Neuroscience of the Lonely Brain

Mandated curfews, lockdowns, and isolation periods - with the resurgence of COVID-19 cases around the world over the past two years, the implementation of various infection control measures have exacerbated the mental wellbeing of the global population at a remarkable scale [1]. Historically, communicable diseases and their transmission from an affected patient to unaffected individuals have accelerated the development of preventative infection control with an unspoken acknowledgement of its repercussions for long-term mental health outcomes. For many, celebrating the holiday season this year has been a conspicuous anomaly: in fact, the inability to meaningfully reconnect with family and friends has coerced 18% of Americans to feel as if they have severed closely held social connections in their life, catalyzing what many scientists have characterized as the “Double Pandemic” [2]. 

Throughout human evolution, interpersonal dependency has manifested itself as a salient component of flourishing social relationships, and ultimately, as a pervasive modulator of cognition, life expectancy, and in some estimates, even the emergence of senescence-related neurodegenerative disorders [3]. Therefore, it may not be surprising to reconcile why the very perception of loneliness sufficiently casts a menacing shadow over the unique neural patterning signatures associated with selection pressures for sociality [4]. The nature of social exchange is a sophisticated one; encompassing higher-order neurocognitive mechanisms which allow an agent to synthesize coherent thoughts and intentions. 

Recently, however, a compelling study conducted by neuroscience researchers at McGill University has advanced some more nuanced insight into the neural correlates for unmet desires for social interactions in humans, suggesting a link with the evolution of higher-order associative cortical regions and their biological profiles. The multi-modal imaging-genetics cohort, organized by the UK BioBank initiative and constituted by 40,000 adults, elucidated how lonely individuals exhibit greater volumes of gray and distinct white matter structure, in addition to increased functional connectivity in brain regions dedicated to wakeful rest, or default mode networks (DMNs) [5]. 

Default networks, by definition, is a term used to describe a collection of several brain regions that are engaged when focus is diverted to contemplating tasks beyond the real world [6]. Conversely, it might be convenient to consider DMNs as active during periods of idled existence - whether that's daydreaming of the alternatives, resmicing over the past, or refining your expectations for the future. Implicated in the mental representation of the self and other social agents across space and time, simulating for intentions, identities, and motivations [7]. In the study, chronic abstention from intimate social connections was deemed as a significant predictor of shifted functional activity in the brain, leading the researchers to believe sustained loneliness carries broad implications for our brain’s architecture. 

The neuroscience of loneliness and its consequential implications for public health policymaking remains a dormant avenue of research. However, with novel endeavors to understand how social deprivation manifests itself as increased self-reflection in the mind, the urgency for mitigating loneliness in today’s society becomes increasingly clear. 

References

1. Greenberg, M. Do Lonely People Have Different Brains? Psychology Today - Sussex publishers [Online] 2020. https://www.psychologytoday.com/us/blog/the-mindful-self-express/202012/do-lonely-people-have-different-brains 

2. Holt-Lunstad, J. The Double Pandemic Of Social Isolation And COVID-19: Cross-Sector Policy Must Address Both. Health Affairs Forefront Blog - Project Hope [Online] 2020. https://www.healthaffairs.org/do/10.1377/forefront.20200609.53823 

3. Spreng, R. The default network of the human brain is associated with perceived social isolation. Nature Communications - Springer Nature [Online] 2020. https://www.nature.com/articles/s41467-020-20039-w 

4. Spreng, R. "Lonely brain" imaging study reveals unexpected neural patterns. New Atlas [Online] 2020. https://newatlas.com/science/loneliness-brain-imaging-study-neural-signature-default-mode/ 

5. Andrews-Hanna, J. Functional-anatomic fractionation of the brain's default network. ScienceDirect - Neuron Cell Press [Online] 2010. https://pubmed.ncbi.nlm.nih.gov/20188659/ 

6. Allen, S. The associations between loneliness, social exclusion and pain in the general population. ScienceDirect - Journal of Psychiatric Research [Online] 2020. https://pubmed.ncbi.nlm.nih.gov/32791383/ 

7. Mars, R. On the relationship between the “default mode network” and the “social brain”. Human Cognitive Neuroscience - Frontiers Media [Online] 2012. https://www.frontiersin.org/articles/10.3389/fnhum.2012.00189/full

8. McCrimmon, K. Loneliness during the COVID-19 pandemic: Fight it with kindness. UCHealth Today Digest - UCHealth Publishers [Online] 2020. https://www.uchealth.org/today/loneliness-during-the-covid-19-pandemic-fight-it-with-kindness/

Changing Habits With Activity Dependent Neural Plasticity

Changing one’s habits and the most action-oriented approaches to doing so has remained an age-old question yielding a diverse array of answers. Perhaps, the idea that your brain is in a perpetual state of change is something you have encountered previously, through a television show, a book, or maybe even as you peruse the local newspaper. At first, notions pertaining to this scientific phenomenon, known as activity-dependent neural plasticity, may come across as slightly contradictory: all throughout our schooling years, we’ve been told that our brains are subject to the modular outputs of a dynamic biochemical environment prevailing within our brain’s cells after all. So how could it be that these ostensibly inanimate ions, voltage-gated channels, and synaptic clefts are operating independently of stimuli perception? 

Recent advancements within the realm of neuroscience have conferred mankind with a uniquely nuanced insight into the intricate mechanisms facilitating neural modulation. Analogous to how your plastic water bottle warps in conformity to direct sunlight, scientists have recently discovered that our brain is increasingly implicated by everything occurring in transcendence of our subconscious thought: every single observation, interaction, smell, sight… as it turns out, there is not much information that goes unnoticed by our minds [1]. Contemporary neuroimaging techniques have served to capture the extent of this dynamic rewiring that prevails within each of our brains; this redefines our collective approach to the interplay between the mind, brain, and body necessary to ensure the fruition of our consciousness [2]. 

What exactly does this information mean for us, as individual agents embedded within the crosshairs of highly developed sociocultural institutions around the world? Like many other things prominent within our day-to-day lives, neural plasticity can be reverse engineered to promote only the most positive feelings within people: namely, contentment, satisfaction, and ultimately, serve to provide such individuals with a way of altering their negative habits. For instance, the persistent practice of one’s desired habits under a number of different conditions has the potential to change the functional activity of neurons across the brain, housing over 100 billion neurons which strive to communicate across 100 trillion synaptic connections [3]. Contemporary somatic therapeutic interventions, predicated upon the functioning of neural plasticity mechanisms to incite positive development, can be revitalized by the maintenance of a persistently positive personal state with repeated practice and a defined goal.

So the next time your mother scolds you for habitually consuming your fingernails, or falls victim to the notion that it simply is not possible to develop a highly outcome-oriented habit, try to remember that you have immediate access to a dynamic community of 100 billion neurons communicating over 100 trillion gaps in space. Similar to your favorite hiking trail, the neuronal circuitry constituting the foundation of basic actions remains vulnerable to changes in one's habits, strengthening over time as the status quo is challenged with sheer willpower.

References

[1] Taylor, B. Breaking Bad Habits, With Neuroplasticity. EduGuide Developmental Biology - Lumina Foundation [Online] 2015. https://www.eduguide.org/content/2015/02/13/breaking-bad-habits-with-neuroplasticity/

[2] Foss, R. How to Change Your Behavior and The Science Behind Neuroplasticity. Kwik Learning for Academic Success [Online] 2018. https://kwiklearning.com/kwik-tips/how-to-change-your-behavior-the-science-behind-neuroplasticity/ 

[3] Ganguly, K.; Poo, M. Activity-Dependent Neural Plasticity from Bench to Bedside. Cell Neuron [Online] 2013, 86, 122-134.. https://doi.org/10.1016/j.neuron.2013.10.028 

[4] Bergland, C. How Do Neuroplasticity and Neurogenesis Rewire Your Brain? Psychology Today [Online] 2017. https://www.psychologytoday.com/us/blog/the-athletes-way/201702/how-do-neuroplasticity-and-neurogenesis-rewire-your-brain