[dipl] Perustieteiden korkeakoulu / SCI

Permanent URI for this collectionhttps://aaltodoc.aalto.fi/handle/123456789/21

Browse

Browsing [dipl] Perustieteiden korkeakoulu / SCI by Degree programme/Major subject "Brain and Mind"

Filter results by typing the first few letters
Now showing 1 - 3 of 3
  • Brain Basis of Complex Emotions: An fMRI Study
    (2014-08-19) Ejtehadian, Farzaneh
     Perustieteiden korkeakoulu | Master's thesis
    In the past, several studies have been conducted in order to examine the psychological and neural bases of emotions. These studies have mostly concentrated on a narrow range of often negative basic emotions, thus neglecting psychologically complex emotions. Only in recent years neuroimaging studies have begun to describe the neuroanatomy of more complex emotions. In this study, functional magnetic resonance imaging (fMRI) is used to investigate the brain activation for basic and complex emotions in 25 healthy participants. 15 different emotions are induced using a series of short emotional stories. The brain activation is analysed by categorical and parametric designs, as well as using the behavioural ratings of dimensions of complex emotion stimuli. The objective is to examine if specific brain regions are associated with activation in different emotions, and whether these regions are common for multiple emotions. In addition, the difference in activation for basic and complex emotions is discussed. Furthermore, the brain activation pattern underlying the dimensions of valence and arousal is investigated. The findings point to the involvement of a network of structures in the midbrain regions and the somatosensory and motor cortices for a group of emotions. Also, several brain areas, including the middle and inferior occipital cortex, cerebellum, precuneus and cuneus, are found to underlie the dimensions of negative valence and positive arousal.
  • Investigating via Transcranial Magnetic Stimulation (TMS) the interaction between Visual Short Term Memory (VSTM) and mental imagery in the Early Visual Cortex (EVC).
    (2016-04-28) Wojciechowska, Maria
     Perustieteiden korkeakoulu | Master's thesis
    Visual mental imagery and visual short term memory are often assumed to play similiar roles. There are many evidence showing that they both involve visual cortical neurons which encode incoming sensory information. On the cognitive level it has been explained in terms of the visual cache, which is nvolved in the maintenance of visual short term memory and imagery content. Even though menatl imagery and visual short term memroy may share cogntive resources, they are nevertheless two distinct psychological processes that can be dissociated behaviorally. In this study, we wanted to see if those two processes diverges in early visual cortex. To be able to do it, we used transcranial magnetic stimualtion as a probe of visual cortical activation state. Experiment consists of three diffrent blocks: VSTM alone, mental imagery alone and concurrent VSTM and imagery. The concurrent condition was carried out to understand how imagery and VSTM might interact when they are engaged simultaneously.
  • Magnetoencephalographic (MEG) Inter-subject Correlation using Continuous Music Stimuli
    (2014-11-04) Thiede, Anja
     Perustieteiden korkeakoulu | Master's thesis
    Music has existed throughout cultures for thousands of years and has been able to create powerful and intercultural connections between humans. Yet, early neurocognitive studies on music have utilized mainly artificial stimuli. Going towards more complex, real-world stimuli, this study examines magnetoencephalographic (MEG) brain responses to listening to continuous music in 24 musically trained and 19 untrained listeners. Three whole musical pieces of different genres were presented as stimuli. To investigate how similarly listeners’ brains process the music, inter-subject correlations (ISC) of the dynamics of specific MEG frequency bands were computed. This approach is a novel method for analyzing complex stimuli with MEG. Compared to functional magnetic resonance imaging (fMRI) studies, it adds to the information about synchronous processing of continuous music stimuli in the brain. Our MEG results show that auditory processing areas, including middle and superior temporal gyri, transverse temporal cortex and insula with enhanced right hemispheric responses, synchronize across subjects. The extend of synchronization differs depending on the selected frequency band and music stimulus. For the song that elicited highest ISCs across subjects, in the 4–8 Hz and 8–12 Hz frequency bands, musicians exhibit higher synchrony in auditory processing areas compared to non-musicians. In summary, listening to real music induces brain-to-brain coupling especially in auditory cortices. Coupling in musicians during listening to a piece with a variety and complexity of musical features is higher compared to non-trained participants.