Andrea Clarici

EFFECTS OF LEFT BASAL GANGLIA LESIONS ON LANGUAGE PRODUCTION

Three patients with lesions mainly confined to the left basal ganglia were studied with a series of neuropsychological and neurolinguistic tests. Two patients were nonfluent, whereas one presented with fluent spontaneous speech. All of them produced agrammatic sentences and lexical and semantic mistakes. Perseverations and echolalias were two further characteristic disorders of their speech production. The linguistic symptoms observed in these three patients suggest that the left basal ganglia play an important role (a) in regulating arousal and speech initiation, (b) in monitoring the semantic and lexical aspects of language, and (c) in switching from one linguistic element to the following during language production.

Anxiety, Depression and Emotional Profile in Renal Transplant Recipients and Healthy Subjects: A Comparative Study

BACKGROUND Renal transplantation is a well established treatment for end-stage renal disease. However, recipients have been shown to develop emotional distress and affective disorders, such as anxiety and depression, associated with a compromised quality of life. Some accounts report an improvement of affective disorders after transplantation, others draw opposite conclusion. METHODS The present cross-sectional study selected 42 transplant recipients and 42 control subjects matched for gender, age, educational background, and marital status. Symptoms of anxiety, depression and general emotional profiles were compared using the Zung Self-Rating Anxiety Scale, the Beck Depression Inventory (BDI), and the Affective Neuroscience Personality Scale (ANPS), a self-report inventory that evaluates 6 neurally based affective tendencies: seeking, caring, and playfulness (positive affects) and fear, anger, and sadness (negative affects). RESULTS No significant differences were observed between transplanted patients and controls in scores for anxiety and depression, as evaluated with Zung and BDI scales. However, transplanted patients scored significantly lower than control subjects in fear and anger scales and in general negative emotions. Transplant recipients did not display any symptom of anxiety or depression, however, a significant reduction in negative affect, evaluated through the ANPS scale revealed psychological distress. CONCLUSIONS These findings suggest that affective profile in transplanted patients should be more extensively examined to review all facets in their mental and emotional assessment, especially regarding the role played by this emotional pattern in complying with medical treatment, which is well known to be a clinically critical feature of these patients.

Evolutionary aspects of self- and world consciousness in vertebrates

Although most aspects of world and self-consciousness are inherently subjective, neuroscience studies in humans and non-human animals provide correlational and causative indices of specific links between brain activity and representation of the self and the world. In this article we review neuroanatomic, neurophysiological and neuropsychological data supporting the hypothesis that different levels of self and world representation in vertebrates rely upon (i) a “basal” subcortical system that includes brainstem, hypothalamus and central thalamic nuclei and that may underpin the primary (or anoetic) consciousness likely present in all vertebrates; and (ii) a forebrain system that include the medial and lateral structures of the cerebral hemispheres and may sustain the most sophisticated forms of consciousness [e.g., noetic (knowledge based) and autonoetic, reflective knowledge]. We posit a mutual, bidirectional functional influence between these two major brain circuits. We conclude that basic aspects of consciousness like primary self and core self (based on anoetic and noetic consciousness) are present in many species of vertebrates and that, even self-consciousness (autonoetic consciousness) does not seem to be a prerogative of humans and of some non-human primates but may, to a certain extent, be present in some other mammals and birds

Individual Differences in Prefrontal Cortex Activity during Perception of Bitter Taste Using fNIRS Methodology

Although bitter taste has a crucial role in nutrition by preventing the ingestion of toxic foods, there are few studies on bitter taste neuroimaging. To identify cortical areas involved in bitter taste perception and to determine if individual differences in taste sensitivity to 6-n-propylthiouracil (PROP) are represented in the brain by different cortical activation patterns, we examined 48 healthy volunteers using functional near-infrared spectroscopy. Participants rated the perceived intensity of filter paper disks impregnated with PROP and NaCl during the imaging procedure and were then classified as PROP tasters and nontasters. We monitored cortical activity in both the anterior and posterior regions of the dorsolateral prefrontal cortex (DLPFC) and in the ventrolateral prefrontal cortex (VLPFC). No activity was detected in the anterior DLPFC in any of the participants. However, during the administration of PROP, significant cortical activation was detected in the more posterior regions of the left DLPFC and in the left and right VLPFC but only in PROP tasters. PROP nontasters showed no cortical activity in these areas. These data suggest that the prefrontal cortex is involved in the conscious perception of the bitter taste of PROP and that the pattern of activity is consistent with individual differences in the ability to taste this compound. Thus, the PROP phenotype is associated with fundamental differences in cortical taste processing.

Differences in time course activation of dorsolateral prefrontal cortex associated with low or high risk choices in a gambling task.

Prefrontal cortex plays an important role in decision making (DM), supporting choices in the ordinary uncertainty of everyday life. To assess DM in an unpredictable situation, a playing card task, such as the Iowa Gambling Task (IGT), has been proposed. This task is supposed to specifically test emotion-based learning, linked to the integrity of the ventromedial prefrontal cortex (VMPFC). However, the dorsolateral prefrontal cortex (DLPFC) has demonstrated a role in IGT performance too. Our aim was to study, by multichannel near-infrared spectroscopy, the contribution of DLPFC to the IGT execution over time. We tested the hypothesis that low and high risk choices would differentially activate DLPFC, as IGT execution progressed. We enrolled 11 healthy adults. To identify DLPFC activation associated with IGT choices, we compared regional differences in oxy-hemoglobin variation, from baseline to the event. The time course of task execution was divided in four periods, each one consisting of 25 choices, and DLPFC activation was distinctly analyzed for low and high risk choices in each period. We found different time courses in DLPFC activation, associated with low or high risk choices. During the first period, a significant DLPFC activation emerged with low risk choices, whereas, during the second period, we found a cortical activation with high risk choices. Then, DLPFC activation decreased to non-significant levels during the third and fourth period. This study shows that DLPFC involvement in IGT execution is differentiated over time and according to choice risk level. DLPFC is activated only in the first half of the task, earlier by low risk and later by high risk choices. We speculate that DLPFC may sustain initial and more cognitive functions, such as attention shifting and response inhibition. The lack of DLPFC activation, as the task progresses, may be due to VMPFC activation, not detectable by fNIRS, which takes over the IGT execution in its second half.

SPEAKING SPEED EFFECTS ON DELAYED AUDITORY FEEDBACK DISRUPTION OF SPEECH FLUENCY

24 Italian medical students performed a task of verbal fluency. 12 students (the control group) receiving Normal Auditory Feedback and 12 students receiving Delayed Auditory Feedback (delay of 200 msec.) performed six trials in six different experimental settings: normal or increased speaking rate, and, for each condition, once with bilateral input of the auditory feedback, once to the right ear, and once to the left ear. At the normal speaking rate, the disruptive effect of delayed feedback was confirmed. As the speaking rate increased, the total number of errors increased within the control group but decreased within the group given delayed feedback, although the total number of errors was always greater for the latter. In addition, speech was more disrupted when the auditory input was returned to the right ear (left hemisphere) for all the different conditions: Normal and Delayed Auditory Feedback, normal and increased speaking rate. In particular, the left hemisphere was less resistant to the disruptive effect of the delayed feedback than the right hemisphere. From these results, we suggest that, when speaking more quickly, one uses more central mechanisms of movement programming (cortical-cerebellum-thalamus-cortical, cortical-corpus striatum-thalamus-cortical, and cortical-thalamus-cortical circuits), or attentional control (cortico-reticular-cortical circuits) than peripheral mechanisms (tactile, proprioceptive, and acoustic circuits). This may explain the decreased disruptive influence of delayed auditory feedback on speed, fluency, and quality at increased speaking rates. Hemispheric specialization processes, however, may explain the more pronounced susceptibility of the left hemisphere or the less pronounced susceptibility of the right hemisphere during the delayed feedback condition. In fact, the former processes phonemic, grammatical, and lexical features of words whilst the latter is competent in using metaphors and prosody in controlling the emotional aspects of language. Moreover, the right hemisphere is more active on attentional tasks.

Effects of Prone and Supine Position on Cerebral Blood Flow in Preterm Infants

We evaluated the effect of prone and supine position on cerebral blood flow (CBF) in stable preterm infants. CBF, PO(2), and PCO(2) were measured in the two positions. Peripheral oxygenation increased and CBF decreased in prone position. We speculate that CBF autoregulation may compensate for increased peripheral oxygenation, by decreasing CBF.

Validation of the Italian Translation of the Affective Neuroscience Personality Scales

The theoretical perspective on affective neuroscience advanced by Panksepp, identified six basic innate affective systems: the SEEK, FEAR, ANGER, SADNESS, PLAY, and CARE systems. It has been proposed that the fundamental elements of human personality and its variants may be based on the different expressions of these basic emotional systems and their combinations. A self-report inventory, the Affective Neuroscience Personality Scales (ANPS), has been devised with the aim of studying and evaluating personality from this perspective. This study reports data on the initial validation of ANPS Italian translation on a sample of 418 adult participants. Descriptive statistics for each scale were calculated, assessing also their internal consistency, as a measure of reliability and factorial validity. Acceptable internal consistency was found in all but one scale (SADNESS), and a second-order factor analysis identified a more general affective feature of personality hinging on relational characteristics, independent of the dimensions of general positive and negative affect.

Description and validation of a geriatric multidimensional graphical instrument for promoting longitudinal evaluation

The debate about the adoption of standard multidimensional geriatric assessment instruments is mainly due to the lack of consensus on the feasibility and requirements for such instruments by both the health and the social care professions. A tool called ValGraf was developed in the attempt to give an original answer to these and other controversial issues. The aim of this study was to evaluate the ValGraf for acceptability, concurrent validity and factorial structure. The functional and cognitive impairments as ascertained by the ValGraf were compared with Katz index and Folsteins Mini Mental State Examination (MMSE). Subjects (N=210) of four nursing homes were assessed by two independent teams of nurses. The factorial validity study involved 8280 subjects living in nursing homes. Assessments were conducted throughout the 2001 by 20 geriatricians. The agreement between the ValGraf sections concerning independence in daily living and Katzs index was almost total (r=0.96) and that between ValGraf items on cognition and MMSE was very good (0.73). Factor analysis revealed that 13 coherent factors explained 53% of total variance. ValGraf was proved to be acceptable and comprehensive, criterion valid, at least as daily activities and cognitive status are concerned, and to have a coherent factorial structure.

Non-invasive assessment of hemispheric language dominance by optical topography during a brief passive listening test: A pilot study

Summary Background The Wada test is usually used for pre-surgical assessment of language lateralization. Considering its invasiveness and risk of complications, alternative methods have been proposed but they are not always applicable to non-cooperative patients. In this study we explored the possibility of using optical topography (OT) – a multichannel near-infrared system – for non-invasive assessment of hemispheric language dominance during passive listening. Material/Methods Cortical activity was monitored in a sample of healthy, adult Italian native speakers, all right-handed. We assessed changes in oxy-haemoglobin concentration in temporal, parietal and posterior frontal lobes during a passive listening of bi-syllabic words and vowel-consonant-vowel syllables lasting less then 3 minutes. Activated channels were identified by t tests. Results Left hemisphere showed significant activity only during the passive listening of bi-syllabic words. Specifically, the superior temporal gyrus, the supramarginal gyrus and the posterior inferior parietal lobe were activated. Conclusions During passive listening of bi-syllabic words, right handed healthy adults showed a significant activation in areas already known to be involved in speech comprehension. Although more research is needed, OT proved to be a promising alternative to the Wada test for non-invasive assessment of hemispheric language lateralization, even if using a particularly brief trial, which has been designed for future applications with non-cooperative subjects.