Neural correlates of cognitive dissonance and choice-induced preference change

According to many modern economic theories, actions simply reflect an individual's preferences, whereas a psychological phenomenon called “cognitive dissonance” claims that actions can also create preference. Cognitive dissonance theory states that after making a difficult choice between two equally preferred items, the act of rejecting a favorite item induces an uncomfortable feeling (cognitive dissonance), which in turn motivates individuals to change their preferences to match their prior decision (i.e., reducing preference for rejected items). Recently, however, Chen and Risen [Chen K, Risen J (2010) J Pers Soc Psychol 99:573–594] pointed out a serious methodological problem, which casts a doubt on the very existence of this choice-induced preference change as studied over the past 50 y. Here, using a proper control condition and two measures of preferences (self-report and brain activity), we found that the mere act of making a choice can change self-report preference as well as its neural representation (i.e., striatum activity), thus providing strong evidence for choice-induced preference change. Furthermore, our data indicate that the anterior cingulate cortex and dorsolateral prefrontal cortex tracked the degree of cognitive dissonance on a trial-by-trial basis. Our findings provide important insights into the neural basis of how actions can alter an individual's preferences

Mitotic blockage following laser micro-irradiation of prosphase chromosomes

An argon laser microbeam was used to irradiate prophase chromosomes of the salamander () and the established cell of the rat kangaroo (PTK1, ). In both cell types mitosis was significantly blocked when irradiation occurred in early prophase regardless of whether or not the irradiated chromosomes were nucleola-associated. It was also determined that with identical irradiation conditions, the salamander cells were more susceptible to mitotic inhibition than the kangaroo cells. The results are compared with earlier studies performed with lower energy densities.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34174/1/0000463.pd