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You’ve woken up in an unfamiliar room, stains on your clothes and one ripped knee of your pants. Your ID is missing, along with your room key, the only thing you remember is that last round of shots you took last night. You’re experiencing the common phenomenon known as a blackout, but what does that actually mean?
There are two distinguishable forms of alcohol-induced amnesia, en bloc and fragmentary. En bloc is an episode of permanent memory loss caused by intoxicating events. Fragmentary episodes, also known as “brownouts”, are temporary instances of memory loss, that can typically be retrieved through clues. These periods of memory loss are “anterograde,” meaning that while intoxicated, the person is unable to establish new memories, but can recall memories made before the point of intoxication. Both types are due to a neurophysiological disruption in the hippocampus, a region of the brain in charge of memory formation.
According to the Modal Model of Memory, originally proposed in 1968 by Atkinson and Shiffrin, there are three stages to memory formation. When one experiences sensory information, it is quickly transferred from sensory memory to short–term memory. This stage can last from seconds to minutes (depending on the amount of rehearsal), before it is transferred to long–term storage. Alcohol can influence all three stages of the Modal Model to some degree, but it has the largest impact on the transfer of information from short–term to long–term. While intoxicated, subjects can recall immediate or current information and keep it in short–term memory for 1 minute or more, if not being distracted. However, subjects with higher levels of alcohol begin to show impairments in the ability to transfer memories into long–term storage.
National Institute on Alcohol Abuse and Alcoholism
According to a 2011 study, alcohol interferes with receptors located in the hippocampus. These receptors are responsible for transmitting glutamate, a compound that relays signals from neuron to neuron. Alcohol disables some neurons from working properly, while activating others. This interference causes neurons to form steroids that prevent the proper neuron interaction vital for long-term potentiation (LTP), an important process for memory formation.
“It takes a lot of alcohol to block LTP and memory,” said study researcher Charles Zorumski, of the Washington University School of Medicine in St. Louis. “The alcohol triggers these receptors to behave in seemingly contradictory ways, and that’s what actually blocks the neural signals that create memories. It also may explain why individuals who get highly intoxicated don’t remember what they did the night before.”
Researchers involved in the study exposed the brains of rats to different levels of alcohol. They didn’t detect any changes at low levels in the cells’ interaction. However, at fairly large levels, affects in the rats’ ability to form memories became apparent. The researchers were able to yield the steroid-making process with prostate-reduction drugs, and observed that this allowed the rats to form memories, even at high alcohol levels.
Thus, when the cells of the brain are exposed to large amounts of alcohol they lose their ability to communicate with each other. These connections are essential for long-term potentiation. Therefore, according to LiveScience, “If the connections can’t be made, the memories of experiences can’t be saved.”
Now that we know the science behind those troublesome blackouts, is there anyway we can avoid possible episodes in the future? As in any alcohol related scenario, it is always wise to drink on a full stomach. According to studies, a blackout’s main catalyst is a dramatic increase in blood alcohol content. Therefore, one must pace themselves and keep track of the amount of alcohol they consume. The best way to avoid a blackout is to drink less and at a lower rate.
References:
Jackson, Jon. “What Happens To Your Brain When You Get Black-Out Drunk?” Gizmodo. Kinja, 22 Feb. 2013. Web. 16 Nov. 2014. <http://gizmodo.com/5977688/what-happens-to-your-brain-when-you-get-black-out-drunk>.
Welsh, Jennifer. “Alcohol’s Memory Impairment Not Due to ‘Killing Brain Cells'” LiveScience. Tech Media Network, 07 July 2011. Web. 16 Nov. 2014. <http://www.livescience.com/14952-alcohol-blackouts.html>.
White, Aaron M., Ph.D. “What Happened? Alcohol, Memory Blackouts, and the Brain.” What Happened? Alcohol, Memory Blackouts, and the Brain. National Institute on Alcohol Abuse and Alcoholism, July 2004. Web. 16 Nov. 2014. <http://pubs.niaaa.nih.gov/publications/arh27-2/186-196.htm>.
Hartzler, B., and K. Fromme. “Result Filters.” National Center for Biotechnology Information. U.S. National Library of Medicine, July 2003. Web. 16 Nov. 2014. <http://www.ncbi.nlm.nih.gov/pubmed/12921196>.
This is such a good topic to talk about because it is something that college students can relate to! At first while reading this blog I was thinking of different ways you could test levels of alcohol and memory, but then you posted the experiment with rats. I think this experiment is well done and is good evidence as to how someone could black out. I’m curious though as to if the size of the rats had an affect as to when their memory was impaired. It is difficult to determine an exact level of BAC when someone will start to forget because the size of a person makes a big difference when it comes to drinking. This article I found discusses how it doesn’t matter how many drinks you have had, and sometimes it could take more or less drinks than the last time.
http://www.hercampus.com/health/physical-health/blacking-out-why-it-s-more-dangerous-you-think
I always wondered why people don’t remember the events of the previous night if there was heavy drinking involved. I never thought it would affect the cells directly. But to be honest I never really thought into the scientific understanding of all of it. I had a perceived notion that alcohol just messes with the ability to remember what happens while intoxicated. But after reading your blog and having a rudimentary understanding of both biology and chemistry it makes sense what you are proposing. If the alcohol has a negative effect with the cells its comes in contact with in the brain than it makes sense that something bad would happen to you. We as human beings should be lucky that alcohol only effects our memory while intoxicated instead of messing with long term memory and short term memory while sober. That would be awful. This is a really interesting blog and it makes me want to do more research on alcohol and it’s effects on the brain.