Washington, Oct 29 : When it comes to the brain, there is fine line between love and hate, say researchers from the Wellcome Laboratory of Neurobiology at University of California, who claim to have identified brain’s "hate circuit.”

According to boffins, the new scans of the brain''s "hate circuit" have confirmed similarities between the two powerful emotions.

But whereas loved-up partners are likely to be less rational, the new scans show hate to be colder and more calculating.

"Hate is often considered to be an evil passion that should, in a better world, be tamed, controlled, and eradicated. Yet to the biologist, hate is a passion that is of equal interest to love,” said Semir Zeki of University College London, UK.

During the study the researchers recruited seventeen subjects, both female and male, who had their brains scanned while viewing pictures of their hated person as well as that of neutral faces with which they were familiar.

They found that viewing a hated person showed activity in distinct areas of the brain that, together, may be thought of as a ''hate circuit''.

The ''hate circuit'' includes structures in the cortex and in the sub-cortex and has components that are important in generating aggressive behaviour, and translating this into action.

The subcortical activity involves two distinct structures, the putamen and insula. The former has been implicated in the perception of contempt and disgust.

"Significantly, the putamen and insula are also both activated by romantic love. This is not surprising,” he said.

“The putamen could also be involved in the preparation of aggressive acts in a romantic context, as in situations when a rival presents a danger,” he added. 

Previous studies have suggested that the insula may be involved in responses to distressing stimuli, and the viewing of both a loved and a hated face may constitute such a distressing signal.

"A marked difference in the cortical pattern produced by these two sentiments of love and hate is that, whereas with love large parts of the cerebral cortex associated with judgment and reasoning become de-activated, with hate only a small zone, located in the frontal cortex, becomes de-activated,” he added. (ANI)