Stability of rTMS on Cognition and Brain Networks on Healthy Subjects.

Effect of Repetitive Transcranial Magnetic Stimulation (rTMS) on Cognition and Brain Networks in Healthy Subjects in 2 Sessions 15 Days Apart

Episodic and working memory processes are the most affected cognitive domains in Alzheimer's Disease (AD) and its early stage, Mild Cognitive Impairment (MCI).

Transcranial Magnetic Stimulation (TMS) is a unique tool to interfere with cognitive processes by inducing "virtual and transient lesions", mimicking those observed in MCI. It has proven repeatedly its capacity to interfere with encoding-retrieval memory task. However, to date, only few imaging data exist on the cerebral pathways involved in encoding memory task. Moreover, the stability of TMS effects over time remains to be investigated. If proven to be a stable interfering challenge, TMS could be used to investigate the potential restoring effect of new medication in AD.

The study is the pilot study of a larger clinical trial which aims to prove the utility of rTMS as a potential model for prediction of clinical efficacy using a combination of cognitive and neuroimaging endpoints.

Inclusion Criteria:

• Healthy male subjects aged between 18 and 40 years-old inclusive.
• Education level: at least secondary.
• Right-handed (Edinburgh Handedness Inventory).
• The subjects are in good health on the basis of the medical interview (medical history, symptoms), the physical examination and vital signs.
• No history of psychiatric disorders (assessed by Structured Clinical Interview for DSM IV Disorders (SCID) for Barcelona and by the Mini International Neuropsychiatric Interview (MINI) for Marseille).
• No history of neurological disorders
• No history of concussion (cranial or facial trauma) without or with loss of consciousness.
• Subject without history of brain disease (severe brain trauma, stroke, cerebral tumor...).
• Subject without lesion on MRI.
• Subject without abnormal electrical activities on standard clinical EEG.
• No history of drug or alcohol abuse.
• No smoker or ≤ 5 cg/ day.
• The subject can complete the neuropsychological test battery during the training session.
• Subject without contraindication to MRI.
• The subject is able to read and understand the Information Form and comply with the protocol instructions and restrictions.
• The subject is covered by a social insurance.
• The subject has provided written informed consent.

Exclusion Criteria:

• History or presence of psychiatric illness (Psychiatric interview).
• History or presence of neurologic illness.
• The subject, in the opinion of the investigator, is unlikely to comply with the study protocol or is unsuitable for any other reason.
• The subject participates in another clinical trial or is still being within a washout period of 1 month since last taking of a previous clinical trial, or subjects who have received more than 4500 Euros in the previous 12 months for participating in clinical trials.
• Presence of metallic objects within the body.
• Subjects with pacemaker.
• Claustrophobia.
• Individual and familial history of epileptic seizure.
• Any medication listed (see annexe) in the safety guidelines published by the Safety of TMS Consensus Group (Rossi et al., 2009) will be forbidden.
• Subject with a correct hit rate during the retrieval session of the memory task