The effect of non-invasive neuromodulation of the pineal gland in healthy, adult males

INTERVENTION: The sleep hygiene of healthy adult, male participants, between 18‐55 years old is appraised for three nights prior to the experimental intervention. Participants’ sleep hygiene will be assessed via both subjective and objective measures. The subjective measures will be recorded via the use of a sleep diary which records subjective reporting of information pertaining to sleep time, wake time, time spent asleep, number of awakenings, length of time spent awake, ease of falling asleep, sleep disturbance, feeling of refreshment following awakening, caffeine and alcohol consumption, heavy meal consumption 2‐3 hours prior to sleep, the likelihood of daytime dozing, and mood. Objective measures obtained from the wrist‐worn actigraph devices include: sleep time, wake time, sleep duration, sleep onset latency, wake after sleep onset, sleep efficiency, light exposure, and any time the actigraph device was not worn. If participants’ sleep hygiene is assessed as suitable for the study, they progress to the experimental phase. The experimental phase consists of a researcher‐lead stimulation session during the day and a participant‐lead stimulation session during the night. Each stimulation frequency is applied for one day time and one night time phase. For the experimental phase during the day, measures of sleepiness, pupil diameter, and blood flow changes are captured using electroencephalography (EEG), eye‐tracker glasses, and pulse oximetry, respectively. These measures are used before, during, and after 10 minutes of transcutaneous electrical nerve stimulation (TENS) delivered at the C2 dermatome. Saliva samples are collected before and after stimulation. The experimental phase during the night is conducted in participants’ homes. Here, they self‐administer TENS stimulat CONDITION: Mental Health ‐ Studies of normal psychology, cognitive function and behaviour Neurological ‐ Studies of the normal brain and nervous system Sleep ; ; Sleep; ; ; PRIMARY OUTCOME: Effect of electrical stimulation of the C2 dermatome on the sleep time measured objectively via wrist‐worn actigraphy.[This will be continuously measured during sleep for each intervention night. This is a primary objective.] Effect of electrical stimulation of the C2 dermatome on melatonin levels[measured using pre‐ and post‐stimulation saliva sampling and subsequent ELISA (Buhlmann direct saliva melatonin ELISA)] Effect of electrical stimulation of the C2 dermatome on wake time measured objectively via wrist‐worn actigraphy. [This will be continuously measured during sleep for each intervention night.] SECONDARY OUTCOME: Effect of electrical stimulation of the C2 dermatome on blood flow to the superficial structures of the head and neck measured using pulse oximetry[Measured continuously for 10‐minutes before, 10‐minutes during, and 10 minutes following daytime stimulation] Effect of electrical stimulation of the C2 dermatome on ease of falling asleep. INCLUSION CRITERIA: Healthy, (no neurological/cognitive impairments and not on any regular medication) male volunteers between the ages of 18 and 55 years old, with good sleep hygiene and no problems associated with sleep. ; [This will be measured subjectively via self‐reporting using a sleep diary once following waking up after each intervention night. ] Effect of electrical stimulation of the C2 dermatome on mood.[This will be measured subjectively via self‐reporting using a sleep diary once following waking up after each intervention night. ] Effect of electrical stimulation of the C2 dermatome on pupil diameter measured using eye tracker glasses (Tobii Pro eye tracker)[Measured continuously for 10‐minutes before, 10‐minutes during, and 10 minutes following daytime stimulation ] Effect of electrical stimulation of the C2 dermatome on sedation measured using bispectral (BIS) index of EEG recordings[Measured continuously for 10‐minutes before, 10‐minutes during, and 10 minutes following daytime stimulation] Effect of electrical stimulation of the C2 dermatome on sleep duration.[This will be continuously measured during sleep for each intervention night and will be measured objectively via wrist‐worn actigraphy. This is a primary objective.] Effect of electrical stimulation of the C2 dermatome on sleep efficiency.[This will be continuously measured during sleep for each intervention night and will be measured objectively via wrist‐worn actigraphy. This is a primary objective.] Effect of electrical stimulation of the C2 dermatome on sleep onset latency.[This will be continuously measured during sleep for each intervention night and will be measured objectively via wrist‐worn actigraphy. This is a primary objective.] Effect of electrical stimulation of the C2 dermatome on the feeling of refreshment upon awakening.[This will be measured subjectively via self‐reporting using a sleep diary once following waking up after each intervention night. ] Effect of electrical stimulation of the C2 dermatome on the likelihood of daytime dozing.[This will be measured subjectively via self‐reporting using a sleep diary once following waking up after each intervention night. ] Effect of electrical stimulation of the C2 dermatome on wake after sleep onset.[This will be continuously measured during sleep for each intervention night and will be measured objectively via wrist‐worn actigraphy. This is a primary objective.]