Birgitta Söderfeldt

Pharmacokinetics of levetiracetam during pregnancy, delivery, in the neonatal period, and lactation

Summary:  Purpose: To study pharmacokinetics of levetiracetam (LEV) during pregnancy, delivery, lactation, and in the neonatal period.

Topiramate kinetics during delivery, lactation, and in the neonate : Preliminary observations

Summary:  Purpose: To study the pharmacokinetics of topiramate (TPM) during delivery, lactation, and in the neonate.

Signed and spoken language perception studied by positron emission tomography

Sign and spoken language seem to be localized in the same brain areas. They elicit similar regional cerebral blood flow (rCBF) patterns, even though sign language is dependent on spatial information. We investigated sign and spoken language perception in a group of healthy bilingual subjects. Four videotaped activation conditions were used during PET imaging: (1) sign language, (2) spoken language, (3) spoken language with mouth covered, and(4) spoken language on a sound track while showing a motionless face. Spoken language (condition 4) activated significantly the perisylvian cortex(Brodmann areas 22 and 43) bilaterally. Sign language activated the visual association areas (Brodmann areas 37 and 19) but did not selectively activate parietal regions. A reciprocal relationship was observed between the level of activation in visual language perception areas and that in auditory perception areas. We conclude that when healthy bilingual subjects use the visual route for sign language perception, the functional anatomy overlaps that of language processing containing both auditory and visual components.

Metabolic, Circulatory, and Structural Alterations in the Rat Brain Induced by Sustained Pentylenetetrazole Seizures

Summary: Previous studies have demonstrated that bicuculline‐induced seizures of 1–2 h in duration lead to structural, metabolic, and circulatory alterations in the rat brain. Such alterations were observed even though cerebral oxygenation seemed adequate. In the present study, we explored whether pentylenetetrazole, a convulsant which interferes with ‐v‐aminobutyric acid inhibition by mechanisms other than that of bicuculline, leads to similar structural alterations and to similar cerebral metabolic and circulatory changes. The drug was given to paralyzed and artificially ventilated rats in a dose of 100 mg/ kg i.v., and seizures were allowed to continue for 1–120 min. The onset of seizures was accompanied by a small perturbation of cerebral cortical energy state, but sustained changes were confined to decreases in phosphocreatine, glycogen, and glucose and increases in lactate, pyruvate, and cyclic nucleotides. A sustained increase in free fatty acid concentration was observed, with the largest change occurring in arachidonic acid concentration. In the cerebellum, metabolic perturbation was clearly less pronounced, but cyclic nucleotide concentrations rose substantially. Local cerebral blood flow increased in all but two structures (frontal cortex and caudoputamen), but pronounced interstructural changes occurred. Nerve cell changes and astrocytic swelling were observed in the cerebral cortex. There was marked status spongiosus due to edema, which was mainly astrocytic and most prominent in cortical layer 3 and in parts of hippocampus. Nerve cell changes were of two basic types. The type 1 injured neurons, condensed and triangular in shape, were mainly confined to the edematous areas. Many of them had cytoplasmic vacuoles which on electron microscopy proved to be mainly dilated Golgi cis‐ternae or mitochondria. As compared with bicuculline‐induced epilepsy such abnormal mitochondria appeared to be more frequent. The type 2 neurons had slit‐formed intracytoplasmic and perinuclear vacuoles resulting from dilatation of the endoplasmic reticulum cisternae and the nuclear envelope. The cerebellum looked normal by light microscopy. We conclude that, in the rat, sustained seizure activity induced by pentylenetetrazole is accompanied by alterations in EEG activity, in cerebral metabolism and circulation, and in cell structure similar to those elicited by bicuculline.

Brain Activation During Compassion Meditation: A Case Study

OBJECTIVES B.L. is a Tibetan Buddhist with many years of compassion meditation practice. During meditation B.L. uses a technique to generate a feeling of love and compassion while reciting a mantra. The aim of the present study was to investigate the neural correlates of compassion meditation in 1 experienced meditator. METHODS B.L. was examined by functional magnetic resonance imaging during compassion meditation, applying a paradigm with meditation and word repetition blocks. RESULTS The most significant finding was the activation in the left medial prefrontal cortex extending to the anterior cingulate gyrus. Other significant loci of activation were observed in the right caudate body extending to the right insula and in the left midbrain close to the hypothalamus. CONCLUSIONS The results in this study are in concordance with the hypothesis that compassion meditation is accompanied by activation in brain areas involved with empathy as well as with happy and pleasant feelings (i.e., the left medial prefrontal cortex and the anterior cingulate gyrus).

Regional Cerebral Blood Flow in Sign Language Users

Cerebral activation was compared during sign and spoken language comprehension. Nine hearing children of deaf parents were studied and the cerebral activation was measured by recordings of the regional cerebral blood flow. Comprehension of a complex material gave a bilateral activation of posterior temporal regions for both spoken and signed language. It seems that sign language activates the cortex in a way which is very similar to spoken language, when the listener watches the speaker. Cortical areas usually regarded to be important for spatial ability do not show enhanced activation during sign language perception.

The cognitive neuroscience of signed language.

The present article is an assessment of the current state of knowledge in the field of cognitive neuroscience of signed language. Reviewed lesion data show that the left hemisphere is dominant for perception and production of signed language in aphasics, in a fashion similar to spoken language aphasia. Several neuropsychological dissociations support this claim: Non-linguistic visuospatial functions can be dissociated from spatial functions and general motor deficits can be dissociated from execution of signs. Reviewed imaging data corroborate the lesion data in that the importance of the left hemisphere is re-confirmed. The data also establish the role of the right hemisphere in signed language processing. Alternative hypotheses regarding what aspects of signed language processing are handled by the right hemisphere are currently tested. The second section of the paper starts by addressing the role that early acquisition of signed and spoken language play for the neurofunctional activation patterns in the brain. Compensatory cognitive and communicative enhancements have also been documented as a function of early sign language use, suggesting an interesting interaction between language and cognition. Recent behavioural data on sign processing in working memory--a cognitive system important for language perception and production suggest e.g. phonological loop effects analogous to those obtained for speech processing. Neuroimaging studies will have to address this potential communality.

Functional magnetic resonance imaging of hippocampal activation during silent mantra meditation.

OBJECTIVES The objective of the present study was to investigate whether moderately experienced meditators activate hippocampus and the prefrontal cortex during silent mantra meditation, as has been observed in earlier studies on subjects with several years of practice. METHODS Subjects with less than 2 years of meditation practice according to the Kundalini yoga or Acem tradition were examined by functional magnetic resonance imaging during silent mantra meditation, using an on-off block design. Whole-brain as well as region-of-interest analyses were performed. RESULTS The most significant activation was found in the bilateral hippocampus/parahippocampal formations. Other areas with significant activation were the bilateral middle cingulate cortex and the bilateral precentral cortex. No activation in the anterior cingulate cortex was found, and only small activation clusters were observed in the prefrontal cortex. CONCLUSIONS In conclusion, the main finding in this study was the significant activation in the hippocampi, which also has been correlated with meditation in several previous studies on very experienced meditators. We propose that the hippocampus is activated already after moderate meditation practice and also during different modes of meditation, including relaxation. The role of hippocampal activity during meditation should be further clarified in future studies, especially by investigating whether the meditation-correlated hippocampal activity is related to memory consolidation.

Quality of life in newly-debuted epilepsy. An empirical study

Objectives ‐ This study aimed to illuminate adults experienced quality of life in newly‐debuted epilepsy and to test the American instrument Quality of Life Index (QLI) for the first time on an epilepsy population. A second aim was to find appropriate questions to measure patient perceptions in epilepsy. Material and methods ‐ All persons 18–65 fulfilling criteria (n=41) and diagnosed during a 15‐month period at 2 Swedish hospitals, answered questionnaires (n= 37/41) on quality of life and perceptions of epilepsy. Results ‐ Patients experienced the highest quality in the “Family” domain and the lowest in the “Psychological/ spiritual”. Significant correlations were found between quality of life and experienced change of life situation, own perceptions of epilepsy, seizure frequency after diagnosis, gender and side effects from antiepileptic drugs. The QLI was well applicable on people with epilepsy. Conclusions ‐ Data indicates that debut of epilepsy has an evident impact on quality of life and a more extensive study is required.

Restricted Canonical Correlation Analysis in Functional MRI—Validation and a Novel Thresholding Technique

To validate the performance of an analysis method for fMRI data based on restricted canonical correlation analysis (rCCA) and adaptive filtering, and to increase the usability of the method by introducing a new technique for significance estimation of rCCA maps.