The complexity of the human brain - with its 86 billion neurons - has puzzled scientists ever since the Greek philosopher Plato attempted to understand how it worked . Now researchers are claiming that our brains may in fact be far simpler than had previously been believed - and it took research on sea slugs to reveal it . Neuroscientists based at Manchester University and the Rosalind Franklin University of Medicine and Science in Chicago , have studied the brains of sea slugs as they move . Researchers studied the brains of the sea slug Aplysia ( pictured above ) , which have around 18,000 neurons . Their brains , while far smaller than our own , share some of the complex structures of higher organisms while their neurons are large and easy to observe . The researchers found that rather than creating a mass of confusing signals that appear in scans of the human brain , they were able to see neurons acting as groups . The act of remembering may be one of the major reasons why we forget , researchers have said . The groundbreaking research was able to identify identify neural fingerprints of specific memories , distinguishing brain activity patterns produced when viewing a picture of a necklace , say , from a picture of Marilyn Monroe . The study proved that intentional recall is beyond a simple reawakening of a memory ; and actually leads us to forget other competing experiences that interfere with retrieval . The study from the University of Birmingham and the MRC Cognition and Brain Sciences Unit in Cambridge is the first to isolate the 'adaptive forgetting ' mechanism in the human brain . The brain imaging study found that remembering dynamically alters which aspects of our past remain accessible . They found that these groups were actually laid out like tiles to form a circuit . The scientists say that similar patterns exist in the brains of other organisms , including humans , but are scaled up by millions of times . Dr Mark Humphries , a Medical Research Council fellow at Manchester University who was involved in the research , said : 'What happens in the brain during movement is currently only well understood for small , dedicated neural circuits . 'This research introduces new methods for pulling apart neural circuits to expose their inner building blocks . 'Our methods could be used to help understand how brain networks change in disease states and how drugs act to restore normal brain function . ' Sea slugs have just 18,000 neurons in their entire nervous systems yet have been found to be remarkably similar to other organisms . Previous research has shown that they can form memories and signal muscle movements in the same way as higher organisms . Until recently scientists have had to study brain activity by looking at the action of individual neurons using electrodes . Even sophisticated brain scanning technology like functional magnetic resonance fails to provide a clear picture of how the brain is organised beyond its physical structures . The scientists studied neurons in the ganglion area of the brains of sea slugs , shown in the image above . The human brain ( shown in the model above ) is known to have specific structures that perform different roles but how neurons are organised within those has remained a mystery as studying them as they work is difficult . In the new research , which is published in the journal Neuron , the team of scientists were able to map how the large neurons in the brains of the sea slug Aplysia as they moved . Led by Angela Burno from the Rosalind Franklin University of Medicine and Science , the researchers were able to do this by using a voltage sensitive dye and detecting the tiny spikes in current that occurred in the slugs ' brains as the nerves that drive their muscles fired . They found there were four classes of neural ensembles that behaved in different ways - oscillatory , bursters , pausers and those where there was no strong activity . Until now scientists have had to study electrical signals of individual neurons or the whole brain ( like above ) These tended to be organised into modules or tiles that had related activity and pass signals between them in a loop . The researchers say the sea slugs could provide a useful analogy for when studying human brains . Professor William Frost , a cell biologist at the Rosalind Franklin University of Medicine and Science in Chicago , said : 'This is a really exciting time . 'This collaboration has created an approach that cuts the time taken to map neural networks from years to a few hours . '
Scientists at Manchester University studied brains of the Apylsia sea slug . They created maps that let them look at neuron networks across the brain . Sea slug brains share some of the complex structures of higher organisms . They found neurons formed groups that were laid out like tiles in the brain . Findings suggest the brain is organised in less complex way than believed . Researchers say it could help them unpick how the human brain works .