Effect of Monday-Thursday Fasting on Cognitive Function of Teenager

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RAJA ARIA OCTIVANO

G34103041

DEPARTMENT OF BIOLOGY

FACULTY OF MATHEMATIC AND NATURAL SCIENCES

BOGOR AGRICULTURAL UNIVERSITY

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ABSTRACT

RAJA ARIA OCTIVANO. Effect of Monday-Thursday Fasting on Cognitive Function of Teenager. Supervised by BAMBANG SURYOBROTO and AKICHIKA MIKAMI.

Cognitive function consists many aspects, one of them is memory. Memory is a complex cognitive function that allows the recording, maintenance, and utilization of new information. Memory can be distinguished into two types: short-term memory and long-term memory. One part of short-term memory is the working memory. All the function takes place in human brain which requires large amount of energy which came from glucose degradation of daily food. A recent study shows there is no effect of fasting on cognitive function of university student, but there is no current data about teenager. So, the objective of this research is to find whether fasting influences performance on memory task of teenager. Sequential Probe Delayed Matching to Sample (SPDMS) task was selected as a memory task, which subjects was ordered to perform a test in two conditions: fasting and no fasting. Data was analyzed by ANOVA implemented in R statistical program. The result shows that fasting affected working memory task. Task performances got better under fasting condition, possibly because the effect of stress on subjects performances. There were also influences from sex difference due to male’s brain advantage in spatial skill which is necessary for SPDMS task. Learning process from previous session also gave influence, but the effect was small. It is due to the efficiency of human brain to study about new information. In conclusion, fasting was the main factor influencing working memory task, while session and sex difference gave only small.

ABSTRAK

RAJA ARIA OCTIVANO. Efek dari Puasa Senin-Kamis terhadap Fungsi Kognitif Remaja. Dibimbing oleh BAMBANG SURYOBROTO dan AKICHIKA MIKAMI.

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ON COGNITIVE FUNCTION OF TEENAGER

Raja Aria Octivano

G3413041

Minithesis

To obtain Bachelor’s of Science

In

Department of Biology

DEPARTMENT OF BIOLOGY

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Title : Effect of Monday-Thursday Fasting on Cognitive Function of Teenager Name : Raja Aria Octivano

NRP : G34103041

Approved:

Advisor 1 Advisor 2

Dr. Bambang Suryobroto Prof. Dr. Akichika Mikami

NIP 131779503

Endorsed by:

Dean Faculty of Mathematic and Natural Sciences Bogor Agricultural University

Dr. drh. Hasim, DEA.

NIP 131578806

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Praise the God for all kindness and benevolence, this minithesis is finally done.

People usually think fasting is a kind of activity that limits your body. Especially for people who think if you don’t eat, you will have no power for your activity. Is this kind of think true? What about Muslim people who perform fasting regularly? That is the purpose of this research, to find whether fasting is truly a bad activity for your body, or the opposite, brings a good effect for you.

Writer acknowledgments send to Dr. Bambang Suryobroto and Prof. Dr. Akichika Mikami, MD as writer’s advisors. Also deepest gratitude to Dra. Taruni Sri Prawasti, Dr.Ir. Achmad Farajallah, M.Si, Dr. Ir. Diah Perwitasari, M.Si, Dr. Ir. Rika Raffiudin, M.Si, Ir. Tri Heru, M.Si, Ir. Tri Atmowidi, M.si and all staff in Zoology laboratory for the support and kindness. To all my friends in Biology 40 who gave motivation and friendship. To Mr. Solay for all of your kindness, and all of my subjects for their participation and motivation. Writer’s acknowledgment especially send to Parent and my lovely “Queen” for their love, support, kindness, motivation, and their pray.

Hopefully, this minithesis could be useful.

Bogor, April 2008

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CURRICULUM VITAE

Writer was born in Jakarta on 11th October 1985 as the first child from parent, Djoko Hadi Tjiptanto and Ramayulis.

On 2003, writer graduated from SMU Labschool Rawamangun, Jakarta and entered the Department of Biology, Faculty of Mathematic and Natural Sciences, Bogor Agricultural University via ‘Undangan Saringan Masuk IPB’ (USMI).

On 2005, writer did field study at Situ Gunung, Sukabumi with “Effect of Light to Sellaginella Leaf Surface” as a title and related topic. Writer also did field work on 2006 at Taman Safari Indonesia Cisarua, Bogor with “Ex-Situ Conservation of Sumatran Tiger (Panthera tigris sumatrae) at Taman Safari Indonesia” as a title. On 2007 writers become assistant in practical class of Basic Biology, Animal Developing, and Animal Physiology.

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Page

LIST OF FIGURES ……….………. . VIII

LIST OF TABLES ………. VIII

LIST OF APPENDIX ……….……….. VIII

INTRODUCTION ………. 1

MATERIAL AND METHODS ...………. 1

Method ……… ……….…….. 1

Procedures ………..…. 2

Statistical Analytic ………..……….…… 2

RESULT ……….………... 2

Blood Glucose Level Measured………. 2

Highest Level Achieved ………...……. 2

Performance Achieved .………. 3

Reaction Time Attained ………. 3

DISCUSSION ..………..……….………. 4

CONCLUSION …... 4

REFERENCES……….…...……….. 4

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LIST OF FIGURES

Page

1 Scheme structures and procedures of DMTS task………..……… 1

2 Model of experiment...……… 2

3 Highest level achieved during fasting condition………. 2

4 Performance achieved from the 1st to 2nd session……… 3

5 Performance achieved during fasting condition……….……….. 3

6 Reaction time attained during fasting condition……… 3

LIST OF APPENDIX

Page

1 ANOVA tables of highest level achieved……….……… 6

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INTRODUCTION

Background

Cognitive function consists of many aspects, such as perception, learning, memory, reasoning, and speech (human) (Redmond 2006). It distincts from emotion and volition. Memory is a complex cognitive function that allows the recording, maintenance, and utilization of new information (Thompson 2005). Construction of memory consists of two separate stages: encoding and retrieval. Encoding refers to initial process of information that will potentially be stored as memory episodes. Retrieval refers to process that result from the encoded episodes (Buckner 1998). Based on the storage capacity, memory can be distinguished into two types: short-term and long-term systems. Short-term memory has a limited capacity and memory trace can spontaneously fade within seconds, while the long-term one has massive capacity and durability (Baddeley 1996).

One kind of short-term memory is the working memory. Working memory is the ability to hold an item of information transiently in mind in the service of comprehension, thinking, and planning. It serves as a workspace for holding items and information in mind as they are recalled, manipulated, and / or associated to other ideas and incoming information (Goldman 1996).

Cognitive function is processed in brain. Brain is only a small part of our body, but consumes large amount of energy. It uses about 20% of total body energy in order to perform cognitive and other tasks. This energy comes from glucose degradation (Benton 1998). The brain uses glucose almost exclusively for its energy needs and requires continual supply of this sugar for normal function (Frissel 1990). An overnight and morning fast could lower the brain function such as has been shown for the lowering of memory process and attention level of school children (Pollit 1998). On the opposite, there is evidence that short-term food deprivation has little or no effect on cognitive function (Green 1995). The deficits of cognitive function associated with spontaneous dieting are not due to any direct physiological or nutritional effect. Instead, psychological effect of this condition might be more important.

1500ms blank 1500ms blank 1500ms stimulus 1 1050ms indicator l <5000ms 8 stimuli <5000ms matching

Monday-Thursday fasting (MTFast) is a religious and cultural fasting that is performed by Indonesian people, including teenagers. MTFast provides a model of how caloric restriction influences performance on memory task.

Erlangga (2006) showed that visual and spatial working memory of university students didn’t affected by this kind of fasting. All of the subjects had study experience for 14 years or more, so generally they are highly intelligence. In average, they could reach high performance on working memory task. Both sex (male and female) had a same performance on memory task. On the other hand, learning process was found as a primary factor influencing the memory task performance. Currently there is no data for memory task performance of younger people, such as teenager in junior high school. In this research, I will show you the positive effect of MTFast on working memory of teenager.

Objective

To find whether MTFast influences performance on memory task of teenager.

MATERIAL AND METHODS

Place and Time

Research was done from March 2007 until February 2008. Primary data collection was taken at junior high schools in Jakarta. Data analysis was done at Section of Biosysthematics and Ecology of Animals, Department of Biology, Faculty of Mathematics and Nature Sciences Bogor Agricultural University.

Method

Working memory involves spatial, phonological and somatosensory memories (Baddeley 1996). In this research, visual and spatial memories are the primary basic for Sequential Probe Delayed Matching to Sample (SPDMS) task. This task means the subject must choose the right stimulus, on the right order, after a short delay (Elliot 1999). Stimuli were presented as pictures of irregular shapes. The scheme of SPDMS task can be seen in Figure 1.

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2

First, a blank screen appears on the screen. The subject must press the mouse for about 1500 milliseconds (ms), then a picture of random shape appears in the center of the screen. At this point, the subject is still pressing the mouse and after 1500 ms, the picture disappears for about another 1500 ms. This1500 ms is the delay period. Then the picture will appear again, but this time, total of eight pictures of different shapes appears. At this point, the subject may release the mouse button, and then choose the picture they saw before. The subject has 5000 ms to answer, and the screen will displays green color indicating that they answer correctly. If they fail, the screen displays red color.

This task represents one trial and the subject must perform three successive trials correctly before advancing to the next level. Up to maximum of eight levels can be achieved and each level corresponds to the number of objects that have to be kept in memory (for instance, level two consists of two objects, level three consists three objects, etc). If they fail, the task downgraded one level. The model of experiment is shown in Figure 2. If the subject reaches the highest level 8 for three successive trials, the session was ended. Otherwise, the session would be ended after 60 trials at any current level.This represents one session.

Performance is measured by the highest-level attained, relative performance to highest-level 8, and mean response time to identify correct stimuli. Relative performance is a ratio between accumulated scores divided by maximum cumulative scores obtained without down gradations.

Procedure

Samples used on this research were 30 subjects consist of 15 males and 15 females of junior high school students of about 7-9 years of study with age ranges of 13-15 years old. Samples voluntary recruited from Al-Azhar Kemandoran and Labschool Rawamangun

Figure 2. Model of experiment

junior high school Jakarta. The assessments of memory task were done at 11.30 AM -15.00 PM at one isolated place free from distortion/noise. Previous study (Erlangga 2006) did six sessions for each subject. This method was increased the influence of learning effect. So, in this research each participant did only two sessions, one in fasting condition, and the other one in no fasting condition. Before doing memory task, all subjects answered questionnaires about whether the subject had breakfast or fasting; if so, they were asked to write the latest breakfast/lunch time.

Measurement of subject’s blood glucose level was done using Accu Chek Active blood glucose-counter. This device uses a tiny drop of peripheral blood on a test stripe, as a sample for measuring the level of the glucose spectrophotometrically. Blood glucose level was divided into 5 category based on their range; A:

≤80 mg/dl, B: 81-90 mg/dl, C: 91-100 mg/dl, D: 101-110 mg/dl, E: > 110 mg/dl.

Statistical Analysis

Performances such as highest level achieved, relative performance to level 8, and mean reaction time were assumed to be affected by subject’s condition (fasting or no-fasting), session (1st and 2nd ), sex (male or female), and blood glucose level (mg/dl). Analyses of variance were done in R statistical package program.

RESULT

Blood Glucose Level Measured

Average value of blood glucose level for all subject in no fasting condition was 97.9 mg/dl, while in fasting condition was 89.4 mg/dl. This value shows small degradation in fasting condition.

Highest Level Achieved of SPDMS Task

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Figure 3 shows an increasing result of highest level achieved during fasting condition. Mean of achieved level increased for both male and female.

The result of ANOVA between factors that possibly affecting highest level achieved shows that the value of Pr(>F) of fasting is 0.75 % and interaction of fasting and glucose is 9.4 % which is below 10% (see Appendix 1). This value indicates that fasting and glucose had the highest possibility of affecting the highest level achieved.

If we abandon sex and session, and retaining fasting and glucose value, we got fasting as the main factor affecting highest level achieved. However, comparison of both models show that they explained the data similarly (Appendix 1), so we may chose model 2 as the simpler one for further discussion.

Performance Achieved

Figure 4 and 5 show an increasing mean of performance according to sessions and conditions.

Figure 4. Performance achieved from the 1st to 2nd session.

Figure 5. Performance achieved during fasting condition.

Both factors were affecting performance achieved.

The result of ANOVA between factors that possibly affecting performance achieved shows that the value of Pr(>F) of fasting is 0.13% which is below 5% (see Appendix 2). This value indicates that fasting had the highest possibility to affect performance achieved.

If we abandon session, sex and glucose, and retaining fasting value, indeed we got fasting and session as the main factor affecting highest level achieved. Comparison showed that both model explained the data similarly (Appendix 2), so we may chose model 2 as the simpler one for further discussion.

Reaction Time

Figure 6 shows a decreasing mean of reaction time during fasting condition for male. Note there is a different slope for each sex. This means that the way male and female reacts under fasting or no fasting condition were different.

The result of ANOVA between factors that possibly affecting reaction time shows that the value of Pr(>F) of sex is 1.34% and fasting is 5.56%, and the value of sex and fasting interaction is 7.8% which is below 10% (see Appendix 3). This value indicates that sex and fasting had the highest possibility of affecting reaction time.

If we abandon session and glucose, and retaining fasting and sex value, indeed we got fasting as the main factor affecting reaction time. There was also a difference between male and female on reaction time attained. Comparison showed both model may explained the data similarly (Appendix 3), so we may chose model 2 as the simpler one for further discussion.

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In summary, result shows that there were significant effects of fasting on working memory task. Highest level achieved, performance achieved, and reaction time were affected by fasting condition. Session gave a small effect in performance, and sex also showed a small difference between male and female reaction time.

DISCUSSION

Glucose is the main metabolite of brain and working muscle. Homeostasis system in human body performs metabolic adaptation to maintain blood glucose level as constant as possible. During starvation, glucose will be synthesized from the glycerol product of triacylglycerol breakdown and the amino acids from the proteolytic degradation of proteins. Muscle is the major source for these materials. Measurements of peripheral blood glucose level in no fasting and fasting condition showed only small degradation that was still in a normal range. We may safely assume that glucose level in brain also in normal range. However, fasting is a form of stress in human.

Some study showed that human works better under certain psychological stress conditions (Bourne 2003). Besides, without any supply of food, digestion system will suspend their activity so they don’t require energy. This energy can be shifted to other system such as the neural system. Present research shows that, under the circumstances that nutrition level was not harmed, subjects achieved higher working memory performance while in fasting condition. Performances of working memory task were increased. They were shown by higher level achieved, influencing better performance attained for all subjects, and shorter reaction time for male.

Male had a significantly shorter reaction time under fasting condition, while female did not. This result came from the different way of male and female’s brain work. Male’s brain has better spatial ability than female (Pease 2001). Spatial skill is necessary in SPDMS task because the target objects appears in random position.

Session gave small influence in working memory task. Performance got better on the 2nd session, as a result of learning process carried over from the 1st session, so they became familiar and more efficient while doing the task. Previous study (Erlangga 2006) also showed that learning process was carried over affecting working memory task. So, from these facts we

found that human brain is easy and efficient for learning new information.

CONCLUSION

Fasting influences teenager’s visual and spatial memory task although learning process and sex difference modulate this effect.

REFERENCES

Baddeley A. 1996. The fractionation of working memory. Proc Natl Acad Sci 9:13468-13472.

Benton D, Parker PY. 1998. Breakfasts, blood glucose, and cognition. Am J Clin Nutr

67:772-781.

Bourne LE, Yaroush RA. 2003. Stress and cognition: a cognitive psychological perspective. USA: NASA

Buckner RL, Koutstaal W. 1998. Functional neuroimaging studies of encoding, priming, and explicit memory retrieval. Proc Natl Acd Sci. 95: 891-898.

Elliot R. 1999. Differential neural responses during performance of matching and nonmatching to sample tasks at two delay intervals. J Neuroscience 19(12):5066– 5073.

Erlangga D. 2006. Effect of Monday-Thursday fasting on cognitive function. Bogor: IPB Frissel WR. 1990. Human Biochemistry. USA:

Macmillan Publishing Co Inc.

Goldman PS. 1996. Regional and cellular fractionation of working memory. Proc Natl Acad Sci. 93:13473-13480.

Green MW, Elliman NA, Rogers PJ. 1995. Lack of effect of short-term fasting on cognitive function. J Psychiat Res 29(3): 245 253,

Pease B, Pease A. 2001. Why men don’t listen and women can’t read maps. Great Britain: Orion Publishing Group.

Pollit E, Jacoby E. 1998. Fasting and cognition in well and undernourished school children.

Am J Clin Nutr 67:779-812.

Redmond WA. 2006. Cognition. Microsoft Encarta [DVD]. Microsoft Corporation, 2005.

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Appendix 1. ANOVA tables of highest level achieved.

Model 1. ANOVA result of how fasting, sex, session and glucose influence to highest level achieved.

Df Sum Sq. Mean Sq. F value Pr (>F)

Sex 1 0.150 0.150 0.0984 75.55% NS

Fasting 1 12.150 12.150 7.9683 0.75% *

Session 1 0.171 0.171 0.1124 73.92% NS

Glucose 4 2.161 0.540 0.3543 83.95% NS

Sex : Fasting 1 0.141 0.141 0.0927 76.23% NS

Fasting : Session 1 1.363 1.363 0.8941 35% NS

Sex : Glucose 4 3.162 0.791 0.5185 72.26% NS

Fasting : Glucose 4 13.077 3.269 2.1441 9.4% *

Session : Glucose 1 0.218 0.218 0.1427 70.77% NS

Sex : Fasting : Glucose 2 0.923 0.462 0.3027 74% NS

Residuals 39 59.467 1.525

Model 2. ANOVA result of fasting and glucose factors to highest level achieved.

Fasting 1 12.150 12.150 8.911 0.42% *

Glucose 4 2.245 0.561 0.4153 79.68% NS

Fasting : Glucose 4 11.022 2.755 2.0391 10.3% NS

Residuals 50 67.567 1.351

Comparison of each statistic models.

Model 1: Level ~ Sex * Fasting * Session * Glucose Model 2: Level ~ Fasting * Glucose

Res. Df RSS Df Sum of Sq F Pr(>F)

39 59.467

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Appendix 2. ANOVA tables of performance attained.

Model 1. ANOVA result of how fasting, sex, session and glucose influence to performance achieved.

Sex 1 134.4 134.4 0.7426 39.4% NS

Fasting 1 2176.8 2176.8 12.0277 0.13% *

Session 1 401.0 401.0 2.2158 14.5% NS

Glucose 4 112.7 28.2 0.1557 95.9% NS

Sex : Fasting 1 41.1 41.1 0.2268 63.6% NS

Fasting : Session 1 171.3 171.3 0.9464 33.7% NS

Sex : Glucose 4 437.9 109.5 0.6049 66.1% NS

Residuals 39 7058.4 181

Model 2. ANOVA result of fasting factors to performance achieved.

Fasting 1 2176.8 2176.8 12.953 0.06% *

Residuals 58 9747.1 168.1

Comparison of each statistic models

Model 1: Performance8 ~ Sex * Fasting * Session * Glucose Model 2: Performance8 ~ Fasting

Res.Df RSS Df Sum of Sq F Pr(>F) 39 7058.4

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Appendix 3. ANOVA tables of reaction time attained.

Model 1. ANOVA result of how fasting, sex, session and glucose influence to reaction time attained.

Sex 1 189282 189282 6.7153 1.34% *

Fasting 1 109739 109739 3.8933 5.56% *

Session 1 35503 35503 1.2596 26.86% NS

Glucose 4 81659 20415 0.7243 58.1% NS

Sex : Fasting 1 91786 91786 3.2564 7.8% *

Fasting : Session 1 1847 1847 0.0655 79.93% NS

Sex : Glucose 4 64740 16185 0.5742 68.3% NS

Fasting : Glucose 4 136351 34088 1.2094 32.24% NS

Session : Glucose 1 15457 15457 0.5484 46.34% NS

Sex : Fasting : Glucose 2 28697 14349 0.5091 60.5% NS

Residuals 39 1099278 28187

Table 6. ANOVA result of sex and fasting to reaction time attained.

Fasting 1 109739 109739 4.3711 4.1% *

Sex 1 189282 189282 7.5394 0.8% *

Fasting : Sex 1 149401 149401 5.9509 1.8% *

Residuals 56 1405917 25106

Analysis of Variance Table

Model 1: Reaction ~ Sex * Fasting * Session * Glucose Model 2: Reaction ~ Fasting * Sex

Res.Df RSS Df Sum of Sq F Pr(>F)

39 1099278

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Appendix 4. Subject data

Name Sex Fasting Session Glucose Level Performance Performance8 Reaction

A M yes 2 B 3 70.30 34.10 1261

A M no 1 E 3 56.30 27.30 1640

B M yes 2 A 5 81.30 59.10 1226

B M no 1 B 5 60.40 43.90 1467

C M yes 2 B 6 89.80 75.50 1405

C M no 1 B 5 76.70 55.80 1513

D M yes 2 E 5 69.10 50.30 1314

D M no 1 C 5 75.70 55.10 1637

E M no 1 C 2 66.90 23.50 1204

E M yes 2 B 4 52.10 31.80 1062

F M yes 2 D 4 71.10 43.40 1297

F M no 1 D 3 65.60 31.80 1539

G M no 1 B 5 46.90 34.10 1318

G M yes 2 C 6 75.40 63.40 1440

H M yes 2 B 4 68.60 41.90 1466

H M no 1 B 3 55.20 26.80 1594

I M no 1 C 3 59.90 29.00 1566

I M yes 2 B 5 75.30 54.80 1505

J M no 1 D 2 61.20 21.50 1629

J M yes 2 A 2 64.70 22.90 1448

K M yes 2 A 6 75.10 63.10 1572

K M no 1 D 5 67.70 49.20 1977

L M yes 2 D 5 69.40 50.50 1569

L M no 1 D 4 52.90 32.30 1528

M M no 1 B 3 70.30 34.10 1696

M M yes 2 B 2 53.20 18.70 1329

N M yes 2 A 4 85.10 52.00 1384

N M no 1 E 3 67.70 32.80 1531

O M yes 2 C 3 53.60 26.00 1501

O M no 1 C 1 82.10 17.40 1720

O F yes 2 B 4 64.90 39.60 1454

O F no 1 B 3 62.50 30.30 1384

P F yes 2 B 5 67.00 48.70 1431

P F no 1 D 4 56.20 34.30 1356

Q F yes 2 A 3 64.60 31.30 1127

Q F no 1 C 3 61.50 21.80 1367

R F no 2 C 3 88.50 42.90 1168

R F yes 1 B 4 48.80 29.80 1356

S F yes 1 B 3 50.50 24.50 1448

S F no 2 D 3 53.60 26.00 1443

T F no 1 C 3 70.30 34.10 1447

T F yes 2 B 5 75.30 54.80 1449

U F no 1 B 5 50.30 30.60 1280

U F yes 2 D 5 78.80 57.30 1467

V F no 1 C 2 74.80 26.30 1275

V F yes 2 C 6 72.40 60.90 1536

W F no 1 B 3 50.50 24.50 1323

W F yes 2 A 5 75.30 54.80 1506

X F yes 2 D 5 87.80 63.90 1223

X F no 1 E 5 59.00 42.90 1291

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Y F yes 2 D 4 62.80 38.40 1458

Z F no 1 B 2 66.20 23.20 1566

Z F yes 2 A 2 63.30 22.20 1332

AA F no 1 B 3 52.60 25.50 1615

AA F yes 2 A 5 59.00 42.90 1597

AB F no 1 C 2 59.70 21.00 1291

AB F yes 2 B 3 53.60 26.00 1195

AC F yes 2 C 5 76.00 55.30 1012

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RAJA ARIA OCTIVANO

G34103041

DEPARTMENT OF BIOLOGY

(20)

ABSTRACT

RAJA ARIA OCTIVANO. Effect of Monday-Thursday Fasting on Cognitive Function of Teenager. Supervised by BAMBANG SURYOBROTO and AKICHIKA MIKAMI.

Cognitive function consists many aspects, one of them is memory. Memory is a complex cognitive function that allows the recording, maintenance, and utilization of new information. Memory can be distinguished into two types: short-term memory and long-term memory. One part of short-term memory is the working memory. All the function takes place in human brain which requires large amount of energy which came from glucose degradation of daily food. A recent study shows there is no effect of fasting on cognitive function of university student, but there is no current data about teenager. So, the objective of this research is to find whether fasting influences performance on memory task of teenager. Sequential Probe Delayed Matching to Sample (SPDMS) task was selected as a memory task, which subjects was ordered to perform a test in two conditions: fasting and no fasting. Data was analyzed by ANOVA implemented in R statistical program. The result shows that fasting affected working memory task. Task performances got better under fasting condition, possibly because the effect of stress on subjects performances. There were also influences from sex difference due to male’s brain advantage in spatial skill which is necessary for SPDMS task. Learning process from previous session also gave influence, but the effect was small. It is due to the efficiency of human brain to study about new information. In conclusion, fasting was the main factor influencing working memory task, while session and sex difference gave only small.

ABSTRAK

RAJA ARIA OCTIVANO. Efek dari Puasa Senin-Kamis terhadap Fungsi Kognitif Remaja. Dibimbing oleh BAMBANG SURYOBROTO dan AKICHIKA MIKAMI.

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INTRODUCTION

Background

Objective

MATERIAL AND METHODS

Place and Time

Method

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1

INTRODUCTION

Background

Objective

MATERIAL AND METHODS

Place and Time

Method

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Procedure

Statistical Analysis

RESULT

Blood Glucose Level Measured

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2

Procedure

Statistical Analysis

RESULT

Blood Glucose Level Measured

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Figure 3 shows an increasing result of highest level achieved during fasting condition. Mean of achieved level increased for both male and female.

The result of ANOVA between factors that possibly affecting highest level achieved shows that the value of Pr(>F) of fasting is 0.75 % and interaction of fasting and glucose is 9.4 % which is below 10% (see Appendix 1). This value indicates that fasting and glucose had the highest possibility of affecting the highest level achieved.

If we abandon sex and session, and retaining fasting and glucose value, we got fasting as the main factor affecting highest level achieved. However, comparison of both models show that they explained the data similarly (Appendix 1), so we may chose model 2 as the simpler one for further discussion.

Performance Achieved

Figure 4 and 5 show an increasing mean of performance according to sessions and conditions.

Figure 4. Performance achieved from the 1st to 2nd session.

Figure 5. Performance achieved during fasting condition.

Both factors were affecting performance achieved.

The result of ANOVA between factors that possibly affecting performance achieved shows that the value of Pr(>F) of fasting is 0.13% which is below 5% (see Appendix 2). This value indicates that fasting had the highest possibility to affect performance achieved.

If we abandon session, sex and glucose, and retaining fasting value, indeed we got fasting and session as the main factor affecting highest level achieved. Comparison showed that both model explained the data similarly (Appendix 2), so we may chose model 2 as the simpler one for further discussion.

Reaction Time

Figure 6 shows a decreasing mean of reaction time during fasting condition for male. Note there is a different slope for each sex. This means that the way male and female reacts under fasting or no fasting condition were different.

The result of ANOVA between factors that possibly affecting reaction time shows that the value of Pr(>F) of sex is 1.34% and fasting is 5.56%, and the value of sex and fasting interaction is 7.8% which is below 10% (see Appendix 3). This value indicates that sex and fasting had the highest possibility of affecting reaction time.

If we abandon session and glucose, and retaining fasting and sex value, indeed we got fasting as the main factor affecting reaction time. There was also a difference between male and female on reaction time attained. Comparison showed both model may explained the data similarly (Appendix 3), so we may chose model 2 as the simpler one for further discussion.

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DISCUSSION

CONCLUSION

REFERENCES

67:772-781.

Am J Clin Nutr 67:779-812.

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DISCUSSION

CONCLUSION

REFERENCES

67:772-781.

Am J Clin Nutr 67:779-812.

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DISCUSSION

CONCLUSION

REFERENCES

67:772-781.

Am J Clin Nutr 67:779-812.

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DISCUSSION

CONCLUSION

REFERENCES

67:772-781.

Am J Clin Nutr 67:779-812.

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Appendix 1. ANOVA tables of highest level achieved.

Model 1. ANOVA result of how fasting, sex, session and glucose influence to highest level achieved.

Sex 1 0.150 0.150 0.0984 75.55% NS

Fasting 1 12.150 12.150 7.9683 0.75% *

Session 1 0.171 0.171 0.1124 73.92% NS

Glucose 4 2.161 0.540 0.3543 83.95% NS

Sex : Fasting 1 0.141 0.141 0.0927 76.23% NS

Fasting : Session 1 1.363 1.363 0.8941 35% NS

Sex : Glucose 4 3.162 0.791 0.5185 72.26% NS

Fasting : Glucose 4 13.077 3.269 2.1441 9.4% *

Residuals 39 59.467 1.525

Model 2. ANOVA result of fasting and glucose factors to highest level achieved.

Fasting 1 12.150 12.150 8.911 0.42% *

Glucose 4 2.245 0.561 0.4153 79.68% NS

Residuals 50 67.567 1.351

Comparison of each statistic models.

Model 1: Level ~ Sex * Fasting * Session * Glucose Model 2: Level ~ Fasting * Glucose

Res. Df RSS Df Sum of Sq F Pr(>F)

39 59.467

(32)

7

Appendix 2. ANOVA tables of performance attained.

Model 1. ANOVA result of how fasting, sex, session and glucose influence to performance achieved.

Sex 1 134.4 134.4 0.7426 39.4% NS

Fasting 1 2176.8 2176.8 12.0277 0.13% *

Session 1 401.0 401.0 2.2158 14.5% NS

Glucose 4 112.7 28.2 0.1557 95.9% NS

Sex : Fasting 1 41.1 41.1 0.2268 63.6% NS

Fasting : Session 1 171.3 171.3 0.9464 33.7% NS

Sex : Glucose 4 437.9 109.5 0.6049 66.1% NS

Residuals 39 7058.4 181

Model 2. ANOVA result of fasting factors to performance achieved.

Fasting 1 2176.8 2176.8 12.953 0.06% *

Residuals 58 9747.1 168.1

Comparison of each statistic models

Model 1: Performance8 ~ Sex * Fasting * Session * Glucose Model 2: Performance8 ~ Fasting

Res.Df RSS Df Sum of Sq F Pr(>F) 39 7058.4

(33)

Appendix 3. ANOVA tables of reaction time attained.

Model 1. ANOVA result of how fasting, sex, session and glucose influence to reaction time attained.

Sex 1 189282 189282 6.7153 1.34% *

Fasting 1 109739 109739 3.8933 5.56% *

Session 1 35503 35503 1.2596 26.86% NS

Glucose 4 81659 20415 0.7243 58.1% NS

Sex : Fasting 1 91786 91786 3.2564 7.8% *

Fasting : Session 1 1847 1847 0.0655 79.93% NS

Sex : Glucose 4 64740 16185 0.5742 68.3% NS

Fasting : Glucose 4 136351 34088 1.2094 32.24% NS

Session : Glucose 1 15457 15457 0.5484 46.34% NS

Sex : Fasting : Glucose 2 28697 14349 0.5091 60.5% NS

[image:33.612.68.503.127.320.2]

Residuals 39 1099278 28187

Table 6. ANOVA result of sex and fasting to reaction time attained.

Fasting 1 109739 109739 4.3711 4.1% *

Sex 1 189282 189282 7.5394 0.8% *

Fasting : Sex 1 149401 149401 5.9509 1.8% *

Residuals 56 1405917 25106

Analysis of Variance Table

Model 1: Reaction ~ Sex * Fasting * Session * Glucose Model 2: Reaction ~ Fasting * Sex

Res.Df RSS Df Sum of Sq F Pr(>F)

39 1099278

(34)

9

Appendix 4. Subject data

Name Sex Fasting Session Glucose Level Performance Performance8 Reaction

A M yes 2 B 3 70.30 34.10 1261

A M no 1 E 3 56.30 27.30 1640

B M yes 2 A 5 81.30 59.10 1226

B M no 1 B 5 60.40 43.90 1467

C M yes 2 B 6 89.80 75.50 1405

C M no 1 B 5 76.70 55.80 1513

D M yes 2 E 5 69.10 50.30 1314

D M no 1 C 5 75.70 55.10 1637

E M no 1 C 2 66.90 23.50 1204

E M yes 2 B 4 52.10 31.80 1062

F M yes 2 D 4 71.10 43.40 1297

F M no 1 D 3 65.60 31.80 1539

G M no 1 B 5 46.90 34.10 1318

G M yes 2 C 6 75.40 63.40 1440

H M yes 2 B 4 68.60 41.90 1466

H M no 1 B 3 55.20 26.80 1594

I M no 1 C 3 59.90 29.00 1566

I M yes 2 B 5 75.30 54.80 1505

J M no 1 D 2 61.20 21.50 1629

J M yes 2 A 2 64.70 22.90 1448

K M yes 2 A 6 75.10 63.10 1572

K M no 1 D 5 67.70 49.20 1977

L M yes 2 D 5 69.40 50.50 1569

L M no 1 D 4 52.90 32.30 1528

M M no 1 B 3 70.30 34.10 1696

M M yes 2 B 2 53.20 18.70 1329

N M yes 2 A 4 85.10 52.00 1384

N M no 1 E 3 67.70 32.80 1531

O M yes 2 C 3 53.60 26.00 1501

O M no 1 C 1 82.10 17.40 1720

O F yes 2 B 4 64.90 39.60 1454

O F no 1 B 3 62.50 30.30 1384

P F yes 2 B 5 67.00 48.70 1431

P F no 1 D 4 56.20 34.30 1356

Q F yes 2 A 3 64.60 31.30 1127

Q F no 1 C 3 61.50 21.80 1367

R F no 2 C 3 88.50 42.90 1168

R F yes 1 B 4 48.80 29.80 1356

S F yes 1 B 3 50.50 24.50 1448

S F no 2 D 3 53.60 26.00 1443

T F no 1 C 3 70.30 34.10 1447

T F yes 2 B 5 75.30 54.80 1449

U F no 1 B 5 50.30 30.60 1280

U F yes 2 D 5 78.80 57.30 1467

V F no 1 C 2 74.80 26.30 1275

V F yes 2 C 6 72.40 60.90 1536

W F no 1 B 3 50.50 24.50 1323

W F yes 2 A 5 75.30 54.80 1506

X F yes 2 D 5 87.80 63.90 1223

X F no 1 E 5 59.00 42.90 1291

(35)

Y F yes 2 D 4 62.80 38.40 1458

Z F no 1 B 2 66.20 23.20 1566

Z F yes 2 A 2 63.30 22.20 1332

AA F no 1 B 3 52.60 25.50 1615

AA F yes 2 A 5 59.00 42.90 1597

AB F no 1 C 2 59.70 21.00 1291

AB F yes 2 B 3 53.60 26.00 1195

AC F yes 2 C 5 76.00 55.30 1012