Publications 2001

Publications 2001

Driver, J., Vuilleumier, P., Eimer, M., & Rees, G. (2001). Functional magnetic resonance imaging and evoked potential correlates of conscious and unconscious vision in parietal extinction patients. NeuroImage, 14, 68-75.

Eimer, M. (2001). Crossmodal links in spatial attention between vision, audition, and touch: Evidence from event-related brain potentials. Neuropsychologia, 39, 1292-1303.

Eimer, M., Cockburn, D., Smedley, B., & Driver, J. (2001). Cross-modal links in endogenous spatial attention are mediated by common external locations: Evidence from event-related brain potentials. Experimental Brain Research, 139, 398-411.

Eimer, M., & Coles, M.G.H. (2001). The lateralized readiness potential. In M. Jahanshahi & M. Hallett (Eds.). The Bereitschaftspotential: In Honour of Professors Deecke and Kornhuber. New York: Kluwer Academic / Plenum (forthcoming).

Abstract: INTRODUCTION: The pioneering work of Kornhuber and Deecke on the Bereitschaftspotential (Kornhuber & Deecke, 1965) suggested that movement-related brain activity could be recorded from the scalps of human subjects. Not only did this open up the possibility of studying brain-movement relationships using non-invasive procedures, it also pointed to a method by which measures of event-related brain potentials (ERPs) could be used to study cognitive processes. The benefits of the discovery of the Bereitschaftspotential for the analysis of cognitive function were not perhaps as obvious as those that related to the discovery of other ERP components during the 1960s, such as the P300 (Sutton, Braren, Zubin, & John, 1965) and the CNV (Walter, Cooper, Aldridge, McCallum, & Winter, 1964). Nevertheless, it has become clear in the last 35 years that the impact of its discovery has been just as profound. This is because knowledge of covert movement-related processes has proved to be extraordinarily important in exploring human cognitive function.
Models of the structure and dynamics of cognition propose the existence of cognitive processes which function to produce a given behavioural output, usually as a consequence of some input. The problem confronted by the cognitive psychologist is how to evaluate claims about the nature and mode of operation of these processes when the data available are limited to parameters of the output, such as speed and accuracy. It is the problem of making inferences about covert processes from observations of overt behaviour. In this regard, what was so striking about the studies of Kornhuber and Deecke, and those by Vaughan and his colleagues (Vaughan, Costa, & Ritter, 1968) which followed shortly thereafter, was that brain activity could be detected prior to an overt movement, and that the nature of this activity seemed to depend on the nature of the impending movement. The Bereitschaftspotential begins several hundred ms before the movement and, as the time for movement approaches, the scalp distribution depends on what movement is about to be executed.
It was the latter observation that gave rise to the measure called the lateralized readiness potential (LRP). With the studies of Kornhuber and Deecke (1965) as a starting point, Kutas and Donchin (1980) had examined movement-preceding brain activity for a variety of conditions which differed in terms when subjects knew which of two manual responses they would have to make. Kutas and Donchin found that the time at which the brain activity became asymmetrical was closely related to the time at which subjects knew whether a right or left-hand response would be required, and concluded that the asymmetry reflected preparation to execute specific motor acts.
On the basis of these results, groups in Groningen (e.g. Smid, Mulder, & Mulder, 1987) and Illinois (e.g. Coles & Gratton, 1986) simultaneously and independently reasoned that, under certain circumstances, the presence of asymmetries could be used to infer the presence of preferential preparatory activity. They proposed procedures to derive a measure of asymmetric, movement-related brain activity and these procedures yielded the measure now referred to as the LRP (although it was originally referred to as “corrected motor asymmetry” by the Groningen group).

Eimer, M., & Driver, J. (2001). Crossmodal links in endogenous and exogenous spatial attention: Evidence from event-related brain potential studies. Neuroscience and Biobehavioral Reviews, 25, 497-511.

Eimer, M., & Schlaghecken, F. (2001). Response facilitation and inhibition in manual, vocal, and oculomotor performance: Evidence for a modality-unspecific mechanism. Journal of Motor Behavior, 33, 16-26.

Abstract: It was studied whether evidence for response facilitation and subsequent inhibition elicited by masked prime stimuli can be observed for output modalities other than manual responding. Masked primes were followed by target stimuli that required a two-choice manual, saccadic, or vocal response. Performance was measured for compatible trials where primes and targets were identical, and incompatible trials where they were mapped to opposite responses. When primes were presented centrally, performance benefits for incompatible trials were obtained, while for peripherally presented primes, performance benefits were found in compatible trial. This pattern of results was obtained for manual responses as well as for saccadic eye movements (Experiment 1), demonstrating that these effects are not mediated by specialised dorsal pathways involved in visuomanual control. An analogous pattern of effects was found when manual and vocal responses were compared (Experiment 2). As vocal responding is controlled by inferotemporal cortex, this result shows that prime-target compatibility effects are not primarily mediated by the dorsal stream. They are assumed to reflect modality-unspecific visuomotor links that allow a rapid activation of motor responses which may later be subject to inhibition.

Kennett, S., Eimer, M., Spence, C., & Driver, J. (2001). Tactile-visual links in exogenous spatial attention under different postures: Convergent evidence from psychophysics and ERPs. Journal of Cognitive Neuroscience, 13, 462-478.

Schlaghecken, F., & Eimer, M. (2001). Partial response activation to masked primes is not dependent on response readiness. Perceptual and Motor Skills, 92, 208-222.

Abstract: It was investigated whether partial response activation and inhibition triggered by masked primes depends on the overall or specific state of response readiness. Response readiness was manipulated by varying the relative frequency of Go-trials in a Go/Nogo task (Exp. 1), and the relative frequency of left- and right-hand responses in a 2-alternative choice RT task (Exp. 2). In both experiments, reaction times were substantially longer in low response readiness conditions than in high response readiness conditions. However, the ‘negative compatibility effect’ observed in similar studies under conditions of high response readiness was replicated and was not affected by the response readiness manipulation, indicating that neither the general ability of masked primes to elicit a partial motor activation, nor the specific time course of this process, is dependent on response readiness. These results can be interpreted as indicating that the execution of an overt response, rather than the activation of this response, is affected by manipulations of response readiness.