Swayed by sound: sonic guidance as a neurorehabilitation strategy in the cerebellar ataxias

Cerebellar disease leads to problems in controlling movement. The most common difficulties are dysmetria and instability when standing. Recent understanding of cerebellar function has expanded to include non -motor aspects such as emotional, cognitive and sensory processing. Deficits in the acquisition and processing of sensory information are one explanation for the movement problems observed in cerebellar ataxia. Sensory deficits result in an inability to make predictions about future events; a primary function of the cerebellum. A question therefore, is whether augmenting or replacing sensory information can improve motor performance in cerebellar disease. This question is tested in this thesis by augmenting sensory information through the provision of an auditory movement guide.A variable described in motor control theory (tau) was used to develop auditory guides that were continuous and dynamic. A reaching experiment using healthy individuals showed that the timing of peak velocity, audiomotor coordination accuracy, and velocity of approach, could be altered in line with the movement parameters embedded in the auditory guides. The thesis then investigated the use of these sonic guides in a clinical population with cerebellar disease. Performance on neurorehabilitation exercises for balance control was tested in twenty people with cerebellar atrophy, with and without auditory guides. Results suggested that continuous, predictive, dynamic auditory guidance is an effective way of improving iii movement smoothness in ataxia (as measured by jerk). In addition, generating and swaying with imaginary auditory guides was also found to increase movement smoothness in cerebellar disease.Following the tests of instantaneous effects, the thesis then investigated the longterm consequences on motor behaviour of following a two -month exercise with auditory guide programme. Seven people with cerebellar atrophy were assessed pre - and post -intervention using two measures, weight -shifting and walking. The results of the weight -shifting test indicated that the sonic -guide exercise programme does not initiate long -term changes in motor behaviour. Whilst there were minor, improvements in walking, because of the weight -shifting results, these could not be attributed to the sonic guides. This finding confirms the difficulties of motor rehabilitation in people with cerebellar disease.This thesis contributes original findings to the field of neurorehabilitation by first showing that on -going and predictive stimuli are an appropriate tool for improving motor behaviour. In addition, the thesis is the first of its kind to apply externally presented guides that convey continuous meaningful information within a clinical population. Finally, findings show that sensory augmentation using the auditory domain is an effective way of improving motor coordination in some forms of cerebellar disease

Consensus paper:Decoding the Contributions of the Cerebellum as a Time Machine. From Neurons to Clinical Applications

Time perception is an essential element of conscious and subconscious experience, coordinating our perception and interaction with the surrounding environment. In recent years, major technological advances in the field of neuroscience have helped foster new insights into the processing of temporal information, including extending our knowledge of the role of the cerebellum as one of the key nodes in the brain for this function. This consensus paper provides a state-of-the-art picture from the experts in the field of the cerebellar research on a variety of crucial issues related to temporal processing, drawing on recent anatomical, neurophysiological, behavioral, and clinical research. The cerebellar granular layer appears especially well-suited for timing operations required to confer millisecond precision for cerebellar computations. This may be most evident in the manner the cerebellum controls the duration of the timing of agonist-antagonist EMG bursts associated with fast goal-directed voluntary movements. In concert with adaptive processes, interactions within the cerebellar cortex are sufficient to support sub-second timing. However, supra-second timing seems to require cortical and basal ganglia networks, perhaps operating in concert with cerebellum. Additionally, sensory information such as an unexpected stimulus can be forwarded to the cerebellum via the climbing fiber system, providing a temporally constrained mechanism to adjust ongoing behavior and modify future processing. Patients with cerebellar disorders exhibit impairments on a range of tasks that require precise timing, and recent evidence suggest that timing problems observed in other neurological conditions such as Parkinson\u2019s disease, essential tremor, and dystonia may reflect disrupted interactions between the basal ganglia and cerebellum. The complex concepts emerging from this consensus paper should provide a foundation for further discussion, helping identify basic research questions required to understand how the brain represents and utilizes time, as well as delineating ways in which this knowledge can help improve the lives of those with neurological conditions that disrupt this most elemental sense. The panel of experts agrees that timing control in the brain is a complex concept in whom cerebellar circuitry is deeply involved. The concept of a timing machine has now expanded to clinical disorders

Synchronisation rythmique déficiente chez l'humain : bases comportementales

Les humains ont naturellement tendance à bouger sur le beat de la musique. Bien que spontané, ce comportement nécessite d'extraire une régularité d'un signal acoustique complexe, ainsi que d'aligner le mouvement à cette périodicité. Il n'est donc pas surprenant que certains individus éprouvent de la difficulté à se synchroniser au beat. Quelques cas ont été décrits ces dernières années. Des causes telles qu'une déficience intellectuelle, de l'ouïe, motrice, ou encore du traitement de la hauteur des notes musicales ont été écartées; leur difficulté semble donc spécifique au traitement du beat. Le but de la thèse est de clarifier la nature d'un tel trouble comme moyen d'éclairer les théories du traitement du beat chez l'humain. Dans un premier temps, nous avons utilisé des mouvements naturels et de la musique populaire originale pour détecter, au sein d'un grand échantillon de jeunes adultes, des individus présentant une faible capacité de synchronisation au beat. Une gradation est apparue: certains cas ont échoué dans toutes les conditions tandis que d'autres ont échoué à plier les genoux mais pas à frapper des mains, sur certaines musiques. Nous avons ensuite étudié un groupe de neuf jeunes adultes présentant une synchronisation déficiente à travers deux formes de mouvement (taper du doigt, rebondir en pliant les genoux). Nous avons évalué la capacité du groupe à juger si un métronome superposé à un extrait musical est ou non aligné sur le beat de celui-ci, et observé un moins bon résultat lorsque comparé à un groupe typique. Cette observation est compatible avec une théorie motrice du beat, où la perception dépend de l'oscillation de populations de neurones dans les régions motrices du cerveau. Néanmoins, six cas de synchronisation déficiente ont obtenu un résultat faible mais dans la norme au test de perception. A l’inverse, un résultat indiquant une perception déficiente malgré une synchronisation faible mais dans la norme a été observé chez deux participants faisant initialement partie du groupe typique. Ces dissociations remettent en question la théorie motrice du beat, pas fermement toutefois puisque les huit cas cités ont obtenu des scores généralement faibles. Nos résultats sont plutôt compatibles avec une origine centrale et commune du trouble de traitement du beat, affectant à la fois perception et synchronisation. Nous avons finalement montré que le trouble est associé à une déficience du traitement temporel à un niveau fondamental, au moyen de deux conditions: taper du doigt de façon régulière sans stimulation et se synchroniser au métronome et maintenir les tapes après que les sons aient cessé, pour des intervalles couvrant le spectre des tempi accessibles (225-1709 millisecondes). Nous avons testé huit des neuf cas de synchronisation déficiente (étude précédente) et observé une moins bonne régularité ainsi qu'une moins bonne flexibilité au changement de tempo que chez des participants contrôles appariés. Dans l’ensemble, nos résultats indiquent qu’une synchronisation et une perception déficientes du beat sont associées, et que le trouble pourrait provenir d'une altération de mécanismes fondamentaux du traitement temporel.Humans across cultures show the propensity to move in time with the beat of music. Despite the spontaneous nature of this behavior, it is one that requires the abstraction of periodicities from acoustically complex signals and the temporally precise coupling between auditory perception and motor action. It is therefore not surprising that some individuals exhibit difficulties to synchronize movements with the beat of music; a few such cases have been reported in recent years. Importantly, their lack of synchronization seems to be attributable to a disorder specific to beat processing, as these individuals did not present deficient intelligence, motor or hearing disabilities, or deficient pitch-related musical processing in previous studies. The aim of this thesis was to clarify the nature of this beat synchronization impairment, as a way to shed light on theories of beat processing in humans. As a first step, we used ecological conditions - natural movements and commercially available music - to screen for synchronization deficits in a large pool of young adults. This approach revealed a gradient of synchronization difficulties across movement types and stimulus complexity. While some individuals displayed an inability to bounce their body and clap their hands with all stimuli, others failed to bounce to a few songs only. Next, we studied a group of nine individuals ("beat-impaired") with deficient synchronization across tapping and bouncing movement forms. We tested their capacity to detect a misalignment of a superimposed metronome soundtrack to the beat of music. We found lower performance for this detection task in the beat-impaired group as compared to typical adults. This association of perception and production deficits is in line with a motor theory of beat finding, according to which beat perception depends on neural oscillations in motor regions of the brain. Nevertheless, we observed deficient synchronization in six beat-impaired cases who were able to perceive the beat normally, albeit in the low range. The opposite pattern, i.e. low but normal synchronization performance in spite of deficient detection, was observed in two other participants initially from the typical group. These dissociations question the motor theory of beat finding, albeit not strongly so, because the eight cases performed poorly in general. Our results thus point towards a central origin of beat impairments, which affects both perception and synchronization. In line with this view, we also showed that deficient synchronization to a musical beat is linked to faulty timekeeping core mechanisms. In this last study, we used two tapping conditions: spontaneous production of a regular sequence and synchronization-continuation with metronome stimuli covering the range of predictive timing in humans (225-1709 milliseconds). By testing eight of the nine beat-impaired cases from the previous study, we found higher temporal variability across conditions and poorer rate flexibility in paced tapping, as compared to a group of closely matched control participants. Altogether, our findings highlight an association between beat perception and synchronization impairments, which may emerge from disrupted timekeeping functions

Advanced MRI techniques in the study of cerebellar cortex

The cerebellum (from the Latin "little brain") is the dorsal portion of the metencephalon and is located in the posterior cranial fossa. Although representing only 10% of the total brain volume, it contains more than 50% of the total number of neurons of the central nervous system (CNS). Its organization resembles the one found in the telencephalon, with the presence of a superficial mantle of gray matter (GM) known as the cerebellar cortex, covering the cerebellar white matter (WM) in which three pairs of deep cerebellar GM nuclei are embedded. The number of studies dedicated to the study of the cerebellum and its function has significantly increased during the last years. Nevertheless, although many theories on the cerebellar function have been proposed, to date we still are not able to answer the question about the exact function of this structure. Indeed, the classical theories focused on the role of the cerebellum in fine-tuning for muscle control has been widely reconsidered during the last years, with new hypotheses that have been advanced. These include its role as sensory acquisition device, extending beyond a pure role in motor control and learning, as well as a pivotal role in cognition, with a recognized cerebellar participation in a variety of cognitive functions, ranging from mood control to language, memory, attention and spatial data management. A huge contribution to our understanding of how the cerebellum participates in all these different aspects of motor and non-motor behavior comes from the application of advanced imaging techniques. In particular, Magnetic Resonance Imaging (MRI) can provide a non-invasive evaluation of anatomical integrity, as well as information about functional connections with other brain regions. This thesis is organized as follows: - In Chapter 1 is presented a general introduction to the cerebellar anatomy and functions, with particular reference to the anatomical organization of cerebellar cortex and its connections with the telencephalon - Chapter 2 will contain a general overview about some of the major advanced MRI methods that can be applied to investigate the anatomical integrity and functional status of the cerebellar cortex - In Chapter 3 will be presented a new method to evaluate the anatomy and integrity of cerebellar cortex using ultra-high field MRI scanners - Chapters 4, 5 and 6 will contain data obtained from the application of some of the previously described advanced imaging techniques to the study of cerebellar cortex in neurodegenerative and neuroinflammatory disorders affecting the CNS

A influência da aprendizagem musical no desempenho na MBEA

O entendimento de certas capacidades musicais como universais e determinadas por processos biológicos provém da existência de constantes transculturais em relação à música, teorias evolutivas sobre a sua origem, estudos genéticos, e estudos que demonstram empiricamente uma apetência musical implícita em todos os seres humanos, na ausência de perturbações do desenvolvimento ou lesões adquiridas. Sendo a música um fenómeno cerebral, vários estudos sugerem a existência de modularidade na cognição musical, a qual é independente de outras funções como a linguagem, e recorre a substratos neurais fixos, corroborando as teorias biológicas da música. A Montreal Battery of Evaluation of Amusia (MBEA) foi concebida para avaliar as capacidades de perceção e memória musical universais e inatas, e para o diagnóstico de amusia. Músicos profissionais treinam minuciosamente o seu ofício, e apresentam alterações estruturais e funcionais no processamento da música. Neste trabalho, que faz parte do estudo de normalização da MBEA para a população portuguesa, averiguámos se a aprendizagem musical influencia o desempenho na bateria. Comparámos as pontuações obtidas por músicos e estudantes de escolas de música em Lisboa (n = 40; média de anos de instrução = 11,4) com as pontuações de sujeitos sem formação musical (n = 40) nos testes de escala, contorno, intervalo, ritmo, métrica, e memória musical, e no índice global. Os músicos conseguiram pontuações significativamente superiores em todos os testes e índices, havendo no entanto sobreposição entre grupos. Verificámos ainda uma correlação (r = 0,357) entre os anos de instrução musical dos músicos e o índice global. Estes resultados contestam a validade de constructo da MBEA, pois sugerem que a bateria não avalia somente as competências musicais inatas, mas também habilidades passíveis de serem aprendidas formalmente e treinadas. Assim, como ferramenta para o diagnóstico de amusia, a MBEA deve ter em conta nas suas normas a instrução musical.The understanding that certain musical abilities are universal and determined by biological processes is based on the evidence concerning transcultural musical constants, evolutionary theories about their origin, genetic studies, and empirical studies showing an implicit musical tendency in all humans without developmental disorders or brain damage. Various studies have suggested the existence of modularity in musical cognition, which is independent of other functions such as language, and is supported by fixed neural correlates, in accordance with biological theories of music. The Montreal Battery of Evaluation of Amusia (MBEA) was conceived to assess universal and innate capacities of musical perception and memory, and to provide a tool for the diagnosis of amusia. Professional musicians practice their trade comprehensively, and present structural and functional brain differences in musical processing relative to nonmusicians. In our work, which is part of a larger study intended to establish norms for use of the MBEA on the Portuguese population, we inquired whether musical learning influences performance on the battery. We compared scores obtained by musicians and students in music schools in Lisbon (n = 40; mean years of practice = 11,4) with those of subjects with no musical training whatsoever (n = 40), on the scale, contour, interval, rhythm, meter and memory tests, as well as the global index. Musicians achieved significantly higher scores on all tests and indices than non-musicians, although there was some overlap between groups. Furthermore, the global index scores of musicians correlated with years of practice (r = 0,375). These results put into question the construct validity of the MBEA, since they suggest the battery does not merely assess innate musical abilities, but also those which can be formally learnt and practiced. Therefore, we suggest the years of musical practice be taken into account in the MBEA norms

Making Music Speak: The Role of the “Tuning In” Music Program in Developing Preschool Children’s Oral Language Skills

Evidence shows oral language development in early childhood plays a critical role in social, behavioural and academic development and Australian research indicates that speech development difficulties are relatively common. Research suggests that participating in high quality music education from early childhood not only helps develop musical skills but also induces benefits in aspects of oral language skills, including phonological abilities. Researchers have suggested that music might be a useful and engaging form of intervention for preschool-aged children with oral language delays or disorders, however, to date little research has been conducted to test this. Underpinned by Vygotsky’s sociocultural theory, a concurrent triangulation mixed methods design, consisting of a quasi-experimental study and multiple case study, was used to learn about the effects of the “Tuning In” (TI) music program upon the phonological abilities and use of oral language of four and five-year-old children. TI is the music education program of the Shoalhaven Youth Orchestra, which is based in regional NSW. A five-month intervention was conducted involving 45 children attending four early childhood education and care (ECEC) centres. Children at two centres received a 30-minute weekly TI session taught by a specialist teacher, while children at the other centres received the music programs offered at their centres. Data collected included a pre-intervention parent survey, and pre- and post-testing of the children’s phonological awareness (PA) and phonological memory (PM). Each TI centre formed a case in the multiple case study and data collection included a researcher journal, educator interviews and an attendance and participation record. The TI Group made significantly greater improvements than the Comparison Group in Sound Matching (an aspect of PA) (p \u3c.05), and strong trends were also found across PM tests. These results were supported by the multiple case study, which found that the quality and quantity of children’s speech improved, particularly in children with language disorders. Children were found to engage strongly with the TI sessions. Warm and responsive relationships between the music teacher and children contributed to the children’s engagement in music and to their motivation to communicate. Several music- specific “active ingredients” were identified, including providing a variety of music experiences to develop beat and rhythm skills, which supported children’s engagement and learning. Providing children with choice to participate in different ways was also found to lead to increased participation rates over time. This thesis provides an important contribution to literature on how music in ECEC settings could be used to support children’s oral language development, particularly for those with language difficulties; a thus far under-researched field. The TI program demonstrated positive effects upon the development of the phonological skills and children’s use of speech for a range of purposes, and highlighted the critical role that social relationships play in children’s development. This thesis also demonstrated that group music sessions conducted in ECEC settings could be used to complement traditional interventions for language development problems

MUSIC THERAPY IN THE COGNITIVE AND NEURAL REHABILITATION OF TRAUMATIC BRAIN INJURY

Traumatic brain injury (TBI) can have lifelong cognitive, emotional, and physical consequences. Music engages many cognitive, motor, and emotional functions making it a promising rehabilitation tool, but the effects of music in TBI are still largely unknown. The aim of this thesis was to explore the efficacy of neurological music therapy in the rehabilitation of moderate and severe TBI, particularly on executive functions (EF). The thesis includes three studies based on a cross-over randomized controlled trial (RCT), in which 40 participants with TBI (time since injury < 2 years) were randomized into two groups (AB/BA) to receive a 3-month neurological music therapy intervention either during the first (AB, n=20) or second (BA, n=20) half of a 6-month follow-up period. Neuropsychological and motor testing, questionnaires, and structural and functional magnetic resonance imaging (MRI) were performed at baseline and at the 3-month and 6-month stage. Results from Study I showed that general EF and set shifting improved more in the AB group than in the BA group over the first 3-month period, and the effect on general EF was maintained in the 6-month follow-up. Voxel-based morphometry analysis of the structural MRI data indicated that gray matter volume in the right inferior frontal gyrus increased significantly in both groups during the intervention versus control period, which also correlated with cognitive improvement in set shifting ability. Findings from Study II reporting the questionnaire data showed that the Behavioural Regulation Index of the Behaviour Rating Inventory of Executive Function (BRIEF-A) improved more in the AB than BA group from baseline to 3-month stage, and the effect was maintained in the 6-month follow-up. Finally, Study III explored functional connectivity patterns using resting-state functional MRI and revealed both changes towards increased and decreased functional connectivity within and between several networks. Importantly, behavioral improvements in EF correlated with resting-state functional connectivity changes within the frontoparietal network and between the default mode and sensorimotor networks. All in all, these results suggest that neurological music therapy enhances EF skills, including general EF, set shifting ability and behavioral self-regulation, after TBI and that these gains are linked to volumetric and functional neuroplastic changes in the brain. These novel findings give support to the use of music therapy in rehabilitation of moderate and severe TBI.Traumaattinen aivovaurio on varsin yleinen toimintakykyä alentava vamma, joka voi aiheuttaa elinikäisiä kognitiivisia, emotionaalisia ja fyysisiä oireita. Musiikki on monimuotoinen ja motivoiva toiminto, joka aktivoi useita kognitiivisia, motorisia ja emotionaalisia aivoverkostoja, mikä tekee siitä lupaavan hoitomuodon neurologisessa. Musiikin vaikuttavuutta aivovammakuntoutuksessa on kuitenkin toistaiseksi selvitetty varsin vähän. Tässä väitöskirjassa tutkitaan neurologisen musiikkiterapian vaikuttavuutta keskivaikeiden ja vaikeiden aivovammojen hoidossa ja erityisesti toiminnanohjaustaitojen kuntoutuksessa. Tähän tutkimukseen rekrytointiin 40 potilasta, joiden vammautumisesta oli kulunut alle 2 vuotta ja heidät satunnaistettiin kahteen ryhmään AB/BA. Ensimmäinen ryhmä (AB, n=20) sai neurologista musiikkiterapiaa 6 kuukauden seurantajakson alkupuoliskolla (3 kk) ja toinen ryhmä (BA, n=20) sai intervention seurantajakson jälkimmäisellä puoliskolla. Mittaukset, mukaan lukien neuropsykologiset ja motoriset testaukset, kyselylomakkeet sekä strukturaalinen ja funktionaalinen magneettikuvaus, suoritettiin alussa, 3 kuukauden ja 6 kuukauden kohdalla. Tutkimuksen I tulokset osoittavat, että yleiset toiminnanohjaustaidot (Frontal Assessment Battery -testistöllä arvioituna) sekä erityisesti kognitiivisen prosessoinnin joustavuus (Number-Letter Task -testillä testattuna) paranivat AB-ryhmässä BA-ryhmään verrattuna seurantajakson alkupuoliskolla ja positiivinen vaikutus yleisiin toiminnanohjaustaitoihin säilyi vielä 6 kuukauden seurannassa. Myös harmaan aineen volyymi oikealla alemmalla otsolohkopoimulla kasvoi merkittävästi molemmissa ryhmissä interventiojaksolla verrattuna kontrollijaksoon. Tämä harmaan aineen lisääntyminen korreloi kognitiivisen suorituksen kanssa prosessoinnin joustavuutta vaativassa tehtävässä. Tutkimuksessa II, jossa raportoidaan kyselylomakkeiden tulokset, osoitetaan että itse raportoitu käyttäytymisen säätely Behaviour Rating Inventory of Executive Function (BRIEF-A) mittarissa kohentui enemmän AB- kuin BA-ryhmässä ensimmäisen kolmen kuukauden seurannan aikana ja saavutettu taso säilyi vielä 6 kuukauden seurannassa. Tutkimuksessa III selvitettiin aivojen toiminnallisissa verkostoissa musiikkiterapian vaikutuksesta tapahtuneita muutoksia, joita mitattiin lepotilaverkostojen toiminnallisella magneettikuvauksella. Tulokset osoittavat, että useiden lepotilaverkostojen sisällä ja välillä tapahtui joko yhteyksien vahvistumista tai rauhoittumista. Muutokset toiminnanohjaustaidoissa korreloivat frontoparietaalisen verkoston sisällä sekä oletustilaverkoston ja sensorimotoristen verkkojen välillä tapahtuvien funktionaalisten muutosten kanssa. Kokonaisuudessaan nämä tulokset osoittavat, että aivovamman jälkeen musiikkiterapia kohentaa toiminnanohjaustaitoja mukaan lukien yleistä toiminnanohjausta, kognitiivisen prosessoinnin joustavuutta sekä käyttäytymisen säätelyä ja nämä muutokset ovat yhteydessä aivojen rakenteellisiin ja toiminnallisiin neuroplastisiin muutoksiin. Nämä uudet tulokset tukevat musiikkiterapian hyödyntämistä keskivaikeiden ja vaikeiden aivovammojen kuntoutuksessa

Intentionality, Modularity and Time

L'abast d'aquesta tesi és el de proporcionar una explicació del temps psicològic que s'adhereix al concepte de modularitat de les funcions cognitives com va ser formulada per Fodor. Aquest compte té per objecte demostrar que el nostre "sentit" de temps (i la capacitat relacionada amb la gestió d'informació en temps) és el resultat cognitiu d'una sèrie de processos que es duen a terme per dos components de processament independents i neutralment aïllables que són part de la porció de l'arquitectura mental, dedicat als sistemes modulars. Intento demostrar que aquests subsistemes poden estar al seu torn es fa referència com a mòduls, ja que cada un té la possibilitat d'especialitzar en el processament temporal. Dins d'aquesta funcionals delimitacions arquitectura entre aquests diferents mètodes de processament s'organitzen d'acord amb els principis que tenen el seu fonament en la tesi de la modularitat de Fodor. Utilitzant la referència de "mòdul" per a la noció de ‘specious present’ meu argument procedeix a organitzar el processament temporal en una jerarquia, amb la finalitat de representar la informació de temps des de les primeres etapes de la percepció a etapes superiors de la cognició. Si aquesta hipòtesi és correcta, podria oferir pautes útils per explorar capacitat de sincronització en els éssers humans, i proporcionar un marc creïble per a la futura investigació dels mecanismes psicològics i neuronals de processament temporal.El alcance de esta tesis es el de proporcionar una explicación del tiempo psicológico que se adhiere al concepto de modularidad de las funciones cognitivas como fue formulada por Fodor. Esta cuenta tiene por objeto demostrar que nuestro "sentido" de tiempo (y la capacidad relacionada con la gestión de información en tiempo) es el resultado cognitivo de una serie de procesos que se llevan a cabo por dos componentes de procesamiento independientes y neutralmente aislables que son parte de la porción de la arquitectura mental, dedicado a los sistemas modulares. Trato de demostrar que estos subsistemas pueden estar a su vez se hace referencia como módulos, ya que cada uno tiene la posibilidad de especializarse en el tiempo de procesamiento. Dentro de esta funcionales delimitaciones arquitectura entre estos diferentes métodos de procesamiento se organizan de acuerdo a los principios que tienen su fundamento en la tesis de la modularidad de Fodor. Utilizando la referencia de "módulo" para la noción de ‘specious present’ mi argumento procede a organizar el procesamiento temporal en una jerarquía, con el fin de representar la información de tiempo desde las primeras etapas de la percepción a etapas superiores de la cognición. Si esta hipótesis es correcta, podría ofrecer pautas útiles para explorar capacidad de sincronización en los seres humanos, y proporcionar un marco creíble para la futura investigación de los mecanismos psicológicos y neuronales de procesamiento temporal.The scope of this thesis is to provide an explanation of psychological time which adheres to the concept of modularity of cognitive functions as formulated by Fodor. This account seeks to demonstrate that our ‘sense’ of time (and the related ability to manage time information) is the cognitive result of a series of processes carried out by two independent and neutrally isolable processing components which are part of the portion of mental architecture dedicated to modular systems. I try to demonstrate that these sub-systems can themselves be referred to as modules, as each has the potential to specialize in time processing. Within this functional architecture delimitations between these different processing methods are organised according to principles which have their basis in Fodor's modularity thesis. Using the reference of 'module' for the notion of specious present my argument proceeds to arrange time processing into a hierarchy, in order to represent time information from the early stages of perception to higher stages of cognition. If such a hypothesis is correct, it could offer useful guidelines for exploring timing ability in humans, and provide a plausible framework for future investigation of the psychological and neuronal mechanisms of time processing

Benefícios cognitivos e sensoriomotores da tDCS associada ao treinamento musical de idosos : estudo randomizado, controlado, duplo cego

Tese (Doutorado) — Universidade de Brasília, Faculdade de Ciências da Saúde, Programa de Pós-Graduação em Ciências Da Saúde, 2022.A música pode ser considerada um dos estímulos mais complexos e de múltiplos domínios para o cérebro. Dentre os elementos que constituem a música, o ritmo é uma estrutura central e indispensável, pois ordena o movimento de padrões musicais no tempo e proporciona sustentação às demais estruturas musicais. Estudos que utilizam técnicas de neuromodulação como a estimulação transcraniana por corrente contínua (tDCS) têm demonstrado modificações das funções perceptivas, cognitivas e comportamentais. Estudos com músicos indicam que o desempenho musical pode ser aprimorado com a aplicação da tDCS sobre regiões como as áreas motoras e cerebelo. Infere-se ainda que a tDCS possa auxiliar na diminuição dos efeitos da idade sobre a cognição e a atividade cerebral. Considerando tais aspectos, o objetivo do presente estudo foi investigar os benefícios cognitivos e sensoriomotores da tDCS para idosos com e sem treinamento musical. Participaram do estudo 48 idosos com idades entre 60 e 86 anos, divididos em dois grupos, sendo 25 com treinamento musical e 23 sem treinamento musical. Dos participantes com treinamento musical, 10 (40%) foram submetidos à estimulação por tDCS anódica no cerebelo e 15 (60%) na área motora (M1). Entre os participantes sem treinamento musical, 10 (43,48%) receberam estimulação na área cerebelar e 13 (56,52%) na área motora. O instrumento utilizado para identificar as nuances rítmicas dos sujeitos da pesquisa foi o teste HBAT (Harward Beat Assessment Test). Para fins da verificação das funções executivas foram utilizados os instrumentos: MoCA, teste de STROOP, testes da bateria CANTAB - Cambridge Neuropsychological Test AutomatedBattery: MOT (Motor ScreeningTask) SWN (Spatial Working Memory), PAL (Paired Associates Learning). Para rastreio da capacidade/desempenho motor foi utilizado o SEQTAP (Sequential Finger Tapping Task). Os testes STROOP, SEQTAP e H-BAT foram realizados em duas sessões, separadas por um período de uma semana. Dentro de cada sessão foram realizados um teste pré e pós-tDCS de todos os testes, com a exceção dos testes MoCA, MOT, SWM e PAL. Os testes foram realizados antes e após a estimulação por tDCS, aplicada por 20 minutos no cerebelo e na área motora esquerda (M1). Os resultados do estudo revelaram, em relação às funções executivas, um leve comprometimento cognitivo na maior parte da amostra. Não foram observados benefícios da tDCS em relação aos testes cognitivos. As diferenças significativas se concentraram no grupo de indivíduos sem treinamento musical, com estimulação cerebelar. A estimulação não provocou efeitos ou provocou efeitos negativos, provocando piora no desempenho dos participantes. No tocante à sincronização sensório-motora, os resultados sugerem que a tDCS produziu efeito significativo nos índices de consistência e acurácia da sincronização verificados a partir do Music Tapping Test (MTT), tanto para indivíduos com treinamento quanto para participantes sem treinamento musical. Os possíveis efeitos foram verificados principalmente na área motora (M1). Com respeito à percepção rítmico-musical, foram constatados prováveis efeitos da estimulação por tDCS nas duas áreas estimuladas, sendo que os efeitos decorrentes da estimulação cerebelar se concentraram principalmente entre os participantes sem treinamento musical. Em comparação com o cerebelo, a área motora apresentou resultados mais satisfatórios advindos da neuromodulacão. Finalmente, no que concerne à aprendizagem de tarefa de digitação motora, os achados relacionados ao teste SEQTAP, os prováveis efeitos significativos foram verificados principalmente em indivíduos com treinamento musical, com maior efeito da estimulação na área motora (M1). Futuras pesquisas com perfis longitudinais poderão representar um formato importante para incrementar dados referentes aos efeitos da estimulação por tDCS nas áreas motora (M1) e cerebelo sobre a percepção e produção rítmico-musical de indivíduos idosos.Music can be considered one of the most complex and multi-domain stimuli for the brain. Among the elements that constitute music, rhythm is a central and indispensable structure, as it orders the movement of musical patterns in time and provides support to other musical structures. Studies using neuromodulation techniques such as transcranial direct current stimulation (tDCS) have demonstrated changes in perceptual, cognitive and behavioral functions. Studies with musicians indicate that musical performance can be improved with the application of tDCS on regions such as the motor area and cerebellum. It is also inferred that tDCS may help to reduce the effects of age on cognition and brain activity. Considering these aspects, the objective of the present study was to investigate the cognitive and sensorimotor benefits of tDCS for elderly people with and without music training.The study included 48 elderly people aged between 60 and 86 years, divided into two groups, 25 with musical training and 23 without musical training. Of the participants with musical training, 10 (40%) under went stimulation by anodic tDCS in the cerebellum and 15 (60%) in the motor area (M1). Among the participants without musical training, 10 (43.48%) received stimulation in the cerebellar area and 13 (56.52%) in the motor area. The instrument used to identify the rhythmic nuances of the research subjects was the H-BAT test (Harward Beat Assessment Test). The following instruments were used to verify executive functions: MoCA, STROOP test, CANTAB battery tests - Cambridge Neuropsychological Test Automated Battery: MOT (Motor Screening Task) SWN (Spatial Working Memory), PAL (Paired Associates Learning). The SEQTAP (Sequential Finger Tapping Task) was used to track motor capacity/performance. The STROOP, SEQTAP and H-BAT tests were performed in two sessions, separated by a period of one week. Within each session, a pre and post-tDCS test of all tests was performed, with the exception of the MoCA, MOT, SWM and PAL tests. The tests were performed before and after stimulation by tDCS, applied for 20 minutes in the cerebellum and in the left motor area (M1). The results of the study revealed, in relation to executive functions, a mild cognitive impairment in most of the sample. No benefits of tDCS were observed in relation to cognitive tests. The significant differences were concentrated in the group of individuals without musical training, with cerebellar stimulation. The stimulation did not cause effects or caused negative effects, causing a worsening in the performance of the participants. Regarding sensorimotor synchronization, the results suggest that tDCS produced a significant effect on the consistency and accuracy of synchronization rates verified from the Music Tapping Test (MTT), both for individuals with training and for participants without musical training. The possible effects were verified mainly in the motor area (M1). Regarding the rhythmic-musical perception, probable effects of stimulation by tDCS were observed in the two stimulated areas, and the effects resulting from cerebellar stimulation were mainly concentrated among participants without musical training. In comparison with the cerebellum, the motor area showed more satisfactory results from neuromodulation. Finally, regarding the learning of the motor typing task, the findings related to the SEQTAP test, the probable significant effects were verified mainly in individuals with musical training, with greater effect of stimulation in the motor area (M1). Future research with longitudinal profiles may represent an important format to increase data regarding the effects of stimulation by tDCS in the motor areas (M1) and cerebellum on the perception and rhythmicmusical production of elderly individuals

Pioneers in CNS inhibition: 2. Charles Sherrington and John Eccles on inhibition in spinal and supraspinal structures

This article reviews the contributions of the English neurophysiologist, Charles Scott Sherrington [1857–1952], and his Australian PhD trainee and collaborator, John Carew Eccles [1903–1997], to the concept of central inhibition in the spinal cord and brain. Both were awarded Nobel Prizes; Sherrington in 1932 for “discoveries regarding the function of neurons,” and Eccles in 1963 for “discoveries concerning the ionic mechanisms involved in excitation and inhibition in central portions of the nerve cell membrane.” Both spoke about central inhibition at their Nobel Prize Award Ceremonies. The subsequent publications of their talks were entitled “Inhibition as a coordinative factor” and “The ionic mechanism of postsynaptic inhibition”, respectively. Sherrington's work on central inhibition spanned 41 years (1893–1934), and for Eccles 49 years (1928–1977). Sherrington first studied central inhibition by observing hind limb muscle responses to electrical (peripheral nerve) and mechanical (muscle) stimulation. He used muscle length and force measurements until the early 1900s and electromyography in the late 1920s. Eccles used these techniques while working with Sherrington, but later employed extracellular microelectrode recording in the spinal cord followed in 1951 by intracellular recording from spinal motoneurons. This considerably advanced our understanding of central inhibition. Sherrington's health was poor during his retirement years but he nonetheless made a small number of largely humanities contributions up to 1951, one year before his death at the age of 94. In contrast, Eccles retained his health and vigor until 3 years before his death and published prolifically on many subjects during his 22 years of official retirement. His last neuroscience article appeared in 1994 when he was 91. Despite poor health he continued thinking about his life-long interest, the mind-brain problem, and was attempting to complete his autobiography in the last years of his life