Nicotine does not enhance basic semantic priming

Rationale: Utilising a cognitively demanding strategy-based priming paradigm, we recently observed that acute transdermal nicotine selectively influenced controlled semantic processing but not related-word links within semantic memory per se as reported by Holmes et al. (Int J Neuropsychopharmacol 11:389-399, 2008). Objective: The current study employed a less cognitively demanding priming paradigm to investigate whether nicotine influences the activation/access of links within semantic memory, and if the selective nicotinic influence on controlled but not automatic semantic processing could also be observed with these more general priming procedures. Methods: Transdermal nicotine patches (7 mg/24 h) were administered to healthy young adults in a double-blind, placebo-controlled, crossover design. The automatic priming task (∈n∈∈=∈18) had a low relatedness proportion (RP) and was presented at a short stimulus onset asynchrony (SOA), while the controlled priming task (∈n∈∈=∈18) had a high RP and long SOA. Results: The patterns of priming effects indicated that automatic and controlled processing were operating for the respective tasks. However, a nicotinic influence on semantic processing was not evident for either task, nor was interplay of nicotine and relatedness observed. Conclusions: Together, the findings from the previous and current study suggest that an influence of nicotine on semantic processing may only emerge when effortful controlled processing is invoked. Furthermore, the findings suggest that nicotinic modulation of links within semantic memory may only be mediated by mnemonic processes.