Can Exercise Improve Sequence Learning with the Help of the Hippocampus?
The question framed for this study is, does physical exercise have an impact on sequence memory? The research study also focuses on the insight from other studies that physical exercise increases memory by increasing neuron plasticity within the hippocampus. (Marin Bosch et al., 2020) The hippocampus is a structure in the brain that retrieves explicit and implicit memories and is known as a plastic structure. (Kalat, 2014, p. 403) A simple way to explain plasticity in the hippocampus it that it is similar to a bunch of swinging bridges that can disconnect and connect to different structures. This allows the hippocampus to make new routes to be able to retrieve memories.
To start the experiment the researchers got the participants to do a sequence test. They had to memorize a sequence of buttons that lit up on a screen and match it by pressing buttons in front of them that coordinated to the ones on the screen in a timely manner. This sequence test is one measure used in the study; it is a starting point on how well each participants memory is before any exercise.
To test the hypothesis that physical exercise does improve sequence memory function, the researchers studied three main factors. They looked at participants behavior, fMRI, and anandamide levels within their blood. The reason the researchers choose these to test is from previous research studies that have been done before.
From other resources the researchers knew that damage to the hippocampus can harm the ability to retrieve implicit and explicit memories (Marin Bosch et al., 2020) An explicit memory would be factual like recalling how to do a math problem and an implicit memory would be remembering how to play the guitar or another skill. (Kalat, 2014, p. 403) Other known knowledge is that physical exercise does improve explicit memories by increasing plasticity or “bridge rerouting”. (Marin Bosch et al., 2020) Since there was this research available but no further studies done on physical exercise, and sequence memory this was a main focus for this study, and the hypothesis. A hypothesis is a scientific question that one can test to be true or false.
Marin Bosch et al. (2020) also stated that in previous studies, physical exercise in animals increase the neurotransmitter anandamide which is a chemical messenger within the body. During this study anandamide levels were taken before and after a participant exercised then did a sequence test. The results were that there was a positive relationship between anandamide levels and the performance on the sequence test, which means when one factor increased so did the other. One relationship they couldn’t say existed was between anandamide levels and hippocampus activities.
After receiving the starting measure by doing the sequence task, the participants then exercised and redid the sequence test in a fMRI machine. A fMRI is equivalent to having multiply light bulbs and one light switch, when the switch is turned on one bulb will brighten and you with know what room has light. This is the same with the human brain, when the fMRI detects exercise it will “light up” and then you will know what structure is showing brain exercise. When doing this in the study, the researchers found that while doing the sequence test in the fMRI the hippocampus and another structure called caudate nucleus “lit up” and showed brain exercise. The study also found increased exercise in another brain region involved with memory called the precuneus. This region had increased exercise after the participants exercised compared to no exercise before the memory sequence.
To summarize the findings in the study, the researchers found that after exercising the participants had higher levels of the neurotransmitter anandamide in their blood. This neurotransmitter is linked to plasticity “bridges rerouting” in the hippocampus which is involved in retrieving memories. They also found that when participants were doing the memory sequences in the fMRI, the hippocampus and caudal nucleus would “turn on like a light bulb”. This indicated that there was a relationship between sequence training and these brain structures. This study included results that showed how physical exercise will increase anandamide levels. It also showed how hippocampal, and caudate nucleus activity will increase when doing the sequence test. These findings as well as other research helped demonstrate the hypotheses that physical exercise does increase sequence learning.
References
Kalat, J. W. (2014). Biological psychology. Boston, MA: Cengage Learning.
Marin Bosch, B., Bringard, A., Logrieco, M.G. et al. Effect of acute physical exercise on motor
sequence memory. Sci Rep 10, 15322 (2020). https://doi.org/10.1038/s41598-020-72108-1
