Motor Aspects of Lateralization: Evidence for Evaluation of the Hypotheses of Chapter 8
Robert Miller in Axonal Conduction Time and Human Cerebral Laterality, 2019
Two papers reporting on eye movement disorders after unilateral hemispheric damage contribute to defining the special roles of the two hemispheres in motor control. Gaymard et al. (1993) studied three patients with lesion of the right supplementary motor area, and three with damage to the corresponding area on the left. When asked to perform single saccades to previously memorised positions neither group of patients were impaired. In a task involving sequential saccades to three positions pre-ordered in memory, many more errors were found for the left hemisphere patients than the right hemisphere ones. This result is similar to that of Kimura (1982) for sequences of manual or oral gestures. Given that saccades are an equivalent to ballistic, open-loop control of the limbs, the result supports the hypothesised role of the left hemisphere in such movements.
Vocal Motor Disorders *
Rolland S. Parker in Concussive Brain Trauma, 2016
While a speech disorder may be accompanied by the localization of a lesion, disordered performance reflects the performance after the brain has adjusted to a loss and alteration of function. Significant disorder of a particular aspect of vocalization is frequently accompanied by a variety of vocalization disorders. Abnormal articulation is based upon differential impairment of motor subsystems. Dysarthria constitutes one-third of communication impairments observed in head-injured persons. It is associated with severe brain injury. Its most common etiology is spasticity resulting from bilateral UMN damage, affecting pyramidal and extrapyramidal motor tracts (Theodoros et al., 2001b). Dysarthria is found in amyotrophic lateral sclerosis associated with degeneration of corticobulbar projections (Brown, 2001). Postcentral (kinesthetic) articulatory dyspraxia (Glezerman & Balkoski, 1999, p. 98) refers to substitution of particular articulatory components by similar ones, resulting in mispronunciation of consonants more than vowels. Slurred speech and speech arrest are associated with a lesion of the supplementary motor area. Dysarthria with inarticulate, intermittent explosive speech occurs commonly in bilateral cerebral hemisphere.
Neurologic Diagnosis
Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw in Hankey's Clinical Neurology, 2020
This readiness potential indicates preparation for self-paced voluntary movements. It has components arising from the presupplementary motor area, supplementary motor area, and the premotor cortex. The potential comprises a slowly increasing negative potential beginning 1–2 seconds before the movement, and then a steeper increasing negativity (the NS′) about 400 ms before the movement (Figure 1.59). It can be recorded from the scalp EEG, triggering the acquisition with EMG electrodes placed over a muscle involved in the movement and then back-averaging the EEG preceding the movement. Jerk-locked back-averaging of an EEG requires a bandwidth to include low frequencies. In patients with suspected functional jerky movements, the presence of a Bereitschaftspotential (BP) strongly supports voluntary movement and a psychogenic origin. Limitations include continuous and pleomorphic movements preventing discrete triggering for back-averaging, and the BP is not always seen with voluntary movements in normal subjects.
Postoperative Focal Lower Extremity Supplementary Motor Area Syndrome: Case Report and Review of the Literature
Published in The Neurodiagnostic Journal, 2021
Nicholas B. Dadario, Joanna K. Tabor, Justin Silverstein, Xiaonan R. Sun, Randy S. DAmico
The supplementary motor area (SMA) is found bilaterally within the posterior frontal lobe in the medial frontal gyrus. The SMA is bordered posteriorly by primary motor cortex and inferiorly by the cingulate sulcus and cingulate, and the genu of the corpus callosum. Cortical models suggest that the SMA demonstrates extensive connections within and outside of the motor network and participates in a variety of functions Briggs et al. (2021). Primarily, the SMA is involved in the initiation and coordination of internal and externally cued movements – especially speech and bilateral motor control (Sheets et al. 2021; Vergani et al. 2014). Recent data suggest that the SMA is part of a prefrontal cognitive initiation “axis” in the medial frontal lobe where it coordinates with the default mode network and salience network to execute goal-directed behavior (Poologaindran et al. 2020).
The Role of Primary Motor Cortex: More Than Movement Execution
Published in Journal of Motor Behavior, 2021
Sagarika Bhattacharjee, Rajan Kashyap, Turki Abualait, Shen-Hsing Annabel Chen, Woo-Kyoung Yoo, Shahid Bashir
In contrast, the PMA and other regions of the frontal lobe such as the supplementary motor area (SMA) and the cingulate motor area (CMA) (Chouinard & Paus, 2006) form the secondary motor areas. Many previous reviews have shown that these secondary motor areas are involved in cognitive processes such as planning, coordination, and selecting voluntary movement (Nachev et al., 2008; Rizzolatti et al., 2002). For example, Rizzolatti et al. (2002) consolidated the results of the studies performed on primates and humans to conclude that the ventral sectors of the PMA (including Brodmann area 44) are involved in action organization, motor imagery, and action understanding. Similarly, Goldberg (1985) and Roland et al. (1980) reported the involvement of SMA in the organization of voluntary motor movement. Borich et al. (2015) reviewed the role of primary SMA in motor control, motor learning, and functional recovery. Though these studies open up vast opportunities for the exploration of M1, the possibility that M1 can play a crucial role in motor cognition remains understudied.
Motor imagery and gait control in Parkinson’s disease: techniques and new perspectives in neurorehabilitation
Published in Expert Review of Neurotherapeutics, 2022
Giovanna Cuomo, Valerio Maglianella, Sheida Ghanbari Ghooshchy, Pierluigi Zoccolotti, Marialuisa Martelli, Stefano Paolucci, Giovanni Morone, Marco Iosa
Essential components of MI are visual and kinesthetic imagery, which refer to the mental proprioceptive perception of muscle contractions and changes [17]. Kinesthetic motor imagery involves the imagination of the sensation of the movement, not just the visualization of the movement as in visual MI, so kinesthetic MI yielded more activity in motor-associated structures and the inferior parietal lobule, suggesting that these two modalities of imagery could be mediated through separate neural systems, whereas visual MI activated predominantly the occipital regions and the superior parietal lobules, so they may contribute differently during processes of motor learning and neurorehabilitation [18]. Gait in MI tasks involves fronto-parietal areas and subcortical areas such as basal ganglia, brainstem, and cerebellum as the actual movements do [19]. Inhibitory and excitatory signals from the brainstem and spinal cord modulate the muscle tone in locomotion*** [19–24]***. Limbic system and basal ganglia have a role in the gait emotional expression [25]. Supplementary motor area appears fundamental to initiate and stop motor gait: lesions in this area result in gait apraxia [26]. Posterior-parietal areas contribute to motor planning and visual feedback, while cerebellum supports proprioception and balance [27,28]. Individual differences in gait imagery abilities might lead to differences in the pattern of brain activation, but the same areas of the gait network are involved [17].
Related Knowledge Centers
- Bereitschaftspotential
- Caudate Nucleus
- Cingulate Sulcus
- Cytoarchitecture
- Epithalamus
- Motor Cortex
- Putamen
- Supplementary Eye Field
- Globus Pallidus