COMPUTATIONAL ASPECTS OF PRIMATE MEMORY

活跃的短期记忆在行为、推理和语言的时间组织中起着关键作用。它在各种精神障碍中受损，特别是在精神病、主要情感障碍和由大脑病理性老化引起的综合征中。最近的实验证据表明，活跃的短期记忆包括大脑皮层广泛的相互连接的神经元组件网络的持续激活。记忆网络分布广泛，超出了解剖学定义的大脑皮层区域的界限。主动记忆的机制被认为包括神经元冲动在一个这样的网络中的持续循环。这项研究将试图证实活跃的短期记忆的分布性，以及被认为是短期记忆保持的基础的神经冲动的重新进入。这一目标的实验将在非人类灵长类动物身上进行，这些灵长类动物被训练成执行听觉、触觉和跨模式记忆任务。在这些任务的执行过程中--在某种程度上，学习过程中--大脑皮层额叶和顶叶区域的场电位和细胞放电将被记录下来。将分析细胞放电的频率和模式，以寻找在感觉信息的短期记忆过程中，这些皮质区域内部和之间的神经元相互作用的证据。将使用时间序列分析的特殊计算方法来探索这些相互作用。一些相互作用将通过额叶皮质可逆性功能抑制(通过局部降温)及其对壁细胞放电和动物触觉记忆任务表现的影响的研究来进一步探索。这些研究的结果有望阐明大脑皮层记忆网络的功能结构，以及记忆的编码、保持和提取机制。更好地了解记忆的神经动力学可能有助于我们更好地了解精神病患者记忆障碍的发病机制，从而指导更好的治疗。

Active short-term memory plays a critical role in the temporal organization of behavior, reasoning, and language. It is impaired in a variety of mental disorders, notably in the psychoses, major affective disorders and syndromes resulting from pathological aging of the brain. Recent experimental evidence indicates that active short-term memory consists in the sustained activation of an extensive network of interconnected neuronal assemblies of the cerebral cortex. Memory networks are widely distributed, extending beyond the boundaries of anatomically defined cortical areas. The mechanisms of active memory are believed to include the sustained circulation of neuronal impulses within one such network. This research will attempt to substantiate the distributed nature of active short-term memory and the reentry of neural impulses presumed to be the basis of short-term memory retention. Experiments with that objective will be conducted in nonhuman primates trained to perform auditory, tactile, and cross-modal memory tasks. Fields potentials and cell discharge will be recorded from frontal and parietal regions of the cortex during performance-and also to some extent during learning-of those tasks. Frequency and pattern of cell discharge will be analyzed for evidence of neuronal interactions within and between those cortical regions during the short-term memorization of sensory information. Special computational methods of time-series analysis will be used to explore those interactions. Some of the interactions will be further explored by reversible functional depression (by local cooling) of frontal cortex and the study of its effects on parietal cell discharge and the animal's performance of haptic memory tasks. The results of these studies are expected to shed light on the functional architecture of cortical memory networks and on the mechanisms of encoding, retention, and retrieval of memory. A better understanding of the neural dynamics of memory may help us better understand the pathogenesis of memory disorders in the mentally ill and thus lead to better treatments.