Our primitive reflexes may be more sophisticated than they appear, study shows

Supposedly 'primitive' reflexes may involve more sophisticated brain function than previously thought, according to researchers at Imperial College London.

The Vestibular-Ocular Reflex (or VOR), common to most , is what allows us to keep our eyes focused on a fixed point even while our heads are moving. Up until now, scientists had assumed this reflex was controlled by the lower , which regulates eating, sleeping and other low-level tasks.

Researchers at Imperial's Division of Brain Sciences conducted tests to examine this reflex in left- and right-handed subjects, revealing that handedness plays a key role in the way it operates. This suggests that higher-level functions in the cortex, which govern handedness, are involved in the control of primitive reflexes such as the VOR.

The research, published in The Journal of Neuroscience, involved seating volunteers in a motorised chair which was then spun around at a speed of one revolution every four seconds. This allowed the experimenters to study the VOR by measuring the time it took for the eyes to adjust to the spinning motion. The subjects were then presented with what are known as bistable visual phenomena, which appear to flip between two images. Famous examples include the duck which resembles a rabbit, and the cube outline which appears to come out of and go into the page simultaneously.

Scientists already know that this bistable perception is controlled by a part of the cortex which governs more complex, decision-based tasks. Because of this, researcher Qadeer Arshad and his colleagues did not expect to find any link between the two processes.

They were surprised to find that processing bistable phenomena disrupted people's ability to stabilise their , following rightward rotation in right handers and leftward rotation in left handers. Arshad said "This is the first time that anything of this kind has been shown. Up until now, the Vestibular-Ocular Reflex was considered a low-level reflex, not even approaching higher-order . Now it seems that this primitive reflex was specialised into the , the part of the brain which governs our sense of direction."

This study could help scientists understand why some people become dizzy through experiencing purely , such as flickering lights or busy supermarket aisles. Professor Adolfo Bronstein, a co-author on the paper, said "Most causes of dizziness start with an inner ear - or vestibular - disorder but this initial phase tends to settle quite rapidly. In some patients, however, dizziness becomes a problematic long term problem and their dizziness becomes visually induced. The experimental set-up we used would be ideally suited to help us understand how visual stimuli could lead to long-term dizziness. In fact, we have already carried out research at Imperial around using complex visual stimuli to treat patients with long-term dizziness"

More information: www.jneurosci.org/content/33/7/3221.full

Related Stories

Streamlining brain signals for speed and efficacy

Oct 22, 2008

Life exists at the edge of chaos, where small changes can have striking and unanticipated effects, and major stimuli may go unheard. But there is no space for ambiguity when the brain needs to transform head motion into precise ...

Why evolutionarily ancient brain areas are important

Nov 30, 2011

Structures in the midbrain that developed early in evolution can be responsible for functions in newborns which in adults are taken over by the cerebral cortex. New evidence for this theory has been found in the visual system ...

Study offers hope for sufferers of vertigo

Oct 05, 2012

We've known for a while that the vestibular system in the inner ear is responsible for helping us keep our balance. And while researchers have already developed a basic understanding of how the brain constructs our perceptions ...

Decoding the secrets of balance

Jul 25, 2012

(Medical Xpress) -- New understanding of how the brain processes information from inner ear offers hope for sufferers of vertigo.

Recommended for you

What happens in our brain when we unlock a door?

10 hours ago

People who are unable to button up their jacket or who find it difficult to insert a key in lock suffer from a condition known as apraxia. This means that their motor skills have been impaired – as a result ...

Sport can help multiple sclerosis patients

14 hours ago

A study developed at the Miguel Hernández University of Elche (Spain) has preliminarily concluded that people with multiple sclerosis may reduce perceived fatigue and increase mobility through a series of ...

Obama's BRAIN initiative gets more than $300 million

18 hours ago

President Barack Obama's initiative to study the brain and improve treatment of conditions like Alzheimer's and autism was given a boost Tuesday with the announcement of more than $300 million in funds.

User comments