Working Memory and Response Inhibition as One Integral Phenotype of Adult ADHD? A Behavioral and Imaging Correlational Investigation

Objective: It is an open question whether working memory (WM) and response inhibition (RI) constitute one integral phenotype in attention deficit hyperactivity disorder (ADHD). Method: The authors investigated 45 adult ADHD patients and 41 controls comparable for age, gender, intelligence, and education during a letter n-back and a stop-signal task, and measured prefrontal oxygenation by means of functional near-infrared spectroscopy. Results: The authors replicated behavioral and cortical activation deficits in patients compared with controls for both tasks and also for performance in both control conditions. In the patient group, 2-back performance was correlated with stop-signal reaction time. This correlation did not seem to be specific for WM and RI as 1-back performance was correlated with go reaction time. No significant correlations of prefrontal oxygenation between WM and RI were found. Conclusion: The authors’ findings do not support the hypothesis of WM and RI representing one integral phenotype of ADHD mediated by the prefrontal cortex

Is There a Negative Interpretation Bias in Depressed Patients? An Affective Startle Modulation Study

Background/Aims: Scientists proposed that patients with depression favour negative interpretations when appraising ambiguity. As self-report measures seem prone to response bias, implicit measures of emotional valence should be additionally used. Methods: A total of 16 patients with depression and 19 controls underwent an acoustic imagery task comprising neutral and negative words, as well as ambiguous words that could be understood either way. Affective startle modulation and direct interrogation were used to assess implicit and explicit emotional valence, respectively. We expected a negative bias for ambiguous words in the patient group, resulting in augmented startle magnitudes and preference for negative interpretations of the ambiguous words in the interrogation. Results: Surprisingly, both groups preferred neutral interpretations and showed augmented startle magnitudes to ambiguous words. Furthermore, both groups displayed an emotional startle potentiation for negative words. Conclusion: In summary, our results do not confirm a negative interpretation bias or a blunted emotional response in patients with major depression. The mismatch between self-report and affective startle reaction to ambiguous targets might reflect defensive mobilization or attention effects

Functional imaging of cognition in an old-old population: A case for portable functional near-infrared spectroscopy

In this study, functional near-infrared spectroscopy (fNIRS) was used to record brain activa- tion during cognitive testing in older individuals (88±6yo; N = 19) living in residential care communities. This population, which is often associated with loss of personal independence due to physical or cognitive decline associated with aging, is also often under-represented in neuroscience research because of a limited means to participate in studies which often take place in large urban or university centers. In this study, we demonstrate the feasibility and initial results using a portable 8-source by 4-detector fNIRS system to measure brain activity from participants within residential care community centers. Using fNIRS, brain sig- nals were recorded during a series of computerized cognitive tests, including a Symbol Digit Coding test (SDC), Stroop Test (ST), and Shifting Attention Test (SAT). The SDC and SAT elicited greater activity in the left middle frontal region of interest. Three components of the ST produced increases in the right middle frontal and superior frontal, and left superior frontal regions. An association between advanced age and increased activation in the right middle frontal region was observed during the incongruent ST. Although none of the partici- pants had clinical dementia based on the short portable mental status questionnaire, the group performance was slightly below age-normed values on these cognitive tests. These results demonstrate the capability for obtaining functional neuroimaging measures in resi- dential settings, which ultimately may aid in prognosis and care related to dementia in older adults

Visuospatial working memory in children and adolescents with 22q11.2 deletion syndrome; an fMRI study

22q11.2 deletion syndrome (22q11DS) is a genetic disorder associated with a microdeletion of chromosome 22q11. In addition to high rates of neuropsychiatric disorders such as schizophrenia and attention deficit hyperactivity disorder, children with 22q11DS have a specific neuropsychological profile with particular deficits in visuospatial and working memory. However, the neurobiological substrate underlying these deficits is poorly understood. We investigated brain function during a visuospatial working memory (SWM) task in eight children with 22q11DS and 13 healthy controls, using fMRI. Both groups showed task-related activation in dorsolateral prefrontal cortex (DLPFC) and bilateral parietal association cortices. Controls activated parietal and occipital regions significantly more than those with 22q11DS but there was no significant between-group difference in DLPFC. In addition, while controls had a significant age-related increase in the activation of posterior brain regions and an age-related decrease in anterior regions, the 22q11DS children showed the opposite pattern. Genetically determined differences in the development of specific brain systems may underpin the cognitive deficits in 22q11DS, and may contribute to the later development of neuropsychiatric disorders

Association between Catechol-O-Methyltrasferase Val108/158Met Genotype and Prefrontal Hemodynamic Response in Schizophrenia

BACKGROUND:"Imaging genetics" studies have shown that brain function by neuroimaging is a sensitive intermediate phenotype that bridges the gap between genes and psychiatric conditions. Although the evidence of association between functional val108/158met polymorphism of the catechol-O-methyltransferase gene (COMT) and increasing risk for developing schizophrenia from genetic association studies remains to be elucidated, one of the most topical findings from imaging genetics studies is the association between COMT genotype and prefrontal function in schizophrenia. The next important step in the translational approach is to establish a useful neuroimaging tool in clinical settings that is sensitive to COMT variation, so that the clinician could use the index to predict clinical response such as improvement in cognitive dysfunction by medication. Here, we investigated spatiotemporal characteristics of the association between prefrontal hemodynamic activation and the COMT genotype using a noninvasive neuroimaging technique, near-infrared spectroscopy (NIRS). METHODOLOGY/PRINCIPAL FINDINGS:Study participants included 45 patients with schizophrenia and 60 healthy controls matched for age and gender. Signals that are assumed to reflect regional cerebral blood volume were monitored over prefrontal regions from 52-channel NIRS and compared between two COMT genotype subgroups (Met carriers and Val/Val individuals) matched for age, gender, premorbid IQ, and task performance. The [oxy-Hb] increase in the Met carriers during the verbal fluency task was significantly greater than that in the Val/Val individuals in the frontopolar prefrontal cortex of patients with schizophrenia, although neither medication nor clinical symptoms differed significantly between the two subgroups. These differences were not found to be significant in healthy controls. CONCLUSIONS/SIGNIFICANCE:These data suggest that the prefrontal NIRS signals can noninvasively detect the impact of COMT variation in patients with schizophrenia. NIRS may be a promising candidate translational approach in psychiatric neuroimaging

The influence of gestures and visuospatial ability in learning of movements with dynamic visualizations: An fNIRS study

There is increasing evidence that learning manual tasks from dynamic visualizations (e.g., origami folding) is facilitated when human hands are shown or gestures can be observed in the visualizations. This study examined whether observing and making gestures improves learning about non-human biological movements (i.e., fish locomotion) and whether gestures that correspond to the to-be-learned movement are superior to non-corresponding gestures. Moreover, learners’ visuospatial ability was assessed as a possible moderator. Regarding underlying neurophysiological processes, functional near-infrared spectroscopy (fNIRS) was used to investigate whether gestures activate the human mirror-neuron system (hMNS) and whether this activation mediates the facilitation of learning. During learning, participants viewed animations that were supplemented with either a self-gesturing instruction (yes/no) and/or a gesture video (corresponding/non-corresponding/no gesture) resulting in six conditions (2x3-between-subjects design). Results showed that higher-visuospatial-ability learners benefitted from learning with non-corresponding gestures, whereas those gestures were detrimental for lower-visuospatial-ability learners. Furthermore, activation of the inferior frontal cortex (part of hMNS) tended to predict better learning outcomes. Making gestures did not influence learning, but participants observing corresponding gestures showed higher inferior frontal cortex activation if they self-gestured than when they did not self-gesture. Implications of the results for the design of instructional materials are discussed

European Association for Research on Learning and Instruction (EARLI)

Abstract. This study investigates whether observing hand actions in dynamic and static visualizations is helpful for learning hand-manipulative tasks in terms of knot tying. Functional near-infrared spectroscopy (fNIRS) was used to address whether dynamic visualizations or/and observing hands in the visualizations activate the human mirror-neuron-system and whether its activation mediates the facilitation of learning. During learning to tie two knots (Trucker’s Hitch and Bowline) participants viewed either dynamic or static visualizations with or without hands (2x2-between-subjects-design). Moreover, learners’ spatial ability was measured as a potential moderator during learning with different types of visualizations. Participants performed a motor skills task (knot tying performance) and a cognitive task (reasoning about the knot tying process). Results differed in dependence of the task, the to-be-tied knot, and learners’ spatial ability. Higher-spatial-ability learners showed better motor skill performance from viewing dynamic visualizations (Bowline knot) and visualizations with hands (Trucker’s Hitch knot). Lower-spatial-ability learners showed lower cognitive task performance from viewing the dynamic visualizations (Bowline knot) and visualizations with hands (Trucker’s Hitch and Bowline knot). The fNIRS data are currently analyzed. In sum, the effectiveness of different types of visualizations in terms of their dynamism (dynamic or static) and hand visibility (with or without) depends on the to-be-tied knot, the to-be-accomplished task (motor skills performance vs. cognitive reasoning) as well as spatial ability. Whereas higher-spatial-ability learners acquire better motor skills from learning with dynamic visualizations and observing hands in visualizations, lower-spatial-ability learners suffer from the same instructional formats on cognitive reasoning tasks

The time course of temporal discrimination: An ERP study

Auditory processing during sleep was investigated in premature infants by auditory event related potentials (AERPs). Twenty-six premature infants (mean GA 30 week\u2013 range 25\u201335) admitted to a neonatal intensive care unit were studied, prior to discharge, in active and quiet sleep at a mean post-conceptional age of 35 weeks. Infant state was determined by behavioral observation according to standard criteria. An auditory odd-ball paradigm was used with frequently occurring \u2018standard\u2019 tones at 1000 Hz and infrequent \u2018deviant\u2019 tones at 2000 Hz. Waveforms were recorded at Fz, Cz, Pz, T3 and T4 scalp locations. Measurements were performed in 18 patients because 8 preterm infants were excluded since they had less than the required artifact-free deviant trials in each sleep state. The responses to standard tones were equally recorded in both active and quiet sleep, but auditory responses to deviant tones consisting of an increased frontal negativity in the time period from 200 to 300 ms after the stimulus were recorded only in active sleep. A significant effect of electrode placement, for frontal location by sleep condition and sleep condition by 50 ms time windows was shown by repeated measures analyses of variance. The significance of these findings on evoked potential methodology in preterm infants admitted to neonatal intensive care unit is discussed