Sensory cortices are defined by responses to physical stimulation in specific modalities. Recently, additional associatively induced responses have been reported for stimuli other than the main specific modality for each cortex in the human and mammalian brain. In this study, to investigate a type of consolidation, associative responses in the guinea pig cortices (auditory, visual, and somatosensory) were simultaneously measured using optical imaging after first- or second-order conditioning comprising foot shock as an aversive stimulus and tone and light as sensory stimuli. Our findings indicated that (1) after the first- and second-order conditioning, associative responses in each cortical area were additionally induced to stimulate the other specific modality; (2) an associative response to sensory conditioning with tone and light was also seen as a change in the response at the neuronal level without behavioral phenomena; and (3) when fear conditioning with light and foot shock was applied before sensory conditioning with tone and light, the associative response to foot shock in the primary visual cortex (V1) was decreased (extinction) compared with the response after the first-order fear conditioning, whereas the associative response was increased (facilitation) for fear conditioning after sensory conditioning. Our results suggest that various types of bottom-up information are consolidated as associative responses induced in the cortices, which are traced repetitively or alternatively by a change in plasticity involving facilitation and extinction in the cortical network. This information-combining process of cortical responses may play a crucial role in the dynamic linking of memory in the brain.

感觉皮层由特定模式下对物理刺激的反应来定义。最近，除了人类和哺乳动物大脑中每个皮层的主要特定模式之外，还报道了其他刺激的关联诱导反应。在这项研究中，为了研究一种巩固，在一阶或二阶调节后使用光学成像同时测量豚鼠皮质（听觉、视觉和体感）中的联想反应，包括足部电击作为厌恶刺激和音调光作为感官刺激。我们的研究结果表明：（1）在一阶和二阶条件反射之后，每个皮层区域的联想反应被额外诱导以刺激其他特定模式；(2) 对音调和光的感觉调节的联想反应也被视为神经元水平反应的变化，没有行为现象；和 (3) 当在用音调和光进行感觉调节之前应用光和足部电击的恐惧条件反射时，初级视觉皮层 (V1) 中对足部电击的联想反应与一阶后的反应相比减少（消退）恐惧条件反射，而在感觉条件反射后，恐惧条件反射的联想反应增加（促进）。我们的研究结果表明，各种类型的自下而上的信息被巩固为在皮质中引起的联想反应，这些反应通过涉及皮质网络中的促进和消退的可塑性变化重复或替代地追踪。