An fMRI investigation into the neural mechanisms of spatial attentional selection in a location-based negative priming task

How processing emotion affects language control in bilinguals

Research has shown that several variables affect language control among bilingual speakers but the effect of affective processing remains unexplored. Chinese-English bilinguals participated in a novel prime-target language switching experiment in which they first judged the affective valence (i.e., positive or negative) of auditorily presented words and then named pictures with neutral emotional valence in either the same (non-switch trial) or different language (switch trial). Brain activity was monitored using functional magnetic resonance imaging (fMRI). The behavioral performance showed that the typical switch cost (i.e., the calculated difference between switch and non-switch trials) emerged after processing positive words but not after negative words. Brain imaging demonstrated that processing negative words immediately before non-switch picturing naming trials (but not for switch trials) increased activation in brain areas associated with domain-general cognitive control. The opposite patterns were found after processing positive words. These findings suggest that an (emotional) negative priming effect is induced by spontaneous exposure to negative words and that these priming effects may be triggered by reactive emotional processing and that they may interact with higher level cognitive functions.

Statistical Learning of Frequent Distractor Locations in Visual Search Involves Regional Signal Suppression in Early Visual Cortex

Observers can learn locations where salient distractors appear frequently to reduce potential interference-an effect attributed to better suppression of distractors at frequent locations. But how distractor suppression is implemented in the visual cortex and within the frontoparietal attention networks remains unclear. We used fMRI and a regional distractor-location learning paradigm with two types of distractors defined in either the same (orientation) or a different (color) dimension to the target to investigate this issue. fMRI results showed that BOLD signals in early visual cortex were significantly reduced for distractors (as well as targets) occurring at the frequent versus rare locations, mirroring behavioral patterns. This reduction was more robust with same-dimension distractors. Crucially, behavioral interference was correlated with distractor-evoked visual activity only for same- (but not different-) dimension distractors. Moreover, with different- (but not same-) dimension distractors, a color-processing area within the fusiform gyrus was activated more when a distractor was present in the rare region versus being absent and more with a distractor in the rare versus frequent locations. These results support statistical learning of frequent distractor locations involving regional suppression in early visual cortex and point to differential neural mechanisms of distractor handling with different- versus same-dimension distractors.

Transcranial magnetic stimulation over the right dorsolateral prefrontal cortex modulates visuospatial distractor suppression

Visual selective attention allows us to filter relevant inputs from irrelevant inputs during visual processing. In contrast to rich research exploring how the brain facilitates task‐relevant inputs, less is known about how the brain suppresses irrelevant inputs. In this study, we used transcranial magnetic stimulation (TMS) to investigate the causal role of the right dorsolateral prefrontal cortex (DLPFC), a crucial brain area for attentional control, in distractor suppression. Specifically, 10‐Hz repetitive TMS (rTMS) was applied to the right DLPFC and Vertex at the stimuli onset (stimuli‐onset TMS) or 500 ms prior to the stimuli onset (prestimuli TMS). In a variant of the Posner cueing task, participants were instructed to identify the shape of a white target while ignoring a white or colored distractor whose location was either cued in advance or uncued. As anticipated, either the location cue or the colored distractor led to faster responses. Notably, the location cueing effect was eliminated by stimuli‐onset TMS to the right DLPFC, but not by prestimuli TMS. Further analyses showed that stimuli‐onset TMS quickened responses to uncued trials, and this TMS effect was derived from the inhibition at the distractor in both visual fields. In addition, TMS over the right DLPFC had no specific effect on the colored distractor compared to the white one. Considered collectively, these findings indicate that the DLPFC plays a crucial role in visuospatial distractor suppression and acts upon stimuli presentation. Besides, it seems the DLPFC contributes more to location‐based distractor suppression than to color‐based one.

Schizophrenia affects speech-induced functional connectivity of the superior temporal gyrus under cocktail-party listening conditions

The superior temporal gyrus (STG) is involved in speech recognition against informational masking under cocktail-party-listening conditions. Compared to healthy listeners, people with schizophrenia perform worse in speech recognition under informational speech-on-speech masking conditions. It is not clear whether the schizophrenia-related vulnerability to informational masking is associated with certain changes in FC of the STG with some critical brain regions. Using sparse-sampling fMRI design, this study investigated the differences between people with schizophrenia and healthy controls in FC of the STG for target-speech listening against informational speech-on-speech masking, when a listening condition with either perceived spatial separation (PSS, with a spatial release of informational masking) or perceived spatial co-location (PSC, without the spatial release) between target speech and masking speech was introduced. The results showed that in healthy participants, but not participants with schizophrenia, the contrast of either the PSS or PSC condition against the masker-only condition induced an enhancement of functional connectivity (FC) of the STG with the left superior parietal lobule and the right precuneus. Compared to healthy participants, participants with schizophrenia showed declined FC of the STG with the bilateral precuneus, right SPL, and right supplementary motor area. Thus, FC of the STG with the parietal areas is normally involved in speech listening against informational masking under either the PSS or PSC conditions, and declined FC of the STG in people with schizophrenia with the parietal areas may be associated with the increased vulnerability to informational masking.

The negative priming paradigm: An update and implications for selective attention

Negative Priming (NP) is an influential paradigm in cognitive psychology that was originally developed to measure attentional selection. Yet, up to the mid-1990s, a large number of experimental reports questioned whether the NP effect is based on attentional inhibition and/or episodic retrieval processes. In this review, we summarize findings since the mid-1990s and discuss new and old theoretical approaches to Negative Priming. We conclude that more than one process contributes to NP and that future research should analyze the conditions under which a particular process contributes to NP. Moreover, we argue that the paradigm--although it does not measure a single cognitive process alone--is still a useful tool for understanding selection in cognition. In fact, it might be a virtue of the paradigm that several cognitive processes work here together as selection in nonexperimental contexts is surely a multidimensional process. From this perspective, research on NP is relevant for all research fields analyzing selection. We therefore close our review by discussing the implications of the new evidence on NP for theories of selective attention.

Transcranial direct current stimulation of the prefrontal cortex increases attention to visual target stimuli

Both functional imaging or EEG studies and studies including neurological patients found the dorsolateral prefrontal cortex (dLPFC) to be an important brain area for the processing of emotion and attention. The aim of the present study was to investigate whether emotion and attention can be modulated through bilateral transcranial direct current stimulation (tDCS) of the dLPFC. Therefore, we measured electroencephalographic occipital (early posterior negativity, EPN) and parietal ERPs (late positive potential, LPP) during an emotional picture viewing paradigm with an additional attentional instruction while applying bilateral anodal and cathodal tDC-stimulation to the left and right dLPFC. Beyond the well-known emotion and attention effects for both EPN and LPP, we found that left cathodal/right anodal tDCS leads to increased LPP amplitudes to target stimuli. In contrast to our hypothesis bilateral tDCS over the dLPFC did not influence emotional processing.

Brain substrates of perceived spatial separation between speech sources under simulated reverberant listening conditions in schizophrenia

BACKGROUND

People with schizophrenia recognize speech poorly under multiple-people-talking (informational masking) conditions. In reverberant environments, direct-wave signals from a speech source are perceptually integrated with the source reflections (the precedence effect), forming perceived spatial separation (PSS) between different sources and consequently improving target-speech recognition against informational masking. However, the brain substrates underlying the schizophrenia-related vulnerability to informational masking and whether schizophrenia affects the unmasking effect of PSS are largely unknown.

METHOD

Using psychoacoustic testing and functional magnetic resonance imaging, respectively, the speech recognition under either the PSS or perceived spatial co-location (PSC) condition and the underlying brain substrates were examined in 20 patients with schizophrenia and 16 healthy controls.

RESULTS

Speech recognition was worse in patients than controls. Under the PSS (but not PSC) condition, speech recognition was correlated with activation of the superior parietal lobule (SPL), and target speech-induced activation of the SPL, precuneus, middle cingulate cortex and caudate significantly declined in patients. Moreover, the separation (PSS)-against-co-location (PSC) contrast revealed (1) activation of the SPL, precuneus and anterior cingulate cortex in controls, (2) suppression of the SPL and precuneus in patients, (3) activation of the pars triangularis of the inferior frontal gyrus and middle frontal gyrus in both controls and patients, (4) activation of the medial superior frontal gyrus in patients, and (5) impaired functional connectivity of the SPL in patients.

CONCLUSIONS

Introducing the PSS listening condition efficiently reveals both the brain substrates underlying schizophrenia-related speech-recognition deficits against informational masking and the schizophrenia-related neural compensatory strategy for impaired SPL functions.

Baroreceptor activity impacts upon controlled but not automatic distractor processing

Changes within the cardiovascular system have been shown to alter sensorimotor and memory performance, pain perception as well as cortical arousal. This influence is assumed to be mediated by afferent feedback of baroreceptors that when stimulated exert inhibitory effects on cortical structures. Mainly responsible for short-term regulation of blood pressure, afferents of the baroreceptors are widely connected to subcortical and cortical structures like the insular cortex. A putative impact on cognitive control processes remains an open question, however. Using a sequential distractor priming task, the present study investigated whether inhibitory influences of baroreceptor activation apply to selective information processing in the presence of irrelevant information. In particular, we assessed distractor-response binding and Negative Priming as indices of automatic and controlled distractor processing, respectively. Baroreceptor activation was experimentally manipulated by the systematic variation of body position. The results showed that only Negative Priming but not distractor-response binding was modulated by body position suggesting that controlled but not automatic processing of distractors is affected by baroreceptor activity.

Intranasal oxytocin impedes the ability to ignore task-irrelevant facial expressions of sadness in students with depressive symptoms

The administration of oxytocin promotes prosocial behavior in humans. The mechanism by which this occurs is unknown, but it likely involves changes in social information processing. In a randomized placebo-controlled study, we examined the influence of intranasal oxytocin and placebo on the interference control component of inhibition (i.e. ability to ignore task-irrelevant information) in 102 participants using a negative affective priming task with sad, angry, and happy faces. In this task, participants are instructed to respond to a facial expression of emotion while simultaneously ignoring another emotional face. On the subsequent trial, the previously-ignored emotional valence may become the emotional valence of the target face. Inhibition is operationalized as the differential delay between responding to a previously-ignored emotional valence and responding to an emotional valence unrelated to the previous one. Although no main effect of drug administration on inhibition was observed, a drug × depressive symptom interaction (β = -0.25; t = -2.6, p < 0.05) predicted the inhibition of sad faces. Relative to placebo, participants with high depression scores who were administered oxytocin were unable to inhibit the processing of sad faces. There was no relationship between drug administration and inhibition among those with low depression scores. These findings are consistent with increasing evidence that oxytocin alters social information processing in ways that have both positive and negative social outcomes. Because elevated depression scores are associated with an increased risk for major depressive disorder, difficulties inhibiting mood-congruent stimuli following oxytocin administration may be associated with risk for depression.

Altered negative priming in older subjects: first evidence from behavioral and neural level

The impact of aging on the negative priming (NP) effect has been subject of many studies using behavioral measures. Results are inconsistent and corresponding neural data do not exist. We were interested in, whether or not processing of NP is altered in older in comparison to young adults (YA) on behavioral and neural level. Eighteen young and eighteen older healthy adults performed a location-based NP paradigm during fMRI. YA behaviorally showed a NP effect and NP associated fronto-striatal activation, which is in accordance with the inhibitory model of NP. In older subjects no significant behavioral NP effect and no NP-related activation in predefined brain regions could be found. This is discussed in context of the "loss of efficiency" hypothesis. One possible source for the lack of NP-related activation is a reduction of gray matter (GM) volume in older subjects as shown using voxel based morphometry (VBM).

Neuroimaging evidence for processes underlying repetition of ignored stimuli

Prolonged response times are observed with targets having been presented as distractors immediately before, called negative priming effect. Among others, inhibitory and retrieval processes have been suggested underlying this behavioral effect. As those processes would involve different neural activation patterns, a functional magnetic resonance imaging (fMRI) study including 28 subjects was conducted. Two tasks were used to investigate stimulus repetition effects. One task focused on target location, the other on target identity. Both tasks are known to elicit the expected response time effects. However, there is less agreement about the relationship of those tasks with the explanatory accounts under consideration. Based on within-subject comparisons we found clear differences between the experimental repetition conditions and the neutral control condition on neural level for both tasks. Hemodynamic fronto-striatal activation patterns occurred for the location-based task favoring the selective inhibition account. Hippocampal activation found for the identity-based task suggests an assignment to the retrieval account; however, this task lacked a behavioral effect.

Do not look there: the impact of facial expression on location negative priming

This study used the location negative priming (NP) paradigm and the recording of event-related potentials to examine the mechanism of the impact of emotional stimulus on subsequent spatial attentional processing. The results shown to be relative to the happy and neutral condition, a significant behavioural NP effect, as well as decreased N2, increased N2pc, and P3 amplitudes for NP condition, were found selectively in the fearful prime distractor condition. These findings suggest that the effect of fearful stimulus on location NP may be related to early-inhibition processing. Larger P3 amplitudes may reflect the use of increased cognitive resources when one is necessary for overcoming the tendency to avoid viewing the position where a fearful stimulus has recently been seen.

Glücksspiel im Gehirn: Neurobiologische Grundlagen pathologischen Glücksspielens

Hintergrund: Pathologisches Glücksspielen (PG) wird in den internationalen Klassifikationssystemen bislang als Impulskontrollstörung klassifiziert. Erst in jüngster Zeit wird aufgrund der Ähnlichkeiten in Phänomenologie, Ätiologie, Verlauf sowie genetischen und neurobiologischen Faktoren mit der Substanzabhängigkeit eine Einordnung des PGs als Verhaltenssucht diskutiert. Insbesondere neurobiologische und neuropsychologische Befunde haben zu dieser veränderten Sichtweise beigetragen. Methode: Im vorliegenden Beitrag werden Befunde zu neurobiologischen Grundlagen PGs vorgestellt. Der Schwerpunkt liegt auf neurokognitiven Prozessen wie Belohnungs- und Bestrafungsverarbeitung, Cue-Reaktivität, Impulsivität und Entscheidungsfindung. Die Befunde werden im Hinblick auf Ähnlichkeiten und Unterschiede PGs zur Substanzabhängigkeit diskutiert. Ergebnisse: Ähnlich wie bei der Substanzabhängigkeit zeigt sich auch bei pathologischen Spielern Veränderungen mesolimbischer-präfrontaler Netzwerke, die sich in einer verminderten Belohnungs- und Bestrafungssensitivität, Impulshemmung und einer erhöhten Cue-Reaktivität auf glücksspielassoziierte Reize äußern können. Jedoch sind die Befunde teilweise nicht eindeutig und eine Vielzahl der Studien unterliegt methodischen Einschränkungen. Schlussfolgerungen: Bisherige Befunde stützen die Einordnung pathologischen Spielverhaltens als Verhaltenssucht.

Effective connectivity of the multiplication network: a functional MRI and multivariate Granger Causality Mapping study

Developmental neuropsychology and functional neuroimaging evidence indicates that simple and complex mental calculation is subserved by a fronto-parietal network. However, the effective connectivity (connection direction and strength) among regions within the fronto-parietal network is still unexplored. Combining event-related fMRI and multivariate Granger Causality Mapping (GCM), we administered a multiplication verification task to healthy participants asking them to solve single and double-digit multiplications. The goals of our study were first, to identify the effective connectivity of the multiplication network, and second, to compare the effective connectivity patterns between a low and a high arithmetical competence (AC) group. The manipulation of multiplication difficulty revealed a fronto-parietal network encompassing bilateral intraparietal sulcus (IPS), left pre-supplementary motor area (PreSMA), left precentral gyrus (PreCG), and right dorsolateral prefrontal cortex (DLPFC). The network was driven by an intraparietal IPS-IPS circuit hosting a representation of numerical quantity intertwined with a fronto-parietal DLPFC-IPS circuit engaged in temporary storage and updating of arithmetic operations. Both circuits received additional inputs from the PreCG and PreSMA playing more of a supportive role in mental calculation. The high AC group compared to the low AC group displayed a greater activation in the right IPS and based its calculation more on a feedback driven intraparietal IPS-IPS circuit, whereas the low competence group more on a feedback driven fronto-parietal DLPFC-IPS circuit. This study provides first evidence that multivariate GCM is a sensitive approach to investigate effective connectivity of mental processes involved in mental calculation and to compare group level performances for different populations.

Why gamblers fail to win: a review of cognitive and neuroimaging findings in pathological gambling

The purpose of this review is to gain more insight in the neuropathology of pathological gambling (PG) and problem gambling, and to discuss challenges in this research area. Results from the reviewed PG studies show that PG is more than just an impulse control disorder. PG seems to fit very well with recent theoretical models of addiction, which stress the involvement of the ventral tegmental-orbito frontal cortex. Differentiating types of PG on game preferences (slot machines vs. casino games) seems to be useful because different PG groups show divergent results, suggesting different neurobiological pathways to PG. A framework for future studies is suggested, indicating the need for hypothesis driven pharmacological and functional imaging studies in PG and integration of knowledge from different research areas to further elucidate the neurobiological underpinnings of this disorder.

Distinct neural substrates for deductive and mathematical processing

In an effort to clarify how deductive reasoning is accomplished, an fMRI study was performed to observe the neural substrates of logical reasoning and mathematical calculation. Participants viewed a problem statement and three premises, and then either a conclusion or a mathematical formula. They had to indicate whether the conclusion followed from the premises, or to solve the mathematical formula. Language areas of the brain (Broca's and Wernicke's area) responded as the premises and the conclusion were read, but solution of the problems was then carried out by non-language areas. Regions in right prefrontal cortex and inferior parietal lobe were more active for reasoning than for calculation, whereas regions in left prefrontal cortex and superior parietal lobe were more active for calculation than for reasoning. In reasoning, only those problems calling for a search for counterexamples to conclusions recruited right frontal pole. These results have important implications for understanding how higher cognition, including deduction, is implemented in the brain. Different sorts of thinking recruit separate neural substrates, and logical reasoning goes beyond linguistic regions of the brain.