ADVERTISEMENT

Evoked Potentials To Neutral Facial Stimuli, Previously Presented In An Emotionally Negative Context

We all are familiar with the situation from the practice of criminalistics when a number of people are presented to the witness of crime for identification, among whom there is a criminal. One of the problems of identification is that the witness observed the criminal in a strong emotional state, and the persons proposed for identification are in a neutral state. The question arises whether the witness is able to correctly identify the criminal person under these conditions.

In order to get an answer to this question, we conducted two series of experiments, when the subjects were presented with a video fragment, in which the scene of violence was imprinted [Kanunikov, Pavlova, 2017, Kanunikov, Fomicheva, 2015]. After that, the subjects were presented with photographs of people who are not related to the scene of violence (the so-called fillers), as well as the faces of the criminal and the victims in a calm emotional state. Also, control was carried out when the same faces were presented to subjects who did not watch the film. Evoked potentials (EP) on faces were recorded in all subjects.

ADVERTISEMENT

It is shown that the EP to the faces have a three-component structure: a positive component with a latent period of about 100 ms (P100), a negative component with a latency of 160 ms (N160), a second positive component with a latent period of 200 ms (P200).

Analysis of the results of two series of experiments revealed a significantly larger amplitude of component P200 in response to the face of the criminal and an unfamiliar person (filler face) in the temporal lobe of the right hemisphere (T6) compared to the left temporal site (T5), with P200 having a large amplitude in response to the face filler. Components P100 and N170 did not reveal differences in response to the criminal face and filler.

In the case of the control group, no significant differences in the EP were found.

In interpreting the above data, it is necessary to take into account the fact that there are two relatively independent systems in the brain: the face recognition system and the system for identifying their emotional states. This is confirmed, in particular, by the data obtained on a patient with prosopagnosia, who was not able to recognize the face of a familiar person, but correctly recognized the emotion on his face (Bruce, Young, 1986). Neurons sensitive to familiar/unfamiliar faces were found in the region of the upper temporal gyrus, and neurons responsible for emotional expressions were found in the region of the lower temporal sulcus [Hasselmo et al., 1989].

ADVERTISEMENT

Streit et al (2000) concluded that the P2 component (with an average latency of 240 ms peak) reflects the specific processes underlying the recognition of emotional expressions. The large amplitude of the potentials in the temporal retraction of the right hemisphere in comparison with the left hemisphere confirms the hypothesis of its greater participation in the process of facial emotion [Haxby, Hoffman, Gobbini, 2000; Rivolta, 2014].

The fact that differences are observed in the right temporal region (T6) is naturally related to the fact that the right hemisphere is responsible for the perception of negative emotions. Leonard et al. (1985) showed that component P2 reflects a greater degree of activation of the temporal region of the right hemisphere in subjects with a stable negative evaluation of facial images.

Summarizing the above data, one can make the assumption that the neutral face of the criminal is capable of generating a negative emotional image in memory that activates the right temporal region.

References:

  • Bruce, V. and Young, A. W., “Understanding face recognition,” Brit. J. Psychol., 77, 305–327 (1986).
  • Hasselmo M.E., Rolls E.T., Baylis G.C. The role of expression and identity in the face-selective responses of neurons in the temporal visual cortex of the monkey//Behavioral Brain Research. 1989. V.32. pp. 203-218.
  • Haxby J. V., Hoffman, E. A., and Gobbini, M. I., “The distributed human neural system for face perception,” Trends Cogn. Sci., 4, No. 6, 223–233 (2000).
  • Kanunikov, I. E., and Fomicheva, D. A., “Reactions of the human brain to mages of faces presented in an emotionally negative context,” in: The Human Face in Science, Art, and Practice, K. A. Anan’ev, V. A. Barabanshchikov, and Demidov, A. A. (eds.), Cogito-Tsentr, Moscow (2015), pp. 415–426.
  • Kanunikov I.E., Pavlova V.I. Event-Related Potentials to Faces Presented in an Emotional
  • Context. Neuroscience and Behavioral Physiology. 2017. V.47. №8, pp. 967-975.
  • Leonard C.M., Rolls E.T., Wilson F.A.W., Baylis G.C. Neurons in the amigdala of the monkey with responses selective for faces //Behavioral Brain Research. 1985. V.15.P.159-176.
  • Rivolta, D., Prosopagnosia: When All Faces Look the Same, Springer-Verlag, Berlin Heidelberg (2014).
  • Streit, M., Wolwer, W., Brinkmeyer, J., et al., “Electrophysiological correlates of emotional and structural face processing in humans,” Neurosci. Lett., 278, 13–16 (2000).

These findings are described in the article entitled Event-Related Potentials to Faces Presented in an Emotional Context, published by Kanunikov I.E., Pavlova V.I., and Fomicheva D.A. (St. Petersburg State University) in the journal Neuroscience and Behavioral Physiology and in the Human Face in Science, Art, and Practice, K. A. Anan’ev, V. A. Barabanshchikov, and Demidov, A. A. (eds.), Cogito-Tsentr, Moscow (2015).

ADVERTISEMENT

Comments

READ THIS NEXT

Plant Cell Diagram

A plant cell diagram, like the one above, shows each part of the plant cell including the chloroplast, cell wall, […]

The Push-Me-Pull-Me Allure Of Bird Eggs

Playing the Easter Bunny has a long and illustrious history in the field of animal behavior. Two of three ethologists […]

Initial Evolution Of The North Polar Cap Of Mars Revealed By Orbital Radar

The poles of Mars host massive amounts of water ice in the form of polar caps, much like Earth’s Antarctica. […]

Physicists At CERN Use Laser To Manipulate Antimatter

In a study published a few days ago in Nature, a team of physicists at CERN report that they have successfully used […]

Black Phosphorus: A Miracle Material For Future Biomedical Technology

Extensive and profound research in graphene has become a strong driver in the search for other 2 dimensional (2D) materials […]

Perovskite Solar Cells: A Photovoltaic Technology With Outstanding Light-Harvesting Capabilities Under Indoor Illumination

Perovskite solar cells represent an emerging photovoltaic technology being researched and developed by academic and industrial laboratories worldwide because it […]

Can Material Found In Nature Provide Effective Treatments For Acid Drainage?

Acid drainage (AD) refers to the effluent from mining, metallurgy, and various other industrial operations, including tanneries, electroplating, power plants, […]

Science Trends is a popular source of science news and education around the world. We cover everything from solar power cell technology to climate change to cancer research. We help hundreds of thousands of people every month learn about the world we live in and the latest scientific breakthroughs. Want to know more?