The Half Decent Pharmaceutical Chemistry Blog

In 1941, W.R. Brain published an article (Brain.1941; 64: 244-272), where he described a phenomenon he studied on people with injuries of the parietal association cortex, people who suffered from what would have been later called spatial neglect. They were completely unaware of anything that was on their left: either objects on the left field of view or the whole left part of their body.

Two weeks ago, I talked about the relationship between the temporal association area and the ability to recognise things.
What the parietal association cortex does, instead, is processing inner and outer inputs, which results in our ability to recognise, localize and pay attention to whatever is around us. In other words, this part of the brain plays a key role in all the visuospatial tasks we normally perform.

Interestingly, there is a partial hemispheric specialization for what concerns attention: the right hemisphere shows increasing activity with inputs coming either from the right or left, while the left one with those from the right side only.
Consistently, any damage to the left parietal cortex doesn't lead to spatial neglet, since the right hemisphere neutralizes the effect of the injury.

Now, check out how someone, suffering from neglet, draws a clock or cuts a line "in the middle".

Far from being a surprise, spatial neglect makes impossible to do simple actions such as dressing yourself or moving in your own house (as Brain wrote, patients always turned right, opened doors on the right, etc.).