Pilots beware: Too much automation can shrink your brain

Grey matter volume increases in various parts of the brain have been identified in several skilled groups such as musicians, mathematicians, bilinguals, jugglers and medical students.

Professional musicians with increased grey matter volume in Broca’s area (frontal lobe of the brain) were found to show enhanced judgments of line orientation and three-dimensional mental rotation ability. This was attributed to their musical sight-reading and motor-sequencing expertise.

However, this expertise can come at a cost, with some musicians suffering focal dystonia, a loss of control and degradation of skilled hand movements.

Hippocampus is a complex brain structure embedded deep into the temporal lobe. It has a major role in learning and memory. Studies and research have shown that the size of the hippocampus changes with the cognitive and skill functions performed by humans.

The hippocampus has been found to increase in size in fighter pilots and London taxi drivers. While the size increases with the repeated performance of complex tasks and learning, the size could also shrink due to non-usage like reliance on automation for the functions usually performed by the brain.

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Loss of neurons is considered to be an irreversible process since dying cells cannot be replaced. Hippocampus is one of the unique regions in the brain where neurogenesis continues even in adult life.

Though described initially as "too little", neurogenesis in the brain is now thought to be functionally important. It has been seen that the neurons hence produced integrate into the mainstream neurons. They have also, hence, shown to be functionally important. Hippocampus is now known not just to be important in learning and memory but also in:

1. Spatial navigation
2. Emotional behaviour
3. Regulation of hypothalamic functions

Use of GPS and change in the hippocampus

A study was conducted in 2018 on the use of Augmented Reality (AR) glasses with Global Positioning System (GPS) navigation for prolonged use. The study aimed to assess possible changes in the functional connectivity of the hippocampus and other brain regions involved in spatial navigation with the use of a GPS guidance navigational system over three months.

The study found a decrease in functional coupling of the right hippocampus after three months of using GPS navigation. These preliminary observations support the assumption that the externalisation of a mental capacity (spatial navigation) to technological devices has measurable neurobiological consequences.

What researchers at McGill University found was significant in terms of how spatial orientation affects the brain. Functional Magnetic Resonance Imaging (fMRI) scans on people found that the individuals using a spatial navigation strategy had increased activity in the hippocampus.

Conversely, the researchers found that using a GPS excessively might lead to atrophy in the hippocampus as a person ages, which could put them at a higher risk of cognitive diseases later in life. One of these diseases might be Alzheimer’s which impairs the hippocampus and leads to problems with spatial orientation and memory.

The researchers also found a greater volume of grey matter in those who used spatial navigation, and this group scored higher on standardised cognition tests than those who used the other strategy. This study demonstrates that orienteering and building cognitive maps might be better for the brain than using a GPS.

MRI analysis of London taxi drivers and bus drivers

The London taxi drivers perhaps undergo the most difficult test in the world: that of memorising 25,000 streets of London. In research that compared data from MRI scans of the study group, it was found that the taxi drivers' grey matter was higher than that of the bus drivers.

Furthermore, years of navigation experience correlated with hippocampal grey matter volume only in taxi drivers has resulted in right posterior grey matter volume increasing and anterior grey matter volume decreasing with more navigation experience. In addition to structural brain differences, the neuropsychological testing revealed that taxi drivers, while performing better than bus drivers on tests relating to the knowledge of London, were significantly poorer at acquiring or retrieving new visuospatial information from objects and locations.

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In other words, they fared poorly as compared to the others at learning object-place and word-pair associations. This could suggest a broader associative deficit within visual and verbal domains. This could be due to limited capacity for further consolidation and storage in the posterior hippocampus.

The study concluded that it is not enough to focus on the positive effects of being skilled, but that there may be costs associated with expertise that also need to be identified and considered.

Changes in hippocampal volume and shape in early-onset mild cognitive impairment

Mild Cognitive Impairment (MCI), especially the amnestic type of MCI, refers to an early stage of Alzheimer’s Disease (AD), during which patients display cognitive impairment without apparent disabilities in their activities of daily living. Patients with MCI show memory dysfunction and 10–20% of MCIs annually progress into Alzheimer Disease. Atrophy or degeneration of the hippocampus is one of the most sensitive biological indicators of AD, and hippocampal volumetric is the best-established structural biomarker for AD, especially for early diagnosis.

mindFly analysis

The fact is that volumetric changes have been confirmed in several studies of the human brain. These changes could be due to the onset of a disease like Alzheimer's or due to prolonged reliance on external technological aid which reduces the functions usually performed by the brain. Hippocampus, in particular, is divided into posterior and anterior parts, the posterior being mainly responsible for spatial awareness and the anterior being used for emotional response.

While the constant use of one faculty can result in the strengthening of the neural network or even an increase in brain size, there seems to be a limitation to the growth. As seen among the London taxi drivers, the increase in the posterior hippocampus affects certain functions associated with the anterior hippocampus.

There is a need to balance the functional requirements of the pilots not only from the technology point of view but also from a physio-psychological angle so that the overall cognitive functions are not compromised. Technology and Artificial Intelligence (AI) is the future and will take over numerous functions routinely performed by humans but will they take over the cognitive functions or affect them is worth a discussion. 

(This article first appeared in safetymatters.co.in)