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Neuroimaging and neuropsychological studies have implicated left inferior prefrontal cortex (LIPC) in both semantic and phonological processing. In this study, functional magnetic resonance imaging was used to examine whether separate LIPC regions participate in each of these types of processing. Performance of a semantic decision task resulted in extensive LIPC activation compared to a perceptual control task. Phonological processing of words and pseudowords in a syllable-counting task resulted in activation of the dorsal aspect of the left inferior frontal gyrus near the inferior frontal sulcus (BA44/45) compared to a perceptual control task, with greater activation for nonwords compared to words. In a direct comparison of semantic and phonological tasks, semantic processing preferentially

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Here we review recent findings that reveal the functional properties of extra-striate regions in the human visual cortex that are involved in the representation and perception of objects. We characterize both the invariant and non-invariant properties of these regions and we discuss the correlation between activation of these regions and recognition. Overall, these results indicate that the lateral occipital complex plays an important role in human object recognition.

& A still photograph of an object in motion may convey dynamic information about the position of the object immediately before and after the photograph was taken (implied motion). Medial temporal/medial superior temporal cortex (MT/MST) is one of the main brain regions engaged in the perceptual analysis of visual motion. In two experiments we examined whether MT/MST is also involved in representing implied motion from static images. We found stronger functional magnetic resonance imaging (fMRI) activation within MT/MST during viewing of static photographs with implied motion compared to viewing of photographs without implied motion. These results suggest that brain regions involved in the visual analysis of motion are also engaged in processing implied dynamic information from static images. & The perception of motion is critical for our ability to interact with a dynamic environment. Neurophysiological studies in monkeys (for example, Britten, Newsome,

performing a specific visual task (for an exposition of this issue, see Ungerleider and Haxby, 1994; DeYoe et al., 1994; Goodale et al., 1994). Single neuron recordings in the macaque provide evidence both for segregation of visual cues into different †Diagnostic Imaging Department channels (Livingstone and Hubel, 1988; DeYoe et al., The Chaim Sheba Medical Center 1994) and for convergence of several primary cues even Tel Hashomer 52621 at the level of single cortical neurons (Sary et al., 1993). Israel Similarly, studies of anatomical connections indicate ‡School of Cognitive and Computing Sciences the existence of parallel specialized cortical streams University of Sussex, Falmer (Young, 1992) but also show substantial interstream Brighton BN1 9QH communication both between areas (reviewed by Felle-

Where does grammar come from? How does it develop in children? Developmental psycholinguists who set out to answer these questions quickly find themselves impaled upon the horns of a dilemma, caught up in a modern variant of the ancient war between empiricists and nativists. Indeed, some of the fiercest battles in this war have been waged in the field of child language. Many reasonable individuals in this field have argued for a middle ground, but such a compromise has proven elusive thus far, in part because the middle ground is difficult to define. So let us begin with some definitions. The core of this debate is about epistemology, a branch of philosophy that we can define as “The study of knowledge, its form and source, and the process by which it comes to be. ” Within this framework, empiricism can be defined as “The belief that knowledge originates in the environment and comes into the mind/brain through the

e for processing faces than the control groups, but for these analyses, the effect was now on the left side. Greater ITG activation was the pattern found in both control groups during object processing. Conclusions: Individuals with autism spectrum disorders demonstrate a pattern of brain activity during face discrimination that is consistent with featurebased strategies that are more typical of nonface object perception. Arch Gen Psychiatry. 2000;57:331-340 T HE SYMPTOMS of autism spectrum disorders, such as a preference for inanimate objects and lack of interest in the human face, are evident as early as the first year of life. 1-3 Abnormalities in face-recognition skills are of particular interest, as they may provide clues about the developmental mechanisms involved in the pathobiology of autism and Asperger syndrome (AS). Recognition of individual faces is necessary for successful interpersonal relat

Early neuroimaging studies often failed to obtain evidence of medial temporal lobe (MTL) activation during episodic encoding or retrieval, but a growing number of studies using functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) have provided such evidence. We review data from fMRI studies that converge on the conclusion that posterior MTL is associated with episodic encoding; too few fMRI studies of retrieval have reported MTL activations to allow firm conclusions about their exact locations. We then turn to a recent meta-analysis of PET studies (Lepage et al., Hippocampus 1998;8:313-- 322) that appears to contradict the fMRI encoding data. Based on their analysis of the rostrocaudal distribution of activations reported during episodic encoding or retrieval, Lepage et al. (1998) concluded that anterior MTL is strongly associated with episodic encoding, whereas posterior MTL is strongly associated with episodic retrieval. After considering the evidence reviewed by Lepage et al. (1998) along with additional studies, we conclude that PET studies of encoding reveal both anterior and posterior MTL activations. These observations indicate that the contradiction between fMRI and PET studies of encoding was more apparent than real. However, PET studies have reported anterior MTL encoding activations more frequently than have fMRI studies. We consider possible sources of these differences. Hippocampus 1999;9:7--24.

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