Asimakidou Evridiki, Job Xavier, Kilteni Konstantina
Department of Neuroscience, Karolinska Institutet, Solnavägen 9, 17165, Stockholm, Sweden.
Schizophrenia (Heidelb). 2022 Jun 29;8(1):57. doi: 10.1038/s41537-022-00264-6.
The brain predicts the sensory consequences of our movements and uses these predictions to attenuate the perception of self-generated sensations. Accordingly, self-generated touch feels weaker than an externally generated touch of identical intensity. In schizophrenia, this somatosensory attenuation is substantially reduced, suggesting that patients with positive symptoms fail to accurately predict and process self-generated touch. If an impaired prediction underlies the positive symptoms of schizophrenia, then a similar impairment should exist in healthy nonclinical individuals with high positive schizotypal traits. One hundred healthy participants (53 female), assessed for schizotypal traits, underwent a well-established psychophysics force discrimination task to quantify how they perceived self-generated and externally generated touch. The perceived intensity of tactile stimuli delivered to their left index finger (magnitude) and the ability to discriminate the stimuli (precision) was measured. We observed that higher positive schizotypal traits were associated with reduced somatosensory attenuation and poorer somatosensory precision of self-generated touch, both when treating schizotypy as a continuous or categorical variable. These effects were specific to positive schizotypy and were not observed for the negative or disorganized dimensions of schizotypy. The results suggest that positive schizotypal traits are associated with a reduced ability to predict and process self-generated touch. Given that the positive dimension of schizotypy represents the analogue of positive psychotic symptoms of schizophrenia, deficits in processing self-generated tactile information could indicate increased liability to schizophrenia.
大脑预测我们动作的感觉后果，并利用这些预测来减弱对自我产生感觉的感知。因此，自我产生的触摸感觉比相同强度的外部产生的触摸更弱。在精神分裂症中，这种体感减弱会大幅减少，这表明有阳性症状的患者无法准确预测和处理自我产生的触摸。如果预测受损是精神分裂症阳性症状的基础，那么在具有高阳性分裂型特质的健康非临床个体中应该也存在类似的损伤。一百名接受分裂型特质评估的健康参与者（53名女性），进行了一项成熟的心理物理学力辨别任务，以量化他们如何感知自我产生和外部产生的触摸。测量了施加在他们左手食指上的触觉刺激的感知强度（大小）以及辨别刺激的能力（精度）。我们观察到，无论将分裂型特质视为连续变量还是分类变量，较高的阳性分裂型特质都与自我产生触摸的体感减弱和较差的体感精度相关。这些效应特定于阳性分裂型特质，在分裂型特质的阴性或紊乱维度中未观察到。结果表明，阳性分裂型特质与预测和处理自我产生触摸的能力降低有关。鉴于分裂型特质的阳性维度代表了精神分裂症阳性精神病症状的类似物，处理自我产生触觉信息的缺陷可能表明患精神分裂症的易感性增加。
