For tens of thousands of years dogs have been man's best friend, paying close attention to our faces to read our emotions and form a long-lasting bond.

Now, researchers have pinpointed the specific regions of a dog's brain that enable them to form such a strong connection.

By placing dogs in scanners, the experts have found the temporal cortex processes human faces and is the 'pillar of social cognition in dogs'.

Researchers have pinpointed the specific regions of a dog's brain that enable dogs to recognise and read faces. They found the temporal cortex (shown on the FMRI scan above) probably processes human faces and is the 'pillar of social cognition in dogs'.

Researchers at the National Autonomous University of Mexico in Querétaro trained seven domestic dogs to remain awake, still and unrestrained so they could scan their brains using a using functional magnetic resonance imaging (fMRI) machine.

They comprised five border collies, one Labrador retriever and one golden retriever.

While lying still in the scanner, the dogs were shown colour photographs of 50 unfamiliar human faces of both genders with a neutral expression extracted,as well as 50 everyday objects.

Researchers at the National Autonomous University of Mexico in Querétaro trained seven domestic dogs to remain awake, still and unrestrained so they could scan their brains using a using functional magnetic resonance imaging (fMRI) machine. The process and dogs are shown above

The dogs studied comprised five Border collies, one Labrador retriever and one golden retriever (all shown above) While lying still in the scanner, the dogs were shown colour photographs of 50 unfamiliar human faces of both genders with a neutral expression extracted,as well as 50 everyday objects

THE TRAINING PROCESS Owners of disobedient dogs may wonder how the canines were trained to keep still in the fMRI scanner. During a period of around four months, the dogs learned to sit still and watch images. They first learned to rest their chin and avoid movement in a wooden stand. They then got used to the scanning environment, including the noises and use of protective headphones in a mock scanner. They were then trained further in the real scanner and habituated to its imaging coils. Upon completion of training, all the dogs were able to lie still and stay awake for 15 minutes. Advertisement

These images were flashed up on a screen a comfortable distance in front of the dogs and were shown in 'blocks'.

Each 'block' of four images was displayed for seven seconds and 10 blocks were shown in a single session, lasting 190 seconds.

The researchers found: 'The perception of faces changed significantly in several brain regions, but mainly in the bilateral temporal cortex.'

The brain region is associated with the processing of sensory input to form visual memories and understand emotions, for example.

Other regions included the right frontal cortex, medial frontal cortex, thalamus and caudate nucleus.

'The opposite contrast (i.e. everyday objects against human faces) showed no significant brain activity change,' the study, published in the journal Plos One explained.

The study sheds light on the evolution of facial recognition in mammals.

The researchers wrote: 'We suggest that this portion of the temporal cortex in dogs [associated with facial recognition] could be anatomically and functionally similar to regions found in other species, like humans non-human primates and sheep, which suggests a high degree of evolutionary conservation of the ventral visual pathway for face processing.'

These images (examples shown) were flashed up on a screen a comfortable distance in front of the dogs and were shown in 'blocks'. Each 'block' of four images was displayed for seven seconds and 10 blocks were shown in a single session, lasting 190 seconds