Will the same worm respond differently in a situation depending on what it is thinking ? According to new research studying neurons within microscopic roundworms , the answer is an emphatic ‘ yes ’ . They found that worms would choose to respond to a nearby odour depending on what they were ‘ thinking ’ about - suggesting they have free will just like humans . The study was carried out by scientists at Rockefeller University in New York . They found roundworms ( pictured ) would sometimes 'think ' for themselves . All the neurons within this microscopic roundworm are highlighted , with the large cluster at one end representing the brain . The research was carried out by scientists from the Rockefeller University in New York who studied the brain of the microscopic roundworm Caenorhabditis elegans . Its 302 neurons and 7,000 synapses are comparatively tiny compared to the 86 billion neurons and 100 trillion synapses in a human brain . But it is still useful to address tricky neurological questions that would be nearly impossible to broach in our own brains . Worms spend their time wandering , looking for decomposing matter to eat - and when they smell it , they usually stop making random turns and travel straight toward the source . This change in behaviour is initially triggered by a sensory neuron that perceives the smell and feeds that information to the network the researchers studied . As the worms pick up the alluring fruity smell of isoamyl alcohol , the neurons in the network transition into a low activity state that allows them to approach the odour . But sometimes the neurons remain highly active , and the worm continues to wander around - even though its sensory neuron has detected the odour . They found that , if offered a 'delicious ' smell , the roundworm will usually stop its wandering to investigate the source - but sometimes it won ’ t . Just as with humans , the same stimulus does not always provoke the same response , even from the same individual . ‘ We found that the collective state of the three neurons at the exact moment an odour arrives determines the likelihood that the worm will move toward the smell , ’ said study author Dr Cori Bargmann . ‘ So , in essence , what the worm is thinking about at the time determines how it responds . ‘ It goes to show that nervous systems aren ’ t passively waiting for signals from outside , they have their own internal patterns of activity that are as important as any external signal when it comes to generating a behaviour. ’ The researchers also found that by changing the activity of the neurons individually , and in combination , they could pinpoint each neuron ’ s role in generating variability . In humans , the research may suggest ways in which our brains process competing motivations . 'For humans , a hungry state might lead to you walk across the street to a delicious smelling restaurant , ' said author Andrew Gordus . 'However , a competing aversion to the cold might lead you to stay indoors ' ( stock image ) By recording the activity of the neurons , the team found that there were three persistent states among the three neurons : All were off , all were on , or only one , called AIB , was on . If all were off when the odour signal arrived , they stayed off . If all were on , they often - but not always - shut off . By recording the activity of the neurons , the team found that there were three persistent states among the three neurons : All were off , all were on , or only one , called AIB , was on . If all were off when the odour signal arrived , they stayed off . If all were on , they often - but not always - shut off . And , in the third and most telling scenario , if AIB alone was active when the odour arrived , everything shut off . 'This means that for AIB , context matters , ' continued author and research associate Andrew Gordus . AIB is the first neuron in the network to receive the signal , which it then relays to the other two network members , known as RIM and AVA ; AVA sends out the final instruction to the muscles . And , in the third and most telling scenario , if AIB alone was active when the odour arrived , everything shut off . 'This means that for AIB , context matters , ' continued author and research associate Andrew Gordus . 'If it ’ s on alone , its activity will drop when odour is added , but if it ’ s on with the rest of the network , it has difficulty dropping its activity with the others . ' AIB is the first neuron in the network to receive the signal , which it then relays to the other two network members , known as RIM and AVA ; AVA sends out the final instruction to the muscles . When the researchers shut off RIM and AVA individually and together , they found AIB ’ s response to the odour signal improved . This suggests that input from these two neurons competes with the sensory signal as it feeds down through the network . Scaled up to account for the more nuanced behaviours of humans , the research may suggest ways in which our brains process competing motivations . 'For humans , a hungry state might lead to you walk across the street to a delicious smelling restaurant , ' said Professor Gordus . 'However , a competing aversion to the cold might lead you to stay indoors . '
Study was carried out by scientists at RIM in New York . They found worms would sometimes 'think ' for themselves . If offered an odour , they would sometimes - but not always - investigate . Even the same individual did not always have the same response . It suggests that like humans , the worms may have a sense of 'free will '