Want something interesting to tell people about? Try this: a three-pound corpus of neurons, blood vessels, and various cells controls your entire body. It helps you move, learn, feel. It makes sure you’re alive by maintaining vital life processes (e.g. regular heartbeat, breathing), even as you sleep.
If you guessed it’s the brain, you guessed right. As one half of the Central Nervous System (CNS), the other being the spinal cord, the brain acts as the body’s ‘command centre’ that integrates and coordinates information to and from the other organs.
The brain is comprised of numerous subparts that work hand-in-hand, mainly: the cortex, the outermost brain cell layer where voluntary movements and thought processes originate; the basal ganglia, a group of nuclei principally responsible for motor control and coordinating messages between brain subdivisions; the brain stem, the connection between the brain and the spinal cord in charge of basic life functions; and the cerebellum, the key element of the hindbrain involved in balance and coordination.
Furthermore, the brain is commonly split into four lobes: the frontal lobe, for cognitive and motor functions, as well as language production; the parietal lobe, for processing information on sensations; the temporal lobe, for emotion, memory, hearing, and some facets of language; and the occipital lobe, for visual processes.
The CNS works together with the peripheral nervous system (PNS), which is comprised of neurons that run along the extremities and internal organs. The neurons send information from those parts, brings them to the CNS for processing, then carries out orders from the CNS back to the components of the PNS.
Now, let’s bring in alcohol.
While the entire body does feel effects from alcohol consumption, the CNS is more vulnerable than the other body systems. Since alcohol (specifically ethanol) can cross the blood-brain barrier that protects the organ from foreign substances, it is also able to directly affect the neurons in the brain. Once they touch each other, changes in the neurons result in behavioural changes as well.
Here, we’ll look further into which parts of the brain are impaired by alcohol, particularly those that play an important role in memory.
Alcohol and the Brain
As we’ve mentioned earlier, the brain is the body’s command centre that oversees most, if not all, bodily functions. More than 100 billion nerve cells could be found in the organ itself, each of them creating multiple connections. The neurons could either be damaged or ‘killed’ when they come into contact with alcohol.
Alcohol, depending on the amount consumed, can bring either stimulating or tranquilising effects. Regardless, the substance is still categorised as a depressant, meaning it causes the brain’s neurons less excited (as opposed to the ‘waking up’ effect of stimulants like caffeine) and would result to general disorientation.
Initial consumption makes the drinker less reserved and more ‘open’ or sociable. This is because one of the first areas that alcohol affects is behaviours regarding inhibition. As alcohol intake gradually increases, more indications of the brain slowing down become more evident. Some of these indications include reduced reaction time, weakened muscles, imprecise judgment, slurred speech, compromised vision, and hazy memory.
It should be noted, though, that the exact range of delayed brain activity depends on an assortment of dynamics. Genetics, history of substance use/abuse, and amount consumed should be considered.
The Hippocampus and the Effects of Alcohol on Memory
Found in the temporal lobe and both hemispheres of the brain, the hippocampus is the component responsible for memory functions, from short-term to long-term, as well as spatial, declarative, and episodic memories.
Once alcohol enters the system, hippocampal neuronal activities are inhibited, leading to the impairment of memory formation, encoding, and retrieval. Alcohol markedly damages the encoding of episodic memory, which pertains to time-specific and personal events. What’s commonly known as a “blackout” due to high alcohol consumption is a great example of troubles in episodic memory encoding. It is said to be instigated by a hasty upsurge in the concentration of blood alcohol, which results in alterations in the hippocampus’ ability to build new episodic memories.
Encoding and storing new semantic memories (those that refer to cumulatively acquired general world knowledge) are disrupted, but previously learned data are apparently untouched. Short-term or working memory is impaired by alcohol as well. However, the substance mainly affects certain executive functions and mnemonic schemes, rather than reducing the working memory’s basic retaining capability.
Light to moderate drinking is not said to have long-term negative implications on cognitive functioning. In contrast, alcohol abuse, heavy drinking, and/or chronic alcoholism are linked to lasting damage in visual working memory and constant attention.
On a more serious note, over-consumption of alcohol, when combined with the ingestion of other significant food types, can lead to Korsakoff’s syndrome, a more severe form of amnesia brought about by a thiamine deficiency.
Memory creation and retention enable our future selves to go back to whatever we have experienced in the past or the present. It gives us the power to recall previously learned information and encode new ones. However, the toxicity that alcohol brings to the human body dampens this ability immensely. As with every harmful substance, alcohol could cause irreversible effects to our bodies, especially to the brain. Remember to always take the proper precautions whenever you engage in any kind of drinking. Once the alcohol kicks in, your brain may not be able to remember everything that happened when you drank, but the physiological effects will be inevitable.