PAW-PRIOCEPTION

Tavishi

I've recently been getting more and more into neurology and sensation, and something that has particularly interested me is control of motion. What's even more fascinating is the cognitive process that both precedes and succeeds motion: proprioception. Proprioception is the sensation of body position and movement based off of balance and vision that allows us to fundamentally move and to do so without crashing. This is one of those crucial developmental skills that forms over time, which is incidentally why kittens are so shaky on their legs.

When kittens are first born, they're completely useless little beings; they can't even use the restroom on their own. They require maternal stimulation for defecation or urination, and can hardly move on their own. They can't regulate their own temperature, and certainly can't feed themselves. Additionally, neonatal kittens are born with their eyes closed, and so most of their movement is based off of temperature changes. They can't fully support their own weight with their back legs.

As the kitten develops, they progressively gain more motor control and become more independent, eventually weaning from their mother. At about three weeks, the kitten begins to walk, and from there, it all snowballs as motor control as a whole rapidly develops. By six weeks, your kitty is pouncing all over the house. The development of proprioception over the weeks of kitten-hood can be measured with a series of neurological tests: the knuckling test, reflex stepping, tactile placing, visual placing, and wheel barrowing.

The knuckling test is where you place the dorsal side of the cat's paw on the table, or rather, the kitty's knuckles. A normal behavior would result in the cat fixing the paw and walking normally. A cat with improper proprioception would just try to walk on the knuckle.

Reflex stepping is yet another test of paw positioning. Place a kitten's paw on a flat surface and move it sideways. If the kitten fixes it and brings the paw back to the original position, it passes the test of proprioception. Tactile placing and visual placing are both similar tests. In a tactile placing test, vision is not tested. Instead, the cat is held above the table, and the cat approaches the table slowly with the eyes covered. When the paw begins to touch the table, the cat should place their paw on the table. In the visual placing test, the cat can see the table.

And finally, wheelbarrowing is perhaps the silliest. During a wheelbarrowing test, you hold the cat's back legs, shifting weight onto the front paws. If the cat continues to walk, that cat is in good health. Abnormal responses would be falling forwards or carrying head low.

This is my friend Kaci's cat. When I asked her to put her cat in a wheelbarrow position, there was a bit of miscommunication, as you can see. It is clear he can, in fact, climb inside this wheelbarrow, though; this might be a testament to his proprioceptive capabilities. Below is a do-over with the same cat in a more accurate wheelbarrow:

These tests detect proprioceptive issues, and help localize them to the brain as a whole, or issues with motor capabilities. A cat with low motor function in paw positioning may fail knuckling and reflex stepping, but do great at wheelbarrowing. A blind cat may do excellent at tactile placing, but fail visual placing. Spinal deficit may cause a cat to struggle with wheelbarrowing, but excel at other areas. Failure to complete tests as a whole may be indicative of neurological disease. Ataxia is the blanket term for a proprioceptive deficit.

The most well-known disease associated with proprioceptive is cerebellar hypoplasia, colloquially known as wobbly cat. Cerebellar hypoplasia is caused by a poorly developed cerebellum, resulting in an uncoordinated kitty. Cerebellar hypoplasia is caused by a mother infected with feline panleukopenia virus resulting in affected cerebellar development in utero for kittens. (Happy fiftieth post! I hope everyone enjoyed the cats!)