Caffeine And Long Term Memory Essay
Psychology Report
The effect of caffeine on long-term memory
Introduction:
What is caffeine? Caffeine is one of the commonly consumed or most ingested stimulant or psychoactive substance in the world, known for it’s effect on vigilance and alertness level (A. Smith, 2002) or at least perceived to jolt our tired brains, when consumed in normal or moderate quantity. Caffeine is available to us from various sources like coffee, tea, cocoa, soft drinks and other such products. Caffeine is basically 1,3,7-trimethylxanthine (T. Brunye, 2010) and like any other stimulant tends to wear off easily. The body also tends to adapt to regular dosage of caffeine and so a higher dosage might be required to achieve the required effect. It takes about …show more content…
30-60 minutes for the caffeine to be absorbed into the body stream (A. Smith, 2002), so the effect might not be instantaneous, making what most people feel to be a refreshing kick start to their morning activities immediately after an Expresso almost impossible and imaginary, like a placebo. Similarly, a lot of other beliefs are there related to coffee, it being the most popular and biggest source of caffeine consumption in humans, like the caffeine-withdrawal symptoms, addictive nature, etc. and only some of these facts have been proved to be true with recent scientific experiments.
How does this work? In simple words, caffeine molecule impersonates a brain hormone called adenosine. Adenosine is produced by the neurons as they work and fire away and is responsible for the slow shut down process of the brain, basically sleep mode to help the brain cells rejuvenate but caffeine molecules get absorbed by the A1 adenosine receptors instead because of the similarity in their molecular structure and size. (DiSalvo, 2012). By blocking the adenosine receptors effectively but not activating them, caffeine interferes with the monitoring of adenosine and by keeping this in check, the natural neurotransmitters of the brain, the dopamine and glutamate, are free to perform their function as a natural stimulant and thereby we achieve the desired effect. Literature also shows that caffeine consumption activates the frontal lobes of the brains and these areas are responsible for short-term memory and attention (Koppelstaetter, 2005). Thus, caffeine can increase these functions in a person.
From various studies it is a well established fact that (1) Caffeine increases alertness and reduces fatigue in tiring business, for example- working at night, mundane daily chores that doesn't really require us to think (2) Caffeine improves performance on vigilance tasks and simple tasks that require sustained response. (A. Smith, 2002). This leaves us with leading questions about the effect of caffeine on memory as most of us usually end up with a cup of hot chocolate or steaming coffee on the night before the exams. Though it might help some people to stay awake, what effect does it have on our memory? Is caffeine a really good choice during study periods and cram sessions? And will it help us remember what we studied the previous night? Does drinking more coffee mean better chance of remembering our study materials the next day? Aim: The main purpose of this report is to understand the effects of caffeine on memory by studying, analyzing and comparing experiments, thereby gaining a critical and analytical understanding on this topic.
In most of the above-mentioned studies, caffeine was administered before the study, thus making it hard to separate the memory factor out of the equation. However a recently published paper in the journal of Nature Neuroscience talks about the “Post-study caffeine administration enhances memory consolidation in humans”. A quick review of this article tells us that they used a post-study design where effects of certain agents on memory consolidation are optimally detected after the learning experience using a behavioral discrimination task (M.A.Yassa, 2014) and it is found that caffeine enhanced performance 24 h after administration. The conclusion of this experiment was that caffeine enhanced consolidation of long-term memories in humans. Amusingly there was also another published research paper that states that long-term consumption of low doses of caffeine slowed the functions of hippocampus. This area in the brain is responsible for long-term memory and learning. The authors concluded that although caffeine might improve person's alertness for a short period of time, it actually slows down the learning and memory by decreasing the function of hippocampus. ( Dr.Han Me, 2007 ). So as of now we have two extremely different views and which one of them is correct? To solve this dilemma, we need to check and evaluate the experimental method of the chosen experiments.
Experiment 1:
Does caffeine enhance consolidation of long-term memories in humans?
Method:
This experiment was conducted by randomized, double-blind, placebo-controlled trial in caffeine-naive participants. On day 1, participants studied images of objects, then received either 200 mg of caffeine or placebo. Salivary samples at baseline and 1 h, 3 h and 24 h after administration of caffeine or placebo to quantify caffeine metabolites were collected. Twenty-four hours after the study session, participants were asked to recognize picture from targets, similar lures and foils(new pictures).
Construct Validity:
Here the construct validity is not strong because though the word long-term is used, the experiment was just conducted 24 hours later and not after that.
So the term long term consolidation and discrimination wasn't used in a very clear way and could be interpreted differently by different people. Internal Validity:
The relation between the conclusion and the experimental values are pretty strong and hence internal validity holds true. Results from the picture discrimination task. (M.A.Yassa, 2014)
Independent Variables:
Identification of targets, foils and lures and classifying them as old, new and similar, in two groups, one the control group who where given placebo, and the other group under the influence of caffeine.
Dependent variable:
The dependent variable in this case is the response received from both the groups. They could have also recorded the deliberation time to give an in depth understanding on the level of attentiveness, but it isn’t really required for this experiment as we are concentrating more on the memory and consolidation factor.
Part 2: Another part of this experiment studied the effect of different dosage on
consolidation.
Impact of caffeine on consolidation and variable dose effects.
Discrimination as a function of indicated caffeine dose. (M.A.Yassa, 2014)
Independent Variable: Caffeine dosage
Dependent Variable: Lure Discrimination Index(LDI)
External validity:
The results can be generalized only up to a certain extend because the period of experimentation was only 24 hours, which cannot be recognized as a long term memory. Also we have to keep in mind that the participants were caffeine naïve before and the dosage can also have different effects on people according to their metabolism, BMI and other such factors. Another limitation is that they subjects were aware that they were part of an experiment based on caffeine, leading to more alertness while studying the picture. People tend to have this idea of what caffeine does to them and most of the time picture and project these effects by themselves, rather than the drug doing it for them. Experiment 2: Does long-term consumption of low dose caffeine slow hippocampus-dependent learning and impair long-term memory? Method:
Rats were fed caffeinated water and along with a control group of rats, trained to be able to reach a hidden platform and the resulting data were compared. This experiment was carried over a period of four weeks to ensure long-term results. However, caffeine-fed rats performed significantly worse than control rats on the week 2 and week 3 probe trials. (M.E. Han, 2007)
Effects of long-term caffeine consumption on learning and memory
Construct Validity:
Construct validity holds true for this experiment as the operational definition reflect the true theoretical meaning of the variable. We are interested in knowing if caffeine consumption has any effect on learning and memory and this experiment does that exactly by training the rats and checking over the trial period if they are able to remember the pathway and how long it takes for them to do so. Internal validity:
This also hold true because we can draw strong conclusion from the data. Though the experiment has been carried out in rats, the established similarity in the brains of humans and the trial animals give us the window to overlook this fact. External Validity:
The question that could be raised here is whether the learning and memory level of rats the same as that of humans. Though clear and in-depth study has been conducted over brain cell activities, the fact that this experiment hasn't been conducted and proven with human participants could be a slight drawback. Also, this experiment has been conducted only for low caffeine dosage and therefore cannot be generalized for moderate and high dosage.
Comparison and conclusion:
From analyzing the above experiments, we find that o Caffeine can improve memory in caffeine naïve subjects but this effect is not long term (up to 24 hours). In fact the latter study proved that long-term consumption of caffeine could impair memory. o To answer our previous question, yes, Caffeine might help us stay alert and remember things for over a period up to 24 hours but we should deal regular consumption of caffeine more carefully as it could have adverse effect because of the inhibition of neurogenesis in the hippocampus, which is basically the center for memory and learning. o High dosage of caffeine doesn't necessarily mean a higher level of consolidation. In fact, it works very differently with the best chance of retaining our memory within 24 hours, will be to ingest an optimal level of caffeine instead of high dose.
Reference and citations:
➢ M.A.Yassa, et. al, “Post-study caffeine administration enhances memory consolidation in humans”, Nature Neuroscience, January 2014.
➢ T.Brunye, et. al, “Caffeine modulates attention network function”, Brain and Cognition, Volume 72, Issue 2, March 2010, Pages 181–188.
➢ T.Brunye, et. al, “Acute caffeine consumption enhances the executive control of visual attention in habitual consumers”, Brain and Cognition, Volume 74, Issue 3, December 2010, Pages 186–192.
➢ A. Smith, “Effects of caffeine on human behavior”, Food and Chemical Toxicology 40 (2002).
➢ M.E.Han, et. al, “Inhibitory effects of caffeine on hippocampal neurogenesis and function”, Biochemical and Biophysical Research Communications, Volume 356, Issue 4, 18 May 2007, Pages 976–980.
The effect of caffeine on long-term memory
Introduction:
What is caffeine? Caffeine is one of the commonly consumed or most ingested stimulant or psychoactive substance in the world, known for it’s effect on vigilance and alertness level (A. Smith, 2002) or at least perceived to jolt our tired brains, when consumed in normal or moderate quantity. Caffeine is available to us from various sources like coffee, tea, cocoa, soft drinks and other such products. Caffeine is basically 1,3,7-trimethylxanthine (T. Brunye, 2010) and like any other stimulant tends to wear off easily. The body also tends to adapt to regular dosage of caffeine and so a higher dosage might be required to achieve the required effect. It takes about …show more content…
30-60 minutes for the caffeine to be absorbed into the body stream (A. Smith, 2002), so the effect might not be instantaneous, making what most people feel to be a refreshing kick start to their morning activities immediately after an Expresso almost impossible and imaginary, like a placebo. Similarly, a lot of other beliefs are there related to coffee, it being the most popular and biggest source of caffeine consumption in humans, like the caffeine-withdrawal symptoms, addictive nature, etc. and only some of these facts have been proved to be true with recent scientific experiments.
How does this work? In simple words, caffeine molecule impersonates a brain hormone called adenosine. Adenosine is produced by the neurons as they work and fire away and is responsible for the slow shut down process of the brain, basically sleep mode to help the brain cells rejuvenate but caffeine molecules get absorbed by the A1 adenosine receptors instead because of the similarity in their molecular structure and size. (DiSalvo, 2012). By blocking the adenosine receptors effectively but not activating them, caffeine interferes with the monitoring of adenosine and by keeping this in check, the natural neurotransmitters of the brain, the dopamine and glutamate, are free to perform their function as a natural stimulant and thereby we achieve the desired effect. Literature also shows that caffeine consumption activates the frontal lobes of the brains and these areas are responsible for short-term memory and attention (Koppelstaetter, 2005). Thus, caffeine can increase these functions in a person.
From various studies it is a well established fact that (1) Caffeine increases alertness and reduces fatigue in tiring business, for example- working at night, mundane daily chores that doesn't really require us to think (2) Caffeine improves performance on vigilance tasks and simple tasks that require sustained response. (A. Smith, 2002). This leaves us with leading questions about the effect of caffeine on memory as most of us usually end up with a cup of hot chocolate or steaming coffee on the night before the exams. Though it might help some people to stay awake, what effect does it have on our memory? Is caffeine a really good choice during study periods and cram sessions? And will it help us remember what we studied the previous night? Does drinking more coffee mean better chance of remembering our study materials the next day? Aim: The main purpose of this report is to understand the effects of caffeine on memory by studying, analyzing and comparing experiments, thereby gaining a critical and analytical understanding on this topic.
In most of the above-mentioned studies, caffeine was administered before the study, thus making it hard to separate the memory factor out of the equation. However a recently published paper in the journal of Nature Neuroscience talks about the “Post-study caffeine administration enhances memory consolidation in humans”. A quick review of this article tells us that they used a post-study design where effects of certain agents on memory consolidation are optimally detected after the learning experience using a behavioral discrimination task (M.A.Yassa, 2014) and it is found that caffeine enhanced performance 24 h after administration. The conclusion of this experiment was that caffeine enhanced consolidation of long-term memories in humans. Amusingly there was also another published research paper that states that long-term consumption of low doses of caffeine slowed the functions of hippocampus. This area in the brain is responsible for long-term memory and learning. The authors concluded that although caffeine might improve person's alertness for a short period of time, it actually slows down the learning and memory by decreasing the function of hippocampus. ( Dr.Han Me, 2007 ). So as of now we have two extremely different views and which one of them is correct? To solve this dilemma, we need to check and evaluate the experimental method of the chosen experiments.
Experiment 1:
Does caffeine enhance consolidation of long-term memories in humans?
Method:
This experiment was conducted by randomized, double-blind, placebo-controlled trial in caffeine-naive participants. On day 1, participants studied images of objects, then received either 200 mg of caffeine or placebo. Salivary samples at baseline and 1 h, 3 h and 24 h after administration of caffeine or placebo to quantify caffeine metabolites were collected. Twenty-four hours after the study session, participants were asked to recognize picture from targets, similar lures and foils(new pictures).
Construct Validity:
Here the construct validity is not strong because though the word long-term is used, the experiment was just conducted 24 hours later and not after that.
So the term long term consolidation and discrimination wasn't used in a very clear way and could be interpreted differently by different people. Internal Validity:
The relation between the conclusion and the experimental values are pretty strong and hence internal validity holds true. Results from the picture discrimination task. (M.A.Yassa, 2014)
Independent Variables:
Identification of targets, foils and lures and classifying them as old, new and similar, in two groups, one the control group who where given placebo, and the other group under the influence of caffeine.
Dependent variable:
The dependent variable in this case is the response received from both the groups. They could have also recorded the deliberation time to give an in depth understanding on the level of attentiveness, but it isn’t really required for this experiment as we are concentrating more on the memory and consolidation factor.
Part 2: Another part of this experiment studied the effect of different dosage on
consolidation.
Impact of caffeine on consolidation and variable dose effects.
Discrimination as a function of indicated caffeine dose. (M.A.Yassa, 2014)
Independent Variable: Caffeine dosage
Dependent Variable: Lure Discrimination Index(LDI)
External validity:
The results can be generalized only up to a certain extend because the period of experimentation was only 24 hours, which cannot be recognized as a long term memory. Also we have to keep in mind that the participants were caffeine naïve before and the dosage can also have different effects on people according to their metabolism, BMI and other such factors. Another limitation is that they subjects were aware that they were part of an experiment based on caffeine, leading to more alertness while studying the picture. People tend to have this idea of what caffeine does to them and most of the time picture and project these effects by themselves, rather than the drug doing it for them. Experiment 2: Does long-term consumption of low dose caffeine slow hippocampus-dependent learning and impair long-term memory? Method:
Rats were fed caffeinated water and along with a control group of rats, trained to be able to reach a hidden platform and the resulting data were compared. This experiment was carried over a period of four weeks to ensure long-term results. However, caffeine-fed rats performed significantly worse than control rats on the week 2 and week 3 probe trials. (M.E. Han, 2007)
Effects of long-term caffeine consumption on learning and memory
Construct Validity:
Construct validity holds true for this experiment as the operational definition reflect the true theoretical meaning of the variable. We are interested in knowing if caffeine consumption has any effect on learning and memory and this experiment does that exactly by training the rats and checking over the trial period if they are able to remember the pathway and how long it takes for them to do so. Internal validity:
This also hold true because we can draw strong conclusion from the data. Though the experiment has been carried out in rats, the established similarity in the brains of humans and the trial animals give us the window to overlook this fact. External Validity:
The question that could be raised here is whether the learning and memory level of rats the same as that of humans. Though clear and in-depth study has been conducted over brain cell activities, the fact that this experiment hasn't been conducted and proven with human participants could be a slight drawback. Also, this experiment has been conducted only for low caffeine dosage and therefore cannot be generalized for moderate and high dosage.
Comparison and conclusion:
From analyzing the above experiments, we find that o Caffeine can improve memory in caffeine naïve subjects but this effect is not long term (up to 24 hours). In fact the latter study proved that long-term consumption of caffeine could impair memory. o To answer our previous question, yes, Caffeine might help us stay alert and remember things for over a period up to 24 hours but we should deal regular consumption of caffeine more carefully as it could have adverse effect because of the inhibition of neurogenesis in the hippocampus, which is basically the center for memory and learning. o High dosage of caffeine doesn't necessarily mean a higher level of consolidation. In fact, it works very differently with the best chance of retaining our memory within 24 hours, will be to ingest an optimal level of caffeine instead of high dose.
Reference and citations:
➢ M.A.Yassa, et. al, “Post-study caffeine administration enhances memory consolidation in humans”, Nature Neuroscience, January 2014.
➢ T.Brunye, et. al, “Caffeine modulates attention network function”, Brain and Cognition, Volume 72, Issue 2, March 2010, Pages 181–188.
➢ T.Brunye, et. al, “Acute caffeine consumption enhances the executive control of visual attention in habitual consumers”, Brain and Cognition, Volume 74, Issue 3, December 2010, Pages 186–192.
➢ A. Smith, “Effects of caffeine on human behavior”, Food and Chemical Toxicology 40 (2002).
➢ M.E.Han, et. al, “Inhibitory effects of caffeine on hippocampal neurogenesis and function”, Biochemical and Biophysical Research Communications, Volume 356, Issue 4, 18 May 2007, Pages 976–980.