TY  - JOUR
A1  - Pauli, Paul
A1  - Lutzenberger, W.
A1  - Rau, H.
A1  - Birbaumer, N.
A1  - Rickard, T. C.
A1  - Yaroush, R. A.
A1  - Bourne, L. E. J.
T1  - Brain potentials during mental arithmetic: effects of extensive practice and problem difficulty
N2  - Recent behavioral investigations indicate that the processes underlying mental arithmetic change systematically with practice from deliberate, conscious calculation to automatic, direct retrieval of answers from memory [Bourne, L.E.Jr. and Rickard, T.C., Mental calculation: The development of a cognitive skill, Paper presented at the Interamerican Congress of Psychology, San Jose, Costa Rica, 1991; Psychol. Rev., 95 (1988) 492-527]. Results reviewed by Moscovitch and Winocur [In: The handbook of aging and cognition, Erlbaum, Hillsdale, NJ, 1992, pp. 315-372] suggest that consciously controlled processes are more dependent on frontal lobe function than are automatic processes. It is appropriate, therefore to determine whether transitions in the locus of primary brain activity occur with practice on mental calculation. In this experiment, we examine the relationship between characteristics of event-related brain potentials (ERPs) and mental arithmetic. Single-digit mental multiplication problems varying in difficulty (problem size) were used, and subjects were trained on these problems for four sessions. Problem-size and practice effects were reliably found in behavioral measures (RT). The ERP was characterized by a pronounced late positivity after task presentation followed by a slow wave, and a negativity during response indication. These components responded differentially to the practice and problem-size manipulations. Practice mainly affected topography of the amplitude of positivity and offset latency of slow wave, and problem-size mainly offset latency of slow wave and pre-response negativity. Fronto-central positivity diminished from session to session, and the focus of positivity centered finally at centro-parietal regions. This finding suggests that frontal lobe processing is necessary as long as task performance is not automatized, while automatized arithmetic processing requires parietal brain activity only. The pre-response negativity observed in the first session and during more difficult tasks is assumed to reflect excitatory preparatory processes, which could be associated with activation of calculation strategies.
KW  - Psychologie
KW  - Mental arithmetic
KW  - Event-related potential
KW  - Practice
KW  - Automatization
KW  - Problem size
Y1  - 1994
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61345
ER  - 
TY  - JOUR
A1  - Wieser, Matthias J.
A1  - Reicherts, Philipp
A1  - Juravle, Georgiana
A1  - von Leupoldt, Andreas
T1  - Attention mechanisms during predictable and unpredictable threat - a steady-state visual evoked potential approach
JF  - NeuroImage
N2  - Fear is elicited by imminent threat and leads to phasic fear responses with selective attention, whereas anxiety is characterized by a sustained state of heightened vigilance due to uncertain danger. In the present study, we investigated attention mechanisms in fear and anxiety by adapting the NPU-threat test to measure steady-state visual evoked potentials (ssVEPs). We investigated ssVEPs across no aversive events (N), predictable aversive events (P), and unpredictable aversive events (U), signaled by four-object arrays (30 s). In addition, central cues were presented during all conditions but predictably signaled imminent threat only during the P condition. Importantly, cues and context events were flickered at different frequencies (15 Hz vs. 20 Hz) in order to disentangle respective electrocortical responses. The onset of the context elicited larger electrocortical responses for U compared to P context. Conversely, P cues elicited larger electrocortical responses compared to N cues. Interestingly, during the presence of the P cue, visuocortical processing of the concurrent context was also enhanced. The results support the notion of enhanced initial hypervigilance to unpredictable compared to predictable threat contexts, while predictable cues show electrocortical enhancement of the cues themselves but additionally a boost of context processing.
KW  - Event-related potential
KW  - Contextual fear
KW  - Conditioning evidence
KW  - Sustained attention
KW  - Selective attention
KW  - Aversive events
KW  - Time-course
KW  - Virtual-reality
KW  - Anxiety
KW  - Humans
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-187365
VL  - 139
ER  -