Watching short emotional movie clips robustly activates the human dorsal visual stream areas
Rapid advances in neuroimaging method development are currently making it possible to answer one of the most intriguing questions in cognitive neuroscience, specifically, how does seeing emotion-arousing events in one’s environment modulate the various systems (e.g., emotional, attentional, somatomotor) of the brain. Up until relatively recently, neuroimaging studies on the neural basis of emotions utilized stimuli such as emotional pictures and sounds to delineate brain structures responding to emotional events. More naturalistic stimuli such as movies that elicit more robust and genuine emotions have been used recently and in such early studies, more extensive set of brain areas have been shown to be modulated by emotional valence and arousal than in studies using more artificial stimuli, thus warranting further research into the neural basis of emotions with naturalistic stimuli.
In their recent study, Goldberg et al. (2014) presented healthy volunteers with short ~14 s clips taken from commercial movies during functional magnetic resonance imaging of brain hemodynamic activity. The subjects had prior to the scanning session watched longer clips of ~a few minutes that contained the short experimental clips to familiarize the subjects with the emotional events and content of the clips. The clips ranged from neutral to strongly emotional, which was used in modeling hemodynamic activity. In separate control experiments the clips were played upside down, and the soundtrack and video inputs were mixed, to control for the possibility of low-level sensory differences between emotional and neutral clips. The authors observed responses to emotional clips in a number of brain areas, however, the most robust responses to emotionally arousing clips were noted in the dorsal visual stream.
These highly interesting findings of dorsal stream activity enhancement by emotionally arousing movie clips are interpreted by the authors to indicate initial step in the chain of events ultimately leading to action towards emotionally meaningful objects. Methodologically, the study also presents an interesting and a potentially very useful advance: by familiarizing the subjects with the movie material in advance, the authors could effectively utilize very short movie clips to trigger the recollection of the previously seen emotional events during the scanning. Given that there are limitations to how long a given subject can be scanned, and that the signal-to-noise ratio limitations of even modern neuroimaging methods require one to obtain multiple repetitions of similar events (e.g., emotional responses) over the duration of the experiment, this setup of the authors offers an attractive alternative paradigm for further neuroimaging studies of emotions.
Reference: Goldberg H, Preminger S, Malach R. The emotion–action link? Naturalistic emotional stimuli preferentially activate the human dorsal visual stream. Neuroimage (2014) 84: 254–264. http://dx.doi.org/10.1016/j.neuroimage.2013.08.032