Our research activities are focused on neurobiology of emotions. Major research programs and achievements include:
1. Description of functional and behavioral aspects of the mechanisms of extinction and renewal of conditional fear response
The effectiveness of fear extinction memory recall depends on the context. Fear, effectively extinguished in one context (e.g., in the therapist’s office) may be renewed in another context (e.g., in the street). This is one of the main reasons of failure of exposure therapy used for treatment of anxiety disorders. Understanding the neuronal circuits underlying fear extinction may therefore be crucial for the development of new therapies. Our studies suggest that fear extinction is controlled by highly specialized neuronal circuits in the amygdala, prefrontal cortex and hippocampus. These studies also indicated the presence of two distinct neuronal circuits in the lateral nucleus of the amygdala that are activated by recall of memory traces either for fear or for fear extinction. Identification of two distinct neuronal circuits is the first step to explore the possibility of a very specific improvement of fear extinction mechanisms. Moreover, we showed that fear renewal can be socially driven.
2. Development of an experimental model of socially transmitted fear
We have shown that rats living together exchange emotional arousal, which can be seen in the recipients as increased physical activity. Moreover, in recipients and senders of arousal, specific activation of different nuclei of the amygdala – the part of the brain responsible for emotional responses – has been shown. We also showed that socially transferred fear improves learning in otherwise naive animals. Our model can be used to study the neuronal basis of empathy, which in its simplest form can be defined as the ability to read the emotional states of other individuals of the same species, and communication disorders such as autism.
3. Demonstration of different patterns of amygdalar activity related to the type of emotional stimulation
We found that neuronal circuits in different nuclei of the amygdala activated by appetitively and aversively motivated behaviors are different. In particular, the medial part of the central nucleus of the amygdala (CeA) is specifically activated by appetitive training. Moreover, we showed that matrix metalloproteinase-9 (MMP-9, extracellularly operating enzyme) in the CeA is crucial for appetitive, but not for aversive, learning in mice. Since appetitive learning impairments underlie a number of psychiatric disorders such as depression, schizophrenia and autism spectrum disorders (modeled in mice and rats), knowledge of specific neuronal circuits related to this type of learning may be of clinical relevance.
4. Development of new tests to study behavior of mice in an automated IntelliCage system
The IntelliCage system has been recently developed to study behavior of mice living in social groups for many days or even weeks. It allows eliminating two key factors disturbing behavior of mice – the presence of an experimenter and social isolation. Therefore, the results are more reliable and more comparable between different laboratories (due to elimination of large part of random variation of results). We developed a number of experimental procedures, both for phenotyping of transgenic mice and behavioral experiments aimed at studying brain activity.
Please see also: http://en.nencki.gov.pl/laboratory-of-emotions-neurobiology
5 Selected Publications
Knapska E., Lioudyno V., Kiryk A., Mikosz M., Gorkiewicz T., Michaluk P., Gawlak M., Chaturvedi M., Mochol G., Balcerzyk M., Wojcik D.K., Wilczynski G.M., Karczmarek L.(2013) Reward Learning Requires Activity of Matrix Metalloproteinase-9 in the Central Amygdala. J. Neurosci., 33 (36) : 14591-600.
Knapska E., Macias M., Mikosz M., Nowak A., Owczarek D., Wawrzyniak M., Pieprzyk M., Cymerman I.A., Werka T., Sheng M., Maren S., Jaworski J., Kaczmarek L. (2012). Functional anatomy of neural circuits regulating fear and extinction. Proc. Natl. Acad. Sci. USA, 109: 17093–8.
Orsini CA., Kim JH., Knapska E., Maren S. (2011). Hippocampal and prefrontal projections to the basal amygdala mediate contextual regulation of fear after extinction. J. Neurosci., 31 (47): 17269–77.
Knapska E., Mikosz M., Werka T., Maren S. (2009). Social modulation of learning in rats. Learn. Mem., 17 (1): 35–42.
Knapska E., Nikolaev E., Boguszewski P., Walasek G., Blaszczyk J., Kaczmarek L., Werka T. (2006). Between-subject transfer of emotional information evokes specific pattern of amygdala activation. Proc. Natl. Acad. Sci. USA. 103: 3858–3862.
Fellowships, Awards and Honours
2013 Burgen Scholarship, Academia Europea
2008 Reintegration Grant for Polish scientists (Foundation for Polish Science) (till '10)
2007 Polish Prime Minister Award for the PhD thesis
2006 Award of the Polish Neuroscience Society (Konorski Award) and
2006 Award of the Polish Academy of Science (Physiological Sciences) for Knapska et al. 2006
2006 Postdoctoral Fellowship (KOLUMB), Foundation for Polish Science (till '07)
2005 Young Investigator Award of the Polish Neuroscience Society
2004 BRAINS Training Fellowship (Prof. Lipp's Lab, Zurich University, Switzerland)
2000 Scholarship of the Minister for National Education (till '01)