New study finds ‘time cells’ could be key to early Alzheimer’s diagnosis

The discovery of how the brain processes time could one day help detect the early onset of neurodegenerative diseases like Alzheimer’s that affect time perception, give hope to millions living with the condition.

A study from the University of Utah found in mice that a specific set of “time cells” is essential for learning complex behaviors where timing is crucial and these cells fire in an order to map out short periods of time.

Crucially, however, the research team found that as the animals learn to distinguish between differently timed events, the pattern of time cell activity changed to represent each pattern of events differently.

By using advanced brain imaging, the team could  watch the patterns of time cell activity in mice as the rodents were given increasingly complex time-based learning tasks and see how time cells fire in real time.

Initially the rodents’ time cells responded in the same way to every stimulus task. However, as they learned the differently timed patterns of stimulus, the mice would develop different patterns of time cell activity for each pattern of events.

Co-lead author and neurobiologist Dr Hyun-Woo Lee said when the mice got it wrong, the researchers could see that their time cells had often fired in the wrong order, which suggested that the right sequence of time cell activity is critical for performing time-based tasks.

“Time cells are supposed to be active at specific moments during the trial,” he said.

“But when the mice made mistakes, that selective activity became messy.”

However, when the researchers blocked the medial entorhinal cortex (MEC), the activity of the brain region that contains time cells, the mice could still perceive and anticipate the timing of events but they couldn’t learn complex time-related tasks from scratch.

Fellow co-lead author, Erin Bingus said this showed showed that the MEC is more complex and it plays a more complicated role than merely tracking time.

“The MEC isn’t acting like a really simple stopwatch that’s necessary to track time in any simple circumstance,” Bigus said.

“Its role seems to be in actually learning these more complex temporal relationships.”

Although previous studies on the MEC found it was involved in learning spatial information (and building “mental maps,”) this new research found that patterns of brain activity recorded while learning time-based tasks showed some similarities to previously observed patterns involved in spatial learning, while these aspects of both patterns persist even while an animal isn’t actively learning.

Although more research is needed, researcher James Hey said their results suggest that the brain could process space and time in fundamentally similar ways while the anentorhinal cortex might serve a dual purpose, as both as an odometer to track distance and as a clock to track time.

These are the first areas of the brain to be affected by neurodegenerative diseases like Alzheimer’s. We are interested in exploring whether complex timing behavior tasks could be a useful way to detect the early onset of Alzheimer’s disease,” said Heys.

Closer to home, engineers at Monash University developed a small, handheld device that uses world-first patented sensor technology to detect ultra-low concentrations of disease markers in blood within minutes. This innovation is expected to enable GPs to diagnose Alzheimer’s at an early stage.

Associate Professor Sudha Mokkapati from Monash Materials Science and Engineering, developed the proof-of-concept electronic sensor, stating that the device is “simple to use, low-cost and portable so it could be made widely accessible to GPs to screen patients right at the point-of-care”.

“Detecting very early disease in large populations could dramatically change the trajectory of this burdening disease for many patients, and shave millions off associated healthcare costs,” Mokkapati said.