Role of Inferior Frontal Junction (IFJ) in the Control of Feature versus Spatial Attention.

Feature-based visual attention refers to preferential selection and processing of visual stimuli based on their nonspatial attributes, such as color or shape. Recent studies have highlighted the inferior frontal junction (IFJ) as a control region for feature but not spatial attention. However, the extent to which IFJ contributes to spatial versus feature attention control remains a topic of debate. We investigated in humans of both sexes the role of IFJ in the control of feature versus spatial attention in a cued visual spatial (attend-left or attend-right) and feature (attend-red or attend-green) attention task using fMRI. Analyzing cue-related fMRI using both univariate activation and multivoxel pattern analysis, we found the following results in IFJ. First, in line with some prior studies, the univariate activations were not different between feature and spatial attentional control. Second, in contrast, the multivoxel pattern analysis decoding accuracy was above chance level for feature attention (attend-red vs attend-green) but not for spatial attention (attend-left vs attend-right). Third, while the decoding accuracy for feature attention was above chance level during attentional control in the cue-to-target interval, it was not during target processing. Fourth, the right IFJ and visual cortex (V4) were observed to be functionally connected during feature but not during spatial attention control, and this functional connectivity was positively associated with subsequent attentional selection of targets in V4, as well as with behavioral performance. These results support a model in which IFJ plays a crucial role in top-down control of visual feature but not visual spatial attention.SIGNIFICANCE STATEMENT Past work has shown that the inferior frontal junction (IFJ), a prefrontal structure, is activated by both attention-to-feature (e.g., color) and attention-to-location, but the precise role of IFJ in the control of feature- versus spatial-attention is debated. We investigated this issue in a cued visual spatial (attend-left or attend-right) and feature (attend-red or attend-green) attention task using fMRI, multivoxel pattern analysis, and functional connectivity methods. The results show that (1) attend-red versus attend-green can be decoded in single-trial cue-evoked BOLD activity in IFJ but not attend-left versus attend-right and (2) only right IFJ modulates V4 to enhance task performance. This study sheds light on the function and hemispheric specialization of IFJ in the control of visual attention.

Beyond imagination: Hypnotic visual hallucination induces greater lateralised brain activity than visual mental imagery.

Hypnotic suggestions can produce a broad range of perceptual experiences, including hallucinations. Visual hypnotic hallucinations differ in many ways from regular mental images. For example, they are usually experienced as automatic, vivid, and real images, typically compromising the sense of reality. While both hypnotic hallucination and mental imagery are believed to mainly rely on the activation of the visual cortex via top-down mechanisms, it is unknown how they differ in the neural processes they engage. Here we used an adaptation paradigm to test and compare top-down processing between hypnotic hallucination, mental imagery, and visual perception in very highly hypnotisable individuals whose ability to hallucinate was assessed. By measuring the N170/VPP event-related complex and using multivariate decoding analysis, we found that hypnotic hallucination of faces involves greater top-down activation of sensory processing through lateralised neural mechanisms in the right hemisphere compared to mental imagery. Our findings suggest that the neural signatures that distinguish hypnotically hallucinated faces from imagined faces lie in the right brain hemisphere.

Mapping the human auditory cortex using spectrotemporal receptive fields generated with magnetoencephalography.

We present a novel method to map the functional organization of the human auditory cortex noninvasively using magnetoencephalography (MEG). More specifically, this method estimates via reverse correlation the spectrotemporal receptive fields (STRF) in response to a temporally dense pure tone stimulus, from which important spectrotemporal characteristics of neuronal processing can be extracted and mapped back onto the cortex surface. We show that several neuronal populations can be found examining the spectrotemporal characteristics of their STRFs, and demonstrate how these can be used to generate tonotopic gradient maps. In doing so, we show that the spatial resolution of MEG is sufficient to reliably extract important information about the spatial organization of the auditory cortex, while enabling the analysis of complex temporal dynamics of auditory processing such as best temporal modulation rate and response latency given its excellent temporal resolution. Furthermore, because spectrotemporally dense auditory stimuli can be used with MEG, the time required to acquire the necessary data to generate tonotopic maps is significantly less for MEG than for other neuroimaging tools that acquire BOLD-like signals.

Time-to-contact perception in the brain.

Time-to-contact (TTC) perception refers to the ability of an observer to estimate the remaining time before an object reaches a point in the environment, and is of crucial importance in daily life. Noninvasive correlational approaches have identified several brain areas sensitive to TTC information. Here we report the results of two studies, including one during an awake brain surgery, that aimed to identify the specific areas causally engaged in the TTC estimation process. In Study 1, we tested 40 patients with brain tumor in a TTC estimation task. The results showed that four of the six patients with impaired performance had tumors in right upper parietal cortex, although this tumoral location represented only six over 40 patients. In Study 2, 15 patients underwent awake brain surgery electrostimulation mapping to examine the implication of various brain areas in the TTC estimation process. We acquired and normalized to MNI space the coordinates of the functional areas that influenced task performance. Our results seem to demonstrate that the early stage of the TTC estimation process involved specific cortical territories in the ventral region of the right intraparietal sulcus. Downstream processing of TTC could also involve the frontal eye field (middle frontal gyrus) related to ocular search. We also found that deactivating language areas in the left hemisphere interfered with the TTC estimation process. These findings demonstrate a fine grained, cortical representation of TTC processing close to the ventral right intraparietal sulcus and complement those described in other human studies.

Tactile to visual number priming in the left intraparietal cortex of sighted Braille readers.

Numbers can be presented in different notations and sensory modalities. It is currently debated to what extent these formats overlap onto a single representation. We asked whether such an overlap exists between symbolic numbers represented in two sensory modalities: Arabic digits and Braille numbers. A unique group of sighted Braille readers underwent extensive Braille reading training and was tested in an fMRI repetition-suppression paradigm with tactile Braille digit primes and visual Arabic digit targets. Our results reveal cross-modal priming: compared to repetition of two different quantities (e.g., Braille "5" and Arabic "2"), repetition of the same quantity presented in two modalities (e.g., Braille "5" and Arabic "5") led to a reduction of activation in several sub-regions of the Intraparietal Sulcus (IPS), a key cortical region for magnitude processing. Thus, in sighted Braille readers, the representations of numbers read by sight and by touch overlap to a degree sufficient to cause repetition suppression. This effect was modulated by the numerical prime-probe distance. Altogether this indicates that the left parietal cortex hosts neural assemblies that are sensitive to numerical information from different notations (number words or Arabic digits) and modalities (tactile and visual).

A primer on dichotic listening as a paradigm for the assessment of hemispheric asymmetry.

Dichotic listening is a well-established method to non-invasively assess hemispheric specialization for processing of speech and other auditory stimuli. However, almost six decades of research also have revealed a series of experimental variables with systematic modulatory effects on task performance. These variables are a source of systematic error variance in the data and, when uncontrolled, affect the reliability and validity of the obtained laterality measures. The present review provides a comprehensive overview of these modulatory variables and offers both guiding principles as well as concrete suggestions on how to account for possible confounding effects and avoid common pitfalls. The review additionally provides guidance for the evaluation of past studies and help for resolving inconsistencies in the available literature.

Left/right limb judgement task performance following total knee replacement.

PURPOSE: Working body schema (WBS) of the limbs may be indirectly assessed using left/right limb judgement (LRLJ) task performance. This study aimed to investigate if: 1) Total Knee Replacement (TKR) patients perform LRLJ tasks with reference to their WBS; 2) patients have a disrupted WBS following a TKR for the replaced knee compared to the contralateral knee; and 3) lower limb-based LRLJ task performance changes following post-surgical rehabilitation using change in upper limb-based LRLJ task performance as a control. METHODS: In a convenience sample (n= 18, age 69 ± 7 yrs, 12F 6M) of TKR patients < 1 month post-surgery, WBS was assessed using LRLJ task performance for the upper (pictures of the hand) and lower limb (pictures of the foot) before and after rehabilitation. Accuracy and response time (RT) were analysed using a series of 2 × 2 × 2 ANOVAs. RESULTS: LRLJ task performance for images corresponding with the operated and non-operated side were comparable for accuracy (p= 0.83) and RT (p= 0.28). Accuracy for hand images was comparable from baseline to post-rehabilitation (p= 0.54) whereas accuracy for feet images increased significantly (p= 0.03). Responses for awkward posture images were significantly slower than for more natural posture images (p= 0.001). CONCLUSIONS: LRLJ task performance data reflected the typical biomechanical constraints indicative of implicit motor imagery being performed by patients. There was no evidence of a disrupted LRLJ task performance for the replaced knee compared to the contralateral knee. Following post-surgical rehabilitation, patients' lower limb LRLJ task performance improved whilst upper limb LRLJ task performance remained unchanged. These findings are the first to show that WBS improves with rehabilitation following TKR, and this may explain some of the clinical improvements observed. Undertaking LRLJ tasks could theoretically be a useful adjunct to current post-TKR rehabilitation.

Modulating Regional Motor Cortical Excitability with Noninvasive Brain Stimulation Results in Neurochemical Changes in Bilateral Motor Cortices.

Learning a novel motor skill is dependent both on regional changes within the primary motor cortex (M1) contralateral to the active hand and also on modulation between and within anatomically distant but functionally connected brain regions. Interregional changes are particularly important in functional recovery after stroke, when critical plastic changes underpinning behavioral improvements are observed in both ipsilesional and contralesional M1s. It is increasingly understood that reduction in GABA in the contralateral M1 is necessary to allow learning of a motor task. However, the physiological mechanisms underpinning plasticity within other brain regions, most importantly the ipsilateral M1, are not well understood. Here, we used concurrent two-voxel magnetic resonance spectroscopy to simultaneously quantify changes in neurochemicals within left and right M1s in healthy humans of both sexes in response to transcranial direct current stimulation (tDCS) applied to left M1. We demonstrated a decrease in GABA in both the stimulated (left) and nonstimulated (right) M1 after anodal tDCS, whereas a decrease in GABA was only observed in nonstimulated M1 after cathodal stimulation. This GABA decrease in the nonstimulated M1 during cathodal tDCS was negatively correlated with microstructure of M1:M1 callosal fibers, as quantified by diffusion MRI, suggesting that structural features of these fibers may mediate GABA decrease in the unstimulated region. We found no significant changes in glutamate. Together, these findings shed light on the interactions between the two major network nodes underpinning motor plasticity, offering a potential framework from which to optimize future interventions to improve motor function after stroke.SIGNIFICANCE STATEMENT Learning of new motor skills depends on modulation both within and between brain regions. Here, we use a novel two-voxel magnetic resonance spectroscopy approach to quantify GABA and glutamate changes concurrently within the left and right primary motor cortex (M1) during three commonly used transcranial direct current stimulation montages: anodal, cathodal, and bilateral. We also examined how the neurochemical changes in the unstimulated hemisphere were related to white matter microstructure between the two M1s. Our results provide insights into the neurochemical changes underlying motor plasticity and may therefore assist in the development of further adjunct therapies.

Evaluación de parámetros de banda ancha en la determinación de dominancia cerebral durante la hipnosis / Evaluation of wide band parameters in the determination of cerebral dominance during hypnosis

Se realizó un estudio cuasiexperimental de 21 estudiantes que cursaban la carrera de medicina, los cuales se encontraban en estado de hipnosis, atendidos en el Hospital General Docente Dr Juan Bruno Zayas Alfonso de Santiago de Cuba, desde septiembre del 2014 hasta junio del 2015, con vistas a identificar las medidas espectrales de banda ancha sensibles en la determinación de la dominancia cerebral durante dicho estado. Entre las variables analizadas figuraron: nivel de profundidad hipnótica, medidas espectrales de banda ancha y derivación. Se utilizó el estadígrafo false discovery rate como prueba de hipótesis para validar la información estadística y el análisis de varianza multivariado Manova. Los resultados revelaron que el poder relativo theta resultó ser la medida espectral con modificaciones más significativas y mostró un predominio discreto de la energía en el hemisferio izquierdo. Se concluyó que este hallazgo tuvo lugar como consecuencia de las tareas indicadas durante la hipnosis

A quasi-experiment of 21 students that were studying the medicine career, who were in hypnosis state, assisted in Dr Juan Bruno Zayas Alfonso Teaching General Hospital in Santiago de Cuba, was carried out from September, 2014 to June, 2015, aimed at identifying the wide band spectral measures sensitive in the determination of cerebral dominance during this state. Among the analyzed variables we can mention: level of hypnotic depth and spectral measures of wide band and derivation. The false discovery rate stadigraph was used as hypothesis test to validate the statistical information and the Manova multivaried analysis of variance. The results revealed that theta relative power was the spectral measure with more significant modifications and showed a discreet prevalence of energy in the left hemisphere. It was concluded that this finding took place as a consequence of the given tasks during hypnosis

Evaluación de parámetros de banda ancha en la determinación de dominancia cerebral durante la hipnosis / Evaluation of wide band parameters in the determination of cerebral dominance during hypnosis

Se realizó un estudio cuasiexperimental de 21 estudiantes que cursaban la carrera de medicina, los cuales se encontraban en estado de hipnosis, atendidos en el Hospital General Docente Dr. Juan Bruno Zayas Alfonso de Santiago de Cuba, desde septiembre del 2014 hasta junio del 2015, con vistas a identificar las medidas espectrales de banda ancha sensibles en la determinación de la dominancia cerebral durante dicho estado. Entre las variables analizadas figuraron: nivel de profundidad hipnótica, medidas espectrales de banda ancha y derivación. Se utilizó el estadígrafo false discovery rate como prueba de hipótesis para validar la información estadística y el análisis de varianza multivariado Manova. Los resultados revelaron que el poder relativo theta resultó ser la medida espectral con modificaciones más significativas y mostró un predominio discreto de la energía en el hemisferio izquierdo. Se concluyó que este hallazgo tuvo lugar como consecuencia de las tareas indicadas durante la hipnosis(AU)

A quasi-experiment of 21 students that were studying the medicine career, who were in hypnosis state, assisted in Dr Juan Bruno Zayas Alfonso Teaching General Hospital in Santiago de Cuba, was carried out from September, 2014 to June, 2015, aimed at identifying the wide band spectral measures sensitive in the determination of cerebral dominance during this state. Among the analyzed variables we can mention: level of hypnotic depth and spectral measures of wide band and derivation. The false discovery rate stadigraph was used as hypothesis test to validate the statistical information and the Manova multivaried analysis of variance. The results revealed that theta relative power was the spectral measure with more significant modifications and showed a discreet prevalence of energy in the left hemisphere. It was concluded that this finding took place as a consequence of the given tasks during hypnosis(AU)

Microsurgical anatomy of the central core of the brain.

OBJECTIVE The purpose of this study was to describe in detail the cortical and subcortical anatomy of the central core of the brain, defining its limits, with particular attention to the topography and relationships of the thalamus, basal ganglia, and related white matter pathways and vessels. METHODS The authors studied 19 cerebral hemispheres. The vascular systems of all of the specimens were injected with colored silicone, and the specimens were then frozen for at least 1 month to facilitate identification of individual fiber tracts. The dissections were performed in a stepwise manner, locating each gray matter nucleus and white matter pathway at different depths inside the central core. The course of fiber pathways was also noted in relation to the insular limiting sulci. RESULTS The insular surface is the most superficial aspect of the central core and is divided by a central sulcus into an anterior portion, usually containing 3 short gyri, and a posterior portion, with 2 long gyri. It is bounded by the anterior limiting sulcus, the superior limiting sulcus, and the inferior limiting sulcus. The extreme capsule is directly underneath the insular surface and is composed of short association fibers that extend toward all the opercula. The claustrum lies deep to the extreme capsule, and the external capsule is found medial to it. Three fiber pathways contribute to form both the extreme and external capsules, and they lie in a sequential anteroposterior disposition: the uncinate fascicle, the inferior fronto-occipital fascicle, and claustrocortical fibers. The putamen and the globus pallidus are between the external capsule, laterally, and the internal capsule, medially. The internal capsule is present medial to almost all insular limiting sulci and most of the insular surface, but not to their most anteroinferior portions. This anteroinferior portion of the central core has a more complex anatomy and is distinguished in this paper as the "anterior perforated substance region." The caudate nucleus and thalamus lie medial to the internal capsule, as the most medial structures of the central core. While the anterior half of the central core is related to the head of the caudate nucleus, the posterior half is related to the thalamus, and hence to each associated portion of the internal capsule between these structures and the insular surface. The central core stands on top of the brainstem. The brainstem and central core are connected by several white matter pathways and are not separated from each other by any natural division. The authors propose a subdivision of the central core into quadrants and describe each in detail. The functional importance of each structure is highlighted, and surgical approaches are suggested for each quadrant of the central core. CONCLUSIONS As a general rule, the internal capsule and its vascularization should be seen as a parasagittal barrier with great functional importance. This is of particular importance in choosing surgical approaches within this region.

Brain-responsive neurostimulation in patients with medically intractable mesial temporal lobe epilepsy.

OBJECTIVE: Evaluate the seizure-reduction response and safety of mesial temporal lobe (MTL) brain-responsive stimulation in adults with medically intractable partial-onset seizures of mesial temporal lobe origin. METHODS: Subjects with mesial temporal lobe epilepsy (MTLE) were identified from prospective clinical trials of a brain-responsive neurostimulator (RNS System, NeuroPace). The seizure reduction over years 2-6 postimplantation was calculated by assessing the seizure frequency compared to a preimplantation baseline. Safety was assessed based on reported adverse events. RESULTS: There were 111 subjects with MTLE; 72% of subjects had bilateral MTL onsets and 28% had unilateral onsets. Subjects had one to four leads placed; only two leads could be connected to the device. Seventy-six subjects had depth leads only, 29 had both depth and strip leads, and 6 had only strip leads. The mean follow-up was 6.1 ± (standard deviation) 2.2 years. The median percent seizure reduction was 70% (last observation carried forward). Twenty-nine percent of subjects experienced at least one seizure-free period of 6 months or longer, and 15% experienced at least one seizure-free period of 1 year or longer. There was no difference in seizure reduction in subjects with and without mesial temporal sclerosis (MTS), bilateral MTL onsets, prior resection, prior intracranial monitoring, and prior vagus nerve stimulation. In addition, seizure reduction was not dependent on the location of depth leads relative to the hippocampus. The most frequent serious device-related adverse event was soft tissue implant-site infection (overall rate, including events categorized as device-related, uncertain, or not device-related: 0.03 per implant year, which is not greater than with other neurostimulation devices). SIGNIFICANCE: Brain-responsive stimulation represents a safe and effective treatment option for patients with medically intractable epilepsy, including patients with unilateral or bilateral MTLE who are not candidates for temporal lobectomy or who have failed a prior MTL resection.

Offline continuous theta burst stimulation over right inferior frontal gyrus and pre-supplementary motor area impairs inhibition during a go/no-go task.

In a typical go/no-go task a single imperative stimulus is presented each trial, either a go or no-go stimulus. Participants are instructed to initiate a known response upon appearance of the go-signal and withhold the response if the no-go signal is presented. It is unclear whether the go-response is prepared in advance of the imperative stimulus in a go/no-go task. Moreover, it is unclear if inhibitory control processes suppress preparatory go-activation. The purpose of the present experiment was 1) to determine whether the go-response is prepared in advance of stimulus identification with the use of a startling acoustic stimulus (SAS), and 2) investigate the inhibitory role of the right inferior frontal gyrus (rIFG) and pre-supplementary motor area (preSMA) during the performance of a go/no-go task with the use of continuous theta burst stimulation (cTBS). The experiment consisted of three phases; a pre-cTBS phase in which participants completed a go/no-go and simple-RT task, followed by offline cTBS to temporarily deactivate either rIFG or preSMA (with a sham control), then a post-cTBS phase which was identical to the pre-cTBS phase. Results revealed that stimulation to both cortical sites impaired participants' ability to withhold movements during no-go trials. Notably, rIFG or preSMA stimulation did not affect the latency of voluntary go-responses and did not enable the SAS to involuntarily trigger responses. These findings suggest that preparation and initiation of the go-response occurs after the imperative stimulus, with the rIFG and preSMA involved in inhibiting the go-response once the stimulus is identified as a no-go signal.

Hemispheric differences between left and right supramarginal gyrus for pitch and rhythm memory.

Functional brain imaging studies and non-invasive brain stimulation methods have shown the importance of the left supramarginal gyrus (SMG) for pitch memory. The extent to which this brain region plays a crucial role in memory for other auditory material remains unclear. Here, we sought to investigate the role of the left and right SMG in pitch and rhythm memory in non-musicians. Anodal or sham transcranial direct current stimulation (tDCS) was applied over the left SMG (Experiment 1) and right SMG (Experiment 2) in two different sessions. In each session participants completed a pitch and rhythm recognition memory task immediately after tDCS. A significant facilitation of pitch memory was revealed when anodal stimulation was applied over the left SMG. No significant effects on pitch memory were found for anodal tDCS over the right SMG or sham condition. For rhythm memory the opposite pattern was found; anodal tDCS over the right SMG led to an improvement in performance, but anodal tDCS over the left SMG had no significant effect. These results highlight a different hemispheric involvement of the SMG in auditory memory processing depending on auditory material that is encoded.

Arts, Brain and Cognition.

Art is a product of human creativity; it is a superior skill that can be learned by study, practice and observation. Modern neuroscience and neuroimaging enable study of the processes during artistic performance. Creative people have less marked hemispheric dominance. It was found that the right hemisphere is specialized for metaphoric thinking, playfulness, solution finding and synthesizing, it is the center of visualization, imagination and conceptualization, but the left hemisphere is still needed for artistic work to achieve balance. A specific functional organization of brain areas was found during visual art activities. Marked hemispheric dominance and area specialization is also very prominent for music perception. Brain is capable of making new connections, activating new pathways and unmasking secondary roads, it is "plastic". Music is a strong stimulus for neuroplasticity. fMRI studies have shown reorganization of motor and auditory cortex in professional musicians. Other studies showed the changes in neurotransmitter and hormone serum levels in correlation to music. The most prominent connection between music and enhancement of performance or changing of neuropsychological activity was shown by studies involving Mozart's music from which the theory of "The Mozart Effect" was derived. Results of numerous studies showed that listening to music can improve cognition, motor skills and recovery after brain injury. In the field of visual art, brain lesion can lead to the visuospatial neglect, loss of details and significant impairment of artistic work while the lesions affecting the left hemisphere reveal new artistic dimensions, disinhibit the right hemisphere, work is more spontaneous and emotional with the gain of artistic quality. All kinds of arts (music, painting, dancing...) stimulate the brain. They should be part of treatment processes. Work of many artists is an excellent example for the interweaving the neurology and arts.

Temporal voice areas exist in autism spectrum disorder but are dysfunctional for voice identity recognition.

The ability to recognise the identity of others is a key requirement for successful communication. Brain regions that respond selectively to voices exist in humans from early infancy on. Currently, it is unclear whether dysfunction of these voice-sensitive regions can explain voice identity recognition impairments. Here, we used two independent functional magnetic resonance imaging studies to investigate voice processing in a population that has been reported to have no voice-sensitive regions: autism spectrum disorder (ASD). Our results refute the earlier report that individuals with ASD have no responses in voice-sensitive regions: Passive listening to vocal, compared to non-vocal, sounds elicited typical responses in voice-sensitive regions in the high-functioning ASD group and controls. In contrast, the ASD group had a dysfunction in voice-sensitive regions during voice identity but not speech recognition in the right posterior superior temporal sulcus/gyrus (STS/STG)-a region implicated in processing complex spectrotemporal voice features and unfamiliar voices. The right anterior STS/STG correlated with voice identity recognition performance in controls but not in the ASD group. The findings suggest that right STS/STG dysfunction is critical for explaining voice recognition impairments in high-functioning ASD and show that ASD is not characterised by a general lack of voice-sensitive responses.

Universal and language-specific sublexical cues in speech perception: a novel electroencephalography-lesion approach.

SEE CAPPA DOI101093/BRAIN/AWW090 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE : The phonological structure of speech supports the highly automatic mapping of sound to meaning. While it is uncontroversial that phonotactic knowledge acts upon lexical access, it is unclear at what stage these combinatorial rules, governing phonological well-formedness in a given language, shape speech comprehension. Moreover few studies have investigated the neuronal network affording this important step in speech comprehension. Therefore we asked 70 participants-half of whom suffered from a chronic left hemispheric lesion-to listen to 252 different monosyllabic pseudowords. The material models universal preferences of phonotactic well-formedness by including naturally spoken pseudowords and digitally reversed exemplars. The latter partially violate phonological structure of all human speech and are rich in universally dispreferred phoneme sequences while preserving basic auditory parameters. Language-specific constraints were modelled in that half of the naturally spoken pseudowords complied with the phonotactics of the native language of the monolingual participants (German) while the other half did not. To ensure universal well-formedness and naturalness, the latter stimuli comply with Slovak phonotactics and all stimuli were produced by an early bilingual speaker. To maximally attenuate lexico-semantic influences, transparent pseudowords were avoided and participants had to detect immediate repetitions, a task orthogonal to the contrasts of interest. The results show that phonological 'well-formedness' modulates implicit processing of speech at different levels: universally dispreferred phonological structure elicits early, medium and late latency differences in the evoked potential. On the contrary, the language-specific phonotactic contrast selectively modulates a medium latency component of the event-related potentials around 400 ms. Using a novel event-related potential-lesion approach allowed us to furthermore supply first evidence that implicit processing of these different phonotactic levels relies on partially separable brain areas in the left hemisphere: contrasting forward to reversed speech the approach delineated an area comprising supramarginal and angular gyri. Conversely, the contrast between legal versus illegal phonotactics consistently projected to anterior and middle portions of the middle temporal and superior temporal gyri. Our data support the notion that phonological structure acts on different stages of phonologically and lexically driven steps of speech comprehension. In the context of previous work we propose context-dependent sensitivity to different levels of phonotactic well-formedness.

Modulation of hand motor-related area during motor imagery and motor execution before and after middle 2/5 of the MS6 line scalp acupuncture stimulation: An fMRI study.

Scalp acupuncture (SA) combines the concept of cerebral cortex organization with the principles of acupuncture. The SA stimulates sections of the cerebral cortex. We studied the functional modulation of the left hand sensorimotor area induced by SA in order to investigate the specificity of the SA-related functional effects of the middle 2/5 of the MS6 line of the left side, which corresponds to the upper limb motor segment of the primary motor area. To this purpose, we compared the pre- and post-SA functional activation patterns during an implicit motor imagery task (handedness decision in which participants simulated rotational hand movements) and an explicit manual motor execution task. Feet and mouth movements, and the fMRI changes in their respective representations were used as control conditions. Only SA on the hand area of the left side (as compared to the mouth and the foot representations which were used as control conditions) exerted a release effect on the right hand area. In addition, an increased activation of the superior parietal lobe was seen, which is involved in movement control and planning. Taken together, these preliminary findings may shed light on the SA effects and confirm a prolonged effect of SA even after cessation of needling stimulation.

The validity of individual frontal alpha asymmetry EEG neurofeedback.

Frontal asymmetry in alpha oscillations is assumed to be associated with psychopathology and individual differences in emotional responding. Brain-activity-based feedback is a promising tool for the modulation of cortical activity. Here, we validated a neurofeedback protocol designed to change relative frontal asymmetry based on individual alpha peak frequencies, including real-time average referencing and eye-correction. Participants (N = 60) were randomly assigned to a right, left or placebo neurofeedback group. Results show a difference in trainability between groups, with a linear change in frontal alpha asymmetry over time for the right neurofeedback group during rest. Moreover, the asymmetry changes in the right group were frequency and location specific, even though trainability did not persist at 1 week and 1 month follow-ups. On the behavioral level, subjective stress on the second test day was reduced in the left and placebo neurofeedback groups, but not in the right neurofeedback group. We found individual differences in trainability that were dependent on training group, with participants in the right neurofeedback group being more likely to change their frontal asymmetry in the desired direction. Individual differences in trainability were also reflected in the ability to change frontal asymmetry during the feedback.

The nondecussating pathway of the dentatorubrothalamic tract in humans: human connectome-based tractographic study and microdissection validation.

OBJECT The dentatorubrothalamic tract (DRTT) is the major efferent cerebellar pathway arising from the dentate nucleus (DN) and decussating to the contralateral red nucleus (RN) and thalamus. Surprisingly, hemispheric cerebellar output influences bilateral limb movements. In animals, uncrossed projections from the DN to the ipsilateral RN and thalamus may explain this phenomenon. The aim of this study was to clarify the anatomy of the dentatorubrothalamic connections in humans. METHODS The authors applied advanced deterministic fiber tractography to a template of 488 subjects from the Human Connectome Project (Q1-Q3 release, WU-Minn HCP consortium) and validated the results with microsurgical dissection of cadaveric brains prepared according to Klingler's method. RESULTS The authors identified the "classic" decussating DRTT and a corresponding nondecussating path (the nondecussating DRTT, nd-DRTT). Within each of these 2 tracts some fibers stop at the level of the RN, forming the dentatorubro tract and the nondecussating dentatorubro tract. The left nd-DRTT encompasses 21.7% of the tracts and 24.9% of the volume of the left superior cerebellar peduncle, and the right nd-DRTT encompasses 20.2% of the tracts and 28.4% of the volume of the right superior cerebellar peduncle. CONCLUSIONS The connections of the DN with the RN and thalamus are bilateral, not ipsilateral only. This affords a potential anatomical substrate for bilateral limb motor effects originating in a single cerebellar hemisphere under physiological conditions, and for bilateral limb motor impairment in hemispheric cerebellar lesions such as ischemic stroke and hemorrhage, and after resection of hemispheric tumors and arteriovenous malformations. Furthermore, when a lesion is located on the course of the dentatorubrothalamic system, a careful preoperative tractographic analysis of the relationship of the DRTT, nd-DRTT, and the lesion should be performed in order to tailor the surgical approach properly and spare all bundles.