اختلال عصبی در تصویرسازی حرکتی همراه با علائم مثبت در بیماران مبتلا به اسکیزوفرنیا قسمت اول: شواهد از پتانسیل های مغز مرتبط با رویداد
|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|29703||2015||7 صفحه PDF||سفارش دهید||6294 کلمه|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : Psychiatry Research: Neuroimaging, Volume 231, Issue 3, 30 March 2015, Pages 236–243
Motor imagery provides direct insight into an anatomically interconnected system involved in the integration of sensory information with motor actions, a process that is associated with positive symptoms in schizophrenia (SCZ). However, very little is known about the electrophysiological processing of motor imagery in first episode SCZ. In the current study, we used a visual hand mental rotation (MR) paradigm to manipulate the processing of motor imagery while event-related brain potentials (ERPs) were recorded in 42 SCZ participants and 40 healthy controls (HC). The 400–600 ms window was measured and analyzed for peak latencies and amplitudes. Participants with SCZ had slower reaction time (RT) and made more errors than did HC participants. Moreover, SCZ participants had lower amplitudes in the 400–600 ms window and the typical MR function for amplitudes of MR was lacking. Interestingly, the scalp activity maps for MR in SCZ exhibited an absence of activation in the left parietal site as shown in HC. Furthermore, deficits of amplitude for MR were positively correlated with positive symptom scores in SCZ. These results provide novel evidence for relationships between the electrophysiological processing of motor imagery and positive symptoms in SCZ. They further suggest that the impaired information processing of motor imagery indexed by amplitudes and specific topographic characteristics of the EEG during MR tasks may be a potentially useful and early defining biomarker for SCZ.
Mental rotation (MR) is thought to be a cognitive ability that alters mental representations of two- and three-dimensional objects or body parts, and usually involves the creation of a mental image of an object and its subsequent rotation (Shepard and Metzler, 1971). It is often considered as a prototypical form of higher level cognitive processing of motor imagery, which is involved with the integrity of specific cortical–subcortical motor structures (motor and premotor areas and basal ganglia) and sensory systems (somatosensory and visual) (de Lange et al., 2006). The mental simulation of real perceptual-motor behaviors can be regarded as a sort of internal or cognitive analogue of actual movements, useful for motor planning and prediction (Duncombe et al., 1994). Numerous authors (e.g., Parsons, 1987, Wraga et al., 2005 and Lenggenhager et al., 2008) have studied tasks involving body parts in different postures and rotated angles, in which subjects are required to judge whether the body part belongs to the right or left side of the body. These studies have indicated that subjects appear to mentally simulate the kinematic properties of the physical action of their body part moving from its resting posture to that of the stimulus during that procedure. Numerous studies have demonstrated that the amplitude of an event-related brain potential (ERP) component increases linearly with the angle of rotation in a hand MR task, indicating the presence of the expected MR function. This ERP component, known as “rotation-related negativity”, was first reported in a study conducted by Stuss et al. (1983), which suggested that ERP negativity should be considered as a direct electrophysiological correlate of the MR process itself. The ERP component consists of a negative-going waveform, maximum over parietal regions, whose amplitude is modulated by the angle of rotation: the greater the angle of misorientation, the larger the rotation-related negativity (Wijers et al., 1989). The rotation-related negativity has been repeatedly demonstrated in studies with alphanumeric characters (Heil and Rolke, 2002 and Núñez-Peña and Aznar, 2009), letter-like shapes (Hamm et al., 2004 and Núñez-Peña et al., 2005), paper-folding stimuli (Milivojevic et al., 2003), left-right hands (Thayer and Johnson, 2006), and geometric objects (Muthukumaraswamy et al., 2003). Previous studies have demonstrated that the ERP negative-going waveform of MR appears in parietal negativity approximately between 350 and 800 ms (Wijers et al., 1989 and Heil and Rolke, 2002), 400–600 ms (Harris and Miniussi, 2003), around 400–550 ms over the right hemisphere and ~610 ms over the left hemisphere (Milivojevic et al., 2009), and 400–500 ms (Núñez-Peña and Aznar, 2009) post-stimulus onset. Corresponding evidence suggests that the amplitude modulation can be used as a neurophysiological indicator of the high-level cognitive process of MR. It further suggests that the onset of the ERP effect can be used as a chronopsychophysiological marker for the onset of the process. Several studies have indicated that the main underlying cognitive deficits in SCZ patients involve a severe degree of impairment on the ‘general executive function’ factor (Polgár et al., 2010), a difficulty in differentiating between imagination and reality (Brebion et al., 2000), and an inability to anticipate the sensory consequences of their own movements (Wolpert et al., 1995). Given the similarities between motor imagery and physical actions (Jeannerod and Decety, 1995), previous studies have found that SCZ patients have an impaired ability of MR due to problems in imagining the performance of a movement (Potvin et al., 2013). The disruption of motor imagery might be expected to lead to endopathic experiences, in which patients with SCZ can no longer compare the performed movement with the anticipated outcome of these movements and thus feel alienated from their own actions (Frith et al., 2000 and de Vignemont et al., 2006). Furthermore, patients with motor impairments such as parietal damage (Sirigu and Duhamel, 2001) or impairment of the right basal ganglia (Harris et al., 2002) also suffer from difficulties in motor imagery. Motor imagery thus provides direct insight into action representations (de Vignemont et al., 2006). However, while the disrupted information processing of motor imagery has been addressed in numerous studies of patients with motor impairments, very little is known about the processing of motor imagery in SCZ, particularly in first episode patients. The objective of the present study was thus to evaluate whether any impairments would be specific to the brain visuo-motor electrophysiological processing mechanism in SCZ. Based on previous studies (de Vignemont et al., 2006 and Potvin et al., 2013), we hypothesized that if SCZ patients were impaired in motor imagery, the onset of the amplitude modulation of the rotation-related negativity would be delayed and the mean peak amplitudes would be reduced over parietal regions. Moreover, we predicted that the patterns of reaction times (RTs) and the amplitudes of the rotation-related negativity would lead to the absence of a typical MR function. The impaired electrophysiological processing of motor imagery is particularly relevant to positive symptom in SCZ. Such an impairment, if confirmed, might be a potential biomarker of SCZ.
نتیجه گیری انگلیسی
3.1. Behavioural results 3.1.1. Error rates There were significant main effects of Group with SCZ (mean=30.82±10.01%) being significantly higher than those of HC [(mean=14.22±6.32%; F (1, 80)=16.31, p<0.001)], Stimulus side [F (1, 80)=4.06; p=0.026], and Orientation [F (3, 80)=18.01, p<0.001]. A significant Group×Orientation interaction was found [F (3, 80)=14.12, p<0.001]. Post hoc comparisons showed that the Control-Patient differences were found at all rotation angles (all p<0.01). In HC, differences between orientations were found between all rotation orientations (all p<0.01). Moreover, a linear regression trend showed that ERs were gradually linear and increased with the angle of rotation in HC [F (1, 38)=12.68, p<0.001 for left hand; F (1, 38)=11.91, p<0.001 for right hand; see Fig. 2a]. However, in SCZ, there were no differences between the orientations 0–60°, 0–120°, and 60–120° (all p>0.05), and differences were only found between orientations 0–180°, 60–180°, and 120–180° (all p<0.05). ERs did not show a MR linear function [F (1, 40)=0.59, p=0.105 for left hand; F (1, 40)=1.32, p=0.086 for right hand; see Fig. 2a] compared with the HC group. Full-size image (30 K) Fig. 2. Mean error rate (a) and mean reaction time (b) in schizophrenia patients and controls for the hand condition at each angle of orientation. Figure options 3.1.2. Reaction times There were significant effects of Group with SCZ (mean=1006±324 ms) being significantly longer than those of HC [(mean=807±263 ms), F (1, 80)=10.36, p=0.006], Stimulus side [F (1, 80)=2.75; p=0.036], and Orientation [F (3, 80)=12.30, p<0.001]. There was a significant Group×Orientation interaction [F (3, 80)=16.82, p<0.001]. Post hoc comparisons showed that the Control–Patient differences were found at all rotation angles (all p<0.05). This effect was found especially at 0° (p<0.001). In HC, differences between orientations were found between all rotation orientations (all p<0.05). Moreover, a linear regression trend indicated that RTs showed a gradual linear increase as the hand was rotated further from the upright position, indicating the presence of the expected MR function in HC [F (1, 38)=12.05, p<0.001 for left hand; F (1, 38)=13.86, p<0.001 for right hand; see Fig. 2b]. However, in SCZ, there were no differences between the orientations 0–120°, 60–120°, 60–180°, and 120–180° (all p>0.05). In addition, differences were found between the rotation orientations 0–60°, and 0–180° (all p<0.05). RTs did not show a typical MR linear function [F (1, 40)=0.57, p=0.112 for left hand; F (1, 40)=0.61, p=0.103 for right hand; see Fig. 2b] compared with the control group.