On the right (and left) track: Twenty years of progress in studying hemispatial neglect

Abstract

In the last 20 years, several important developments have markedly expanded our understanding of the hemispatial neglect syndrome and, more broadly, of the brain's representation of objects, space, and action. This review follows seven "threads" of scientific development to evaluate some of the changes in our thinking about the mechanisms of neglect, its key characteristics, the spatial frames of reference affected, the psychophysical properties of neglect phenomena, the relationship of neglect in various sensory modalities, the role of deficits in arousal and general attention, and the critical neuroanatomic substrates of the disorder. The progress reviewed illustrates that the cognitive neuropsychology approach to the study of neglect complements insights gleaned from neurophysiological studies in the monkey, functional neuroimaging studies of attention and perception, and other investigative techniques, and thus serves as fertile ground for a convergence approach to cognitive neuroscience.

Cognitive Neuropsychologytwenty years on

“…These issues surface in many of the papers collected here; For example, it is precisely these issues that underlie the comment, made in relation to hemispatial neglect by Buxbaum (2006), who observes that "nearly every possible fractionation of the disorder has been reported, raising the possibility that each patient may be as unique as a snowflake". This is not true just of neglect: It is true of every disorder that has been studied in any detail by cognitive neuropsychologists.…”

“…By way of conclusion: More on cognition and the brain As already noted, cognitive neuropsychology can be considered a branch of cognitive psychology where subjects' performance is used to inform theories of normal cognition. However, as also already noted, there is increasing interest in relating cognitive neuropsychological investigations to developments in cognitive neuroscience (e.g., papers by Buxbaum, 2006, Caramazza & Mahon, 2006, Humphreys & Riddoch, 2006and Vallar, 2006). In fact, Cognitive Neuropsychology has recently published a good number of papers that focus on the interface of cognitive neuropsychology and neuroscience (see, e.g., papers in two special issues edited by Martin & Caramazza, 2003, The organization of conceptual knowledge in the brain: Neuropsychological and neuroimaging perspectives, and by Rumiati & Caramazza, 2005, The multiple functions of sensory-motor representations), and the composition of the Editorial Board increasingly reflects this slight repositioning of the journal vis-à-vis strictly cognitive versus neuroscience accounts of cognitive processes.…”

“…To pursue Buxbaum's (2006) analogy, that would be like trying to collect together a group of snowflakes that all had exactly the same morphology. The number of possible different shapes for snowflakes is so large that the likelihood of obtaining two snowflakes with the same morphology is quite small, which makes the prospect of group studies of snowflake morphology an impractical one.…”

Disorders of Higher Cortical Function

“…Brain areas whose lesion is most frequently associated with UN are the temporal, parietal, frontal, and occipital lobes, the basal ganglia, and the thalamus. 44 …”

“…43,44 UN may be localized within a hemisphere, and has been associated with both cortical and subcortical lesions. Brain areas whose lesion is most frequently associated with UN are the temporal, parietal, frontal, and occipital lobes, the basal ganglia, and the thalamus.…”