by Rideeta Raquib ’19
Fear is an unpleasant emotion that can cause someone to be afraid. Although a small amount of fear has been evolutionarily helpful to organisms for preventing predation, too much fear can be mentally harmful. In fact, phobias and post-traumatic stress disorders can negatively impact the daily lives of many people. A study conducted by neuroscientists from the University of Cambridge, Japan, and the United States tested ways to reduce fear unconsciously. Pavlovian aversive conditioning, a type of therapy used to stop a particular behavior, was administered among 17 subjects. The fear conditioned stimuli (CS+s) were administered in a monotonous manner. This involved causing a fear memory for red and green gratings, a type of visual stimuli, which were the conditioned stimuli (CS+). They also paired it with a slight amount of electric shock (unconditional stimuli).
First, the participants of the study gained a fear response from two types of visual stimuli: the target CS+ and the control CS+. A functional magnetic resonance imaging (fMRI) was employed and a DecNef, which is the decoded fMRI neurofeedback, was utilized in order to observe brain patterns of volunteers. A blue or yellow grating was induced as CS- and unconditioned stimuli were not paired. Half of the participants who received CS+ (green) were assigned blue as CS- while the other half received yellow as CS-. The same was carried out for those who received CS+ red. A skin conductance response, or SCR, which is the sudden conduction of electricity by the skin and emotion analyst, was measured utilizing BrainAmp Ag/AgCl electrode.
All of the participants had positive responses to both the target and control CS+s. At the end of an acquisition session, CS+s induced elevated skin conductance response and its comparison to an unreinforced stimuli (CS-) illustrated fear conditioning to be successful. During neural reinforcement sessions, when patients viewed the gratings associated with the shocks, their SCR values were much lower than before. Overall, these findings illustrate a possibility of implementing such conditioning techniques as clinical treatments for patients with disorders related to fear, such as PTSD. This could reduce the use of drugs utilized in current treatments and prevent side effects.
- A. Koizumi, et al., Fear reduction without fear through reinforcement of neural activity that bypasses conscious exposure. Nature Human Behaviour 1, (2016). doi: 10.1038/s41562-016-006.
- Image retrieved from: http://dreamatico.com/data_images/fear/fear-1.jpg