Fish Fertilize Trees
By Maya C. Lemaire
2018
2018
Nostalgia - How it affects your brain
Do you ever suddenly find yourself longing and yearning for the past? Or perhaps listening to music and being reminded of the ‘good times’ in your childhood? Derived from the Greek term ‘Nostos’ meaning homecoming and ‘Algos’ for longing; Nostalgia, as defined by the Cambridge Dictionary, is ‘a feeling of pleasure and also slight sadness when you think about things that happened in the past’ . In the 17th century, nostalgia was deemed an illness, confined to specific groups, particularly in Swiss mercenaries serving abroad. Today, nostalgia is often associated with reminiscing and many people consider it to be heart-warming; nostalgic feelings are often triggered by sensory stimuli as well as other reminders of the past, for example old pictures. But how exactly does nostalgia work?
Though it is unclear, scientists have theorised that nostalgia is very likely associated with how memories and emotions are stored in the brain. Two separate stages of memory storage include short-term memory and long-term memory. Short-term memory, also known as active memory, refers to the processes of storing, organising, and manipulating memories temporarily (such as where you’ve placed your keys or your phone), therefore, many short-term memories are easily forgotten. On the other hand, long-term memory is responsible for the continuous storage of information, such as people’s names, that can be called easily into working memory. Furthermore, consolidation - a process that moves your long-term memory via neurotransmitters to a deep part of the cranial cavity of the brain called the hippocampus - forms connections between nerve cells that ensure the stability of long-term storage. However, at times of heightened or intense emotions, the imprint and storage of these memories is much more vigorous, possibly because of the secretions of neurotransmitters and hormones at that moment. American neuroscientist, Joseph LeDoux, believes that what is known as ‘flashbulb memory’, a vivid recollection or as sometimes referred to as a ‘snapshot’ of an event concerning consequential matters, may be closely related to this process of mentally imprinting an event as similar to nostalgia, flashbulb memories link emotions to personal memories of an individual. NYU psychologist Elizabeth Phelps carried out scans of people’s brains in 2007 as they recollected specific events and discovered that the amygdala, a part of the brain where emotions are processed, was lit up.
In addition, the limbic system, consisting of the hippocampus and amygdala, is involved in processing and storing memories (in the hippocampus) and emotions (in the amygdala), including those of specific memories; a result of a memory stored during an emotional state. Nostalgic experiences stimulate blood flow and metabolic activity throughout multiple regions of the brain, most notably in the frontal, limbic, paralimbic, and midbrain areas.
It has been proven that greater surges of activity in the inferior frontal gyrus, substantia nigra and cerebellum and insula are experienced in those who listen to music. This induces nostalgic feelings since music stimulates the prefrontal cortex of our brains, thereby creating memories, and triggers the front striatal cortex which releases dopamine and other pleasure-inducing neurotransmitters. It is speculated that during the period of young adulthood and adolescence, emotional memories are at their peak and are strongly associated with nostalgia due to the properties present in the adolescent brain, which forms strong emotional connections. The surplus of pubertal hormones experienced during this period of our life establishes emotional memory as well as heightening it. Therefore, neural activity activated due to songs and music results in the release of dopamine and other ‘feel-good chemicals’ of which its effect is greater between the ages of 12 and 22.
Nostalgia may also be induced by tastes and smell, as our taste buds can carry messages through neural pathways leading to the limbic system and the cerebral cortex. The limbic system is vital in memory formation and emotional states while the frontal cerebral cortex is responsible for processes such as thought processes and conscious identification of messages. Moreover, after entering the nose, scents and smells travel through the cranial nerve and the olfactory bulb (a structure, part of the limbic system, which aids the brain in processing smells). The olfactory bulb has easy access due to a direct link into the amygdala, so the relationship between the amygdala and the olfactory bulb is potentially a significant reason why scents evoke nostalgia.
Despite past assumptions that nostalgia is a destructive disorder which signified that one was unable to let go of the past, nostalgia is now seen as a mostly pleasure-inducing and comforting phenomenon despite sometimes including feelings of heartache.
By Phisira (Paengrum) Chatchupong (Year 11 Student at Bangkok Patana School)
Bibliography:
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Image source: https://ysjournal.com/the-emotional-brain/