A Comprehensive Theoretical Survey on Functionalities and Properties of Adult Neurogenesis under the Influence of Slow Oscillations

2020 Fiscal Year Research-status Report

• Project/Area Number: 19K16885
• Research Institution: Okinawa Institute of Science and Technology Graduate University
• Principal Investigator: Fung ChiChung 沖縄科学技術大学院大学, 神経情報・脳計算ユニット, 研究員 (80757203)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: Dentate Gyrus / Unsupervised Learning / Pattern Separation

Outline of Annual Research Achievements

The principal investigator has recently changed the direction of the study, because the principal investigator has found that the old learning rule has some problems. He found that the learning does not converge to meaningful receptive field. In particular, the units in the middle layer biased to some of the patterns, even though the training order is randomized. Also, not all realization with different initial states lead to qualitatively similar final outcome. So the principal investigator believed that the model with that settings does not deserve resources for further investigation.

In order to solve this problem, the principal investigator has inputted a new learning rule and study their properties. Recently, I found that the middle layer with a dentate-gyrus-like learning rule can separate input patterns without supervising signal, which deserve further studies. Also, the principal investigator found that the output of the middle layer is very helpful to pair with specific labels. For example, the investigator has used MNIST to test the network’s ability. He found that the correct rate can be up to 95% with only one learning iteration. Also, the current learning rule could generate unstable network activity, although the tuning is helpful for pattern separation, which is also a interesting point to follow.

Current Status of Research Progress

3: Progress in research has been slightly delayed.

Reason

Since the old learning rule used in the study suffers from some problem. The investgator has changed to a new learning rule. The new learning should be promising for further studies.

Strategy for Future Research Activity

The investigator is going to study the new unsupervised learning rule, because it seems to suggest that dentate gyrus can separate input patterns without supervising signals.

Causes of Carryover

Due to the pandemic, the money reserved for international conferences is remained for other purpose. For example, it will be used for more equipment for faster simulations.