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Recent research suggests that our sense of time intervals in the range of seconds is directly related to activity in the insular cortex, which contains the primary sensory area for interoception. We therefore investigated whether performance in a duration reproduction task might correlate with individual interoceptive awareness and with measurable changes in autonomic activity during the task. Thirty-one healthy volunteers participated in an interoceptive (heartbeat) perception task and in repeated temporal reproduction trials using intervals of 8, 14, and 20s duration while skin conductance levels and cardiac and respiratory periods were recorded. We observed progressive increases in cardiac periods and decreases in skin conductance level during the encoding and (less reliably) the reproduction of these intervals. Notably, individuals' duration reproduction accuracy correlated positively both with the slope of cardiac slowing during the encoding intervals and with individual heartbeat perception scores. These results support the view that autonomic function and interoceptive awareness underpin our perception of time intervals in the range of seconds.
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During the observation of an ambiguous figure our perception alternates between mutually exclusive interpretations, although the stimulus itself remains unchanged. The rate of these endogenous reversals has been discussed as reflecting basic aspects of endogenous brain dynamics. Recent evidence indicates that extensive meditation practice evokes long-term functional and anatomic changes in the brain, also affecting the endogenous brain dynamics. As one of several consequences the rate of perceptual reversals during ambiguous figure perception decreases. In the present study we compared EEG-correlates of endogenous reversals of ambiguous figures between meditators and non-meditating controls in order to better understand timing and brain locations of this altered endogenous brain dynamics. A well-established EEG paradigm was used to measure the neural processes underlying endogenous perceptual reversals of ambiguous figures with high temporal precision. We compared reversal-related ERPs between experienced meditators and non-meditating controls. For both groups we found highly similar chains of reversal-related ERPs, starting early in visual areas, therewith replicating previous findings from the literature. Meditators, however, showed an additional frontal ERP signature already 160 ms after stimulus onset (Frontal Negativity). We interpret the additional, meditation-specific ERP results as evidence that extensive meditation practice provides control of frontal brain areas over early sensory processing steps. This may allow meditators to overcome phylogenetically evolved perceptual and attentional processing automatisms.
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Eintragsart
Sprache
- Englisch (2)
Thema
- Reaction Time
- Adult (2)
- Analysis of Variance (1)
- *Awareness (1)
- Brain/*physiology (1)
- Cerebral Cortex/*physiology (1)
- Electrocardiography (1)
- Electroencephalography (1)
- Emotions/*physiology (1)
- Evoked Potentials/*physiology (1)
- Evoked Potentials, Visual/*physiology (1)
- Female (2)
- Galvanic Skin Response (1)
- Heart/*physiology (1)
- Heart Rate/physiology (1)
- Humans (2)
- Male (2)
- Meditation/*methods (1)
- Optical Illusions/*physiology (1)
- Perception/*physiology (1)
- *Photic Stimulation (1)
- Photic Stimulation/methods (1)
- Respiration (1)
- Time Factors (1)
- Time Perception/*physiology (1)
- Visual Perception/*physiology (1)
- Young Adult (1)