COMPUTATIONAL ASPECTS OF PRIMATE MEMORY

主动短期记忆在行为、推理和语言的时间组织中起着至关重要的作用。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衰老引起的综合症中。最近的实验证据表明，活跃的短期记忆是由大脑皮层中相互连接的神经元集合的广泛网络的持续激活组成的。记忆网络分布广泛，超出了解剖学定义的皮质区域的边界。主动记忆的机制被认为包括神经脉冲在一个这样的网络内的持续循环。本研究将试图证实活跃短期记忆的分布性质，以及被认为是短期记忆保持基础的神经脉冲的重新进入。这一目标的实验将在非人类灵长类动物中进行，这些灵长类动物被训练去执行听觉、触觉和跨模态记忆任务。在执行这些任务时，大脑皮层的额叶和顶叶区域的场电位和细胞放电将被记录下来，在某种程度上，在学习这些任务时也是如此。我们将分析细胞放电的频率和模式，以证明在短期记忆感觉信息过程中，这些皮层区域内部和区域之间的神经元相互作用。时间序列分析的特殊计算方法将用于探索这些相互作用。部分相互作用将通过额叶皮质可逆性功能抑制（通过局部冷却）及其对顶叶细胞放电和动物触觉记忆任务表现的影响的研究进一步探索。这些研究的结果有望揭示皮层记忆网络的功能结构以及记忆的编码、保留和检索机制。更好地了解记忆的神经动力学可以帮助我们更好地了解精神疾病记忆障碍的发病机制，从而导致更好的治疗。

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.