In Praise Of Walking by Shane O’Mara

The new science of how we walk and why it’s good for us

This is a snippet from the book, In Praise of Walking by Shane O’Mara, which examines the science behind one of the basic skills that defines us as human beings.

Scientists are slowly working out how our sense of direction works.

It’s not just the mechanics of walking that requires brain power. There’s also the question of how we actually know where to go.

Put yourself in the author’s shoes. It’s a good few years ago, before the age of smartphones. You have to walk from North London – Highgate, to be precise – all the way back to your home in Streatham, which is a long way south. You don’t have a map.

How do you do it? Well, essentially, you channel your inner homing pigeon. Dead reckoning, otherwise known as path integration, is our innate ability to move in the right general direction toward a destination.

But as for how that works – scientists are only just coming to grips with it.

The key message here is: Scientists are slowly working out how our sense of direction works.

Strolling right through the heart of London, across the river Thames and down through the south, the author managed to find his way home – even though he was going through areas he didn’t know. He was able to do this because finding our way around isn’t wholly dependent on visual cues.

Several studies have proven that our spatial sense is not greatly affected by our ability to see. In tests measuring a sense of direction, blindfolded people and people with visual impairments performed similarly to those with “normal” sight.

The neuroscientist John O’Keefe has made some pioneering discoveries regarding how the brain determines where we are. He discovered that when rats wander to a place they know, particular cells around the brain’s hippocampus light up. Different cells light up when they move somewhere else. These are known as place cells – they tell us where we are. Humans have them too, and they work most effectively when we walk.

Further research has revealed even more fascinating types of cells in the brain that help us get around. Head-direction cells are essentially an inner compass, indicating our orientation. There are also cells that respond to nearby objects. The author himself has worked on perimeter cells, which respond to the boundaries that surround us. 

All in all, the brain more or less has its own GPS network, constantly updating itself as we are walking around.

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Predictive maps in rats and humans for spatial navigation

Highlights

  • We tested humans, rats, and RL agents on a novel modular maze
  • Humans and rats were remarkably similar in their choice of trajectories
  • Both species were most similar to agents utilizing a SR
  • Humans also displayed features of model-based planning in early trials

Authors

William de Cothi, Nils Nyberg, Eva-Maria Griesbauer, …,
E ́ le onore Duvelle, Caswell Barry, Hugo J. Spiers

Correspondence

w.decothi@ucl.ac.uk (W.d.C.), h.spiers@ucl.ac.uk (H.J.S.)

In brief

De Cothi et al. use a novel open-field modular maze to test the spatial navigation abilities of humans and rats, comparing them to simulated reinforcement learning agents. They find that humans and rats are remarkably similar in their choice of trajectories, with both species displaying most similarity to agents utilizing a successor representation. 


Editors remarks:

This paper is another example of the work being done that shows that rats and humans use similar methods the navigate by which are NOT based on Magnetism.

The paper refers to successor representation (SR) this is reinforcement learning and is the process by which an agent learns to predict long-term future reward.

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Head direction cells in a migratory bird prefer north

Animals exhibit remarkable navigation abilities as if they have an internal compass. Head direction (HD) cells encoding the animal’s heading azimuth are found in the brain of several animal species; the HD cell signals are dependent on the vestibular nuclei, where magnetic responsive cells are present in birds. However, it is difficult to determine whether HD cell signals drive the compass orientation in animals, as they do not necessarily rely on the magnetic compass under all circumstances. Recording of HD cell activities from the medial pallium of shearwater chicks (Calonectris leucomelas) just before their first migration, during which they strongly rely on compass orientation, revealed that shearwater HD cells prefer a north orientation. The preference remained stable regardless of geolocations and environmental cues, suggesting the existence of a magnetic compass regulated by internally generated HD signals. Our findings provide insight into the integration of the direction and magnetoreception senses.

Click here to read the full article.

Editors remarks

This paper is interesting as it talks about the latest research on head direction cells.  Personally I am not persuaded that birds have a magnetic sensor in their beaks, but this is an interesting paper anyway.

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How young animals learn to migrate

While advances in biologging have revealed many spectacular animal migrations, it remains poorly understood how young animals learn to migrate.

Even in social species, it is unclear how migratory skills are transmitted from one generation to another and what implications this may have.

Here we show that in Caspian terns Hydroprogne caspia family groups, genetic and foster male parents carry the main responsibility for migrating with young. During migration, young birds stayed close to an adult at all times, with the bond dissipating on the wintering grounds.

Solo-migrating adults migrated faster than did adults accompanying young. Four young that lost contact with their parent at an early stage of migration all died. During their first solo migration, subadult terns remained faithful to routes they took with their parents as young.

Our results provide evidence for cultural inheritance of migration knowledge in a long-distance bird migrant and show that sex-biased (allo)parental care en route shapes migration through social learning. 

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Olfactory landmarks and path integration converge to form a cognitive spatial map

This paper on olfactory landmarks is interesting as it covers the idea that the distinctive smell of a place can help navigation by creating a new landmark for helping an animal navigate.

The recognition of a spatial landmark by its sensory features poses a problem for neural circuits. Fischler-Ruiz, et al. show how this problem is solved when mice use odour cues to navigate in the dark. In the hippocampus, path integration imposes spatial meaning on odour cues, thereby creating new landmarks.

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Adaptation and Evolution of Bird Migration

In this paper you find a rather fascinating overview of the migration of Birds.

Malik, Y. S., Arun Prince Milton, A., Ghatak, S. & Ghosh, S. 2021 Adaptation and Evolution of Bird Migration. In Role of Birds in Transmitting Zoonotic Pathogens, pp. 3-14. Singapore Springer Singapore. Malik 2021

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‘Frostbit Boy’ rescued among dolphins after 12 hours at sea

Ruairí McSorley who had gone swimming has been rescued after getting into difficulty while swimming off the coast of Co Kerry. He was discovered surrounded by a pod of dolphins four kilometres from the shore of Castlegregory Beach. Read the full story.

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