How the brain's inner clock measures seconds

September 17, 2020

BACKGROUND

Tracking the passage of time to the second is critical for motor control, learning and cognition, including the ability to anticipate future events. While the brain depends on its circadian clock to measure hours and days, the circadian clock does not have a second hand.

Instead the brain measures seconds through changing patterns of cellular activity. Much like a line of falling dominoes, each neuron activates the next, and time is marked by the neuron that is currently active. By analogy, if a sequence of falling dominoes takes 10 seconds from start to finish, one can deduce that 5 seconds has elapsed when the middle domino falls.

FINDINGS

UCLA neuroscientists introduced mice to two different scents. The mice learned that one odor predicted the arrival of a sweet liquid reward after three seconds, while the other odor predicted a reward after six seconds. The mice started licking the spout earlier in anticipation of the reward after they sniffed the first scent than when they smelled the second.

Recordings in the striatum and premotor cortex of the brain revealed that changing patterns of neural activity in both regions encoded time--consistent with the notion that the brain has multiple clocks. But the pattern in the striatum was closer to the sequence of falling dominoes--a pattern referred to as a neural sequence--compared to the patterns in a motor area that provides input to the striatum.

IMPLICATIONS

Timing is a fundamental part of human behavior, learning and thought. By revealing how and where the brain counts and represents seconds, the UCLA discovery will deepen scientists' understanding of normal and abnormal brain function.
-end-
AUTHORS

Dean Buonomano, professor of neurobiology, and Sotiris Masmanidis, associate professor of neurobiology at the David Geffen School of Medicine at UCLA, are available for comment.

FUNDING

Grants from the National Institute of Neurological Diseases and Stroke, the National Science Foundation and Marion Bowen Neurobiology Postdoctoral Grant Program at UCLA supported the research.

PUBLICATION

The journal Neuron published the findings.

University of California - Los Angeles Health Sciences

Related Circadian Clock Articles from Brightsurf:

Pinpointing the cells that keep the body's master circadian clock ticking
UT Southwestern scientists have developed a genetically engineered mouse and imaging system that lets them visualize fluctuations in the circadian clocks of cell types in mice.

The discovery of new compounds for acting on the circadian clock
The research team comprised of Designated Associate Professor Tsuyoshi Hirota and Postdoctoral Fellows Simon Miller and Yoshiki Aikawa, of the Nagoya University Institute of Transformative Bio-Molecules, has succeeded in the discovery of novel compounds to lengthen the period of the circadian clock, and has shed light on their mechanisms of action.

Let there be 'circadian' light
Researchers publishing in Current Biology describe the science behind creating lighting to make us all happy and productive indoors.

U of M research discovers link between stress and circadian clock health
New research from the University of Minnesota Medical School found a little stress can make the circadian clock run better and faster.

The role of GABA neurons in the central circadian clock has been discovered
Temporal order of physiology and behavior is regulated by the central circadian clock located in the SCN.

Researchers take aim at circadian clock in deadly brain cancer
Scientists at USC and UC San Diego have discovered a potential novel target for treating glioblastoma, the deadly brain cancer that took the life of Sen.

Circadian clock and fat metabolism linked through newly discovered mechanism
Princeton University researchers found that the enzyme Nocturnin, known for its role in fat metabolism and circadian rhythm, acts on two well-established molecules in metabolism.

Dead zones in circadian clocks
Circadian clocks of organisms respond to light signals during night but do not respond in daytime.

Circadian clock plays unexpected role in neurodegenerative diseases
Northwestern University researchers induced jet lag in a fruit fly model of Huntington disease and found that jet lag protected the flies' neurons.

Researchers locate circadian clock that controls daily rhythms of aggression
Synchronized by light and darkness, the circadian clock exerts control over wake/sleep cycles, body temperature, digestion, hormonal cycles and some behavior patterns.

Read More: Circadian Clock News and Circadian Clock Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.