Biomedical subjects

C J Price

Publications and source records attributed to C J Price.

At least 55 records · Page 3Linked to original sources

PubMed2000

The anatomy of language: contributions from functional neuroimaging.

This article illustrates how functional neuroimaging can be used to test the validity of neurological and cognitive models of language. Three models of language are described: the 19th Century neurological model which describes both the anatomy and cognitive components of auditory and visual word processing, and 2 20th Century cognitive models that are not constrained by anatomy but emphasise 2 different routes to reading that are not present in the neurological model. A series of functional imaging studies are then presented which show that, as predicted by the 19th Century neurologists, auditory and visual word repetition engage the left posterior superior temporal and posterior inferior frontal cortices. More specifically, the roles Wernicke and Broca assigned to these regions lie respectively in the posterior superior temporal sulcus and the anterior insula. In addition, a region in the left posterior inferior temporal cortex is activated for word retrieval, thereby providing a second route to reading, as predicted by the 20th Century cognitive models. This region and its function may have been missed by the 19th Century neurologists because selective damage is rare. The angular gyrus, previously linked to the visual word form system, is shown to be part of a distributed semantic system that can be accessed by objects and faces as well as speech. Other components of the semantic system include several regions in the inferior and middle temporal lobes. From these functional imaging results, a new anatomically constrained model of word processing is proposed which reconciles the anatomical ambitions of the 19th Century neurologists and the cognitive finesse of the 20th Century cognitive models. The review focuses on single word processing and does not attempt to discuss how words are combined to generate sentences or how several languages are learned and interchanged. Progress in unravelling these and other related issues will depend on the integration of behavioural, computational and neurophysiological approaches, including neuroimaging.

Brain↗

PubMed2000

Evaluation of the developmental toxicity of formamide in Sprague-Dawley (CD) rats.

Timed-pregnant CD(R) outbred albino Sprague-Dawley rats received formamide (50, 100, or 200 mg/kg/day) or vehicle (5 ml/kg deionized/distilled water, po) on gestational days (gd) 6 through 19. Maternal food and water consumption (absolute and relative), body weight, and clinical signs were monitored at regular intervals throughout gestation. At termination (gd 20), confirmed-pregnant females (21-23 per group) were evaluated for clinical status and gestational outcome; live fetuses were examined for external, visceral, and skeletal malformations and variations. There were no maternal deaths and no dose-related clinical signs. At 200 mg/kg/day, maternal body weight on gd 20, weight gain, and gravid uterine weight were significantly decreased. Maternal weight gain, corrected for gravid uterine weight, liver weight (absolute or relative), and food and water consumption (absolute or relative), were not affected. Formamide did not affect prenatal viability or incidences of fetal malformations or variations. Average fetal body weight/litter was decreased at 100 and 200 mg/kg/day. Fetal body weight was affected at lower daily doses than in previously published studies, possibly due to the longer total exposure period and/or lack of a recovery period between cessation of exposure and termination. In summary, the maternal toxicity no-observed-adverse-effect level (NOAEL) was 100 mg/kg/day and the low observed adverse effect level (LOAEL) was 200 mg/kg/day under the conditions of this study. Similarly, the developmental toxicity NOAEL was 50 mg/kg/day and the LOAEL was 100 mg/kg/day.

Abnormalities, Drug-Induced↗

PubMed2000

Vasodilator-stimulated phosphoprotein is involved in stress-fiber and membrane ruffle formation in endothelial cells.

Vasodilator-stimulated phosphoprotein (VASP) is highly expressed in vascular endothelial cells, where it has been implicated in cellular reorganization during angiogenesis, as well as in endothelial retraction and changes in vessel permeability. However, the cellular functions of VASP are not known. In this study, we have expressed wild-type and mutant forms of VASP in endothelial cells to determine in what aspects of cytoskeletal behavior this protein participates. Expression of wild-type VASP induces marked membrane ruffling and formation of prominent stress fibers in bovine aortic endothelial cells. Deletion of the proline-rich domain of VASP abolishes its ability to bind profilin but does not affect ruffling or stress fiber formation. Further deletions reveal a sequence within the carboxy-terminal domain that is responsible for in vivo bundle formation. Ruffling occurs only on the expression of forms of VASP that possess bundling activity and the capacity to bind zyxin/vinculin-derived peptide. The ability of distinct subdomains within VASP to bind adhesion proteins and induce F-actin bundling in vivo suggests that this protein could function in the aggregation and tethering of actin filaments during the formation of endothelial cell-substrate and cell-cell contacts. These data provide a mechanism whereby VASP can influence endothelial migration and organization during capillary formation and modulate vascular permeability via effects on endothelial cell contractility.

Actins↗

PubMed2000

The effects of presentation rate during word and pseudoword reading: a comparison of PET and fMRI.

The effect of stimulus rate and its interaction with stimulus type on brain activity during reading was investigated using functional magnetic resonance imaging (fMRI). This (i) enabled the segregation of brain regions showing differential responses, (ii) identified the optimum experimental design parameters for maximizing sensitivity, and (iii) allowed us to evaluate further the sources of discrepancy between positron emission tomography (PET) and fMRI signals. The effect of visual word rate has already been investigated in a previous PET study. However, rate effects can be very different in PET and fMRI, as seen in previous studies of auditory word processing. In this work, we attempt to replicate rate-sensitive activations observed with PET using fMRI. Our objective was to characterize the discrepancies in regionally specific rate-sensitive effects between the two imaging modalities. Subjects were presented with words and pseudowords at varying rates while performing a silent reading task. The analysis specifically identified regions showing (i) an effect of stimulus rate on brain activity during reading; (ii) modulation of this effect by word type; and (iii) increased activity during reading relative to rest, but with no dependence on stimulus rate. The results identified similar effects of rate for words and pseudowords (no interactions between rate and word type reached significance). Irrespective of word type, strong positive linear effects of rate (i.e., activity increasing with rate) were detected in visual areas, right superior temporal gyrus, and bilateral precentral gyrus. These findings replicate the results of the previous PET study, confirming that activation in regions associated with visual processing and response generation increases with the number of stimuli. Likewise, we detected rate-independent effects reported in the previous PET study in bilateral anterior middle temporal, inferior frontal, and superior parietal regions. These results differentiate the functionally specific responses in rate-dependent and rate-independent areas. However, for negative effects of rate, fMRI did not replicate the effects seen in PET, suggesting some form of hemodynamic "rectification." The discussion focuses on differences between evoked rCBF and BOLD signals.

Adult↗

PubMed2000

A voxel-based morphometry study of semantic dementia: relationship between temporal lobe atrophy and semantic memory.

The cortical anatomy of 6 patients with semantic dementia (the temporal lobe variant of frontotemporal dementia) was contrasted with that of a group of age-matched normal subjects by using voxel-based morphometry, a technique that identifies changes in gray matter volume on a voxel-by-voxel basis. Among the circumscribed regions of neuronal loss, the left temporal pole (Brodmann area 38) was the most significantly and consistently affected region. Cortical atrophy in the left hemisphere also involved the inferolateral temporal lobe (Brodmann area 20/21) and fusiform gyrus. In addition, the right temporal pole (Brodmann area 38), the ventromedial frontal cortex (Brodmann area 11/32) bilaterally, and the amygdaloid complex were affected, but no significant atrophy was measured in the hippocampus, entorhinal, or caudal perirhinal cortex. The degree of semantic memory impairment across the 6 cases correlated significantly with the extent of atrophy of the left anterior temporal lobe but not with atrophy in the adjacent ventromedial frontal cortex. These results confirm that the anterior temporal lobe is critically involved in semantic processing, and dissociate its function from that of the adjacent frontal region.

Aged↗

PubMed1999

Scanning patients with tasks they can perform.

We present an overview of the types of imaging experiments that can be performed on psychologically impaired patients. The critical observation from such studies is a differential pattern of activation in the patients and normals. Underactivity is interpretable only when the patients make normal responses. In this context, a failure to activate a component region of the normal system implies that this region was not necessary for task performance. Overactivity indicates either cognitive or neuronal reorganisation. Neuronal reorganisation is indicated only if the patient performs the task using the same set of cognitive operations as normal subjects. Cognitive reorganisation can be demonstrated if the same activation pattern is elicited by normals when they are co-erced into using the same cognitive implementation as the patient. We conclude that the interpretation of neuroimaging studies of psychologically impaired patients depends on intact task performance and a detailed task analysis. When these criteria are met, patient studies can be used to identify: (1) necessary and sufficient brain systems, (2) dysfunction at sites distant to damage, (3) peri-damage activation, and (4) compensation either at a neuronal level when pre-existing cognitive strategies are re-instantiated using duplicated neuronal systems (degeneracy), or at a cognitive level when alternative cognitive strategies (and their corresponding brain systems) are adopted.

Brain↗

PubMed1999

Dual-process model in semantic priming: A functional imaging perspective.

In this positron emission tomography study, we investigated the neural correlates of semantic priming, where response to a word is facilitated when preceded by a semantically related word. Nine normal subjects were scanned while performing a lexical decision task. Within this condition, the proportion of related prime-target word pairs was varied across scans from 0 to 100%. The control task involved letter decision on consonant letter strings, controlling orthographic processing and response selection. First, lexical decision (relative to letter decision) activated regions previously observed in lexicosemantic tasks, i.e., the left anterior and inferior temporal lobe and left inferior frontal gyrus. Behavioral analysis confirmed significant facilitation of lexical decision to related targets (mean priming effect 68 ms). It also suggested the contribution of both automatic and strategic processes, consistent with theoretical accounts of priming. Automatic priming was indicated by consistent RTs to related targets irrespective of the proportion of related word pairs per scan. Strategic processing was indicated by decreases in RTs to nonwords as the proportion of related targets increased. Nonlinear correlational analysis of cerebral activity during lexical decision revealed a neurophysiological correlate of these behavioral effects in (i) the left anterior temporal lobe (BA 38), a region involved in lexicosemantic processing; (ii) the anterior cingulate cortex, right premotor region (BA 6), and right superior parietal lobe (BA 7), regions associated with attentional processes. We conclude that in this experimental context, semantic priming involves both automatic and strategic processing.

Adult↗

PubMed1999

The critical relationship between the timing of stimulus presentation and data acquisition in blocked designs with fMRI.

This paper concerns the experimental design and statistical models employed by fMRI activation studies which block presentation of linguistic stimuli. In particular, we note that the relationship between the timing of stimulus presentation and data acquisition can have a substantial impact on the ability to detect activations in critical language areas, even when the stimuli are presented in blocks. Using a blocked word rhyming paradigm and repeated investigations on a single subject, activation was observed in Broca's area (left inferior frontal cortex) and Wernicke's area (left posterior temporoparietal cortex) when (i) the timing of data acquisition was distributed throughout the peristimulus time and (ii) an event-related analysis was used to model the phasic nature of the hemodynamic response within each block of repeated word stimuli. In contrast, when the timing of data acquisition relative to stimulus presentation was fixed, activation was detected in Broca's area but not consistently in Wernicke's area. Our results indicate that phasic responses to stimuli occur even in a blocked design and that the sampling and proper modeling of these responses can have profound effects on their detection. Specifically, distributed sampling over peristimulus time is essential in order to detect small activations particularly when they are transient. These findings are likely to generalize to the detection of transient signals in any cognitive paradigm.

Brain Mapping↗

PubMed1999

Three distinct ventral occipitotemporal regions for reading and object naming.

This study investigates word and object processing during naming and viewing tasks and identifies three distinct regions in the left ventral occipitotemporal cortex. Irrespective of task, words and objects (relative to meaningless visual controls) activated the medial surface of the left anterior fusiform gyrus, a region that has previously been associated with semantic knowledge. A more lateral region was differentially active for naming words and objects relative to viewing the same stimuli and a more posterior region was differentially active for objects relative to words irrespective of task. In addition, we found that word processing resulted in greater activation than object processing on the dorsal surface of the left superior temporal gyrus and the left supramarginal gyrus. These regions appear to be important for converting orthography into phonology; their response to words irrespective of task is consistent with established psychological evidence that implicit phonological processing is stronger for words than objects.

Adult↗

PubMed1999

Multisubject fMRI studies and conjunction analyses.

In this paper we present an approach to making inferences about generic activations in groups of subjects using fMRI. In particular we suggest that activations common to all subjects reflect aspects of functional anatomy that may be "typical" of the population from which that group was sampled. These commonalities can be identified by a conjunction analysis of the activation effects in which the contrasts, testing for an activation, are specified separately for each subject. A conjunction is the joint refutation of multiple null hypotheses, in this instance, of no activation in any subject. The motivation behind this use of conjunctions is that fixed-effect analyses are generally more "sensitive" than equivalent random-effect analyses. This is because fixed-effect analyses can harness the large degrees of freedom and small scan-to-scan variability (relative to the variability in responses from subject to subject) when assessing the significance of an estimated response. The price one pays for the apparent sensitivity of fixed-effect analyses is that the ensuing inferences pertain to, and only to, the subjects studied. However, a conjunction analysis, using a fixed-effect model, allows one to infer: (i) that every subject studied activated and (ii) that at least a certain proportion of the population would have shown this effect. The second inference depends upon a meta-analytic formulation in terms of a confidence region for this proportion. This approach retains the sensitivity of fixed-effect analyses when the inference that only a substantial proportion of the population activates is sufficient.

Attention↗

PubMed1999

From objects to names: a cognitive neuroscience approach.

To name an object, we need both to recognize it and to access the associated phonological form, and phonological retrieval itself may be constrained by aspects of the visual recognition process. This paper reviews evidence for such constraints, drawing on data from experimental psychology, neuropsychology, functional imaging, and computational modelling. Data on picture identification in normal observers demonstrate that the speed of name retrieval processes differs for natural objects and artifacts, due at least in part to differences in visual similarity between exemplars within these categories. Also, effects of variables on early and late stages of object identification combine in an interactive rather than an additive manner, consistent with object processing stages operating in a continuous rather than a discrete manner. Neuropsychological evidence supports this proposal, demonstrating that subtle perceptual deficits can produce naming problems, even when there is good access to associated semantic knowledge. Functional activation studies further show increased activity in visual processing areas when conditions stress object naming relative to the recognition of familiar object structures. These studies indicate that object naming is based on a series of continuous processing stages and that naming involves increased visual processing relative to recognition tasks. The data can be modelled within an interactive activation and competition framework.

Adult↗

PubMed1999

Inhibition of calcium-dependent NMDA receptor current rundown by calbindin-D28k.

NMDA receptors are regulated by several different calcium-dependent processes. To determine if the presence of the intracellular calcium-binding protein calbindin-D28k can influence the calcium regulation of NMDA receptor activity, human embryonic kidney 293 cells were co-transfected with cDNAs for NMDA receptor subunits and calbindin. Recordings were made using the nystatin perforated patch technique to preserve intracellular contents. When compared with control cells (transfected with cDNA encoding beta-galactosidase in place of calbindin), the presence of calbindin had no effect on either calcium-dependent inactivation or the calcium-sensitive, time-dependent increase in glycine-independent desensitization of NMDA receptor-mediated currents. However, the development of calcium-dependent rundown of peak glutamate-evoked current was slowed significantly in calbindin versus beta-galactosidase co-transfected cells. This result was true for cells transfected with either NR1/NR2A or NR1/NR2B subunits, although calbindin was relatively less effective at inhibiting rundown in NR1/NR2B-expressing cells. NMDA peak current rundown has been attributed to calcium-induced depolymerization of the actin cytoskeleton. Therefore, our results indicate that although calbindin may not influence calcium-dependent regulatory processes occurring very near the NMDA receptor channel, it appears to be more effective at buffering local elevations in intracellular calcium at the actin cytoskeleton.

Calbindin 1↗

PubMed1999

D1 dopamine receptor-induced cyclic AMP-dependent protein kinase phosphorylation and potentiation of striatal glutamate receptors.

Dopamine receptor activation regulates cyclic AMP levels and is critically involved in modulating neurotransmission in the striatum. Others have shown that alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)-type glutamate receptor-mediated current is potentiated by cyclic AMP-dependent protein kinase (PKA) activation. We made whole-cell patch clamp recordings from cultured striatal neurons and tested whether D1-type dopamine receptor activation affected AMPA receptor-mediated currents. After a 5-min exposure to the D1 agonist SKF 81297 (1 microM), kainate-evoked current amplitude was enhanced in approximately 75% of cells to 121+/-2.5% of that recorded prior to addition of drug. This response was inhibited by the D1 antagonist SCH 23390 and mimicked by activators of PKA. Moreover, by western blot analysis using an antibody specific for the phosphorylated PKA site Ser845 of GluR1, we observed a marked increase in phosphorylated GluR1 following a 10-min exposure of striatal neurons to 1 microM SKF 81297. Our data demonstrate that activation of D1-type dopamine receptors on striatal neurons promotes phosphorylation of AMPA receptors by PKA as well as potentiation of current amplitude. These results elucidate one mechanism by which dopamine can modulate neurotransmission in the striatum.

Action Potentials↗

PubMed1999

Disrupted temporal lobe connections in semantic dementia.

Semantic dementia refers to the variant of frontotemporal dementia in which there is progressive semantic deterioration and anomia in the face of relative preservation of other language and cognitive functions. Structural imaging and SPECT studies of such patients have suggested that the site of damage, and by inference the region critical to semantic processing, is the anterolateral temporal lobe, especially on the left. Recent functional imaging studies of normal participants have revealed a network of areas involved in semantic tasks. The present study used PET to examine the consequences of focal damage to the anterolateral temporal cortex for the operation of this semantic network. We measured PET activation associated with a semantic decision task relative to a visual decision task in four patients with semantic dementia compared with six age-matched normal controls. Normals activated a network of regions consistent with previous studies. The patients activated some areas consistently with the normals, including some regions of significant atrophy, but showed substantially reduced activity particularly in the left posterior inferior temporal gyrus (iTG) (Brodmann area 37/19). Voxel-based morphometry, used to identify the regions of structural deficit, revealed significant anterolateral temporal atrophy (especially on the left), but no significant structural damage to the posterior inferior temporal lobe. Other evidence suggests that the left posterior iTG is critically involved in lexical-phonological retrieval: the lack of activation here is consistent with the observation that these patients are all anomic. We conclude that changes in activity in regions distant from the patients' structural damage support the argument that their prominent anomia is due to disrupted temporal lobe connections.

Anomia↗

PubMed1999

Explicit and implicit processing of words and pseudowords by adult developmental dyslexics: A search for Wernicke's Wortschatz?

Two groups of male university students who had been diagnosed as dyslexic when younger, and two groups of control subjects of similar age and IQ to the dyslexics, were scanned whilst reading aloud and during a task where reading was implicit. The dyslexics performed less well than their peers on a range of literacy tasks and were strikingly impaired on phonological tasks. In the reading aloud experiment, simple words and pseudowords were presented at a slow pace so that reading accuracy was equal for dyslexics and controls. Relative to rest, both normal and dyslexic groups activated the same peri- and extra-sylvian regions of the left hemisphere that are known to be involved in reading. However, the dyslexic readers showed less activation than controls in the left posterior inferior temporal cortex [Brodmann area (BA) 37, or Wernicke's Wortschatz], left cerebellum, left thalamus and medial extrastriate cortex. In the implicit reading experiment, word and pseudoword processing was contrasted to visually matched false fonts while subjects performed a feature detection paradigm. The dyslexic readers showed reduced activation in BA 37 relative to normals suggesting that this group difference, seen in both experiments, resides in highly automated aspects of the reading process. Since BA 37 has been implicated previously in modality-independent naming, the reduced activation may indicate a specific impairment in lexical retrieval. Interestingly, during the reading aloud experiment only, there was increased activation for the dyslexics relative to the controls in a pre-motor region of Broca's area (BA 6/44). We attribute this result to the enforced use of an effortful compensatory strategy involving sublexical assembly of articulatory routines. The results confirm previous findings that dyslexic readers process written stimuli atypically, based on abnormal functioning of the left hemisphere reading system. More specifically, we localize this deficit to the neural system underlying lexical retrieval.

Adult↗

PubMed1999

A functional imaging study of translation and language switching.

The neural systems underlying translation and language switching were investigated using PET. Proficient German-English adult bilinguals were scanned whilst either translating or reading visually presented words in German (L1), English (L2) or alternating L1/L2. We refer to alternating L1/L2 as 'switching'. The results revealed contrasting patterns of activation for translation and switching, suggesting at least partially independent mechanisms. Translation, but not switching, increased activity in the anterior cingulate and subcortical structures whilst decreasing activation in several other temporal and parietal language areas associated with the meaning of words. Translation also increased activation in regions associated with articulation (the anterior insula, cerebellum and supplementary motor area) arguably because the reading response to the stimulus must be inhibited whilst a response in a different language is activated. In contrast, switching the input language resulted in activation of Broca's area and the supramarginal gyri, areas associated with phonological recoding. The results are discussed in terms of the cognitive control of language processes.

Adult↗

PubMed1999

A functional neuroimaging study of the variables that generate category-specific object processing differences.

Brain damage can cause remarkably selective deficits in processing specific categories of objects, indicating the high degree of functional segregation within the brain. The neuroimaging study presented here investigates differences in the neural activity associated with two categories of natural objects (animals and fruit) and two categories of man-made objects (vehicles and tools). Stimuli were outline drawings and the tasks were naming and word-picture matching. For man-made objects, the only category-specific effect was in the left posterior middle temporal cortex, which was most active for drawings of tools, as previously reported. For natural objects, drawings of animals and fruit (relative to drawings of man-made objects) enhanced activity in bilateral anterior temporal and right posterior middle temporal cortices. Critically, these effects with natural objects were not observed when the stimuli were coloured appropriately to facilitate identification. Furthermore, activation in the same right hemisphere areas was also observed for viewing and matching unfamiliar non-objects relative to naming and matching man-made objects. These results indicate that, in the right hemisphere, differences between processing natural relative to man-made objects overlap with the effects of increasing demands on object identification. In the left hemisphere, the effects are more consistent with functional specialization within the semantic system. We discuss (i) how category-specific differences can emerge for multiple reasons and (ii) the implications of these effects on the interpretation of functional imaging data and patients with category-specific deficits.

Adult↗

PubMed1999

Mechanisms of recovery from aphasia: evidence from positron emission tomography studies.

OBJECTIVES: Language functions comprise a distributed neural system, largely lateralised to the left cerebral hemisphere. Late recovery from aphasia after a focal lesion, other than by behavioural strategies, has been attributed to one of two changes at a systems level: a laterality shift, with mirror region cortex in the contralateral cortex assuming the function(s) of the damaged region; or a partial lesion effect, with recovery of perilesional tissue to support impaired language functions. Functional neuroimaging with PET allows direct observations of brain functions at systems level. This study used PET to compare regional brain activations in response to a word retrieval task in normal subjects and in aphasic patients who had shown at least some recovery and were able to attempt the task. Emphasis has been placed on single subject analysis of the results as there is no reason to assume that the mechanisms of recovery are necessarily uniform among aphasic patients. METHODS: Six right handed aphasic patients, each with a left cerebral hemispheric lesion (five strokes and one glioma), were studied. Criteria for inclusion were symptomatic or formal test evidence of at least some recovery and an ability to attempt word retrieval in response to heard word cues. Each patient underwent 12 PET scans using oxygen-15 labelled water (H2(15)O) as tracer to index regional cerebral blood flow (rCBF). The task, repeated six times, required the patient to think of verbs appropriate to different lists of heard noun cues. The six scans obtained during word retrieval were contrasted with six made while the subject was "at rest". The patients' individual results were compared with those of nine right handed normal volunteers undergoing the same activation study. The data were analysed using statistical parametric mapping (SPM96, Wellcome Department of Cognitive Neurology, London, UK). RESULTS: Perception of the noun cues would be expected to result in bilateral dorsolateral temporal cortical activations, but as the rate of presentation was only four per minute the auditory perceptual activations were not evident in all people. Anterior cingulate, medial premotor (supplementary speech area) and dorsolateral frontal activations were evident in all normal subjects and patients. There were limited right dorsolateral frontal activations in three of the six patients, but a similar pattern was also found in four of the nine normal subjects. In the left inferolateral temporal cortex, activation was found for the normal subjects and five of the six patients, including two of the three subjects with lesions involving the left temporal lobe. The only patient who showed subthreshold activation in the left inferolateral temporal activation had a very high error rate when performing the verb retrieval task. CONCLUSIONS: The normal subjects showed a left lateralised inferolateral temporal activation, reflecting retrieval of words appropriate in meaning to the cue from the semantic system. Lateralisation of frontal activations to the left was only relative, with right prefrontal involvement in half of the normal subjects. Frontal activations are associated with parallel psychological processes involved in word retrieval, including task initiation, short term (working) memory for the cue and responses, and prearticulatory processes (even though no overt articulation was required). There was little evidence of a laterality shift of word retrieval functions to the right temporal lobe after a left hemispheric lesion. In particular, left inferolateral temporal activation was seen in all patients except one, and he proved to be very inefficient at the task. The results provide indirect evidence that even limited salvage of peri-infarct tissue with acute stroke treatments will have an important impact on the rehabilitation of cognitive functions.

Adult↗