. For picture naming, an LI of higher than 0.34 gave 100% sensitivity and 92% specificity (positive predictive value (PPV) 91.6%). For auditory naming, a temporal lobe LI higher than 0.18 identified all patients with a clinically significant naming decline with 100% sensitivity and 58% specificity (PPV: 58.3%). No effect was seen for verbal fluency.InterpretationAuditory and picture naming fMRI are clinically applicable to predict postoperative naming decline after left temporal lobe resection in individual patients, with picture naming being more specific.

2288 Neural correlates of face processing in autism spectrum disorder: A quantitative meta-analysis of current literature and future directions

OBJECTIVES/SPECIFIC AIMS: Autism spectrum disorder (ASD) affects 1 in 68 people and includes restricted, repetitive behavior, and social communication deficits. Aspects of face processing (i.e., identity, emotion perception) are impaired in some with ASD. Neuroimaging studies have shown aberrant patterns of brain activation and connectivity of face processing regions. However, small sample sizes and inconsistent results have hindered clinical utility of these findings. The study aims to establish consistent patterns of brain responses to faces in ASD and provide directions for future research. METHODS/STUDY POPULATION: Neuroimaging studies were identified through a multi-database search according to PRISMA guidelines. In total, 23 studies were retained for a sample size of 383 healthy controls and 345 ASD. Peak coordinates were extracted for activation likelihood estimation (ALE) in GingerALE v2.3.6. Follow-up ALE analyses investigated directed Versus undirected gaze, static Versus dynamic, emotional Versus neutral, and familiar Versus unfamiliar faces. RESULTS/ANTICIPATED RESULTS: Faces produced bilateral activation of the fusiform gyrus (FG) in healthy controls (−42 −52 −20; 22 −74 −12, p<0.05, FDR) and left FG activation in ASD (−42 −54 −16, p<0.05, FDR). Activation in both groups was lateral to the mid-fusiform sulcus. Follow-up results pending. DISCUSSION/SIGNIFICANCE OF IMPACT: Reduced right FG activation to faces may inform biomarker or response to intervention studies. Mid-fusiform sulcus proved a reliable predictor of functional divides should be investigated on a subject-specific level.

Effects of a Common Variant in the CD38 Gene on Social Processing in an Oxytocin Challenge Study: Possible Links to Autism

The intranasal application of oxytocin (OT) has been shown to influence behavioral and neural correlates of social processing. These effects are probably mediated by genetic variations within the OT system. One potential candidate could be the CD38 gene, which codes for a transmembrane protein engaged in OT secretion processes. A common variation in this gene (rs3796863) was recently found to be associated with autism spectrum disorders (ASD). Using an imaging genetics approach, we studied differential effects of an intranasal OT application on neural processing of social stimuli in 55 healthy young men depending on their CD38 gene variant in a double-blind placebo-controlled crossover design. Genotype had a significant influence on both behavioral and neuronal measures of social processing. Homozygotic risk allele carriers showed slower reaction times (RT) and higher activation of left fusiform gyrus during visual processing of social stimuli. Under OT activation differences between genotypes were more evident (though not statistically significantly increased) and RT were accelerated in homozygotic risk allele carriers. According to our data, rs3796863 mainly influences fusiform gyrus activation, an area which has been widely discussed in ASD research. OT seems to modulate this effect by enhancing activation differences between allele groups, which suggests an interaction between genetic makeup and OT availability on fusiform gyrus activation. These results support recent approaches to apply OT as a pharmacological treatment of ASD symptoms.

Event-related components of the punishment and reward sensitivity

The present study investigated the properties of feedback-related negativity (FRN) and P3 component of the event-related potentials (ERPs) and their neural sources localization as neurocognitive correlates of the behavioural inhibition and behavioural activation systems (BIS/BAS). The association between BIS/BAS function and anterior cortical asymmetry was tested. Fifty right-handed women were investigated with 30-channel recordings during an instrumental Go/No-Go learning task. ERPs were elicited to feedback signals indicating monetary losses and monetary gains. Learning performance, FRN, and P3 amplitude and latency measures were calculated and related to BIS and BAS measures by means of ANOVA and correlation analysis. The neural sources of FRN and P3 components of the ERPs were estimated using LORETA software. A resting EEG-alpha-power (8-13Hz) asymmetry measure was obtained. High levels of Reward Responsiveness (RR), a first order factor of the BAS, were associated with shorter RTs and enhanced positive feelings. The FRN was larger to signals indicating monetary Loss as compared to monetary Gain and enhanced with higher BIS and individual learning ability. Higher RR scores were related to greater left-sided resting frontal cortical asymmetry associated with approach orientation. High-RR subjects, as compared to Low-RR ones, had a smaller P3 amplitude for Go/Loss signals. The P3 latency to No-Go/Gain signals was the best positive predictor of RR. LORETA source localization for the FRN component displayed significantly higher brain electrical activity in left-fusiform gyrus and right superior temporal gyrus to monetary Loss in comparison to monetary Gain after incorrect No-Go responses. For the P3 wave, the monetary Loss produced significantly higher activations in the left superior parietal lobule, right postcentral gyrus, and in the ACC. The FRN was sensitive to cues of punishment and higher BIS was uniquely related to a larger FRN amplitude on No-Go/Loss trials, linking BIS with conflict monitoring and sensitivity to No-Go cues. Furthermore, the significant interaction found between BIS and RR on FRN amplitude together with the findings linking High-RR levels with shorter RTs, smaller P3 amplitudes and enhanced positive feelings are in line with the hypothesis that both BIS and BAS have the potential to influence punishment-mediated and reward-mediated behaviour. Results open up new perspectives for future investigations on the relationship between BIS/BAS measures and ERP components to monetary reward during learning.

Enhanced speech perception capabilities in a blind listener are associated with activation of fusiform gyrus and primary visual cortex

Blind individuals may learn to understand ultra-fast synthetic speech at a rate of up to about 25 syllables per second (syl)/s, an accomplishment by far exceeding the maximum performance level of normal-sighted listeners (8–10 syl/s). The present study indicates that this exceptional skill engages distinct regions of the central-visual system. Hemodynamic brain activation during listening to moderately- (8 syl/s) and ultra-fast speech (16 syl/s) was measured in a blind individual and six normal-sighted controls. Moderately-fast speech activated posterior and anterior ‘language zones’ in all subjects. Regarding ultra-fast tokens, the controls showed exclusive activation of supratemporal regions whereas the blind participant exhibited enhanced left inferior frontal and temporoparietal responses as well as significant hemodynamic activation of left fusiform gyrus (FG) and right primary visual cortex. Since left FG is known to be involved in phonological processing, this structure, presumably, provides the functional link betweeen the central-auditory and -visual systems.

Modulation of brain activity by multiple lexical and word form variables in visual word recognition: A parametric fMRI study

Psycholinguistic research has documented a range of variables that influence visual word recognition performance. Many of these variables are highly intercorrelated. Most previous studies have used factorial designs, which do not exploit the full range of values available for continuous variables, and are prone to skewed stimulus selection as well as to effects of the baseline (e.g. when contrasting words with pseudowords). In our study, we used a parametric approach to study the effects of several psycholinguistic variables on brain activation. We focussed on the variable word frequency, which has been used in numerous previous behavioural, electrophysiological and neuroimaging studies, in order to investigate the neuronal network underlying visual word processing. Furthermore, we investigated the variable orthographic typicality as well as a combined variable for word length and orthographic neighbourhood size (N), for which neuroimaging results are still either scarce or inconsistent. Data were analysed using multiple linear regression analysis of event-related fMRI data acquired from 21 subjects in a silent reading paradigm. The frequency variable correlated negatively with activation in left fusiform gyrus, bilateral inferior frontal gyri and bilateral insulae, indicating that word frequency can affect multiple aspects of word processing. N correlated positively with brain activity in left and right middle temporal gyri as well as right inferior frontal gyrus. Thus, our analysis revealed multiple distinct brain areas involved in visual word processing within one data set.

Verbal memory encoding in patients with left-sided hippocampal sclerosis

Patients with medial temporal lobe epilepsy based on left hippocampal sclerosis often show severe verbal memory deficits. Recent studies suggest that memory formation in these patients may be reallocated to the right hemisphere owing to left hippocampal pathology. To test this hypothesis, we used functional magnetic resonance imaging to examine encoding-related activity of verbal items in temporal lobe epilepsy patients with left hippocampal sclerosis and patients with idiopathic epilepsy as a control group. Results demonstrated that patients with idiopathic epilepsy showed more activation in both left and right hippocampi. The temporal lobe epilepsy group showed enhanced activation in left fusiform gyrus. We discuss these results in terms of different strategy use by the groups.