Does nicotine harm brain cells?

Is it true that nicotine consumption can cause damage to brain cells? If so, how does it affect the brain and what specific areas are most impacted? Are there any studies that have confirmed this link, and if so, what are the long-term consequences of nicotine use on brain health? Are there any SAFE levels of nicotine consumption, or is it best to avoid it altogether to protect the brain from harm?