Chronoception refers to the sense of time that almost everyone experiences. This can refer to the lapse of time between events or the duration of the event. Chronoception is largely related to consciousness and memory. Because of this, many of the brain regions associated with chronoception also play a role in consciousness and memory. Additionally, chronoception plays a role in maintaining circadian rhythms in mammals. Some research suggests a connection between many psychological diseases (for example, schizophrenia or bipolar disorder) and a malfunction in the natural chronoception of the afflicted individual.
Associated Brain Regions
Widely spread throughout the brain, chronoception is linked to regions of the cerebral cortex, cerebellum, and basal ganglia. Chronoception is not specifically linked to one sensory system, but rather has nuclei spread throughout the brain. Moreover, this sense has nuclei located in almost all the other sensory systems. Research has shown that estimating the time it would take for something to happen in one of your senses activates that region. For example, if you are attempting to determine the duration of an auditory stimulus, regions of the auditory cortex are more activated. Similarly for visual stimuli, visual cortex regions are more active, and estimating the time it would take to complete an action stimulates regions in the primary motor cortex. This breadth of association is important as it takes the brain longer to process some stimuli over others. By having a larger associated region within the brain, chronoception is able to help combine the senses into a cohesive temporal experience. It is capable of integrating the time it will take you to respond to a stimulus that combines two or more of the senses, such as the approach of a fire engine with its siren on simultaneously providing a unified estimation of time.
Chronoception has been shown to play a very large role in the maintenance of circadian rhythms. One specific region chronoception has been closely associated with is the suprachiasmatic nucleus (SCN), which is located in the hypothalamus above the optic chiasm (crossing of the optic nerves into the brain). The SCN plays a large role in maintaining the body’s circadian rhythm, or sleep-wake cycles. Reduction of the light entering the eyes triggers the release of melatonin in the brain, which helps to signal that it is time to sleep. However, the circadian rhythm is not completely controlled by this, and a large part of it is due to the body’s natural sense of time. This has been demonstrated in the fact that most mammals, including humans, maintain their circadian rhythm during 24 hours of darkness.
It is likely that chronoception also plays a role in many other natural rhythms such as sleep patterns and circalunal rhythms (such as the human menstrual cycle). The brain cycles through sleep patterns during slumber. The two main patterns are REM (rapid eye movement) and non-REM sleep. These cycles are repeated throughout the duration of sleep at approximately 90-minute intervals. Chronoception likely plays a role in the maintenance of these cycles. Additionally, menstruation is timed by the body. While a large portion of this is controlled by hormones, chronoception does help with the timing of the cycle. However, a large number of inputs also play a role in the human menstruation cycle, including but not limited to stress, hormonal fluxes, pheromones, medications, and sex.
Time perception issues have been associated with a large number of neurological diseases and disorders. These include depression, Parkinson’s disease, attention deficit hyperactivity disorder (ADHD), and schizophrenia. Chronoceptive hallucinations are considered symptoms of these diseases. In these hallucinations the individual perceives time as moving much differently than it is. For example, something that happened an hour ago might appear to the person as having happened months ago or vice versa. Part of the reason for the association is that these diseases include an abnormality in dopamine levels within the brain. Some research has demonstrated that dopamine plays a large role in the integration of chronoception within the basal ganglia.
Riannon C. Atwater
See also: Circadian Rhythm
Lacquaniti, Francesco, Gianfranco Bosco, Silvio Gravano, Iole Indovina, Barbara La Scaleia, Vincenzo Maffei, & Myrka Zago. (2015). Gravity in the brain as a reference for space and time perception. Multisensory Research, 28(5—6), 397—426.