Tasaka Gennosuke, Ide Yoshinori, Tsukada Minoru, Aihara Takeshi
Graduated School of Engineering, Tamagawa University, Machida, Tokyo 194-8610 Japan.
Brain Science Institute, Tamagawa University, Machida, Tokyo, 194-8610 Japan.
Cogn Neurodyn. 2022 Apr;16(2):283-296. doi: 10.1007/s11571-021-09708-8. Epub 2021 Sep 8.
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.
感觉皮层是由对特定感觉模态下物理刺激的反应所定义的。最近，在人类和哺乳动物大脑中，除了每个皮层的主要特定感觉模态之外，还报道了对其他刺激的额外联合诱导反应。在本研究中，为了研究一种巩固类型，在以足部电击作为厌恶刺激、音调与光作为感觉刺激的一阶或二阶条件反射后，使用光学成像同时测量豚鼠皮层（听觉、视觉和体感）中的联合反应。我们的研究结果表明：（1）在一阶和二阶条件反射后，每个皮层区域的联合反应被额外诱导以刺激其他特定感觉模态；（2）对音调与光的感觉条件反射的联合反应在神经元水平上也表现为反应变化，而无行为现象；（3）当在音调与光的感觉条件反射之前施加光与足部电击的恐惧条件反射时，与一阶恐惧条件反射后的反应相比，初级视觉皮层（V1）中对足部电击的联合反应降低（消退），而在感觉条件反射后的恐惧条件反射中联合反应增强（易化）。我们的结果表明，各种类型的自下而上的信息作为皮层中诱导的联合反应被巩固，这些联合反应通过涉及皮层网络中易化和消退的可塑性变化被重复或交替追踪。皮层反应的这种信息组合过程可能在大脑中记忆的动态关联中起关键作用。
