The quoted text in the query appears in
https://iveybusinessjournal.com/publication/neuroscience-and... (Page 5.) which refers to the original publication.
"The benefits of arousing positive emotions over negative ones have been demonstrated by Fredrickson and Losada (2004) and others. A contagion of positive emotions seems to arouse the Parasympathetic Nervous System, which stimulates adult neurogenesis (i.e., growth of new neurons) (Erickson et. al., 1998), a sense of well being, better immune system functioning, and cognitive, emotional, and perceptual openness.
(McEwen, 1998; Janig and Habler, 1999; Boyatzis, Jack, Cesaro, Passarelli, & Khawaja, 2010)."