Neuroplasticity – A brain with(out) boundaries

The human brain is able to modify itself…

For years, it has been believed that the brain was unalterable. Or, rather, that after a critical developmental period in childhood, the adult brain was a static and unchangeable organ. Although it is true that our brain circuits have greater plasticity at an early age and that this capacity declines over time, plasticity occurs throughout our lifespan. Hence, it does not represent an occasional state of the nervous system; instead, it characterizes its normal ongoing condition [1].

The first evidence of this intrinsic cerebral property began to emerge in the 1870s, but only in the second half of the 20th century, researchers started to show experimentally that the brain can reorganise itself, both physically and functionally. In other words, the brain responds to environmental pressures, physiological changes, and experiences by adapting and re-adjusting with the ultimate goal of restoring a certain function [2]. Correlates of plasticity have been demonstrated on various levels of analysis: from the molecular, to synaptic, to the cellular, and to network and systems levels [3].

Connections within the brain are constantly becoming stronger or weaker, depending on what is being used. One of the underlying fundamental principles of plasticity is associated with the concept of synaptic pruning: neural connections are removed and re-established, mainly in relation to their use. This notion is well explicated by the aphorism – “neurons that fire together, wire together, neurons that fire apart, wire apart” [4]. Thereby, neurons that are engaged together in close temporal proximity strengthen their reciprocal connections.

Our brains are continually shaped by experience. This neuroplastic “revolution” led to important findings in the understanding of how love, sex, pain, relationships, culture, technology, learning processes, and addiction can all have effects on brain architecture. Therefore we talk of a “culturally modified” brain [5]. Contrary, a system capable of flexible reorganization risks unwanted changes, revealing the vulnerability of our cerebral system to outside and inside influences. This discrepancy has been dubbed “the plastic paradox” [5].

Understanding the principles through which the brain dynamically reorganizes itself helps scientists in the investigation of how patients sometimes recover brain functions damaged by injury or disease.

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Can neuroplasticity preserve intact cognitive functions?

The term neuroplasticity is not only found in connection to “damaged” brain circuits when the recovery of lost or impaired capacities is needed. As a matter of fact, much effort have been put on understanding the relationship between neural plasticity and its positive effects on the preservation of cognitive functions and, more generally, on the improvement of lifestyles.

Professor Tony Hannan, head of the Neural Plasticity group at the Florey Institute in Melbourne, states:

“Discoveries in the field of neuroplasticity have implications for how each of us may protect our brain from the relentless weathering of ageing and disease. It’s known that lifestyle factors that are good for the body, such as regular physical exercise and a healthy diet, are also beneficial for the brain. And those who keep their brains stimulated with regular complex mental activities may also help delay onset of common brain diseases, such as Alzheimer’s and dementia.” [7]

A key question is whether specific trainings and interventions, dedicated to the promotion of wellbeing and health, can induce beneficial neuroplastic changes in the brain and sustain positive behavioural outcomes: a current hot topic in cognitive ageing. First of all, it is necessary to distinguish between positive and negative neuroplasticity. Both refer to morphological and neurochemical modifications that occur in the brain. When animals and humans are exposed to a complex and novel environment, they tend to adapt through learning processes: this positive neuroplasticity leads to an increase of cognitive reserve, which refers to the amount, sophistication and strength of the developed neuronal connections. Contrary, when animals and humans are faced with less intricate and challenging contexts, they require fewer adaptations: the term negative neuroplasticity is associated with a decrease of cognitive reserve [8]. These concepts are confirmed by studies employing “enriched environmental paradigms” [9]. Here, greater cognitive reserve was associated with an increased likelihood to endure neuronal injuries and maintain cognitive functions.

With increased age, neurons’ efficacy may be compromised and also connections between them may become impaired; however, if there is sufficient cognitive reserve (for example other neuronal connections), adjacent functional neurons may be able to redirect the communication from the damaged ones, thus preserving cognitive functioning. This means that cognition is somehow a malleable construct and can be “protected” or even increased through the process of neuroplasticity. All of these studies continue to flower and provide useful implications for clinical applications (for instance, in the treatment of dementia or Alzheimer’s disease), but also should be taken into account when talking of healthy human aging and healthcare.

How to use games as cognitive training tools?

 Cognitive training offers the possibility to promote learning and prevent cognitive decline. In many experimental paradigms, video games are being employed in order to enhance cognitive functioning. Gaming can be considered as an intense training of many diverse skills [10]. Positive benefits from video game training on cognitive control capacities have been found in older adults, emphasizing the robust plasticity of the prefrontal cognitive system even in aging brains [11].

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Playing a first-person shooter video game, for example, can alter the neural processes that underlie spatial selective attention, representing an effective training tool for ameliorating a range of attentional and perceptual abilities [12]. It is possible that as little as 10-20 hours of video game training improve performance on attentional, perceptual and executive control tasks [13]. In a further study conducted by Kühn et al. (2014), participants played the popular video game Super Mario for a period of two months for at least half an hour per day. The game consists of navigating through a three-dimensional virtual world and gathering items. Compared to the control group, the training group showed a significant grey matter (GM) augmentation in the right hippocampus, right dorsolateral prefrontal cortex and bilateral cerebellum. These results suggest that video game training increases GM volume in regions crucial for spatial navigation, strategic planning, working memory and motor performance. It has been demonstrated that neuroplastic changes occur only in those individuals who achieve a significant behavioural improvement. One assumption that underlies all these training paradigms is that the skills learnt during trained tasks will transfer to other untrained tasks and, hopefully, to daily life situations.

Although further studies are needed in order to test how different game genres induce distinct structural brain plasticity changes, the video game approach may provide a good clinical tool for the diverse populations that suffer from cognitive deficits [11]. Presenting stimulation through games and tasks is also likely to be generally more accepted and entertaining compared to other types of interventions. The same neuroplastic effects observed in the Super Mario game intervention could, for instance, help contrast risk factors for mental and neurodegenerative disorders, such as Alzheimer’s disease, which has been associated with reduced hippocampal volume. This is just an example and, of course, such trainings should focus on building targeted designs aiming at specific domains and impaired neural processes.

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Brain games are spreading: why should we pay attention?

Neuroplasticity is clearly a huge concept and seems to be an important issue with respect to cognitive decline and ageing. As with other neuro-hypes, careful consideration has to be given to the actual evidence. This is particularly important given the increasing interest in our societies in discovering how to improve cognitive functions and a parallel concern about cognitive decline. In this context, computer-based cognitive-training software, commonly known as “brain games” [14], are becoming more and more popular, promising benefits for many cognitive skills. Simply surfing the Internet, a list of “brain training” apps and exercises will appear. How to improve memory, how to boost IQ, how to fit the brain, … But be careful with what you read online! Often these games are promoted by advertisements that ensure the customers of their scientific roots, but this turns out to be only partially true. In fact, in most cases, they refer just to single studies with small samples of participants, rather than integrating results from a reliable collection of studies.

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Brain games are a hot topic. The Stanford Center on Longevity in Palo Alto, California, and the Max Planck Institute for Human Development in Berlin have assembled opinions from many cognitive psychologists and neuroscientists in order to offer a more exhaustive view to the public [14]. The group agrees that claims supporting brain games are often exaggerated and deceptive when promising general and enduring improvements in several different cognitive tasks. So far, it does not seem appropriate to conclude that training-induced modifications can go beyond the specific skills learned through the game and affect other relevant daily life domains. One more issue to keep in mind is the importance to establish that the improvements observed are not the consequence of other factors notoriously associated with benefits in the performance, such as changes in motivation or learning new strategies. Moreover, the so-called “file drawer effect” has to be taken into account: studies revealing brain games’ positive effects on cognitive abilities have higher chances to be published rather than those with negligible results, misleading the overall picture of the situation.

Final considerations

Everyone is concerned about cognitive decline. And the brain games industry responds reassuring and arousing a worried public. But magic wands do not exist!

As seen before, there is strong evidence that brain structures retain their plasticity over the life span and cognitive trainings and exercises are absolutely important to be engaged continuously for the individual’s wellbeing and health. However additional systematic research, preferably conducted by independent researchers using scientific approaches, is needed to clarify the still vague findings about brain games. Lacking clear evidence, researchers still recommend the traditional “recipe” for preserving cognitive functioning: live cognitively active, socially engaged and maintain healthy lifestyles [14].

Although neuroplasticity is not a new discovery, it seems that it will still be a relevant topic in the future. The growing body of research is increasingly leading towards the establishment of lifestyle behaviours and interventions directed at not only restoring damaged brains, but also improving normal brain development. Some of the reviewed research are already promising and make further studies towards this direction highly desirable.

Just do not blindly trust who promises you the “formula to become a genius”! It is – probably – a false hope.

References:

  1. Pascual-Leone, A., Amedi, A., Fregni, F. & Merabet, L.B. (2005). The plastic human brain cortex. Annual Review of Neuroscience, 28, 377-401.
  1. Stephenson, R. (1993). A review on neuroplasticity: some implications for physiotherapy in the treatment of lesions of the brain. Physiotherapy, 79(10), 699-704.
  1. Nudo, R.J. (2006). Plasticity. NeuroRx, 3(4), 420-427.
  1. Hebb, D.O. (1949). The organization of behaviour. New York: Wiley & Sons.
  1. Doidge, N. (2007). The brain that changes itself: stories of personal triumph from the frontiers of brain science. New York: Wiking Press.
  1. Kleim, J.A. & Jones, T.A. (2008). Principles of experience-dependent neural plasticity: implications for rehabilitation after brain damage. Journal of Speech, Language, and Hearing Research, 51, S225-S239.
  1. Mckay, S. (2015, March 6). Can you rewire your brain? Retrieved from https://www.activememory.com/news/2015/neuroplasticity-can-you-rewire-your-brain
  1. Vance, D.E., Kaur, J. & Lin, F. (2012). Neuroplasticity and successful cognitive aging: a brief overview for nursing.Journal of Neuroscience Nursing, 44(4), 218-227.
  1. Diamond, M.C. (1993). An optimistic view of the aging brain. Generations, 17(1), 31-33.
  1. Looi, C., Duta, M., Brem, A., Huber, S., Nuerk, H. & Kadosh, R.C. (2016). Combining brain stimulation and video game to promote long-term transfer of learning and cognitive enhancement. Scientific Reports, 6.
  1. Anguera, J.A., Boccanfuso, J., Rintoul, J.L., Al-Hashimi, O., Faraji, F., Janowich, J., Kong, E., Larraburo, Y., Rolle, C., Johnston, E. & Gazzaley, A. (2013). Video game training enhances cognitive control in older adults. Nature, 5, 97-101.
  1. Wu, S., Cheng, C.K., Feng, J., D’Angelo, L., Alain, C. & Spence, I. (2012). Playing a first-person shooter video game induces neuroplastic change. Journal of Cognitive Neuroscience, 24(6), 1286-1293.
  1. Kühn, S., Gleich, T., Lorenz, R.C., Lindenberger, U. & Gallinat, J. (2014). Playing Super Mario induces structural brain plasticity: gray matter changes resulting from training with a commercial video game. Molecular Psychiatry, 19(2), 265-271.
  1. A Consensus on the Brain Training Industry from the Scientific Community,” Max Planck Institute for Human Development and Stanford Center on Longevity, accessed on 2016, March 7, http://longevity3.stanford.edu/blog/2014/10/15/the-consensus-on-the-brain-training-industry-from-the-scientific-community/

Hyperlink:

  • More about the brain game debate:

http://www.sciencemag.org/news/2014/10/neuroscientists-speak-out-against-brain-game-hype

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