Wyniki wyszukiwania - Biblioteka Nauki

Ten serwis zostanie wyłączony 2025-02-11.

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

3 Acta Neurobiologiae Experimentalis

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Arousal and activation effects on physiological and behavioral responding during a continuous performance task

100%

VaezMousavi S. M. , Barry R. J. , Rushby J. A. , Clarke A. R.

2007

tom 67

nr 4

461-470

Based on previous work indicating different neural substrates, two aspects of energetic state, 'arousal' and 'activation', have been conceptualized separately in our laboratory. 'Arousal' has been defined as the energetic state at any particular time, and task-related 'activation' as the task-related change in state from resting baseline to the task situation. Both are reflected in electrodermal activity and measured by skin conductance level. Our previous studies in this area have indicated that physiological responses to stimuli in a task are dependent on the arousal level at the time of stimulus presentation, rather than the task-related activation. In contrast, performance on the task is dependent on the task-related activation, rather than the current arousal level. That is, different aspects of the individual's state determine physiological and behavioral responses. Those studies had examined between-subjects differences in arousal and activation. The present study investigated the relevance of this separation in an across-subjects examination of fluctuations in arousal and activation, and their effects on physiological and behavioral responses, during a continuous performance task. It was found that the magnitude of the phasic orienting reflex to the targets during the task was dependent mainly on arousal, rather than task-related relative activation. Reaction time improved with increasing relative activation, but not with arousal. These findings support our earlier conclusions relating to the usefulness of arousal and activation as distinguishable features of the energetics of physiological and behavioral functions.

Evoked cardiac response components in cognitive processing: differential effects of amyotrophic lateral sclerosis

100%

Kaiser J. , Wronka E. , Barry R. J. , Szczudlik A.

1999

tom 59

nr 4

329-334

We investigated the mechanism of two evoked cardiac response components associated with different aspects of information processing. Innocuous stimuli presented in an irrelevant condition elicit a simple cardiac deceleration termed ECR1. The same stimuli presented in a relevant condition (such as results from requesting subjects to silently count the stimuli) elicit a complex biphasic response with a large secondary acceleration in heart rate. This difference is attributed to the additional effect of cognitive task performance, resulting in an addition response component, ECR2. This may be realised by subtraction of the two responses. We investigated the mechanisms involved by comparing cardiac response profiles from a neurologically-impaired group with those from a control group. amyotrophic lateral sclerosis (ALS) has been associated with a loss of synaptic connections in the frontal lobe. Twelve ALS clinically non-demented patients were age-matched with twelve neurological patients without pathological changes in the brain. Cardiac response profiles for ECR1 and ECR2 were examined as a function of group. ECR1 did not differ between the groups, but ECR2 was significantly impaired in the ALS patients. The results are discussed in terms of different brain regions associated with these two cardiac response components. ECR1 may be associated with automatic preattentive stimulus registration involving, in the case of auditory stimuli, the auditory analyser and associated pathways, while ECR2 appears to be a correlate of controlled executive processing, involving the frontal cortex.

Evidence for differentiation of arousal and activation in normal adults

100%

VaezMousavi S. M. , Barry R. J. , Rushby J. A. , Clarke A. R.

2007

tom 67

nr 2

179-186

'Arousal' at a particular time has been defined as the energetic state at that moment, reflected in electrodermal activity and measured by skin conductance level. In contrast, task related 'activation' has been defined as the change in arousal from a resting baseline to the task situation. The present study, replicating some aspects of a previous investigation of these ideas in children, aimed to further explore whether the separation of 'arousal' and 'activation' was useful in describing state effects on the phasic Orienting Response (OR) and behavioral performance. A continuous performance task (CPT) was used with normal adults. It was found that the magnitude of the mean phasic OR to targets was dependent on arousal, but not on task-related activation. A performance measure (reaction time) improved with increasing activation, but not with arousal. These findings support our previous suggestions concerning the value of conceptualizing arousal and activation as separable aspects of the energetics of physiological and behavioral function.