The clock is ticking: a critical review of understanding the neural basis for biological clocks

Abstract

Time and biology share a unique relationship. The biological clock plays a pivotal role in maintaining our daily well-being. There is a presence of cycles which vary from ultradian (short) to circadian (long). The rhythms produced by biological clocks, are responsible for the interaction with cells from various parts of the body. Biological clocks drive basic behaviours such as eating and sleeping as well as complex behaviours such as seasonal migration. The clocks that regulate processes of life do so over an extensive range of time: from seconds of neuronal activity to changes in the season that makes a shift in the daylight over the course of one year. Our biological clocks not only influence our sleep-wake cycles but also hold an important role in regulating other day-to-day activities such as alertness, metabolism, appetite, mood, so on. A dysfunction in biological clock is linked to various disorders such as diabetes, insomnia and depression, among others. The following review is an investigation of timing as it has formed a rich literature. It lays emphasis on the relationship between neural basis and sleep-wake cycle. It addresses the role of serotonin because it synthesizes melatonin, a hormone that is released at night which helps in regulating the body’s biological clock.  It also addresses the relationship between biological clocks and its neural basis, the role of pineal gland, genes and environment. Lastly, the review emphasises on the need for more research in drug efficacy since there are studies that show a link between the timing of drugs based on our biological clocks.