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The authors sought to determine whether errors of action committed by patients with closed head injury (CHI) would conform to predictions derived from frontal lobe theories. In Study 1, 30 CHI patients and 18 normal controls performed routine activities, such as wrapping a present, under conditions of graded complexity. CHI patients committed more errors(More)
Although ideomotor apraxia (IM) has been a topic of investigation since the early 20th century, progress in studying the disorder has been hindered by important (and sometimes unarticulated) differences in the underlying theoretical models of various investigative groups. As a result, it is difficult to draw conclusions about the expected performance of IM(More)
An unselected group of right hemisphere, semi-acute stroke patients (n = 30) was run on a laboratory test of naturalistic action production and was found to commit errors of action at a higher rate than what was previously reported for recovering head injury patients [Schwartz et al., Naturalistic action impairment in closed head injury. Neuropsychology,(More)
A number of conflicting claims have been advanced regarding the role of the left inferior frontal gyrus, inferior parietal lobe and posterior middle temporal gyrus in action recognition, driven in part by an ongoing debate about the capacities of putative mirror systems that match observed and planned actions. We report data from 43 left hemisphere stroke(More)
OBJECTIVE To assess the relative frequency of occurrence of motor, perceptual, peripersonal, and personal neglect subtypes, the association of neglect and other related deficits (e.g., deficient nonlateralized attention, anosognosia), and the neuroanatomic substrates of neglect in patients with right hemisphere stroke in rehabilitation settings. METHODS(More)
It is frequently claimed that ideational apraxia, an impairm ent of the performance of complex actions with objects, is a left-hemisphere syndrome. We assessed the consequences of lefthemisphere damage for naturalistic action performance in two studies. In Study 1, we compared the action errors of left-hemisphere stroke patients (LCVA) to previously(More)
A considerable recent literature argues that the same representations, encoded by inferior prefrontal and parietal cells known as "mirror neurons", may be activated in both production and recognition of object-related actions. Here, we test several predictions derived from the contemporary literature on the parity between production and recognition and the(More)
An influential account of selective semantic deficits posits that visual features are heavily weighted in the representations of animals, whereas information about function is central in the representations of tools (e.g., Warrington & Shallice, 1984 ). An alternative account proposes that information about all types of objects-animate and inanimate(More)
On an influential model of limb praxis, ideomotor apraxia results from damage to stored gesture representations or disconnection of representations from sensory input or motor output (Heilman & Gonzalez Rothi, 1993; Gonzalez Rothi et al., 1991). We report data from a patient with progressive ideomotor limb apraxia which cannot be readily accommodated by(More)
Viewing objects with the intention to act upon them may activate task-irrelevant motor responses. Many manufactured objects are associated with two action classes: grasping in accordance with object structure and skillful use consistent with object function. We studied the potential for within-object competition during action selection by comparing(More)