Mesulam Marsel
Cognitive Neurology and Alzheimer's Disease Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
Ann Neurol. 2008 Oct;64(4):367-78. doi: 10.1002/ana.21534.
The anatomical basis of conscious experience has traditionally been linked to sensory-fugal (inward) pathways that convey sensory information to progressively "higher" association cortices. Current thinking is emphasizing the importance of sensory-petal pathways that run in the opposite (outward) direction. According to emerging views, many aspects of cognition may represent an iterative neural dialogue between sensory-fugal connections, which reflect the physical nature of ambient events, and sensory-petal connections, which infer the nature of the stimulus based on empirical accounts of past experience. These reciprocal pathways, embedded within the internally generated oscillations of the brain, are further modulated by top-down projections from high-order association cortices, most prominently located in prefrontal cortex. This set of top-down projections has the capacity to transcend experience-based representations and to insert internally generated priorities into the interpretation of ongoing events. The characteristically human capacity for resisting stimulus-bound responses and favoring novel interpretations may be linked to the influence of these top-down projections. The reciprocal sensory-processing pathways and their top-down modulations collectively define the conscious interpretation of experience.
传统上,意识体验的解剖学基础与感觉离心(向内)通路相关,这些通路将感觉信息传递到逐渐“更高层次”的联合皮层。当前的观点强调感觉向心(向外)通路的重要性,这些通路朝着相反的方向运行。根据新出现的观点,认知的许多方面可能代表了感觉离心连接(反映周围事件的物理性质)与感觉向心连接(基于过去经验的实证描述推断刺激的性质)之间的反复神经对话。这些相互的通路嵌入在大脑内部产生的振荡中,并受到来自高阶联合皮层(最显著地位于前额叶皮层)的自上而下投射的进一步调节。这组自上而下的投射有能力超越基于经验的表征,并将内部产生的优先级插入到对正在发生事件的解释中。人类抵抗受刺激束缚的反应并倾向于新颖解释的独特能力可能与这些自上而下投射的影响有关。相互的感觉处理通路及其自上而下的调节共同定义了对体验的意识解释。