Post-mortem studies have shown a reduction of the nicotinic receptors density in Alzheimer's disease in temporal cortex and hippocampus. Similarly, in Parkinson's diseases, nicotinic receptor density have been shown to be reduced in fronto-temporal cortex and in pedoculo-pontin nuclei. Recently, point mutation on nicotinic receptor sub-units (alpha4 or beta2) have been objectived in a familial epilepsy: the Autosomic Dominant Noctural Frontal Lobe Epilepsy (ADNFLE). Nicotinic receptor are also involved in tobacco addiction, as they are the main brain target of the nicotine from the cigarette smoking. Human post-mortem studies and animal models suggest that nicotinic receptor density is increased in chronic smoker.