Attentional deficits are thought to accompany damage to a number of different neural regions and are prominent in several neuropsychological syndromes (e.g., neglect). Yet only recently have studies begun to articulate specific attentional operations with different neural regions. The present proposal examines two types of attentional operations (voluntary and automatic shifting of spatial attention) and their role in perceptual processes that connect properties of objects together (i.e., perceptual integration). The first major question addressed by the proposed studies will be whether automatic and/or voluntary attentional shifts will be impaired in patients with unilateral lesions in parietal, temporal, or frontal regions. A voluntary shift of attention is one that is volitionally directed as when we shift our attention from one place to another to scan a complex scene. An automatic shift is one that is elicited without volition as when the sudden appearance of a stimulus attracts attention. Although a number of neuropsychological, neurophysiological, and electrophysiological investigations suggest that these two types of shifts involve different neural mechanisms, there is as yet little consensus. Different investigators have suggested that parietal, temporal, frontal or subcortical areas, as well as various combinations of these areas, might be differentially involved. By examining these two types of attentional shifts in different patient groups in the same study, we should be able to resolve at least part of this controversy. The second major purpose of the proposed studies is to examine the relation between automatic and/or voluntary attentional shifts and perceptual integration in the different patient groups. This issue is especially important since the PI and his colleagues have recently reported data from patients with lesions in the posterior superior temporal gyrus that could be interpreted as a deficit in automatic attentional shifts or as a deficit in perceptual integration. (The findings will be discussed at length in the body of the proposal). Procedures that have been thoroughly studied in normals and are believed to be sensitive to automatic versus voluntary shifts of attention on the one hand and feature integration on the other will be used. In this way, the proposed set of studies will not only clarify the relationship between different cortical regions and automatic and voluntary attentional shifts but will also help distinguish between deficits in attention and deficits in perceptual integration.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
1R01NS027902-01
Application #
2266650
Study Section
Neurology A Study Section (NEUA)
Project Start
1990-01-01
Project End
1992-12-31
Budget Start
1990-01-01
Budget End
1990-12-31
Support Year
1
Fiscal Year
1990
Total Cost
Indirect Cost
Name
U.S. Department/Vets Affairs Medical Center(Martinez)
Department
Type
DUNS #
City
Martinez
State
CA
Country
United States
Zip Code
94553
Lamb, M R; Pond, H M; Zahir, G (2000) Contributions of automatic and controlled processes to the analysis of hierarchical structure. J Exp Psychol Hum Percept Perform 26:234-45
Lamb, M R; Yund, E W (2000) The role of spatial frequency in cued shifts of attention between global and local forms. Percept Psychophys 62:753-61
Lamb, M R; Yund, E W; Pond, H M (1999) Is attentional selection to different levels of hierarchical structure based on spatial frequency? J Exp Psychol Gen 128:88-94
Lamb, M R; Yund, E W (1996) Spatial frequency and attention: effects of level-, target-, and location-repetition on the processing of global and local forms. Percept Psychophys 58:363-73
Lamb, M R; Yund, E W (1993) The role of spatial frequency in the processing of hierarchically organized stimuli. Percept Psychophys 54:773-84
Robertson, L C; Lamb, M R (1991) Neuropsychological contributions to theories of part/whole organization. Cogn Psychol 23:299-330
Lamb, M R (1991) Attention in humans and animals: is there a capacity limitation at the time of encoding? J Exp Psychol Anim Behav Process 17:45-54
Robertson, L C; Lamb, M R; Knight, R T (1991) Normal global-local analysis in patients with dorsolateral frontal lobe lesions. Neuropsychologia 29:959-67
Lamb, M R; Robertson, L C (1990) The effect of visual angle on global and local reaction times depends on the set of visual angles presented. Percept Psychophys 47:489-96
Lamb, M R; Robertson, L C; Knight, R T (1990) Component mechanisms underlying the processing of hierarchically organized patterns: inferences from patients with unilateral cortical lesions. J Exp Psychol Learn Mem Cogn 16:471-83