ResearchPad - Neuropsychology and Physiological Psychology https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Normal aging and Parkinson's disease are associated with the functional decline of distinct frontal-striatal circuits]]> https://www.researchpad.co/product?articleinfo=5b41c07e463d7e0c4367c32c

Impaired ability to shift attention between stimuli (i.e. shifting attentional ‘set’) is a well-established part of the dysexecutive syndrome in Parkinson's Disease (PD), nevertheless cognitive and neural bases of this deficit remain unclear. In this study, an fMRI-optimised variant of a classic paradigm for assessing attentional control (Hampshire and Owen 2006) was used to contrast activity in dissociable executive circuits in early-stage PD patients and controls. The results demonstrated that the neural basis of the executive performance impairments in PD is accompanied by hypoactivation within the striatum, anterior cingulate cortex (vACC), and inferior frontal sulcus (IFS) regions. By contrast, in aging it is associated with hypoactivation of the anterior insula/inferior frontal operculum (AI/FO) and the pre-supplementary motor area (preSMA). Between group behavioural differences were also observed; whereas normally aging individuals exhibited routine-problem solving deficits, PD patients demonstrated more global task learning deficits. These findings concur with recent research demonstrating model-based reinforcement learning deficits in PD and provide evidence that the AI/FO and IFS circuits are differentially impacted by PD and normal aging.

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<![CDATA[Cardiovascular Correlates of Motor Vehicle Accident Related Posttraumatic Stress Disorder and its Successful Treatment]]> https://www.researchpad.co/product?articleinfo=5b7bfa41463d7e03282b579c

Persons with posttraumatic stress disorder (PTSD) have been shown to display elevated baseline cardiovascular activity and a heightened physiological reactivity to trauma-related stimuli. Study 1 examined differences in baseline heart rate (HR) and HR reactivity in 68 survivors of motor vehicle accidents (MVAs) and healthy controls without MVA. MVA survivors with PTSD (n=26), subsyndromal PTSD (n=22), traumatized controls without PTSD (non-PTSD with MVA, n=20) and healthy controls without MVA (HC, n=27) underwent measurement of HR during baseline and exposure to a neutral, positive, negative, and trauma-related picture. PTSD patients showed elevated baseline HR and increased HR reactivity only during exposure to the trauma-related picture. Study 2 investigated whether the elevated physiological responses observed in Study 1 normalized after cognitive behavioral therapy (CBT). We conducted a randomized, controlled treatment trial comparing CBT (n=17) to a Wait-list condition (WLC, n=18). Results showed a greater decrease in HR reactivity for CBT than for WLC. The change in HR reactivity was associated with clinical improvement.

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<![CDATA[How social interactions affect emotional memory accuracy: Evidence from collaborative retrieval and social contagion paradigms]]> https://www.researchpad.co/product?articleinfo=5b0085e4463d7e38d2af87d3

In daily life, emotional events are often discussed with others. The influence of these social interactions on the veracity of emotional memories has rarely been investigated. The authors (Choi, Kensinger, & Rajaram Memory and Cognition, 41, 403–415, 2013) previously demonstrated that when the categorical relatedness of information is controlled, emotional items are more accurately remembered than neutral items. The present study examined whether emotion would continue to improve the accuracy of memory when individuals discussed the emotional and neutral events with others. Two different paradigms involving social influences were used to investigate this question and compare evidence. In both paradigms, participants studied stimuli that were grouped into conceptual categories of positive (e.g., celebration), negative (e.g., funeral), or neutral (e.g., astronomy) valence. After a 48-hour delay, recognition memory was tested for studied items and categorically related lures. In the first paradigm, recognition accuracy was compared when memory was tested individually or in a collaborative triad. In the second paradigm, recognition accuracy was compared when a prior retrieval session had occurred individually or with a confederate who supplied categorically related lures. In both of these paradigms, emotional stimuli were remembered more accurately than were neutral stimuli, and this pattern was preserved when social interaction occurred. In fact, in the first paradigm, there was a trend for collaboration to increase the beneficial effect of emotion on memory accuracy, and in the second paradigm, emotional lures were significantly less susceptible to the “social contagion” effect. Together, these results demonstrate that emotional memories can be more accurate than nonemotional ones even when events are discussed with others (Experiment 1) and even when that discussion introduces misinformation (Experiment 2).

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<![CDATA[Visual short-term memory binding deficit in familial Alzheimer's disease]]> https://www.researchpad.co/product?articleinfo=5afd8443463d7e765406c588

Long-term episodic memory deficits in Alzheimer's disease (AD) are well characterised but, until recently, short-term memory (STM) function has attracted far less attention. We employed a recently-developed, delayed reproduction task which requires participants to reproduce precisely the remembered location of items they had seen only seconds previously. This paradigm provides not only a continuous measure of localization error in memory, but also an index of relational binding by determining the frequency with which an object is misplaced to the location of one of the other items held in memory. Such binding errors in STM have previously been found on this task to be sensitive to medial temporal lobe (MTL) damage in focal lesion cases. Twenty individuals with pathological mutations in presenilin 1 or amyloid precursor protein genes for familial Alzheimer's disease (FAD) were tested together with 62 healthy controls. Participants were assessed using the delayed reproduction memory task, a standard neuropsychological battery and structural MRI.

Overall, FAD mutation carriers were worse than controls for object identity as well as in gross localization memory performance. Moreover, they showed greater misbinding of object identity and location than healthy controls. Thus they would often mislocalize a correctly-identified item to the location of one of the other items held in memory. Significantly, asymptomatic gene carriers – who performed similarly to healthy controls on standard neuropsychological tests – had a specific impairment in object-location binding, despite intact memory for object identity and location. Consistent with the hypothesis that the hippocampus is critically involved in relational binding regardless of memory duration, decreased hippocampal volume across FAD participants was significantly associated with deficits in object-location binding but not with recall precision for object identity or localization. Object-location binding may therefore provide a sensitive cognitive biomarker for MTL dysfunction in a range of diseases including AD.

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<![CDATA[Discrimination of familiar human faces in dogs (Canis familiaris)]]> https://www.researchpad.co/product?articleinfo=5ace7ae5463d7e1617a11978

Faces are an important visual category for many taxa, and the human face is no exception to this. Because faces differ in subtle ways and possess many idiosyncratic features, they provide a rich source of perceptual cues. A fair amount of those cues are learned through social interactions and are used for future identification of individual humans. These effects of individual experience can be studied particularly well in hetero-specific face perception. Domestic dogs represent a perfect model in this respect, due to their proved ability to extract important information from the human face in socio-communicative interactions. There is also suggestive evidence that dogs can identify their owner or other familiar human individuals by using visual information from the face. However, most studies have used only dogs’ looking behavior to examine their visual processing of human faces and it has been demonstrated only that dogs can differentiate between familiar and unknown human faces. Here, we examined the dog's ability to discriminate the faces of two familiar persons by active choice (approach and touch). Furthermore, in successive stages of the experiment we investigated how well dogs discriminate humans in different representations by systematically reducing the informational richness and the quality of the stimuli. We found a huge inter-individual and inter-stage variance in performance, indicating differences across dogs in their learning ability as well as their selection of discriminative cues. On a group level, the performance of dogs significantly decreased when they were presented with pictures of human heads after having learned to discriminate the real heads, and when – after relearning – confronted with the same pictures showing only the inner parts of the heads. However, as two dogs quickly mastered all stages, we conclude that dogs are in principle able to discriminate people on the basis of visual information from their faces and by making active choices.

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<![CDATA[Task-discriminative space-by-time factorization of muscle activity]]> https://www.researchpad.co/product?articleinfo=5989daa5ab0ee8fa60ba760d

Movement generation has been hypothesized to rely on a modular organization of muscle activity. Crucial to this hypothesis is the ability to perform reliably a variety of motor tasks by recruiting a limited set of modules and combining them in a task-dependent manner. Thus far, existing algorithms that extract putative modules of muscle activations, such as Non-negative Matrix Factorization (NMF), identify modular decompositions that maximize the reconstruction of the recorded EMG data. Typically, the functional role of the decompositions, i.e., task accomplishment, is only assessed a posteriori. However, as motor actions are defined in task space, we suggest that motor modules should be computed in task space too. In this study, we propose a new module extraction algorithm, named DsNM3F, that uses task information during the module identification process. DsNM3F extends our previous space-by-time decomposition method (the so-called sNM3F algorithm, which could assess task performance only after having computed modules) to identify modules gauging between two complementary objectives: reconstruction of the original data and reliable discrimination of the performed tasks. We show that DsNM3F recovers the task dependence of module activations more accurately than sNM3F. We also apply it to electromyographic signals recorded during performance of a variety of arm pointing tasks and identify spatial and temporal modules of muscle activity that are highly consistent with previous studies. DsNM3F achieves perfect task categorization without significant loss in data approximation when task information is available and generalizes as well as sNM3F when applied to new data. These findings suggest that the space-by-time decomposition of muscle activity finds robust task-discriminating modular representations of muscle activity and that the insertion of task discrimination objectives is useful for describing the task modulation of module recruitment.

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<![CDATA[Fast mental states decoding in mixed reality]]> https://www.researchpad.co/product?articleinfo=5989da8eab0ee8fa60b9f2d1

The combination of Brain-Computer Interface (BCI) technology, allowing online monitoring and decoding of brain activity, with virtual and mixed reality (MR) systems may help to shape and guide implicit and explicit learning using ecological scenarios. Real-time information of ongoing brain states acquired through BCI might be exploited for controlling data presentation in virtual environments. Brain states discrimination during mixed reality experience is thus critical for adapting specific data features to contingent brain activity. In this study we recorded electroencephalographic (EEG) data while participants experienced MR scenarios implemented through the eXperience Induction Machine (XIM). The XIM is a novel framework modeling the integration of a sensing system that evaluates and measures physiological and psychological states with a number of actuators and effectors that coherently reacts to the user's actions. We then assessed continuous EEG-based discrimination of spatial navigation, reading and calculation performed in MR, using linear discriminant analysis (LDA) and support vector machine (SVM) classifiers. Dynamic single trial classification showed high accuracy of LDA and SVM classifiers in detecting multiple brain states as well as in differentiating between high and low mental workload, using a 5 s time-window shifting every 200 ms. Our results indicate overall better performance of LDA with respect to SVM and suggest applicability of our approach in a BCI-controlled MR scenario. Ultimately, successful prediction of brain states might be used to drive adaptation of data representation in order to boost information processing in MR.

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<![CDATA[Auditory-motor entrainment and phonological skills: precise auditory timing hypothesis (PATH)]]> https://www.researchpad.co/product?articleinfo=5989daabab0ee8fa60ba9628

Phonological skills are enhanced by music training, but the mechanisms enabling this cross-domain enhancement remain unknown. To explain this cross-domain transfer, we propose a precise auditory timing hypothesis (PATH) whereby entrainment practice is the core mechanism underlying enhanced phonological abilities in musicians. Both rhythmic synchronization and language skills such as consonant discrimination, detection of word and phrase boundaries, and conversational turn-taking rely on the perception of extremely fine-grained timing details in sound. Auditory-motor timing is an acoustic feature which meets all five of the pre-conditions necessary for cross-domain enhancement to occur (Patel, 2011, 2012, 2014). There is overlap between the neural networks that process timing in the context of both music and language. Entrainment to music demands more precise timing sensitivity than does language processing. Moreover, auditory-motor timing integration captures the emotion of the trainee, is repeatedly practiced, and demands focused attention. The PATH predicts that musical training emphasizing entrainment will be particularly effective in enhancing phonological skills.

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<![CDATA[A clinical case study of a psychoanalytic psychotherapy monitored with functional neuroimaging]]> https://www.researchpad.co/product?articleinfo=5989dab6ab0ee8fa60bad051

This case study describes 1 year of the psychoanalytic psychotherapy using clinical data, a standardized instrument of the psychotherapeutic process (Psychotherapy process Q-Set, PQS), and functional neuroimaging (fMRI). A female dysthymic patient with narcissistic traits was assessed at monthly intervals (12 sessions). In the fMRI scans, which took place immediately after therapy hours, the patient looked at pictures of attachment-relevant scenes (from the Adult Attachment Projective Picture System, AAP) divided into two groups: those accompanied by a neutral description, and those accompanied by a description tailored to core conflicts of the patient as assessed in the AAP. Clinically, this patient presented defense mechanisms that influenced the relationship with the therapist and that was characterized by fluctuations of mood that lasted whole days, following a pattern that remained stable during the year of the study. The two modes of functioning associated with the mood shifts strongly affected the interaction with the therapist, whose quality varied accordingly (“easy” and “difficult” hours). The PQS analysis showed the association of “easy” hours with the topic of the involvement in significant relationships and of “difficult hours” with self-distancing, a defensive maneuver common in narcissistic personality structures. In the fMRI data, the modes of functioning visible in the therapy hours were significantly associated with modulation of the signal elicited by personalized attachment-related scenes in the posterior cingulate (p = 0.017 cluster-level, whole-volume corrected). This region has been associated in previous studies to self-distancing from negatively valenced pictures presented during the scan. The present study may provide evidence of the possible involvement of this brain area in spontaneously enacted self-distancing defensive strategies, which may be of relevance in resistant reactions in the course of a psychoanalytic psychotherapy.

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<![CDATA[Functional connectivity in the first year of life in infants at-risk for autism: a preliminary near-infrared spectroscopy study]]> https://www.researchpad.co/product?articleinfo=5989db4cab0ee8fa60bdabbf

Background: Autism spectrum disorder (ASD) has been called a “developmental disconnection syndrome,” however the majority of the research examining connectivity in ASD has been conducted exclusively with older children and adults. Yet, prior ASD research suggests that perturbations in neurodevelopmental trajectories begin as early as the first year of life. Prospective longitudinal studies of infants at risk for ASD may provide a window into the emergence of these aberrant patterns of connectivity. The current study employed functional connectivity near-infrared spectroscopy (NIRS) in order to examine the development of intra- and inter-hemispheric functional connectivity in high- and low-risk infants across the first year of life.

Methods: NIRS data were collected from 27 infants at high risk for autism (HRA) and 37 low-risk comparison (LRC) infants who contributed a total of 116 data sets at 3-, 6-, 9-, and 12-months. At each time point, HRA and LRC groups were matched on age, sex, head circumference, and Mullen Scales of Early Learning scores. Regions of interest (ROI) were selected from anterior and posterior locations of each hemisphere. The average time course for each ROI was calculated and correlations for each ROI pair were computed. Differences in functional connectivity were examined in a cross-sectional manner.

Results: At 3-months, HRA infants showed increased overall functional connectivity compared to LRC infants. This was the result of increased connectivity for intra- and inter-hemispheric ROI pairs. No significant differences were found between HRA and LRC infants at 6- and 9-months. However, by 12-months, HRA infants showed decreased connectivity relative to LRC infants.

Conclusions: Our preliminary results suggest that atypical functional connectivity may exist within the first year of life in HRA infants, providing support to the growing body of evidence that aberrant patterns of connectivity may be a potential endophenotype for ASD.

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<![CDATA[The delay effect on outcome evaluation: results from an event-related potential study]]> https://www.researchpad.co/product?articleinfo=5989da28ab0ee8fa60b81969

Behavioral studies demonstrate that the timing of receiving gains or losses affects decision-making, a phenomenon known as temporal discounting, as participants are inclined to prefer immediate rewards over delayed ones and vice versa for losses. The present study used the event-related potential technique with a simple gambling task to investigate how delayed rewards and losses affected the brain activity in outcome evaluations made by 20 young adults. Statistical analysis revealed a larger feedback-related negativity (FRN) effect between loss and gain following immediate outcomes than following future outcomes. In addition, delay impacted FRN only in gain conditions, with delayed winning eliciting a more negative FRN than immediate winning. These results suggest that temporal discounting and sign effect could be encoded in the FRN in the early stage of outcome evaluation.

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<![CDATA[Training of ultra-fast speech comprehension induces functional reorganization of the central-visual system in late-blind humans]]> https://www.researchpad.co/product?articleinfo=5989da7dab0ee8fa60b994b8

Individuals suffering from vision loss of a peripheral origin may learn to understand spoken language at a rate of up to about 22 syllables (syl) per seconds (s)—exceeding by far the maximum performance level of untrained listeners (ca. 8 syl/s). Previous findings indicate the central-visual system to contribute to the processing of accelerated speech in blind subjects. As an extension, the present training study addresses the issue whether acquisition of ultra-fast (18 syl/s) speech perception skills induces de novo central-visual hemodynamic activation in late-blind participants. Furthermore, we asked to what extent subjects with normal or residual vision can improve understanding of accelerated verbal utterances by means of specific training measures. To these ends, functional magnetic resonance imaging (fMRI) was performed while subjects were listening to forward and reversed sentence utterances of moderately fast and ultra-fast syllable rates (8 or 18 syl/s) prior to and after a training period of ca. 6 months. Four of six participants showed—independently from residual visual functions—considerable enhancement of ultra-fast speech perception (about 70% points correctly repeated words) whereas behavioral performance did not change in the two remaining participants. Only subjects with very low visual acuity displayed training-induced hemodynamic activation of the central-visual system. By contrast, participants with moderately impaired or even normal visual acuity showed, instead, increased right-hemispheric frontal or bilateral anterior temporal lobe responses after training. All subjects with significant training effects displayed a concomitant increase of hemodynamic activation of left-hemispheric SMA. In spite of similar behavioral performance, trained “experts” appear to use distinct strategies of ultra-fast speech processing depending on whether the occipital cortex is still deployed for visual processing.

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<![CDATA[An extended case study on the phenomenology of sequence-space synesthesia]]> https://www.researchpad.co/product?articleinfo=5989db40ab0ee8fa60bd68d1

Investigation of synesthesia phenomenology in adults is needed to constrain accounts of developmental trajectories of this trait. We report an extended phenomenological investigation of sequence-space synesthesia in a single case (AB). We used the Elicitation Interview (EI) method to facilitate repeated exploration of AB's synesthetic experience. During an EI the subject's attention is selectively guided by the interviewer in order to reveal precise details about the experience. Detailed analysis of the resulting 9 h of interview transcripts provided a comprehensive description of AB's synesthetic experience, including several novel observations. For example, we describe a specific spatial reference frame (a “mental room”) in which AB's concurrents occur, and which overlays his perception of the real world (the “physical room”). AB is able to switch his attention voluntarily between this mental room and the physical room. Exemplifying the EI method, some of our observations were previously unknown even to AB. For example, AB initially reported to experience concurrents following visual presentation, yet we determined that in the majority of cases the concurrent followed an internal verbalization of the inducer, indicating an auditory component to sequence-space synesthesia. This finding is congruent with typical rehearsal of inducer sequences during development, implicating cross-modal interactions between auditory and visual systems in the genesis of this synesthetic form. To our knowledge, this paper describes the first application of an EI to synesthesia, and the first systematic longitudinal investigation of the first-person experience of synesthesia since the re-emergence of interest in this topic in the 1980's. These descriptions move beyond rudimentary graphical or spatial representations of the synesthetic spatial form, thereby providing new targets for neurobehavioral analysis.

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<![CDATA[The neural control of singing]]> https://www.researchpad.co/product?articleinfo=5989da45ab0ee8fa60b8ba3b

Singing provides a unique opportunity to examine music performance—the musical instrument is contained wholly within the body, thus eliminating the need for creating artificial instruments or tasks in neuroimaging experiments. Here, more than two decades of voice and singing research will be reviewed to give an overview of the sensory-motor control of the singing voice, starting from the vocal tract and leading up to the brain regions involved in singing. Additionally, to demonstrate how sensory feedback is integrated with vocal motor control, recent functional magnetic resonance imaging (fMRI) research on somatosensory and auditory feedback processing during singing will be presented. The relationship between the brain and singing behavior will be explored also by examining: (1) neuroplasticity as a function of various lengths and types of training, (2) vocal amusia due to a compromised singing network, and (3) singing performance in individuals with congenital amusia. Finally, the auditory-motor control network for singing will be considered alongside dual-stream models of auditory processing in music and speech to refine both these theoretical models and the singing network itself.

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<![CDATA[Reading into neuronal oscillations in the visual system: implications for developmental dyslexia]]> https://www.researchpad.co/product?articleinfo=5989d9ffab0ee8fa60b73726

While phonological impairments are common in developmental dyslexia, there has recently been much debate as to whether there is a causal link between the phonological difficulties and the reading problem. An alternative suggestion has been gaining ground that the core deficit in dyslexia is in visual attentional mechanisms. If so, the visual aetiology may be at any of a number of sites along the afferent magnocellular pathway or in the dorsal cortical stream that are all essential for a visuo-spatial attentional feedback to the primary visual cortex. It has been suggested that the same circuits and pathways of top-down attention used for serial visual search are used for reading. Top-down signals from the dorsal parietal areas to primary visual cortex serially highlight cortical locations representing successive letters in a text before they can be recognized and concatenated into a word. We had shown in non-human primates that the mechanism of such a top-down feedback in a visual attention task uses synchronized neuronal oscillations at the lower end of the gamma frequency range. It is no coincidence that reading graphemes in a text also happens at the low gamma frequencies. The basic proposal here is that each cycle of gamma oscillation focuses an attentional spotlight on the primary visual cortical representation of just one or two letters before sequential recognition of letters and their concatenation into word strings. The timing, period, envelope, amplitude, and phase of the synchronized oscillations modulating the incoming signals in the striate cortex would have a profound influence on the accuracy and speed of reading. Thus, the general temporal sampling difficulties in dyslexic subjects may impact reading not necessarily by causing phonological deficits, but by affecting the spatio-temporal parsing of the visual input within the visual system before these signals are used for letter and word recognition.

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<![CDATA[Trait anxiety modulates fronto-limbic processing of emotional interference in borderline personality disorder]]> https://www.researchpad.co/product?articleinfo=5989da70ab0ee8fa60b94a52

Previous studies of cognitive alterations in borderline personality disorder (BPD) have yielded conflicting results. Given that a core feature of BPD is affective instability, which is characterized by emotional hyperreactivity and deficits in emotion regulation, it seems conceivable that short-lasting emotional distress might exert temporary detrimental effects on cognitive performance. Here we used functional magnetic resonance imaging (fMRI) to investigate how task-irrelevant emotional stimuli (fearful faces) affect performance and fronto-limbic neural activity patterns during attention-demanding cognitive processing in 16 female, unmedicated BPD patients relative to 24 age-matched healthy controls. In a modified flanker task, emotionally negative, socially salient pictures (fearful vs. neutral faces) were presented as distracters in the background. Patients, but not controls, showed an atypical response pattern of the right amygdala with increased activation during emotional interference in the (difficult) incongruent flanker condition, but emotion-related amygdala deactivation in the congruent condition. A direct comparison of the emotional conditions between the two groups revealed that the strongest diagnosis-related differences could be observed in the dorsal and, to a lesser extent, also in the rostral anterior cingulate cortex (dACC, rACC) where patients exhibited an increased neural response to emotional relative to neutral distracters. Moreover, in the incongruent condition, both the dACC and rACC fMRI responses during emotional interference were negatively correlated with trait anxiety in the patients, but not in the healthy controls. As higher trait anxiety was also associated with longer reaction times (RTs) in the BPD patients, we suggest that in BPD patients the ACC might mediate compensatory cognitive processes during emotional interference and that such neurocognitive compensation that can be adversely affected by high levels of anxiety.

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<![CDATA[Visual mismatch negativity in the dorsal stream is independent of concurrent visual task difficulty]]> https://www.researchpad.co/product?articleinfo=5989db42ab0ee8fa60bd7122

The manipulation of attention can produce mismatch negativity-like components that are not necessarily connected to the unintentional sensory registration of the violation of probability-based regularity. For clinical purposes, attentional bias should be quantified because it can vary substantially among subjects and can decrease the specificity of the examination. This experiment targets the role of attention in the generation of visual mismatch negativity (vMMN). The visual regularity was generated by a sequence of two radial motions while subjects focused on visual tasks in the central part of the display. Attentional load was systematically varied and had three levels, no-load, easy, and difficult. Rare, deviant, and frequent standard motions were presented with a 10/60 ratio in oddball sequences. Data from 12 subjects was recorded from 64 channels and processed. vMMN was identified within the interval of 142–198 ms. The mean amplitude was evaluated during the aforementioned interval in the parietal and fronto-central regions. A general linear model for repeated measures was applied to the mean amplitude with a three-factor design and showed a significant difference [F(1, 11) = 17.40, p = 0.002] between standard and deviant stimuli and between regions [F(1, 11) = 8.40, p = 0.01]; however, no significant effect of the task [F(2, 22) = 1.26, p = 0.30] was observed. The unintentional detection of irregularity during the processing of the visual motion was independent of the attentional load associated with handling the central visual task. The experiment did not demonstrate an effect of attentional load manipulation on mismatch negativity (MMN) induced by the motion-sequence, which supports the clinical utility of this examination. However, used stimulation paradigm should be further optimized to generate mismatch negativity that is stable enough to be usable not only for group comparisons but also for a single subject assessment.

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<![CDATA[Predicting speech fluency and naming abilities in aphasic patients]]> https://www.researchpad.co/product?articleinfo=5989da6dab0ee8fa60b936f7

There is a need to identify biomarkers that predict degree of chronic speech fluency/language impairment and potential for improvement after stroke. We previously showed that the Arcuate Fasciculus lesion load (AF-LL), a combined variable of lesion site and size, predicted speech fluency in patients with chronic aphasia. In the current study, we compared lesion loads of such a structural map (i.e., AF-LL) with those of a functional map [i.e., the functional gray matter lesion load (fGM-LL)] in their ability to predict speech fluency and naming performance in a large group of patients. The fGM map was constructed from functional brain images acquired during an overt speaking task in a group of healthy elderly controls. The AF map was reconstructed from high-resolution diffusion tensor images also from a group of healthy elderly controls. In addition to these two canonical maps, a combined AF-fGM map was derived from summing fGM and AF maps. Each canonical map was overlaid with individual lesion masks of 50 chronic aphasic patients with varying degrees of impairment in speech production and fluency to calculate a functional and structural lesion load value for each patient, and to regress these values with measures of speech fluency and naming. We found that both AF-LL and fGM-LL independently predicted speech fluency and naming ability; however, AF lesion load explained most of the variance for both measures. The combined AF-fGM lesion load did not have a higher predictability than either AF-LL or fGM-LL alone. Clustering and classification methods confirmed that AF lesion load was best at stratifying patients into severe and non-severe outcome groups with 96% accuracy for speech fluency and 90% accuracy for naming. An AF-LL of greater than 4 cc was the critical threshold that determined poor fluency and naming outcomes, and constitutes the severe outcome group. Thus, surrogate markers of impairments have the potential to predict outcomes and can be used as a stratifier in experimental studies.

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<![CDATA[Neural substrates of cognitive control under the belief of getting neurofeedback training]]> https://www.researchpad.co/product?articleinfo=5989da2dab0ee8fa60b830ad

Learning to modulate one's own brain activity is the fundament of neurofeedback (NF) applications. Besides the neural networks directly involved in the generation and modulation of the neurophysiological parameter being specifically trained, more general determinants of NF efficacy such as self-referential processes and cognitive control have been frequently disregarded. Nonetheless, deeper insight into these cognitive mechanisms and their neuronal underpinnings sheds light on various open NF related questions concerning individual differences, brain-computer interface (BCI) illiteracy as well as a more general model of NF learning. In this context, we investigated the neuronal substrate of these more general regulatory mechanisms that are engaged when participants believe that they are receiving NF. Twenty healthy participants (40–63 years, 10 female) performed a sham NF paradigm during fMRI scanning. All participants were novices to NF-experiments and were instructed to voluntarily modulate their own brain activity based on a visual display of moving color bars. However, the bar depicted a recording and not the actual brain activity of participants. Reports collected at the end of the experiment indicate that participants were unaware of the sham feedback. In comparison to a passive watching condition, bilateral insula, anterior cingulate cortex and supplementary motor and dorsomedial and lateral prefrontal areas were activated when participants actively tried to control the bar. In contrast, when merely watching moving bars, increased activation in the left angular gyrus was observed. These results show that the intention to control a moving bar is sufficient to engage a broad frontoparietal and cingulo-opercular network involved in cognitive control. The results of the present study indicate that tasks such as those generally employed in NF training recruit the neuronal correlates of cognitive control even when only sham NF is presented.

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<![CDATA[Fear of negative evaluation modulates electrocortical and behavioral responses when anticipating social evaluative feedback]]> https://www.researchpad.co/product?articleinfo=5989dae6ab0ee8fa60bbd6a9

Cognitive models posit that the fear of negative evaluation (FNE) is a hallmark feature of social anxiety. As such, individuals with high FNE may show biased information processing when faced with social evaluation. The aim of the current study was to examine the neural underpinnings of anticipating and processing social-evaluative feedback, and its correlates with FNE. We used a social judgment paradigm in which female participants (N = 31) were asked to indicate whether they believed to be socially accepted or rejected by their peers. Anticipatory attention was indexed by the stimulus preceding negativity (SPN), while the feedback-related negativity and P3 were used to index the processing of social-evaluative feedback. Results provided evidence of an optimism bias in social peer evaluation, as participants more often predicted to be socially accepted than rejected. Participants with high levels of FNE needed more time to provide their judgments about the social-evaluative outcome. While anticipating social-evaluative feedback, SPN amplitudes were larger for anticipated social acceptance than for social rejection feedback. Interestingly, the SPN during anticipated social acceptance was larger in participants with high levels of FNE. None of the feedback-related brain potentials correlated with the FNE. Together, the results provided evidence of biased information processing in individuals with high levels of FNE when anticipating (rather than processing) social-evaluative feedback. The delayed response times in high FNE individuals were interpreted to reflect augmented vigilance imposed by the upcoming social-evaluative threat. Possibly, the SPN constitutes a neural marker of this vigilance in females with higher FNE levels, particularly when anticipating social acceptance feedback.

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