Can our Amygdala See?
New research into brain functioning has shown that even when our eyes are closed, there is another part of our brain, separate from the visual cortex, that may be capable of picking up visual information – the amygdala.
Originally, the amygdala is the brain region that determines whether any external stimulus is a threat. Located in the temporal lobe (at the back of the brain) the amygdala is also known to play a huge role in processing emotion, the fight or flight response to stress, and aggression. But this new finding is pretty astonishing.
Research came about due to a study conducted by Jennifer Milne, PhD, et al (University of Western Ontario), which investigated whether the brain can still track targets even when it believes the targets are no longer there. Researchers used the ‘connectedness illusion’ – involving two groups of circles connected to lines; in one group the lines connect the circles together and in the other group they do not. The illusion is that our eyes perceive less circles in the connected group, even though there are the same amount of circles in both.
It was suggested that, when given a chance to ‘act’ on these circles (known in the study as targets), they engaged in ‘brain sight’. This is because participants made plans/actions using ALL of the targets, even though they did not visually perceive them.
Said lead researcher Jennifer Milne: “It’s as though we have a semi-autonomous robot in our brain that plans and executes actions on our behalf with only the broadest of instructions from us.”
So it is no surprise that researchers wanted to take this further. Neuroscientists now wanted to know if the brain could still ‘see’ even when the ability to pick up visual information has been taken away. They used a patient suffering from cortical blindness – meaning the visual cortex no longer functions. Even though their eyes do still work (technically) they’re not able to perceive the world visually through them.
They exposed this patient to gazes directed towards him and away from him whilst in an fMRI scanner. What most would conclude is that neither gaze should make a difference as the patient can’t actually ‘see’. However, amazingly, the brain activity showed that the patient could perceive these gazes, and react to them.
The amygdala (as mentioned previously) showed a different activation pattern when the gaze was directed towards the patient. So, the patients visual perception was not important in this case, as the amygdala seemed to be able to perceive the gaze itself.
Whilst it is not quite clear how this has come about, it is assumed that the brain has an intuitive sense. Our brains are adaptive. It is possible that this patients brain has adapted to the loss of sight, and compensated for it elsewhere. When one system is injured, or broken, then another will take its place. But just quite how this occurs is what researchers are hoping to uncover in the future.
Whilst this research only touches the surface of brain functioning, it shows how much more there is to learn. Our brains are amazing! And I, personally, am looking forward to hearing more about what is in store for neuropsychology in the coming years.