Time flies when you’re having fun: what time can teach us about the brain

Most people experience shifts in perceived time whether they notice or not. When you feel bored or anxious, thirty minutes can feel more like several hours. On the other hand, thirty minutes might quickly slip away if you’re having fun. The number of minutes measured by the clock are the same in both cases, but your own experience of the same length of time changes based on how you feel! How do our brains create that subjective difference in time?

Understanding how sensory organs like our eyes and ears communicate with our brains to produce sensations like sight and sound has been a major goal in neuroscience for decades. Scientists have been able to identify the pathways from our external sensory organs (like our eyes and ears) to our brains and understand how our brain creates the sensations we feel. However, some sensations, such as the feeling of time passing cannot be attributed to any of our sensory organs. Do our hands feel time passing? Do our ears hear time passing? No, there is no obvious sensory route for the brain to get information about how long 30 seconds feels. Therefore, studying our brain’s way to perceive time gives neuroscientists the opportunity to study how we process information about something universal, yet intangible.

Luckily for neuroscientists, the ability to track time in seconds-to-minutes is preserved across many different species, including common laboratory animals like mice, rats, and birds[1], [2]. Scientists can test timing tasks in animals that are almost identical to timing tasks used in human research. Behavioral experiments that study time often use operant chambers, which are boxes where rodents canmake responses to earn rewards  while scientists monitor their movement and brain function. Researchers can record the activity of brain cells while animals time their responses to match different lengths of time, such as 10 or 20 seconds. Neuroscientists can then use those brain cell activity measurements to make theories about how the brain represents time[3]. We can not only use animal models to learn more about how the brain tracks time under normal circumstances, but also to study how time perception changes in people with brain diseases.

Our brain isn’t able to properly produce time intervals in many neuropsychiatric and neurodevelopmental disorders such as schizophrenia, Parkinson’s disease, and autism spectrum disorders[4]–[6]. Importantly, each of these patient populations displays a different general pattern of timing impairments. For example, when patients with Parkinson’s disease are tasked with mentally measuring two different lengths of time, such as 8 seconds vs. 21 seconds, they have a ‘migration effect’ where their estimates for each length of time are closer to the other length of time they experienced [4]. Ways of producing the same ‘migration effect’ in timing can then be tested in the lab. If the experimental changes in the brains of lab animals produces the same pattern of impaired timing behavior, it offers a clue into what might be happening in the brains of patients. Therefore, time perception has great potential to reveal how brain function is affected in many brain disorders [7], [8]. 

Citations: 

[1] C. Malapani and S. Fairhurst, “Scalar Timing in Animals and Humans,” Learning and Motivation, vol. 33, no. 1, pp. 156–176, Feb. 2002, doi: 10.1006/lmot.2001.1105.

[2] C. V. Buhusi and W. H. Meck, “What makes us tick? Functional and neural mechanisms of interval timing,” Nat Rev Neurosci, vol. 6, no. 10, pp. 755–765, Oct. 2005, doi: 10.1038/nrn1764.

[3] P. Simen, F. Balci, L. deSouza, J. D. Cohen, and P. Holmes, “A Model of Interval Timing by Neural Integration,” Journal of Neuroscience, vol. 31, no. 25, pp. 9238–9253, Jun. 2011, doi: 10.1523/JNEUROSCI.3121-10.2011.

[4] C. Malapani et al., “Coupled Temporal Memories in Parkinson’s Disease: A Dopamine-Related Dysfunction,” Journal of Cognitive Neuroscience, vol. 10, no. 3, pp. 316–331, May 1998, doi: 10.1162/089892998562762.

[5] S. Thoenes and D. Oberfeld, “Meta-analysis of time perception and temporal processing in schizophrenia: Differential effects on precision and accuracy,” Clinical Psychology Review, vol. 54, pp. 44–64, Jun. 2017, doi: 10.1016/j.cpr.2017.03.007.

[6] S. Isaksson, S. Salomäki, J. Tuominen, V. Arstila, C. M. Falter-Wagner, and V. Noreika, “Is there a generalized timing impairment in Autism Spectrum Disorders across time scales and paradigms?,” Journal of Psychiatric Research, vol. 99, pp. 111–121, Apr. 2018, doi: 10.1016/j.jpsychires.2018.01.017.

[7] R. D. Ward, C. Kellendonk, E. R. Kandel, and P. D. Balsam, “Timing as a window on cognition in schizophrenia,” Neuropharmacology, vol. 62, no. 3, pp. 1175–1181, Mar. 2012, doi: 10.1016/j.neuropharm.2011.04.014.

[8]F. Balcı and D. Freestone, “The Peak Interval Procedure in Rodents: A Tool for Studying the Neurobiological Basis of Interval Timing and Its Alterations in Models of Human Disease,” BIO-PROTOCOL, vol. 10, no. 17, 2020, doi: 10.21769/BioProtoc.3735.

Edited by Alexandra Fink