A spatiotemporal dipole model of the stimulus preceding negativity (spn) prior to feedback stimuli

Abstract

Ten subjects performed a time production task, in which they were instructed to press a button four seconds after the presentation of an auditory stimulus. Two seconds after the button press they received either auditory or visual feedback on the temporal accuracy of their response. In such a paradigm negative slow brain potentials can be recorded preceding the response (Movement Preceding Negativity, MPN) as well as preceding the feedback stimulus (Stimulus Preceding Negativity, SPN). Spatiotemporal dipole modelling is used to gain insight in the possible generators of MPN and SPN. From the models it follows that the MPN can be described by one contralateral radial dipole and a bilateral pair of tangential dipoles. All three dipoles are located near central electrode positions, so the generators of the MPN probably reside within the motor cortex. The SPN is modelled by a bilateral frontotemporal pair of dipoles, hypothetically representing activation of the Insulae Reili. The insular cortex is involved in the processing of affective-motivational input, such as carried by the feedback in the present paradigm. However, processing of the information content of the feedback stimulus might by itself also activate the frontal cortex. Both the response and the feedback stimulus are followed by a positive peak, which can be described by the same deep posterior dipole. Both peaks probably represent a P3, which is related to context updating.

Event-related desynchronization related to the anticipation of a stimulus providing knowledge of results

“…It has been suggested that the occurrence of an SPN depends on whether the anticipated stimulus has an affective-motivational value (Damen and Brunia, 1994). This interpretation is further supported by a spatiotemporal dipole modelling study (Böcker et al, 1994c), where a large part of the pre-KR SPN could be explained by a pair of dipoles which probably represents activity in the Insulae Reili, a bilateral cortical structure buried within the Sylvian fissure. This structure has connections which suggest that the insular cortex is involved in the processing of affectivemotivational stimuli (Mesulam and Mufson, 1985).…”

“…This is in contrast with a dipole model of the SPN that was based on the same data set as has been used in the present experiment (Böcker et al, 1994c). Together with the fact that we found no right hemisphere dominance in the ERD as opposed to what is usually reported for the SPN, this could suggest that ERD is less sensitive to the anticipation of an affective-motivational event than its slow potential analogy, which would make ERD an excellent candidate for identifying modality-specific, visual anticipatory attention.…”

“…In order to obtain reference-free data and to remove ERD/ ERS effects at the reference electrodes, the recorded potentials were transformed to scalp current density (SCD) fields by estimating a spherical spline function, which is the recommended procedure by Perrin et al (1987Perrin et al ( , 1989); see Böcker et al, 1994c for the resulting SCD maps). This method has the advantage of yielding reliable estimates of the SCD at electrode positions that are at the border of the electrode montage, so it is preferable to computing a local average reference (Hjorth, 1975), as is mostly done in ERD computation (e.g.…”

“…A statistical analysis of the behavioral data and the potential data, as well as a spatiotemporal dipole model of the potential data have been presented elsewhere (Böcker et al, 1994c). Fig.…”

“…15-18). Its onset has been reported to be at least as early as 2000 ms pre-stimulus (Damen and Brunia, 1994;Böcker et al, 1994c). The SPN has a widespread scalp distribution, with a frontal plateau and a parietal ramp-like potential, usually with a right-hemisphere preponderance (Brunia and Damen, 1988).…”