Gur Raquel E, Turetsky Bruce I, Loughead James, Snyder Wendy, Kohler Christian, Elliott Mark, Pratiwadi Ramapriyan, Ragland J Daniel, Bilker Warren B, Siegel Steven J, Kanes Stephen J, Arnold Steven E, Gur Ruben C
Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
Am J Psychiatry. 2007 Mar;164(3):442-9. doi: 10.1176/ajp.2007.164.3.442.
Schizophrenia patients have problems directing attention. Sustained attention requires ensuring that brain resources are focused on a selected target (top-down task) while ignoring irrelevant distractors (bottom-up interference). Whether patients have too little ability to focus or too much interference from distraction has not been clarified. The oddball paradigm embeds infrequent targets and distractors into the stimulus train, and schizophrenia deficits have been linked to diminished responses to both. Cerebral activity underlying abnormal attention can be examined with event-related functional magnetic resonance imaging.
A visual oddball task was presented to 22 patients with schizophrenia and 28 comparison subjects. Statistical probability maps reflecting blood-oxygenation-level-dependent changes were generated for infrequent targets and novel distractors relative to frequent standard stimuli. Activation was related to performance and symptoms.
Activation specific to targets and distractors was associated with faster performance. For targets, patients had diminished activation in superior temporal and frontal gyri, cingulate, thalamus, and basal ganglia. They had increased activation in right insula, mid-frontal gyrus, posterior cingulate, and left inferior parietal lobule. For distractors, patients showed less activation in occipital regions and left inferior parietal lobule but increased activation in parietal-occipital, right mid-frontal, and left inferior frontal gyri. Abnormal activation correlated with positive and negative symptoms.
Abnormal activation in schizophrenia in response to attentional demands reflects both insufficient recruitment of brain systems required for target detection and overcommitment of resources for processing irrelevant distractors. Schizophrenia patients appear to have an inability both to focus on targets and ignore distraction.
精神分裂症患者存在注意力指向问题。持续注意力要求确保大脑资源集中于选定目标（自上而下的任务），同时忽略无关干扰因素（自下而上的干扰）。患者是聚焦能力不足还是受干扰因素的影响过大尚不清楚。异常球范式将罕见目标和干扰因素嵌入刺激序列中，精神分裂症的缺陷与对两者的反应减弱有关。可通过事件相关功能磁共振成像检查异常注意力背后的脑活动。
对22例精神分裂症患者和28名对照受试者进行视觉异常球任务。针对相对于频繁标准刺激的罕见目标和新干扰因素生成反映血氧水平依赖性变化的统计概率图。激活与表现和症状相关。
目标和干扰因素特有的激活与更快的表现相关。对于目标，患者在颞上回、额回、扣带回、丘脑和基底神经节的激活减弱。他们在右侧岛叶、额中回、后扣带回和左侧顶下小叶的激活增加。对于干扰因素，患者在枕叶区域和左侧顶下小叶的激活较少，但在顶枕叶、右侧额中回和左侧额下回的激活增加。异常激活与阳性和阴性症状相关。
精神分裂症患者对注意力需求的异常激活既反映了目标检测所需脑系统的募集不足，也反映了处理无关干扰因素的资源过度投入。精神分裂症患者似乎既无法专注于目标，也无法忽略干扰因素。
