The concept of affordance is rapidly gaining popularity in neuroscientific accounts of perception and action. This concept was introduced by James Gibson to refer to the action possibilities of the environment. By contrast, standard cognitive neuroscience typically uses the concept to refer to (action-oriented) representations in the brain. This paper will show that the view of affordances as representations firmly places the concept in the subject-object framework that dominates both psychology and neuroscience. Notably, Gibson introduced the affordance concept to overcome this very framework. We describe an account of the role of the brain in perception and action that is consistent with Gibson. Making use of neuroscientific findings of neural reuse, degeneracy and functional connectivity, we conceptualize neural regions in the brain as dispositional parts of perceptual and action systems that temporarily assemble to enable animals to directly perceive and - in the paradigmatic case - utilize the affordances of the environment.

Objectives Adaptive interaction with the environment requires the ability to predict both human and non-biological motion trajectories. Prior accounts of the neurocognitive basis for prediction of these two motion classes may generally be divided into those that posit that non-biological motion trajectories are predicted using the same motor planning and/or simulation mechanisms used for human actions, and those that posit distinct mechanisms for each. Using brain lesion patients and healthy controls, this study examined critical neural substrates and behavioral correlates of human and non-biological motion prediction. Methods Twenty-seven left hemisphere stroke patients and 13 neurologically intact controls performed a visual occlusion task requiring prediction of pantomimed tool use, real tool use, and non-biological motion videos. Patients were also assessed with measures of motor strength and speed, praxis, and action recognition. Results Prediction impairment for both human and non-biological motion was associated with limb apraxia and, weakly, with the severity of motor production deficits, but not with action recognition ability. Furthermore, impairment for human and non-biological motion prediction was equivalently associated with lesions in the left inferior parietal cortex, left dorsal frontal cortex, and the left insula. Conclusions These data suggest that motor planning mechanisms associated with specific loci in the sensorimotor network are critical for prediction of spatiotemporal trajectory information characteristic of both human and non-biological motions.

We investigated whether the control of movement of the left hand is more likely to involve the use of allocentric information than movements performed with the right hand. Previous studies (Gonzalez et al. in J Neurophys 95:3496–3501, 2006; De Grave et al. in Exp Br Res 193:421–427, 2009) have reported contradictory findings in this respect. In the present study, right-handed participants (N = 12) and left-handed participants (N = 12) made right- and left-handed grasps to foveated objects and peripheral, non-foveated objects that were located in the right or left visual hemifield and embedded within a Müller-Lyer illusion. They were also asked to judge the size of the object by matching their hand aperture to its length. Hand apertures did not show significant differences in illusory bias as a function of hand used, handedness or visual hemifield. However, the illusory effect was significantly larger for perception than for action, and for the non-foveated compared to foveated objects. No significant illusory biases were found for reach movement times. These findings are consistent with the two-visual system model that holds that the use of allocentric information is more prominent in perception than in movement control. We propose that the increased involvement of allocentric information in movements toward peripheral, non-foveated objects may be a consequence of more awkward, less automatized grasps of nonfoveated than foveated objects. The current study does not support the conjecture that the control of left-handed and right-handed grasps is predicated on different sources of information.

Ecological psychology has been criticized for ignoring the brain in its theory formation. In recent years, however, a number of researchers have started asking ecologically-inspired questions about the ways in which not only the embodied activity of the organism in its environment, but also the particulars of the organism's nervous system matter. This work has typically appeared in neuroscience journals, thereby potentially escaping the attention of ecological psychologists. The current article introduces a Special Issue of Ecological Psychology that aims to correct this problem. This issue brings together one empirical and six theoretical articles that develop ideas about the contributions of the nervous system to perception-action. We briefly review each of the articles, identify common themes, and point out the surprising variety in theoretical positions. It is hoped that this Special Issue will help guide discussions amongst ecological psychologists and (ecological) neuroscientists as they confront the question "What should a 'Gibsonian neuroscience' look like?"A psychology cannot be explained by a physiology until one has a psychology to explain. (Tolman, 1958, p. 118) Ecological psychology has been criticized for ignoring the brain in its investigations of how perception and action come about, treating it as "wonder tissue, resonating with marvelous sensitivity to a host of sophisticated affordances" the last few decades ecological psychologists have generally followed Mace's (1977, p. 43) dictum of "Ask[ing] not what's inside your head, but what your head's inside of." During much of this time, disembodied and disembedded accounts of perception and action were clearly dominant, and the focus on studying the sensitivity of active organisms to information in the environmentat the expense of studying the neural contributions to this processwas therefore a natural one. In addition, most neuroscientific studies were (and unfortunately still are) guided by the mechanistic and cognitivist assumptions that ecological psychology disputes, and hence ill-positioned to guide ecological theory formation. Finally, it can be argued that the right conceptual framework needs to be in place before one can study the neurophysiological contributions; obviously, questions about what an animal does have to

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