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Cathy Price

Publications and source records attributed to Cathy Price.

7 recordsLinked to original sources
PubMed2005

Speech-specific auditory processing: where is it?

Are speech-specific processes localized in dedicated cortical regions or do they emerge from developmental plasticity in the connections among non-dedicated regions? Here we claim that all the brain regions activated by the processing of auditory speech can be re-classified according to whether they respond to non-verbal environmental sounds, pitch changes, unfamiliar melodies, or conceptual processes. We therefore argue that speech-specific processing emerges from differential demands on auditory and conceptual processes that are shared by speech and non-speech stimuli. This has implications for domain- vs. process-specific cognitive models, and for the relative importance of segregation and integration in functional anatomy.

Auditory Perception↗
PubMed2005

Fusiform activation to animals is driven by the process, not the stimulus.

Previous studies have found that the lateral posterior fusiform gyri respond more robustly to pictures of animals than pictures of manmade objects and suggested that these regions encode the visual properties characteristic of animals. We suggest that such effects actually reflect processing demands arising when items with similar representations must be finely discriminated. In a positron emission tomography (PET) study of category verification with colored photographs of animals and vehicles, there was robust animal-specific activation in the lateral posterior fusiform gyri when stimuli were categorized at an intermediate level of specificity (e.g., dog or car). However, when the same photographs were categorized at a more specific level (e.g., Labrador or BMW), these regions responded equally strongly to animals and vehicles. We conclude that the lateral posterior fusiform does not encode domain-specific representations of animals or visual properties characteristic of animals. Instead, these regions are strongly activated whenever an item must be discriminated from many close visual or semantic competitors. Apparent category effects arise because, at an intermediate level of specificity, animals have more visual and semantic competitors than do artifacts.

Adult↗
PubMed2003

Hemispheric dissociation in access to the human semantic system.

Patient studies suggest that speech and environmental sounds are differentially processed by the left and right hemispheres. Here, using functional imaging in normal subjects, we compared semantic processing of spoken words to equivalent processing of environmental sounds, after controlling for low-level perceptual differences. Words enhanced activation in left anterior and posterior superior temporal regions, while environmental sounds enhanced activation in a right posterior superior temporal region. This left/right dissociation was unchanged by different attentional/working memory contexts, but it was specific to tasks requiring semantic analysis. While semantic processing involves widely distributed networks in both hemispheres, our results support the hypothesis of a dual access route specific for verbal and nonverbal material, respectively.

Acoustic Stimulation↗
PubMed2003

Respiratory function after unilateral percutaneous cervical cordotomy.

Percutaneous cervical cordotomy (PCC) is a recognized procedure for control of pain due to thoracic malignancies. Caution with PCC in those with precarious lung function has previously been advised. Thirty-five patients were studied in a prospective study of respiratory function before and after PCC for control of pain from pleural mesothelioma or other thoracic malignancy using standard, easily applied tests. Mean duration of survival was 83 days (range 3-360 days). FEV1.0 and FVC did not alter significantly after the procedure. There was no relationship between any of the respiratory function variables measured and survival. Transient nocturnal hypoxemia occurred during the night immediately following PCC in 6 patients. Unilateral PCC does not worsen respiratory function in patients with pleural mesothelioma or other thoracic malignancies. Poor respiratory function before PCC does not predict survival or complications. It should not be a barrier to use of PCC.

Adult↗
PubMed2002

Continuous venovenous hemodiafiltration in hypernatremic hyperglycemic nonketotic coma.

Rapid changes in serum sodium concentration can result in adverse neurological outcome. The gradual correction of hypernatremia in the setting of acute renal failure can be difficult to achieve. We describe an obese female teenager who presented with severe hypernatremia, hyperosmolar hyperglycemic nonketotic coma, acute renal failure, and rhabdomyolysis. Her hypernatremia and other serum chemistries were gradually corrected by repeatedly adjusting the dialysate electrolyte composition used during continuous venovenous hemodiafiltration. She had a full recovery of her renal function. She does not have clinical neurological sequelae from hypernatremia during a 1-year follow-up period.

Acidosis↗
PubMed2002

Echo time dependence of BOLD contrast and susceptibility artifacts.

Echo-planar imaging with gradient echo allows whole-brain images to be rapidly acquired. However, its main limitation is that magnetic field inhomogeneities in regions of the brain close to bone and air-filled sinuses result in reduced signal-to-noise ratio and signal loss. In particular this is a problem for imaging the temporal lobes, and can therefore affect the results of some language-related studies. Decreasing the echo time (TE) increases the signal-to-noise ratio and reduces the amount of signal loss in susceptible regions. In this study we investigate the TE dependence of BOLD (blood oxygenation level-dependent) contrast and, in particular, how it is influenced in regions with susceptibility artifacts. We use a dual echo-time sequence to compare brain activations measured with two different TEs, TE = 40 ms and TE = 27 ms. The paradigm involves comparing famous faces to scrambled faces, a low-level control condition. It was chosen because famous faces have been repeatedly shown to activate the fusiform gyri and anterior temporal lobes in both PET and fMRI. Our results show that it is possible to detect robust activations at a lower TE in brain regions not affected by susceptibility artifacts (i.e., fusiform gyri), allowing for faster scanning times. However, although the amount of signal loss is reduced at the lower TE, this does not appear to be sufficient to recover the BOLD signal in regions affected by susceptibility artifacts (i.e., anterior temporal lobes).

Adult↗