Low frequency (0.5Hz) rTMS over the right (non-dominant) motor cortex does not affect ipsilateral hand performance in healthy humans

Weiler, Fernanda; Brandão, Pedro Renato de Paula; Barros-Filho, Jairo de; Uribe, Carlos Enrique; Pessoa, Valdir Filgueiras; Brasil‐Neto, Joaquim P.

doi:10.1590/s0004-282x2008000500006

Cited by 10 publications

(3 citation statements)

References 31 publications

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“…The cytoarchitectonic similarities between regions suggest that there is a “canonical” connectivity between excitatory cells in the same column. Indeed, vertically oriented excitatory neurons are well connected in a direction-selective manner ( Weiler et al, 2008 ; Lefort et al, 2009 ). Thalamic afferents synapse on to Layer 4 stellate cells, which project to Layer 2/3 pyramidal neurons.…”

Section: Spatial and Functional Organization Of Neocortical Interneurmentioning

confidence: 99%

Production and organization of neocortical interneurons

Sultan

Brown

Shi

2013

Front. Cell. Neurosci.

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Inhibitory GABA (γ-aminobutyric acid)-ergic interneurons are a vital component of the neocortex responsible for shaping its output through a variety of inhibitions. Consisting of many flavors, interneuron subtypes are predominantly defined by their morphological, physiological, and neurochemical properties that help to determine their functional role within the neocortex. During development, these cells are born in the subpallium where they then tangentially migrate over long distances before being radially positioned to their final location in the cortical laminae. As development progresses into adolescence, these cells mature and form chemical and electrical connections with both glutamatergic excitatory neurons and other interneurons ultimately establishing the cortical network. The production, migration, and organization of these cells are determined by vast array of extrinsic and intrinsic factors that work in concert in order to assemble a proper functioning cortical inhibitory network. Failure of these cells to undergo these processes results in abnormal positioning and cortical function. In humans, this can bring about several neurological disorders including schizophrenia, epilepsy, and autism spectrum disorders. In this article, we will review previous literature that has revealed the framework for interneuron neurogenesis and migratory behavior as well as discuss recent findings that aim to elucidate the spatial and functional organization of interneurons within the neocortex.

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Section: Spatial and Functional Organization Of Neocortical Interneurmentioning

confidence: 99%

Production and organization of neocortical interneurons

Sultan

Brown

Shi

2013

Front. Cell. Neurosci.

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“…Also, rTMS with 0.5Hz applied on the left motor cortex improves ipsilateral hand function in healthy subjects by reduction of excitability of the dominant primary motor cortex [11]. Moreover, rTMS at 0.5Hz induces anti-epileptic effects [12] [13].…”

Section: Methodsmentioning

confidence: 99%

Time change of perceptual reversal of ambiguous figures by rTMS

Nojima

Katayama

et al. 2010

2010 Annual International Conference of the IEEE Engineering in Medicine and Biology

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The aim of this study was to investigate the effect of stimulus frequency and number of pulses during rTMS (repetitive transcranial magnetic stimulation) on the phenomenon of perceptual reversal. Particularly, we focused on the temporal dynamics of perceptual reversal in the right SPL (superior parietal lobule), using the spinning wheel illusion. We measured the IRT (inter-reversal time) of perceptual reversal. To investigate whether stimulus frequency or the number of pulses is critical for the rTMS effect, we applied the following schedules over the right SPL and the right PTL (posterior temporal lobe): 0.25Hz 60 pulses, 0.25Hz 120pulses, 0.5Hz 120 pulses, and 1Hz 120 pulses biphasic rTMS at 90% of the resting motor threshold. As a control, we included a No-TMS condition. The results showed that rTMS with 0.25Hz 60 pulses over the right SPL caused shorter IRT. There were no significant differences between IRTs for rTMS with 0.25Hz 120 pulses, 0.5Hz 120 pulses or 1Hz 120 pulses over the right SPL. Comparing these results with those of a previous study, we found that an rTMS condition with 60 pulses causes shorter IRT; 240 pulses causes longer IRT; and 120 pulses does not change IRT. Therefore, when applying rTMS over the right SPL, the IRT of perceptual reversal is primarily affected by the number of pulses.

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“…Thus, morphologically the non-dominant hand relies on white matter with less integrity contrasted to the dominant hand. Furthermore, rTMS studies demonstrate an improvement of non-dominant left hand performance after inhibition of the ipsilateral left M1 (Kobayashi et al, 2004), but no improvement of dominant right hand performance after inhibition of the ipsilateral right M1 (Weiler et al, 2008). Additionally, in AWNS, interhemispheric inhibition from the dominant to the non-dominant M1 is stronger than vice versa (Netz et al, 1995;Samii et al, 1997).…”

Section: No Effects On Right Hand Performance In Both Groupsmentioning

confidence: 99%

Cortical and subcortical mechanisms of persistent stuttering

Neef¹

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allowed me to study the consolidation of speech motor learning in children who stutter by using the Optotrak, a system that delivers a 3D tracking and measuring of speech kinematics. These ongoing studies are not included here.As the drafts of the studies themselves give only limited space to introduction of the topic, a more detailed introduction is given in sections 1.1 to 1.5. Components of the process of fluent articulationStuttering is a disorder with intermittent interruptions of fluent articulation. Fluent articulation is one of human's most complex motor skills. It comprises the coordinated use of approximately 100 muscles and it is fascinating how effortless this skill is managed by almost every human being. Rapid, complex movements are essential to articulate the sounds of speech. Here I briefly summarize the structures involved in articulation, which is the ultimate readout of language planning and speech motor control processes.Subsequently, I refer to influential theories on language planning and speech motor control because all these aspects are implied in different approaches to explain stuttering.Articulation involves three anatomically distinct subsystems: the respiratory, laryngeal and supralaryngeal system. The respiratory system regulates the outflow of air during speech and thus provides the energy for the acoustic targets of speech. The core structures of the laryngeal system are the vocal folds, controlling voicing and loudness of speech. During voicing the oscillation of the vowel folds generates the fundamental frequency on which resonation builds. The larynx provides the quasiperiodic and tone-like sound fundamental for vowels and voiced consonants (e.g. [b], [z] and [m]). The supralaryngeal system contains the pharyngeal, oral and nasal cavities whose architecture and configuration shape the timbre and the sound of the generated acoustic signal. The supralaryngeal system also called the vocal tract can be constricted at different places for example via lip closure, lip protrusion, tongue tip or body elevation or retraction, and velum elevation. Characteristic sound features of speech vowels are generated by overlapping vocal tract actions such as jaw lowering, tongue body elevation, and lip protrusion. In contrast, the striking acoustic features of consonants are generated by the magnitude of obstruction, resulting in bursts due to closure and friction-like noise due to fine-tuned constriction.2 to 6 years after stuttering onset recovery rates range between 65% and 85% Yairi and Ambrose, 2005). For a considerable number of affected individuals, however, stuttering continues unmitigated, resulting in a prevalence of about 1% among adults Yairi and Ambrose, 1999). The sex ratioFor stuttering the sex ratio appears to be roughly equal at the onset of the disorder (3 girls : 4 boys), and studies indicate that among those children who continue to stutter in adulthood, 75% to 80% are males (Bloodstein, 1970;.

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Low frequency (0.5Hz) rTMS over the right (non-dominant) motor cortex does not affect ipsilateral hand performance in healthy humans

Cited by 10 publications

References 31 publications

Production and organization of neocortical interneurons

Production and organization of neocortical interneurons

Time change of perceptual reversal of ambiguous figures by rTMS

Cortical and subcortical mechanisms of persistent stuttering

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