Valence of Affective Verbal Fluency: fMRI Studies on Neural Organization of Emotional Concepts Joy and Fear.

The present study was designed to examine the underlying brain mechanisms of positive and negative emotional verbal fluency. Three verbal fluency tasks (one non-emotional phonemic task, two emotional tasks: Joy and Fear) were used in this study. The results were analyzed for 35 healthy, Polish-speaking, right-handed adults aged 20-35. Functional magnetic resonance imaging (3T) was used to show brain activity during active participation in emotional verbal fluency tasks. The results reported for emotional fluency confirmed activation of different brain regions for the negative and positive emotional verbal fluency: in positive emotional verbal fluency Joy elicits greater activation in the frontal regions and the cingulate cortex, while in negative verbal fluency Fear is reflected in activation of parietal and temporal areas. The study provides an evidence for differentiation in neural mechanisms between positive and negative emotional verbal fluency and/or positive and negative retrieving processes, and differentiation in brain-related determinants of the emotional concepts organization.

Pure alexia after damage to the right fusiform gyrus in a right-handed male.

Pure alexia refers to a rare acquired reading disorder commonly associated with damage to the posterior part of the left medial occipito-temporal (fusiform) gyrus, which is known as the visual word-form area (VWFA) and thought to be the neural basis for visual processing of letters and words. Right-sided lesions very rarely lead to pure alexia in right-handed individuals. We report a case of a 33-year-old right-handed man with isolated pure alexia resulting from a hemorrhagic lesion to the right fusiform gyrus. A limited recovery of reading skills was observed within six weeks post onset. During this period, the patient spontaneously developed a letter-by-letter reading strategy. Functional magnetic resonance imaging revealed right-hemisphere dominance for language as well as bilateral reading-related activity in the fusiform gyri. Our case indicates that pure alexia may arise as a consequence of damage to the right fusiform gyrus even in right-handed patients (who still may have right hemisphere dominance for language and reading skills), and may lead to a severe reading disorder, as in individuals with left-hemisphere dominance for language.

Brain activation in teenagers with isolated spelling disorder during tasks involving spelling assessment and comparison of pseudowords. fMRI study.

METHODS: The present study aimed at defining the specific traits of brain activation in teenagers with isolated spelling disorder in comparison with good spellers. fMRI examination was performed where the subject's task involved taking a decision 1/whether the visually presented words were spelled correctly or not (the orthographic decision task), and 2/whether the two presented letters strings (pseudowords) were identical or not (the visual decision task). Half of the displays showing meaningful words with an orthographic difficulty contained pairs with both words spelled correctly, and half of them contained one misspelled word. Half of the pseudowords were identical, half of them were not. The participants of the study included 15 individuals with isolated spelling disorder and 14 good spellers, aged 13-15. RESULTS: The results demonstrated that the essential differences in brain activation between teenagers with isolated spelling disorder and good spellers were found in the left inferior frontal gyrus, left medial frontal gyrus and right cerebellum posterior lobe, i.e. structures important for language processes, working memory and automaticity of behaviour. CONCLUSION: Spelling disorder is not only an effect of language dysfunction, it could be a symptom of difficulties in learning and automaticity of motor and visual shapes of written words, rapid information processing as well as automating use of orthographic lexicon.

Design and evaluation of an innovative MRI-compatible Braille stimulator with high spatial and temporal resolution.

Neural correlates of Braille reading have been widely studied with different neuroimaging techniques. Nevertheless, the exact brain processes underlying this unique activity are still unknown, due to suboptimal accuracy of imaging and/or stimuli delivery methods. To study somatosensory perception effectively, the stimulation must reflect parameters of the natural stimulus and must be applied with precise timing. In functional magnetic resonance imaging (fMRI) providing these characteristics requires technologically advanced solutions and there have been several successful direct tactile stimulation devices designed that allow investigation of somatotopic organization of brain sensory areas. They may, however, be of limited applicability in studying brain mechanisms related to such distinctive tactile activity as Braille reading. In this paper we describe the design and experimental evaluation of an innovative MRI-compatible Braille Character Stimulator (BCS) enabling precise and stable delivery of standardized Braille characters with high temporal resolution. Our device is fully programmable, flexible in stimuli delivery and can be easily implemented in any research unit. The Braille Character Stimulator was tested with a same-different discrimination task on Braille characters during an event-related fMRI experiment in eleven right-handed sighted adult subjects. The results show significant activations in several cortical areas, including bilateral primary (SI) and secondary somatosensory (SII) cortices, bilateral premotor and supplementary motor areas, inferior frontal gyri, inferior temporal gyri and precuneus, as well as contralateral (to the stimulated hand) thalamus. The results validate the use of the BCS as a method of effective stimuli application in fMRI studies, in both sighted and visually impaired subjects.

Dissociable contributions of the left and right posterior medial orbitofrontal cortex in motivational control of goal-directed behavior.

Several findings from both human neuroimaging and nonhuman primate studies suggest that the posterior medial orbitofrontal cortex (OFC) may be critical for the motivational control of goal-directed behavior. The present study was conducted to clarify the role of the left and right posterior medial OFC in that function by examining the effects of focal unilateral lesions to this region on the performance on an incentive working memory task. The study covered patients who had undergone surgery for an ACoA aneurysm and normal control subjects (C). The patients were subdivided into three groups: those with resection of the left (LGR+) or right (RGR+) posterior part of the gyrus rectus, and without such a resection (GR-). Participants performed a 2-back working memory task under three motivational conditions (penalty, reward, and no-incentive). The C group performed worse in the penalty condition and better in the reward condition as compared to the no-incentive condition. Similar results were obtained for the GR- group. Performance of the LGR+ group did not depend on incentive manipulations, whereas the RGR+ group performed better in both the penalty and reward conditions than in the no-incentive condition. The results show that the posterior medial OFC is involved in the motivational modulation of working memory performance. Our findings also suggest that the left posterior medial OFC plays a crucial role in this function, whereas the right posterior medial OFC is particularly involved in the processing of the punishing aspect of salient events and it probably mediates in guiding behavior on the basis of negative outcomes of action.

[Correlation of auditory-verbal skills in patients with cochlear implants and their evaluation in positone emission tomography (PET)]. / Korelacja zmian w funkcjonowaniu sluchowo-werbalnym pacjentów po wszczepieniu implantu slimakowego z ich ocena w badaniu pozytonowej emisyjnej tomografii komputerowej (PET).

INTRODUCTION: An assumption was taken that in central nervous system (CNS) in patients above 15 years of age there are possible mechanisms of neuronal changes. Those changes allow for reconstruction or formation of natural activation pattern of appropriate brain structures responsible for auditory speech processing. AIM: The aim of the study was to observe if there are any dynamic functional changes in central nervous system and their correlation to the auditory-verbal skills of the patients. MATERIAL AND METHODS: Nine right-handed patients between 15 and 36 years of age were examined, 6 females and 3 males. All of them were treated with cochlear implantation and are in frequent follow-up in the Department of Otolaryngology at the Medical University of Warsaw due to profound sensorineural hearing loss. In present study the patients were examined within 24 hours after the first fitting of the speech processor of the cochlear implant, and 1 and 2 years subsequently. Combination of performed examinations consisted of: positone emission tomography of the brain, and audiological tests including speech assessment. In the group of patients 4 were postlingually deaf, and 5 were prelinqually deaf. RESULTS: Postlingually deaf patients achieved great improvement of hearing and speech understanding. In their first PET examination very intensive activation of visual cortex V1 and V2 (BA17 and 18) was observed. There was no significant activation in the dominant (left) hemisphere of the brain. In PET examination performed 1 and 2 years after the cochlear implantation no more V1 and V2 activation region was observed. Instead particular regions of the left hemisphere got activated. In prelingually deaf patients no significant changes in central nervous system were noticeable neither in PET nor in speech assessment, although their hearing possibilities improved. CONCLUSIONS: Positive correlation was observed between the level of speech understanding, linguistic skills and the activation of appropriate areas of the left hemisphere of the brain in postlingually deaf patients treated with cochlear implants. No such correlation was noted in prelingualy patients treated with the same method.

[Preoperative anxiety assessed by questionnaires and patient declarations]. / Kwestionariuszowy i deklaratywny poziom leku chorych przed operacja.

BACKGROUND: The perioperative period can be anxiety-provoking for any patient scheduled for surgery. The anxiety can be divided into three categories: physiological, psychological and behavioural. For objective assessment, special questionnaires have been used, yet since they are too complicated for everyday use, simpler methods have been proposed. We have compared three measurements of anxiety to determine their equivalence in assessing anxiety before surgery: the State Trait Anxiety Inventory (STAI), the Visual Analogue Scale (VAS) and patient declaration in the form of an answer to a single question. METHODS: Thirty-eight ASA I and II adult patients, of both sexes, aged 18-60 years, and scheduled for elective abdominal or ENT surgery, were enrolled into the study. All patients were interviewed one day before the procedure and were asked to complete the STAI questionnaire, rate their fear on the VAS, and answer the question: "Are you afraid of anything?" The Kolmogorow-Smirnov test, t-Student test and r-Pearson correlation test were used for statistical analysis. RESULTS: Sixty six per cent of the questioned patients expressed a feeling of fear and their mean STAI-T (traid) score was 42.9 +/- 7.9, STAI-S (scale) 44.6 +/- 10.5. The VAS score was 3.7 +/- 2.6. Among those who did not declare a feeling of fear, the scores were: STAI-T: 36.9 +/- 8.2, STAI-S: 41.0 +/- 6.3, and VAS: 1.5 +/- 1.7. Females expressed a feeling of fear more often than males (p=0.03). There were no statistically significant differences related to age, the type of scheduled surgery or ASA score. The results obtained by all methods were closely correlated. CONCLUSION: We conclude that, since the results of anxiety measurement were comparable in all tests, a simple question or the VAS scale should be sufficient for proper assessment of preoperative anxiety.