Institutional creator:

Instytut Biologii Doświadczalnej im. Marcelego Nenckiego PAN

Contributor:

Knapska, Ewelina (1977- ) : Supervisor ; Michałowski, Jarosław M. : Supervisor

Publisher:

Nencki Institute of Experimental Biology PAS

Place of publishing:

Warsaw

Description:

80 pages : illustrations ; 30 cm ; Bibliography ; Summary in Polish

Degree grantor:

Instytut Biologii Doświadczalnej im. Marcelego Nenckiego PAN

Type of object:

Thesis

Abstract:

Fear contagion is an automatic process of aligning one animal's emotional state with another's emotional distress. It has been described in different social species, including rats and humans. Reading the emotional states of others has recently been suggested to play an essential role in detecting danger. If so, one could expect fear contagion to be a cross-species phenomenon. However, this hypothesis has yet to be tested. Both rat and human studies implicated the amygdala, a brain structure crucial for processing emotions, in fear contagion.Further, the rat studies showed that two main parts of the amygdala, which differ morphologically and functionally - the basolateral and centromedial nuclei - are involved in emotional transfer. Such a detailed analysis of the amygdala activity has yet to be performed for human-human emotional transfer. In this doctoral thesis, I aimed to test whether the cross- species (human-rat) fear transfer occurs and whether it involves the basolateral and centromedial parts of the amygdala (study 1). Their involvement was also verified during the human-human fear contagion (study 2).In study 1, the habituated rats were handled by familiar humans who underwent the fear conditioning task (or an emotionally neutral task in the control condition). Following the interaction, the rats' amygdala activations were analyzed using the expression of c-Fos, a marker of neuronal activation. I observed that the rat amygdala was activated to a greater extent in the experimental rats compared to the control rats. That was true for both the basolateral and centromedial divisions. The behavioral differences between the experimental and control rats further confirmed the successful transfer of fear from human to rat.Study 2 was performed using functional magnetic resonance imaging (fMRI). Participants (so-called observers) were placed in the fMRI scanner and watched their friends (so-called demonstrators) undergoing the classical fear conditioning paradigm. In this task, a neutral stimulus was repeatedly paired with aversive electrical stimulation applied to the forearm. I analyzed the observers' brain responses to the electric shocks administered to their friends and found enhanced activations in the amygdala. Also, here, both the basolateral and centromedial divisions were activated.The thesis provides the first neural evidence for interspecies fear contagion. The findings indicate that both main divisions of the amygdala respond when human fear is transmitted to another human and a rat. This suggests a common brain circuit involved in perceiving fear socially in humans and rats. I argue that it could have evolved to enable sharing of the emotional cues essential for survival across species

Detailed Resource Type:

PhD Dissertations

Resource Identifier:

oai:rcin.org.pl:239129

Source:

IBD PAN, call no. 20267

Language:

eng

Language of abstract:

pol

Digitizing institution:

Nencki Institute of Experimental Biology of the Polish Academy of Sciences

Original in:

Library of the Nencki Institute of Experimental Biology PAS

Access:

Open