【英语演讲】Informative Speech

写在前面：

本专栏用于收纳我本学期在《英语演讲》课上的present的所有演讲文稿，一来是记录文案防止在自己电脑上误删了hh（虽然成功传上来我可能就立马会删掉orz），二来是方便大家学习与交流（啦）。如果之后有时间+final score还不错的话，我可以写一下这门课的“通关技巧”，供同校的朋友们参考~

本期为Informative Speech，要求是：①科普介绍一个事物或规律等；②演讲时长为5min左右；③使用视觉辅助物品（如PPT、实物、板书等），这个是选做（但最好是做了。）

The Hidden Secrets Behind Memory

Please recall a very happy and vivid memory and raise your left hand if you get one. Now, please raise your right hand if you remember what specific dishes you had last Thursday. Okay, I see that this question may be a little bit confusing to some of you. Have you ever thought about why we only remember some things clearly, why many memories eventually fade and how we can protect our memory? Today I am going to show you in a biological way.

Let’s focus on how memories form in the first place. When you undergo something, the experience is converted into a pulse of electrical energy that zips along a network of neurons. Information first lands in short term memory, where it’s available from anywhere from a few seconds to a couple of minutes. It’s then transferred to long-term memory through areas such as the hippocampus, and finally to several storage regions across the brain. Neurons throughout the brain communicate at dedicated sites called synapses, using specialized neurotransmitters. If 2 neurons communicate repeatedly, a remarkable thing happens--the efficiency of communication between them increases. This process, called long term potentiation, is considered to be a storage mechanism of long-term memory.

But how do memories get vanished? Age is one factor. As we get older, synapses begin to falter and weaken, affecting how easily we can retrieve our memories. Scientists have several theories about synapses deterioration such as actual brain shrinkage and the decreasing production of neurotransmitters. According to the published research “Correlation between metabolite concentrations and age in different regions of hippocampus during normal brain aging”, the hippocampus loses 5% of its neurons every decade, for a total loss of 30% by the time you reach 80.

Another leading cause of memory loss is chronic stress. When we are constantly overloaded with work, our bodies are on hyper alert. Although stress chemicals help mobilize energy and increase alertness, our bodies will be flooded with these chemicals under chronic stress. This situation can result in a loss of brain cells and incompetence of forming new ones and prevent us from retaining new information.

Besides, depression is on the list. People who are depressed are 40% more likely to develop memory problems. Dwelling on sad events in the past makes it difficult to pay attention to the present, affecting the ability to store short-term memories. Isolation attached to depression can be a memory thief too. A study by the Harvard School of Public Health found that older people with high levels of social integration had a slower rate of memory decline over a 6-year period. The exact reason remains unclear, but experts suspect that social interaction gives our brain a mental workout, just like muscle strength.

You may find yourself as a victim. Don’t panic! There are several methods to aid your brain in preserving memory. First, stay physically active. Increased blood flow to the brain is helpful. Second, maintain a healthy diet. Your brain needs balanced and sufficient nutrition to function correctly. Third, give your brain a workout. Exposing your brain to challenges, like delivering a speech today, is the best defense to keep memory intact.

In conclusion, the hidden secrets of memory lie in its formation, influencing factors and preservation. Escaping age may sound impossible, but following the suggestions is easy. So next time you open “flashing campus”, don’t wear a bitter face. Remember that you are running for your memory, not running for scores!

Thank you!

Ps：上完这节课真的会很想退课！我花了起码五个小时背吧，但是最后还是没背下来（毕竟大家的稿子都是500-700词，真的太多了......），之后可能发一下我做的PPT吧~

PPT：