Brain Talks
Past lectures
27.09 Patrick Johnson Queensland University of Technology, Australia):  "Prediction and error in the visual brain" 
18.10 Introduction to Research colloquium at the BPCN  
01.11 Gyula Kovacs (BPCN): "The predictive Brain"
08.11 Daniel Kaiser (FU Berlin): "Visual object processing in a structured world"
15.11 Charlotta Eick (FSU): Albinism and the visual system 

Upcoming lectures

22.11 Alina Peter (Max Planck Frankfurt): Stimulus-dependent increases and decreases in gamma synchronization in primate V1

Repetitions of visual stimuli typically lead to reduced responses throughout the visual system. This phenomenon is called adaptation or, especially in higher-order cortical areas, ‘repetition suppression’. However, behavioral performance often remains stable or improves with repetition. One potential explanation for this apparent discrepancy is a switch to a more efficient stimulus representation by increased spike synchrony. 
Brunet et al. (2014) indeed showed that over the course of a session of repeating grating stimuli, there was an increase in gamma-band synchrony both within and between early and mid-level visual cortex (V1 and V4). Multi-unit spike rate in V4 (where spiking data was available) decreased, whereas the gamma-band synchrony of the spikes generally increased. However, since this study confounded the factors of time in the session and stimulus repetition, the stimulus-specificity of the effects was unclear. 
We therefore set out to investigate repetition-related synchronization changes by presenting pseudo-randomly repeating natural images to monkeys engaged in a change detection task on the presented objects. Neuronal activity was recorded from area V1 in four monkeys. 
For the first few repetitions of an image, MUA showed response decreases, followed by a more stable response, similarly to results previously observed in IT. Furthermore, the natural images induced highly stimulus-specific responses in relative gamma power and spike-field locking. V1 gamma showed stimulus-specific repetition effects that included stable responses, decreases of the shape observed in the MUA, but also response enhancement. Whether stimulus repetition induced increases or decreases correlated with the overall gamma response strength at the recording site, such that weak responses decreased and stronger responses increased with repetition.  


  
29.11 Steffen Kluckow: UJH TBA  
06.12. Catarina Amado: FUTURE DIRECTIONS 
07.12 (DONNERSTAG!) Sabrina Trapp: TBA
03.01 Mareike Grotheer (Stanford): TBA 
17.01 Jürgen Kaufmann (General Psychology I, FSU Jena): TBA 
24.01 Sophie-Marie Rostalski: Repetition suppression and learning 
31.01. Charlotta Eick-Géza Ambrus-Gyula Kovacs: Presentation of the TMS face network grant 
07.02 Géza Gergely Ambrus: Machine learning  
Prof. Dr. Gyula Kovács
Géza Gergely Ambrus, PhD
Catarina Amado, MSc
Charlotta Eick, MSc
Kathrin Wiese
 
The temporal context of face perception

Predictive processes in the brain

vMMN mechanisms

Number processing in the brain

The hierarchy and parallelity of the visual face processing network

Body processing

The role of visual noise in perception 

BDNF and memory

Implicit learning in the brain
 
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