One common finding is that nicotine administration (Domino et al. 2000b; Stapleton et al. 2003b) or cigarette smoking (Yamamoto et al. 2003) results in decreased global brain activity. Similarly, smokers who smoke ad lib prior to SPECT scanning (including the morning of the scan) have decreased global brain activity compared to former smokers and nonsmokers (Rourke et al. 1997). These findings are generally supported by studies using transcranial Doppler ultrasound or the Xe 133 inhalation method to measure responses to smoking, with some (Cruickshank et al. 1989; Kubota et al. 1983, 1987; Rogers et al. 1983), but not all (Kodaira et al. 1993; Terborg et al. 2002), studies showing diminished cerebral blood flow.
