I-Function with Circadian Rhythms

            The circadian rhythm’s independent internal activity is observable when mismatched with separate incoming patterns of activity input from the environment. Circadian rhythm is the body’s internal twenty-four hour clock that regulates biological processes such as wakefulness, metabolic rate, and body temperature. The internal clock is fundamental to a living organism’s daily activity. (1)  Seasonal changes can cause the environmental inputs to be interpreted as different from the circadian rhythms. A person’s daily behavior can modify to the surrounding environment. As a result, the I-function is stimulated by a difference and the person becomes uncomfortably aware of the environmental change.  The body’s circadian rhythms neurological signals go unnoticed until a change creates inputs different from those of the internal body clock.

            Seasonal Affective Disorder (SAD) stimulates the I-function because of a difference between inputs from the environment and circadian rhythms. This seasonal disorder causes depression and other psychosomatic symptoms due to a lack of sunlight exposure in the winter months. (2) The amount of sunlight and the action potentials it causes in the body are the inputs from the environment. In winter, decreased amounts of sunlight reach the hormone melatonin and the eye’s photoreceptors than in the other seasons. (2) Melatonin and the photoreceptors send out fewer action potentials because of the decrease in light. As a result, the nervous system has an output of depression, oversleeping and overeating.

People with SAD feel these changes in their body; therefore, the I-function must be stimulated. The lack of action potentials puts the person on different daily cycle from that of the circadian rhythms. The person needs to be aware of the difference and sense the changes in order to adapt. As a result, the difference between the behaviors generated from the internal body clock and the environment stimulate the I-function.

            Not all people, however, experience SAD for numerous reasons. Besides several biological reasons, could the degree of difference between the input from the environment and the circadian rhythms not be significant enough to stimulate the I-function during winter? Could the I-function sensitivity vary among individuals?

The body has an infinite number of neurons that can create infinite patterns of activity. A few signals from a select number of neurons can exponentially trigger other neurons, which in turn produce a high frequency of action potentials. The nervous system interprets the environmental signals and through many connections of neurons, produces a higher amount of neural activity. In the case of SAD, it seems possible to produce an output closer to the circadian rhythm output because of a certain patterns of neuron connections.

Despite the increased level of neural activity, some nervous systems may consider the level similar to the circadian rhythms while others may not. There could be enough neural activity to not cause a significant difference; however, the likelihood that it will be significant is raised. The I-function would not be simulated because the patterns of activity are the same and the person does not feel a change in the body.

            Circadian rhythms are subject to change in order to adjust to the surrounding environment. Light therapy commonly treats people affected by SAD by exposing the body to artificial UV light in winter. A 10,000-lux light box produces UV light which should be absorbed daily by the body for 10-15 minutes session. (3) Light triggers action potentials from the skin’s sensory neurons and the eye’s photoreceptors. The action potentials created by phototherapy best increase the amount of neural activity. Usually, these levels equal or come closer to the circadian rhythms signals. Phototherapy directly affects the number of neuron signals sent to the nervous system. SAD symptoms are reduced with proper and consistent use of light therapy.

            The nervous system is continuously bombarded with inputs and outputs rendering it impossible to be conscious of all neural activity. Signals that reach the I-function result in a person being aware of the patterns of activity occurring in the nervous system. Otherwise, signals that do not reach the I-function are not consciously noticed by the person. When signals from the environment are constant and steady, the nervous system eventually does not send those signals to the I-function. Constant signals do not necessarily need to be detected by a person; rather, a person needs to be aware of changes or disruptions.

WORKS CITED

1. http://www.clevelandclinic.org/health/health-info/docs/3700/3712.asp?index=12115

General overview of circadian rhythms

2. http://www.nami.org/Content/ContentGroups/Helpline1/Seasonal_Affective_Disorder_(SAD).htm

General overview of Seasonal Affective Disorder and winter blues

3.  http://www.clevelandclinic.org/health/health-info/docs/1400/1484.asp?index=6412

Seasonal Affective Disorder and Light Therapy