H.‐J. Freund

Abstract Functional magnetic resonance imaging (fMRI) was used to localize brain areas that were active during the observation of actions made by another individual. Object‐ and non‐object‐related actions made with different effectors (mouth, hand and foot) were presented. Observation of both object‐ and non‐object‐related actions determined a somatotopically organized activation of premotor cortex. The somatotopic pattern was similar to that of the classical motor cortex homunculus. During the observation of object‐related actions, an activation, also somatotopically organized, was additionally found in the posterior parietal lobe. Thus, when individuals observe an action, an internal replica of that action is automatically generated in their premotor cortex. In the case of object‐related actions, a further object‐related analysis is performed in the parietal lobe, as if the subjects were indeed using those objects. These results bring the previous concept of an action observation/execution matching system (mirror system) into a broader perspective: this system is not restricted to the ventral premotor cortex, but involves several somatotopically organized motor circuits.

The review discusses how CO2 surface chemistry has developed since the early 1950s. Emphasis is given to studies of well-characterized surfaces of metals, oxides and some more complex systems involving in particular alkali modified surfaces and also of coadsorbed molecules.

Partial table of contents: The Noncontinuous Nature of Movement Execution (R. Llinas). How Is Motor Behavior Reflected in the Organization of Spinal Systems? (H. Hultborn & M. Illert). Spatial Transformations in Vestibular Reflex Systems (B. Peterson & J. Baker). How Do Sensory and Motor Signals Interact During Locomotion (F. Clarac). The Neural Control of Orienting Eye and Head Movements (D. Sparks). How is Grasping Modified by Somatosensory Input? (R. Johansson). What Is the Evidence for Multiple Motor Areas in the Human Brain? (H. Freund). How Do the Different Cortical Motor Areas Contribute to Motor Learning and Compensation Following Brain Dysfunction? (K. Sasaki & H. Gemba). List of Participants with Fields of Research. Subject Index. Author Index.

It has been shown in nonhuman primates that the posterior parietal cortex is involved in coordination of arm and eye movements in space, whereas the anterior intraparietal area in the anterior lateral bank of the intraparietal sulcus plays a crucial role in fine finger movements, such as grasping. In this study we show by optoelectronic movement recordings that patients with cortical lesions involving the anterior lateral bank of the intraparietal sulcus have selective deficits in the coordination of finger movements required for object grasping, whereas reaching is much less disturbed. Patients with parietal lesions sparing the cortex lining the anterior intraparietal sulcus showed intact grasping behavior. Complementary evidence was obtained from functional MRI in normal control subjects showing a specific activation of the anterior lateral bank of the intraparietal sulcus during grasping. In conclusion, this combined lesion and activation study suggests that the anterior lateral bank of the intraparietal sulcus, possibly including the human homologue of the anterior intraparietal area, mediates the processing of sensorimotor integration of precisely tuned finger movements in humans.

We have investigated the electronic and geometric structure of a thin oxide film grown by oxidation on NiAl(110) using electron spectroscopic techniques, i.e., LEED, EELS, XPS and ARUPS. This film is inert to adsorption of, respectively reaction with many molecules up to temperatures of about 800 K. It is well ordered as deduced from the LEED pattern and covers the whole surface. We find that the oxide film is about 5 Å thick, consisting of aluminium oxide as shown by EELS, XPS and ARUPS. It is most likely formed of two aluminium layers and two quasihexagonal oxygen layers with oxygen surface termination. Since the oxide film is rather thin it only shows a two-dimensional band structure which has been investigated using ARUPS. For the electronic levels of the oxide strong periodic dispersions are observed with bandwidths compatible to dispersion bandwidths calculated for the ΓX direction of α-Al2O3.