TY  - JOUR
A1  - Widmann, Annekathrin
A1  - Artinger, Marc
A1  - Biesinger, Lukas
A1  - Boepple, Kathrin
A1  - Peters, Christina
A1  - Schlechter, Jana
A1  - Selcho, Mareike
A1  - Thum, Andreas S.
T1  - Genetic Dissection of Aversive Associative Olfactory Learning and Memory in Drosophila Larvae
JF  - PLoS Genetics
N2  - Memory formation is a highly complex and dynamic process. It consists of different phases, which depend on various neuronal and molecular mechanisms. In adult Drosophila it was shown that memory formation after aversive Pavlovian conditioning includes—besides other forms—a labile short-term component that consolidates within hours to a longer-lasting memory. Accordingly, memory formation requires the timely controlled action of different neuronal circuits, neurotransmitters, neuromodulators and molecules that were initially identified by classical forward genetic approaches. Compared to adult Drosophila, memory formation was only sporadically analyzed at its larval stage. Here we deconstruct the larval mnemonic organization after aversive olfactory conditioning. We show that after odor-high salt conditioning larvae form two parallel memory phases; a short lasting component that depends on cyclic adenosine 3’5’-monophosphate (cAMP) signaling and synapsin gene function. In addition, we show for the first time for Drosophila larvae an anesthesia resistant component, which relies on radish and bruchpilot gene function, protein kinase C activity, requires presynaptic output of mushroom body Kenyon cells and dopamine function. Given the numerical simplicity of the larval nervous system this work offers a unique prospect for studying memory formation of defined specifications, at full-brain scope with single-cell, and single-synapse resolution.
KW  - genetic dissection
KW  - Drosophila
KW  - memory formation
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166672
VL  - 12
IS  - 10
ER  - 
TY  - JOUR
A1  - Xiu, Daiming
A1  - Geiger, Maximilian J.
A1  - Klaver, Peter
T1  - Emotional face expression modulates occipital-frontal effective connectivity during memory formation in a bottom-up fashion
JF  - Frontiers in Behavioral Neuroscience
N2  - This study investigated the role of bottom-up and top-down neural mechanisms in the processing of emotional face expression during memory formation. Functional brain imaging data was acquired during incidental learning of positive ("happy"), neutral and negative ("angry" or "fearful") faces. Dynamic Causal Modeling (DCM) was applied on the functional magnetic resonance imaging (fMRI) data to characterize effective connectivity within a brain network involving face perception (inferior occipital gyrus and fusiform gyrus) and successful memory formation related areas (hippocampus, superior parietal lobule, amygdala, and orbitofrontal cortex). The bottom-up models assumed processing of emotional face expression along feed forward pathways to the orbitofrontal cortex. The top-down models assumed that the orbitofrontal cortex processed emotional valence and mediated connections to the hippocampus. A subsequent recognition memory test showed an effect of negative emotion on the response bias, but not on memory performance. Our DCM findings showed that the bottom-up model family of effective connectivity best explained the data across all subjects and specified that emotion affected most bottom-up connections to the orbitofrontal cortex, especially from the occipital visual cortex and superior parietal lobule. Of those pathways to the orbitofrontal cortex the connection from the inferior occipital gyrus correlated with memory performance independently of valence. We suggest that bottom-up neural mechanisms support effects of emotional face expression and memory formation in a parallel and partially overlapping fashion.
KW  - medial temporal lobe
KW  - human orbitofrontal cortex
KW  - subsequent memory
KW  - recognition memory
KW  - fMRI
KW  - event-related fMRI
KW  - posterior parietal cortex
KW  - short-term-memory
KW  - human brain
KW  - prefrontal activity
KW  - neural mechanisms
KW  - Dynamic Causal Modeling
KW  - facial affect
KW  - memory formation
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-143211
VL  - 9
IS  - 90
ER  -