Academic journal article Attention, Perception and Psychophysics

Changes in Trunk Orientation Do Not Induce Asymmetries in Covert Orienting

Academic journal article Attention, Perception and Psychophysics

Changes in Trunk Orientation Do Not Induce Asymmetries in Covert Orienting

Article excerpt

Abstract We explored the effect of trunk orientation on responses to visual targets in five experiments, following work suggesting a disengage deficit in covert orienting related to changes in the trank orientation of healthy participants. In two experiments, participants responded to the color of a target appearing in the left or right visual field following a peripheral visual cue that was informative about target location. In three additional experiments, participants responded to the location (left/right) of a target using a spatially compatible motor response. In none of the experiments did trunk orientation interact with spatial-cuing effects, suggesting that orienting behavior is not affected by the rotation of the body relative to the head. Theoretical implications are discussed.

Keywords Attention · Space · Posture · Trunk · Vision

We need to be able to accurately locate objects relative to ourselves and other objects in the environment for many of our daily activities, such as in navigating around furniture, reaching to grasp a coffee cup, or identifying the source of an unfamiliar sound. Thus, it is not surprising that neurons in many regions of the human cortex are sensitive to the spatial locations of sensory events. Neurophysiological research in macaques (Avillac, Denève, Olivier, Pouget, & Duhamel, 2005; Batista et al., 2007; Buneo, Jarvis, Batista, & Andersen, 2002; Caminiti, Johnson, Galli, Ferraina, & Burnod, 1991; Lacquaniti, Guigon, Bianchi, Ferraina, & Caminiti, 1995) and both neuroimaging (Wu & Hatsopoulos, 2006, 2007) and behavioral (Andersen, Snyder, Bradley, & Xing, 1997; Culham & Kanwisher, 2001; Graziano & Gross, 1998; Jones & Henriques, 2010; Mountcastle, Lynch, Georgopoulos, Sakata, & Acuna, 1975; Wandell, 1999) studies in humans have shown that the central nervous system (CNS) uses multiple reference frames (Previc, 1990, 1998) to code the locations of sensory events. The present investigation focused on the body-centered reference frame, which has been revealed through biases of spatial processing in patients suffering from hemispatial neglect (Bartolomeo & Chokron, 1999, 2002; De Renzi, 1982).

Hemispatial neglect (HSN) is a syndrome characterized by a spatially graded impairment in detecting and responding to sensory information (Butler, Lawrence, Eskes, & Klein, 2009). Hemispatial neglect typically affects the left side of space following a lesion to the right cortex (although this is not always the case; Bowen, McKenna, & Tallis, 1999). Some lines of evidence have suggested that the spatial impairment observed in HSN may arise from a rightward shift in the egocentric representation of body position with respect to objects in the environment (e.g., Bisiach, Capitani, & Porta, 1985; Karnath, 1994; Karnath, Schenkel, & Fischer, 1991; Rorden, Karnath, & Driver, 2001). For example, Karnath et al. (1991) found that rotating the trunk to the left eliminated the left-right asymmetry in saccadic onset times (i.e., the longer reaction times [RTs] to stimuli presented in the left visual field when the head and body were oriented forward) for patients with left HSN, an effect that did not occur in stroke patients without neglect or in healthy control participants. Karnath (1994) later reported that left-side caloric stimulation (i.e., the infusion of cool water into one ear) and neck tendon vibration improved a 15° rightward bias in perceptual "straight ahead" in three patients with left HSN. No effects of caloric stimulation or neck vibration alone were found in healthy control participants, suggesting that the improvements seen in the HSN patients were not due to general effects on covert orienting of spatial attention (i.e., the intentional or sensory event-driven allocation of attentional resources to specific regions of space in the absence of changes in the orientation of the sensory apparatus; Klein, 2004). Instead, the benefits seen in HSN appeared to reflect the amelioration of a pathological asymmetry in a body-centered reference frame that is influenced by sensory input from neck proprioceptors and the vestibular system (Karnath, 1994). …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.