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R Schandry

Publications and source records attributed to R Schandry.

22 records · Page 2Linked to original sources
PubMed1983

A comparative investigation of ERP components and the SCR in a habituation and dishabituation paradigm.

The present experiment investigated the trial-by-trial habituation in the event-related potential (ERP) and the skin conductance response (SCR) to repeated stimuli and dishabituation to rare stimuli. In a balanced design, two groups of subjects passively observed either large black discs as repeated stimuli and small as rare, or vice versa. No consistent effects of stimulus size were obtained between the groups. Late positivity was composed of a double peak at Cz, containing contributions from P3a and P300; the latter only was observed at Pz. The SCR and P3a and P300 at Cz demonstrated habituation, but not the N100 or P200, nor the P300 at Pz. Rare stimuli elicited an enhancement, albeit nonsignificant, in SCR amplitude only. No dishabituation of any of the responses by these stimuli was observed. The SCR correlated significantly with late positivity at Cz and Pz. Discussion focuses on SCR and late positivity as OR components.

Acoustic Stimulation↗
PubMedDate not supplied

Heartbeat evoked potentials (HEP): topography and influence of cardiac awareness and focus of attention.

Heartbeat evoked potentials (HEP) were recorded from good and poor heartbeat perceivers under two conditions differing in focus of attention. Under the first condition (ATT), subjects were instructed to count their heartbeats. Under the second condition (DIS), subjects were distracted from their heartbeats by having them count external tones. Electrical brain activity was recorded from 19 electrodes. EEG epochs were triggered by the R wave of the EKG. Analyses of variance yielded a significant difference for focus of attention in HEP amplitudes at central electrodes (Cz, C3, and C4) in the latency range 350-550 msec post R wave. No significant differences occurred between good and poor perceivers. The interaction between the Group and Condition factors was significant at F4, C4 and T6. The potential map of good perceivers showed a fronto-temporal positivity, which was reduced in poor perceivers. Our data suggest that paying attention to an internal event such as the heartbeat can modify the cortical evoked response associated with that event.

Adult↗