Musical training increases functional connectivity, but does not enhance mu suppression.

Musical training provides an ideal platform for investigating action representation for sound. Learning to play an instrument requires integration of sensory and motor perception-action processes. Functional neuroimaging studies have indicated that listening to trained music can result in the activity in premotor areas, even after a short period of training. These studies suggest that action representation systems are heavily dependent on specific sensorimotor experience. However, others suggest that because humans naturally move to music, sensorimotor training is not necessary and there is a more general action representation for music. We previously demonstrated that EEG mu suppression, commonly implemented to demonstrate mirror-neuron-like action representation while observing movements, can also index action representations for sounds in pianists. The current study extends these findings to a group of non-musicians who learned to play randomised sequences on a piano, in order to acquire specific sound-action mappings for the five fingers of their right hand. We investigated training-related changes in neural dynamics as indexed by mu suppression and task-related coherence measures. To test the specificity of training effects, we included sounds similar to those encountered in the training and additionally rhythm sequences. We found no effect of training on mu suppression between pre- and post-training EEG recordings. However, task-related coherence indexing functional connectivity between electrodes over audiomotor areas increased after training. These results suggest that long-term training in musicians and short-term training in novices may be associated with different stages of audiomotor integration that can be reflected in different EEG measures. Furthermore, the changes in functional connectivity were specifically found for piano tones, and were not apparent when participants listened to rhythms, indicating some degree of specificity related to training.

Using CForest to Analyze Diffusion Tensor Imaging Data: A Study of White Matter Integrity in Healthy Aging.

Healthy aging has been associated with a global reduction in white matter integrity, which is thought to reflect cognitive decline. The present study aimed to investigate this reduction over a broad range of the life span, using diffusion tensor imaging analyzed with conditional inference random forest modeling (CForest). This approach is sensitive to subtle and potentially nonlinear effects over the age continuum and was used to characterize the progression of decline in greater detail than has been possible in the past. Data were collected from 45 healthy individuals ranging in age from 19 to 67 years. Fractional anisotropy (FA) was estimated using probabilistic tractography for a number of major tracts across the brain. Age coincided with a nonlinear decrease in FA, with onset beginning at ∼30 years of age and the steepest declines occurring later in life. However, several tracts showed a transient increase before this decline. The progression of decline varied by tract, with steeper but later decline occurring in more anterior tracts. Finally, strongly right-handed individuals demonstrated relatively preserved FA until more than a decade following the onset of decline of others. These results demonstrate that using a novel, nonparametric analysis approach, previously reported reductions in FA with healthy aging were confirmed, while at the same time, new insight was provided into the onset and progression of decline, with evidence suggesting increases in integrity continuing into adulthood.

Mu rhythm suppression demonstrates action representation in pianists during passive listening of piano melodies.

Musicians undergo extensive training which enhances established neural links between auditory and motor areas of the brain. Long-term training develops, strengthens and enables flexibility in these connections allowing proficiency in performance. Previous research has indicated that passive listening of trained music results in the recruitment of premotor areas. It has been argued that this sound-action representation may rely on activity in mirror neuron systems and that these systems are heavily dependent on actual sensorimotor experience. Action observation studies using electroencephalography have associated changes in mu rhythm activity with the mirror neuron system in the visuomotor domain. We aimed to investigate similar effects in the audiomotor domain. We utilised a mu suppression method in our action-listening study to detect involuntary motor coactivation when pianists passively listened to piano melodies. Wavelet analysis revealed sensorimotor mu rhythm suppression while pianists listened passively to piano melodies. Thus, we show that this spectral analysis method can also be used to demonstrate that auditory stimuli can activate the human mirror neuron system when sounds are linked to actions. Mu suppression could be a useful index for further research on action representation and training-induced plasticity.

Behavioural and electrophysiological effects related to semantic violations during braille reading.

This study investigated the potential to detect event related potentials (ERPs) occurring in response to a specific task in braille reading. This would expand current methodologies for studying the cognitive processes underlying braille reading. An N400 effect paradigm was utilised, whereby proficient blind braille readers read congruent- and incongruent-ending braille sentences. Kinematic and electroencephalography (EEG) data were obtained simultaneously and synchronised. The ERPs differed between the incongruent and congruent sentences in a manner consistent with the N400 effect found with a previous sighted reading paradigm, demonstrating that ERPs can be obtained during braille reading. The frequency of finger reversals and the degree of intermittency in the finger velocity were significantly higher when reading incongruent versus congruent sentence endings. Both reversals and the potential N400 effect may reflect processes involved in semantic unification. These findings have significant implications for the modelling of braille reading. The refinement of the technique will enable other ERPs to be identified and related to behavioural responses, to further our understanding of the braille reading process.

Difficulties with pitch discrimination influences pitch memory performance: evidence from congenital amusia.

Music processing is influenced by pitch perception and memory. Additionally these features interact, with pitch memory performance decreasing as the perceived distance between two pitches decreases. This study examined whether or not the difficulty of pitch discrimination influences pitch retention by testing individuals with congenital amusia. Pitch discrimination difficulty was equated by determining an individual's threshold with a two down one up staircase procedure and using this to create conditions where two pitches (the standard and the comparison tones) differed by 1x, 2x, and 3x the threshold setting. For comparison with the literature a condition that employed a constant pitch difference of four semitones was also included. The results showed that pitch memory performance improved as the discrimination between the standard and the comparison tones was made easier for both amusic and control groups, and more importantly, that amusics did not show any pitch retention deficits when the discrimination difficulty was equated. In contrast, consistent with previous literature, amusics performed worse than controls when the physical pitch distance was held constant at four semitones. This impaired performance has been interpreted as evidence for pitch memory impairment in the past. However, employing a constant pitch distance always makes the difference closer to the discrimination threshold for the amusic group than for the control group. Therefore, reduced performance in this condition may simply reflect differences in the perceptual difficulty of the discrimination. The findings indicate the importance of equating the discrimination difficulty when investigating memory.

Investigation of cortical and subcortical plasticity following short-term unilateral auditory deprivation in normal hearing adults.

There is growing evidence that auditory stimulation or deprivation can induce physiological and perceptual changes in the auditory system of normal hearing adults. The present study investigated cortical (hemispheric asymmetry) and subcortical (acoustic reflex threshold) changes in 11 normal hearing adults after 7 days of continuous unilateral earplug use (around 30 dB of attenuation at the high frequencies). The results revealed: (a) a decrease in high frequency acoustic reflex thresholds of around 7 dB in the ear that had been plugged and (b) no change in hemispheric asymmetry. The change in acoustic reflex is consistent with subcortical plasticity. It is unclear if homoeostatic plasticity preserved the normal hemispheric asymmetry or if this is the result of the experimental paradigm.

Amusia results in abnormal brain activity following inappropriate intonation during speech comprehension.

Pitch processing is a critical ability on which humans' tonal musical experience depends, and which is also of paramount importance for decoding prosody in speech. Congenital amusia refers to deficits in the ability to properly process musical pitch, and recent evidence has suggested that this musical pitch disorder may impact upon the processing of speech sounds. Here we present the first electrophysiological evidence demonstrating that individuals with amusia who speak Mandarin Chinese are impaired in classifying prosody as appropriate or inappropriate during a speech comprehension task. When presented with inappropriate prosody stimuli, control participants elicited a larger P600 and smaller N100 relative to the appropriate condition. In contrast, amusics did not show significant differences between the appropriate and inappropriate conditions in either the N100 or the P600 component. This provides further evidence that the pitch perception deficits associated with amusia may also affect intonation processing during speech comprehension in those who speak a tonal language such as Mandarin, and suggests music and language share some cognitive and neural resources.

Impaired categorical perception of lexical tones in Mandarin-speaking congenital amusics.

The degree to which cognitive resources are shared in the processing of musical pitch and lexical tones remains uncertain. Testing Mandarin amusics on their categorical perception of Mandarin lexical tones may provide insight into this issue. In the present study, a group of 15 amusic Mandarin speakers identified and discriminated Mandarin tones presented as continua in separate blocks. The tonal continua employed were from a high-level tone to a mid-rising tone and from a high-level tone to a high-falling tone. The two tonal continua were made in the contexts of natural speech and of nonlinguistic analogues. In contrast to the controls, the participants with amusia showed no improvement for discrimination pairs that crossed the classification boundary for either speech or nonlinguistic analogues, indicating a lack of categorical perception. The lack of categorical perception of Mandarin tones in the amusic group shows that the pitch deficits in amusics may be domain-general, and this suggests that the processing of musical pitch and lexical tones may share certain cognitive resources and/or processes (Patel 2003, 2008, 2012).

Musician's cramp as manifestation of maladaptive brain plasticity: arguments from instrumental differences.

Musician's cramp is a task-specific movement disorder that presents itself as muscular incoordination or loss of voluntary motor control of extensively trained movements while a musician is playing the instrument. It is characterized by task specificity and gender bias, affecting significantly more males than females. The etiology is multifaceted: a combination of a genetic predisposition, termed endophenotype, and behavioral triggering factors being the leading features for the manifestation of the disorder. We present epidemiological data from 591 musician patients from our outpatient clinic demonstrating an influence of fine-motor requirements on the manifestation of dystonia. Brass, guitar, and woodwind players were at greater risk than other instrumentalists. High temporospatial precision of movement patterns, synchronous demands on tonic and phasic muscular activation, in combination with fine-motor burdens of using the dominant hand in daily life activities, constitute as triggering factors for the disorder and may explain why different body parts are affected.

Effects of trifluoromethylphenylpiperazine (TFMPP) on interhemispheric communication.

BACKGROUND: 'Party Pills' containing trifluoromethylphenylpiperazine (TFMPP) and benzylpiperazine are legally available in many countries and marketed as safe alternatives to other illicit substances such as methamphetamine and methylenedioxymethamphetamine (or Ecstasy). They have gained huge popularity around the world, especially amongst young adults. However, there is no information currently available describing the acute neurophysiological effects of these psychoactive drugs in humans. The purpose of this study is to investigate the effects of TFMPP on central information processing speed in humans. METHODS: A randomised, double blind, placebo-controlled study using electroencephalography (EEG) was carried out to investigate the effects of TFMPP on interhemispheric transfer time (IHTT). Healthy, right-handed males (age: 25 ± 5.6 years) were given placebo (n = 15) or TFMPP (0.94 mg/kg, oral, n = 15) and tested both pre- and 2 h post-drug administration. High-density EEG recordings (128 channels which were re-referenced using an average reference to make 129 electrodes) were used to record event-related potentials. The N160 component was defined as the biggest negative peak in the range between 140 and 220 ms after the event. The IHHTs were analysed by deducting the N160 latency obtained in the contralateral hemisphere from the N160 latency obtained in the hemisphere ipsilateral to stimulus signal. RESULTS: Statistical analysis using a split-plot design analysis of variance revealed that TFMPP significantly reduced the IHTT but did not affect reaction time. No statistically significant changes were observed in the placebo group. CONCLUSIONS: This study is the first to report the neurophysiological effects of TFMPP in humans and suggests that TFMPP may affect transmitter systems involved in speeding of interhemispheric communication in the male brain.

Processing melodic contour and speech intonation in congenital amusics with Mandarin Chinese.

Congenital amusia is a disorder in the perception and production of musical pitch. It has been suggested that early exposure to a tonal language may compensate for the pitch disorder (Peretz, 2008). If so, it is reasonable to expect that there would be different characterizations of pitch perception in music and speech in congenital amusics who speak a tonal language, such as Mandarin. In this study, a group of 11 adults with amusia whose first language was Mandarin were tested with melodic contour and speech intonation discrimination and identification tasks. The participants with amusia were impaired in discriminating and identifying melodic contour. These abnormalities were also detected in identifying both speech and non-linguistic analogue derived patterns for the Mandarin intonation tasks. In addition, there was an overall trend for the participants with amusia to show deficits with respect to controls in the intonation discrimination tasks for both speech and non-linguistic analogues. These findings suggest that the amusics' melodic pitch deficits may extend to the perception of speech, and could potentially result in some language deficits in those who speak a tonal language.

Impaired sensorimotor integration in focal hand dystonia patients in the absence of symptoms.

BACKGROUND: Functional imaging studies of people with focal hand dystonia (FHD) have indicated abnormal activity in sensorimotor brain regions. Few studies however, have examined FHD during movements that do not provoke symptoms of the disorder. It is possible, therefore, that any differences between FHD and controls are confounded by activity due to the occurrence of symptoms. Thus, in order to characterise impairments in patients with FHD during movements that do not induce dystonic symptoms, we investigated the neural correlates of externally paced finger tapping movements. METHODS: Functional MRI (fMRI) was used to compare patients with FHD to controls with respect to activation in networks modulated by task complexity and hand used to perform simple and complex tapping movements. RESULTS: In the 'complexity network,' patients with FHD showed significantly less activity relative to controls in posterior parietal cortex, medial supplementary motor area (SMA), anterior putamen and cerebellum. In the 'hand network,' patients with FHD showed less activation than controls in primary motor (M1) and somatosensory (S1) cortices, SMA and cerebellum. Conjunction analysis revealed that patients with FHD demonstrated reduced activation in the majority of combined network regions (M1, S1 and cerebellum). CONCLUSION: Dysfunction in FHD is widespread in both complexity and hand networks, and impairments are demonstrated even when performing tasks that do not evoke dystonic symptoms. These results suggest that such impairments are inherent to, rather than symptomatic of, the disorder.

Semantic processing of mathematical gestures.

OBJECTIVE: To examine whether or not university mathematics students semantically process gestures depicting mathematical functions (mathematical gestures) similarly to the way they process action gestures and sentences. Semantic processing was indexed by the N400 effect. RESULTS: The N400 effect elicited by words primed with mathematical gestures (e.g. "converging" and "decreasing") was the same in amplitude, latency and topography as that elicited by words primed with action gestures (e.g. drive and lift), and that for terminal words of sentences. SIGNIFICANCE AND CONCLUSION: Findings provide a within-subject demonstration that the topographies of the gesture N400 effect for both action and mathematical words are indistinguishable from that of the standard language N400 effect. This suggests that mathematical function words are processed by the general language semantic system and do not appear to involve areas involved in other mathematical concepts (e.g. numerosity).

The neural networks involved in pitch labeling of absolute pitch musicians.

Investigating the neural substrates of auditory processing of absolute pitch musicians has relevance for understanding the capabilities of the human brain for plasticity. Electroencephalography was used to examine the N1 of auditory-evoked potentials from absolute pitch musicians, nonabsolute pitch musicians, and nonmusicians during tone labeling tasks with and without presentation of a reference tone. Source localization using low-resolution electromagnetic tomography revealed that when labeling tones without a reference, absolute pitch musicians generated greater activity than nonabsolute pitch musicians in the left and right hemispheres. This suggests that when required to label tones without an external reference, absolute pitch musicians have the ability to recruit a greater network than nonabsolute pitch musicians or nonmusicians.

Psychological functioning and health-related quality of life in adulthood after preterm birth.

The aim of this study was to determine if preterm birth is associated with socioeconomic status (SES), psychological functioning, and health-related quality of life (HRQoL) in adulthood. We used prospective follow-up of 192 adult offspring of mothers who took part in a randomized controlled trial of antenatal betamethasone for the prevention of neonatal respiratory distress syndrome (66 born at term [33 males, 33 females] 126 born preterm [66 males, 60 females]). Cognitive functioning was assessed using the Wechsler Abbreviated Scale of Intelligence. Working memory and attention was assessed using the Benton Visual Retention Test, the Paced Auditory Serial Addition Test, and the Brown Attention Deficit Disorder Scale. Psychiatric morbidity was assessed using the Beck Depression Inventory II, the State-Trait Anxiety Inventory, and the Schizotypy Traits Questionnaire. Handedness was assessed using the Edinburgh Handedness Inventory. HRQoL was assessed using the Short Form-36 Health Survey. Moderately preterm birth (median gestation 34wks, mean birthweight 1946g [SD 463g]) was not related to later marital status, educational attainment, SES, cognitive functioning, working memory, attention, or symptoms of anxiety or schizotypy at 31 years of age. Preterm birth was associated with fewer symptoms of depression and higher levels of satisfaction in three of the eight HRQoL domains measured (bodily pain, general health perception, and social functioning). Adults who were born moderately preterm have SES, psychological functioning, and HRQoL consistent with those who were born at term. This good long-term outcome cannot be extrapolated to those with early childhood disability or very low birthweights.

Health related quality of life in patients with dystonia and their caregivers in New Zealand and Australia.

Health Related Quality of Life (HRQL) was assessed by the SF-36 in a group of patients with dystonia in New Zealand and Australia. The caregivers of these people were also asked to participate. Low scores from the SF-36 indicate a disability or limitation in HRQL. Compared with the national norms of the respective countries, the participants with dystonia for both countries were significantly lower in the eight dimensions of the SF-36, suggesting that patients with dystonia have lower HRQL compared with their respective national norms without dystonia. In contrast to the patients with dystonia, caregivers did not show lower HRQL scores than their national norms, suggesting that while dystonia affects the HRQL of those with the disorder, their caregivers may be less affected. Descriptive and demographic information were also gathered and are discussed. An important factor that may affect the HRQL of patients with dystonia is the length of time required to be diagnosed in this sample and the number of medical practitioners the patients consulted prior to a confirmed diagnosis.

Decreased desychronisation during self-paced movements in frequency bands involving sensorimotor integration and motor functioning in Parkinson's disease.

This study examined sensorimotor integration and motor functioning in seven patients with Parkinson's disease (PD) who had mild symptoms, and seven age-matched controls. Neuro-oscillations were recorded by high-density 128-channel electroencephalography (EEG). Participants were required to perform two tasks: simple tapping of the index finger and thumb and a complex Luria finger apposition task. Both tasks were performed unimanually and bimanually. There were no significant group differences in the task-related power (TRPow) within alpha 1 (mu1) or in beta 1 frequencies (beta1). In contrast, there were significant group differences in the alpha 2 (mu2) and beta 2 frequencies (beta2). Patients had less desychronisation than controls at the electrodes covering the central regions of the scalp. Alpha 2 and beta 2 frequencies have been associated with task-specific sensorimotor integration and motor function, respectively. This activity difference in patients with Parkinson's disease may be due to deficits in sensorimotor integration.

The yips in golf: multimodal evidence for two subtypes.

PURPOSE: To determine whether a model of two subtypes of yips is supported by evidence from a range of physiological, behavioral, and psychological measures. METHODS: Fifteen golfers who experience yips symptoms while putting (mean age 58.1 yr, SD 13.6 yr), and nine golfers with no yips symptoms (mean age 39.6 yr, SD 19.3 yr) were recruited. Participants completed a golf history questionnaire to determine their playing experience and the nature of any yips symptoms experienced. In experiment 1, participants performed a putting task while electromyographic data were recorded from the forearm flexors and extensors and biceps brachii, bilaterally. The task was performed in two sessions, under low-pressure and high-pressure experimental conditions. The high-pressure condition was intended to increase anxiety through the use of a monetary incentive, video-taping of performance, and the presence of a confederate who provided negative feedback. Participants' state of anxiety was assessed using a questionnaire before each of the experimental sessions. In experiment 2, participants completed a task that required the inhibition of an anticipated response. Their accuracy and ability to inhibit their response was determined. RESULTS: The golfers who experienced yips could be categorized according to whether they reported mainly movement-related symptoms (Type I) or anxiety-related symptoms (Type II). The Type I group exhibited greater muscle activity during putting and greater errors and less inhibition of the anticipated response task. The Type II group exhibited greater changes in cognitive anxiety and normal performance of the anticipated response task. CONCLUSION: This study provides evidence in support of two yips subtypes. Type I is related to impaired movement initiation and execution, whereas Type II is related to performance anxiety.

Kinesthetic but not visual imagery assists in normalizing the CNV in Parkinson's disease.

OBJECTIVE: This study investigated whether kinesthetic and/or visual imagery could alter the contingent negative variation (CNV) for patients with Parkinson's disease (PD). METHODS: The CNV was recorded in six patients with PD and seven controls before and after a 10min block of imagery. There were two types of imagery employed: kinesthetic and visual, which were evaluated on separate days. RESULTS: The global field power (GFP) of the late CNV did not change after the visual imagery for either group, nor was there a significant difference between the groups. In contrast, kinesthetic imagery resulted in significant group differences pre-, versus post-imagery GFPs, which was not present prior to performing the kinesthetic imagery task. In patients with PD, the CNV amplitudes post-, relative to pre-kinesthetic imagery, increased over the dorsolateral prefrontal regions and decreased in the ipsilateral parietal regions. There were no such changes in controls. CONCLUSIONS: A 10-min session of kinesthetic imagery enhanced the GFP amplitude of the late CNV for patients but not for controls. SIGNIFICANCE: While the study needs to be replicated with a greater number of participants, the results suggest that kinesthetic imagery may be a promising tool for investigations into motor changes, and may potentially be employed therapeutically, in patients with Parkinson's disease.

Antenatal exposure to betamethasone: psychological functioning and health related quality of life 31 years after inclusion in randomised controlled trial.

OBJECTIVES: To determine if antenatal exposure to betamethasone for the prevention of neonatal respiratory distress syndrome alters psychological functioning and health related quality of life in adulthood. DESIGN: Follow-up of the first and largest double blind, placebo controlled, randomised trial of a single course of antenatal betamethasone for the prevention of neonatal respiratory distress syndrome. SETTING: Tertiary obstetric hospital in Auckland, New Zealand. PARTICIPANTS: 192 adult offspring, mean age 31 years, of mothers who took part in a randomised controlled trial of antenatal betamethasone for the prevention of neonatal respiratory distress syndrome (87 exposed to betamethasone and 105 exposed to placebo). INTERVENTIONS: Mothers received two doses of betamethasone or placebo 24 hours apart. MAIN OUTCOME MEASURES: Cognitive functioning assessed with Wechsler abbreviated scale of intelligence; working memory and attention assessed with Benton visual retention test, paced auditory serial addition test, and Brown attention deficit disorder scale; psychiatric morbidity assessed with Beck depression inventory II, state-trait anxiety inventory, and schizotypy traits questionnaire; handedness assessed with Edinburgh handedness inventory; health related quality of life assessed with short form 36 health survey. RESULTS: No differences were found between groups exposed to betamethasone and placebo in cognitive functioning, working memory and attention, psychiatric morbidity, handedness, or health related quality of life. CONCLUSIONS: Prenatal exposure to a single course of betamethasone does not alter cognitive functioning, working memory and attention, psychiatric morbidity, handedness, or health related quality of life in adulthood. Obstetricians should continue to use a single course of antenatal betamethasone for the prevention of neonatal respiratory distress syndrome.