The research comes from Northwestern University, with a focus on asking a perennial question – can pets tell the time? The answer appears to be ‘yes’. This answer is based on an examination of the brain’s medial entorhinal cortex. Through this the scientists discovered a set of neurons, which had not previously been discovered, that function to switch on something analogous to an internal a clock. This appears to trigger when the animal is waiting.
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If the question was posed – does your dog or cat know that you took twice as long to feed it today as it did yesterday – the answer is that the animal does. According to lead researcher Dr. Daniel Dombeck: “This is one of the most convincing experiments to show that animals really do have an explicit representation of time in their brains when they are challenged to measure a time interval.”
Dr. Dombeck’s research team undertook a study of the medial entorhinal cortex. This is an area of the brain located in the medial temporal lobe and functioning as a hub in a widespread network for memory, navigation and the perception of time. This region of the brain encodes spatial information in episodic memories. The researchers were keen to establish if this area of brain was also responsible for encoding time.
Episodic memories have two features – space and time. By space, this means a particular, often familiar, environment. Take a human. If a person can recall their sixth birthday party, but not what they were doing the day before their sixth birthday, this is an episodic memory.
The research used what is called a virtual “door stop” experiment, using mice running on a treadmill (which was physically present) against a virtual reality background. Through the study, the rodent learns to run down a hallway to a door, positioned halfway down the track. After six seconds, the door opens, and the mouse continues along the hallway to gain a food reward.
After several exercises, the researchers made the door invisible. However, the trials showed that the mouse still knows where the door is. The researchers say this is linked to the brain’s sense of time. This was further demonstrated by changing other parameters in the virtual reality program. Further analysis showed how the “timing cells” in brain do not operate during active running, only at rest. In this state, the cells encode how much time the animal has been resting.
The research findings have been published in the journal Nature Neuroscience. The research is titled “Evidence for a subcircuit in medial entorhinal cortex representing elapsed time during immobility.”
