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.

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.

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

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.

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.

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.

Dynamic changes in sleep-related breathing abnormalities in bilateral paramedian mesencephalon and thalamus stroke: a follow-up case study.

BACKGROUND: Bilateral paramedian thalamic stroke is characterized by hypersomnia, vertical gaze palsy, amnestic alteration, and apathic state. Combined lesion of the paramedian thalamus and mesencephalon bilaterally is extremely rare. Little is known about the breathing disturbances of the particular region due to the lesion. The following describes the specific case of a woman, age 62, with bilateral paramedian thalamic and mesencephalic stroke. Initially, the patient's complaints exhibited altered vigilance and vertical gaze palsy. Notably, following the acute phase, fluctuating hypersomnia was detected. The MRI (brain) revealed an ischemic lesion in the medial part of the mesencephalon and paramedian thalamus, bilaterally. AIMS: The aim of the present study is to elucidate the involvement and characteristics of sleep-related breathing abnormalities in the clinical manifestation of the combined paramedian thalamic and mesencephalic stroke. METHODS: Polysomnographic recordings were accomplished seven times with 1-week interval between the consecutive recordings, toward investigating the early changes of sleep and sleep-related breathing abnormalities. RESULTS: Sleep structure examination featured a decrease in N3 and REM ratio and an increase in N1 and N2 ratio with minimal improvement during the recovery period. In contrast, significant changes were found in the breathing pattern: the initial central apnea dominance was followed by obstructive apneas with a gradual decrease of the total pathological respiratory events. CONCLUSION: In addition to the structural abnormality of the sleep regulating network, sleep-disordered breathing is another possible cause of hypersomnia in patients afflicted with the present localization of the lesion.

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.

Mindfulness-based training attenuates insula response to an aversive interoceptive challenge.

Neuroimaging studies of mindfulness training (MT) modulate anterior cingulate cortex (ACC) and insula among other brain regions, which are important for attentional control, emotional regulation and interoception. Inspiratory breathing load (IBL) is an experimental approach to examine how an individual responds to an aversive stimulus. Military personnel are at increased risk for cognitive, emotional and physiological compromise as a consequence of prolonged exposure to stressful environments and, therefore, may benefit from MT. This study investigated whether MT modulates neural processing of interoceptive distress in infantry marines scheduled to undergo pre-deployment training and deployment to Afghanistan. Marines were divided into two groups: individuals who received training as usual (control) and individuals who received an additional 20-h mindfulness-based mind fitness training (MMFT). All subjects completed an IBL task during functional magnetic resonance imaging at baseline and post-MMFT training. Marines who underwent MMFT relative to controls demonstrated a significant attenuation of right anterior insula and ACC during the experience of loaded breathing. These results support the hypothesis that MT changes brain activation such that individuals process more effectively an aversive interoceptive stimulus. Thus, MT may serve as a training technique to modulate the brain's response to negative interoceptive stimuli, which may help to improve resilience.

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.

Executive functions in obsessive-compulsive disorder: An activation likelihood estimate meta-analysis of fMRI studies.

OBJECTIVES: To identify activation changes assessed in functional magnetic resonance imaging (fMRI) studies of obsessive-compulsive disorder (OCD) through Activation Likelihood Estimate meta-analysis. METHODS: We included 28 peer-reviewed standard stereotactic space studies assessing adult OCD patients (OCDpts) vs. healthy controls (HCs) with fMRI during executive task performance. RESULTS: In within-group analyses, HCs showed task-related activations in bilateral inferior frontal gyri, right middle frontal gyrus, right inferior parietal lobule, right claustrum, bilateral cingulate gyri, and left caudate body. OCDpts showed task-related left-sided activations in the superior, medial, and inferior frontal gyri, and thalamus, and bilateral activations in the middle frontal gyri, inferior parietal lobule, and insular cortices. Subtraction analysis showed increased left middle frontal gyrus activation in OCDpts. In between-groups analyses, OCDpts hypoactivated the right caudate body, left putamen, left ACC, and right medial and middle frontal gyri. Right caudate hypoactivation persisted also after applying Family-wise error algorithms. CONCLUSIONS: This meta-analysis confirms that during executive functioning OCDpts show a functional deficit of the right caudate body, which could represent a major neural functional correlate of their illness.

On the Use of Dance as a Rehabilitation Approach for Children with Cerebral Palsy: A Single Case Study.

Cerebral Palsy (CP) is the most common motor disability in childhood. It is a group of permanent disorders that affect child development causing disorders of movement and posture and activity limitations. The impairment of psychomotor skills of children with Cerebral Palsy is attributed to a permanent alteration occurred in non-progressive brain development of the fetus or nursing infant. Some motor related symptoms can be treated using proper physical therapy. However, one of the biggest problems of the usual physical therapy is adherence to therapy. Ballet can be an alternative or a complement to physiotherapy, with the added attraction of not being part of a to therapy, but a fun activity with the extra reward associated with the realization of an artistic activity. For some years the ballet is used as therapeutically valuable for both children with cerebral palsy: Intensive ballet training can generate changes in the sensorimotor cortex. Ballet is characterized by a complex process of movements that have to be in a musical rhythm (hence have to be precise), in which there is an overall coordination of the muscles. It is also a highly motivating and rewarding activity that allows many children with CP sharing the activities of their peers without special needs. Objective measurements of the Full Port de Bras movement has been chosen as an index of improvement. The results shows progressive improvements of the execution in a single case.

Tone-language speakers show hemispheric specialization and differential cortical processing of contour and interval cues for pitch.

Electrophysiological studies demonstrate that the neural coding of pitch is modulated by language experience and the linguistic relevance of the auditory input; both rightward and leftward asymmetries have been observed in the hemispheric specialization for pitch. In music, pitch is encoded using two primary features: contour (patterns of rises and falls) and interval (frequency separation between tones) cues. Recent evoked potential studies demonstrate that these "global" (contour) and "local" (interval) aspects of pitch are processed automatically (but bilaterally) in trained musicians. Here, we examined whether alternate forms of pitch expertise, namely, tone-language experience (i.e., Chinese), influence the early detection of contour and intervallic deviations within ongoing pitch sequences. Neuroelectric mismatch negativity (MMN) potentials were recorded in Chinese speakers and English-speaking nonmusicians in response to continuous pitch sequences with occasional global or local deviations in the ongoing melodic stream. This paradigm allowed us to explore potential cross-language differences in the hemispheric weighting for contour and interval processing of pitch. Chinese speakers showed differential pitch encoding between hemispheres not observed in English listeners; Chinese MMNs revealed a rightward bias for contour processing but a leftward hemispheric laterality for interval processing. In contrast, no asymmetries were observed in the English group. Collectively, our findings suggest tone-language experience sensitizes auditory brain mechanisms for the detection of subtle global/local pitch changes in the ongoing auditory stream and exaggerates functional asymmetries in pitch processing between cerebral hemispheres.

The effects of preparation and acoustic stimulation on contralateral and ipsilateral corticospinal excitability.

A loud auditory stimulus (LAS) presented together with an imperative stimulus during preparation for motor actions can speed their initiation. The effects of LAS on corticospinal excitability (CSE), however, depend on the state of preparation of the motor system for action. CSE also depends on the brain hemisphere controlling the responding limb. Usually, CSE is increased just before movement onset in the hemisphere controlling the movement and inhibited on the other side. This study investigated the impact of LAS on CSE of the contralateral and ipsilateral hemispheres, while participants prepared for a voluntary abduction of the index finger. In Experiment 1, we attempted to identify the pattern of modulation of the ipsilateral cortex (resting side) by determining the time course of corticospinal changes in anticipatory timing actions using transcranial magnetic stimulation. In Experiment 2, we investigated the impact of LAS on the ipsilateral and contralateral CSE during anticipatory preparation. Results found no modulation of ipsilateral CSE during preparation, but indicate an increase in CSE after EMG onset on the acting limb. Moreover, we found that LAS presentation increased CSE on the contralateral side (active side).

Hemispheric specialization for visual words is shaped by attention to sublexical units during initial learning.

Selective attention to grapheme-phoneme mappings during learning can impact the circuitry subsequently recruited during reading. Here we trained literate adults to read two novel scripts of glyph words containing embedded letters under different instructions. For one script, learners linked each embedded letter to its corresponding sound within the word (grapheme-phoneme focus); for the other, decoding was prevented so entire words had to be memorized. Post-training, ERPs were recorded during a reading task on the trained words within each condition and on untrained but decodable (transfer) words. Within this condition, reaction-time patterns suggested both trained and transfer words were accessed via sublexical units, yet a left-lateralized, late ERP response showed an enhanced left lateralization for transfer words relative to trained words, potentially reflecting effortful decoding. Collectively, these findings show that selective attention to grapheme-phoneme mappings during learning drives the lateralization of circuitry that supports later word recognition. This study thus provides a model example of how different instructional approaches to the same material may impact changes in brain circuitry.