Visuo-spatial imagery impairment in posterior cortical atrophy: a cognitive and SPECT study

This study investigated the cognitive profile and the cerebral perfusion pattern in a highly educated 70 year old gentleman with posterior cortical atrophy (PCA). Visuo-perceptual abilities, spatial memory, spatial representation and navigation, visuo-spatial mental imagery, semantic and episodic-autobiographical memory were assessed. Regional cerebral blood flow (rCBF) was imaged with SPECT. Cognitive testing showed visual-perceptual impairment, apperceptive visual and landmark agnosia, topographical disorientation with way-finding deficits, impaired map learning and poor mental image generation. Semantic memory was normal, while episodic-autobiographical memory was impaired. Reduced rCBF was found mainly in the right hemisphere, in the precentral gyrus, posterior cingulate and middle temporal gyri, cuneus and precuneus, in the left superior temporal and lingual gyri and in the parahippocampus bilaterally. Hypoperfusion in occipito-parietal regions was associated with visuo-spatial deficits, whereas deficits in visuo-spatial mental imagery might reflect dysfunction related to hypoperfusion in the parahippocampus and precuneus, structures which are responsible for spatial and imagery processing. Dissociating performance between preserved semantic memory and poor episodic-autobiographical recall is consistent with a pattern of normal perfusion in frontal and anterior temporal regions but abnormal rCBF in the parahippocampi. The present findings indicate that PCA involves visuo-spatial imagery deficits and provide further validation to current neuro-cognitive models of spatial representation and topographical disorientation.     

Emotional processing following cortical and subcortical brain damage: contribution of the fronto-striatal circuitry

The present study examined the differential contribution of cortical and subcortical brain structures in emotional processing by comparing patients with focal cortical lesions (n = 32) to those with primarily subcortical dysregulation of the basal ganglia (Parkinson's disease n = 14). A standardized measure of emotional perception (Tübingen Affect Battery) was used. Only patients in the more advanced stages of Parkinson's disease and patients with focal damage to the (right) frontal lobe differed significantly from controls in both facial expression and affective prosody recognition. The findings imply involvement of the fronto-striatal circuitry in emotional processing.     

“Octave illusion” or “Deutsch’s illusion”?

The “Deutsch’s illusion” occurs in most people when a dichotic pair of tones spaced an octave apart is presented repeatedly in alternation, so that when the right ear receives the high tone, the left ear receives the low tone, and vice versa. The illusory percept consists typically in a single low tone heard at one ear alternating with a single high tone heard at the other ear. Here, we investigate whether the frequency interval between the tones and their duration play a role in the perception of the illusion. By testing 74 subjects we demonstrate that the illusion is not confined to tones spaced an octave apart but it is perceivable also with tones separated by a major seventh, a minor ninth, a major ninth, and a minor tenth. Regarding duration, the present results show that the illusion is stronger with tones lasting 500 than 200 ms. The present results suggest that the perceptual mechanisms at the basis of the illusion are not strictly linked to the frequency relationships between the dichotic tones.     

Dysfunctional personality traits in adolescence: effects on alerting,orienting and executive control of attention

The present study examined attentional networks performance in 39 adolescents with dysfunctional personality traits, split into two group, Group < 10 and Group ≥ 10, according to the number of criteria they met at the Structured Clinical Interview for DSM-IV Axis II Personality Disorders. The attentional performance has been tested by means of a modified version of the Attentional Network Test (ANTI-V) which allows testing both phasic and tonic components of the alerting system, the exogenous aspect of the orienting system, the executive network and their interactions. Results showed that the orienting costs of having an invalid spatial cue were reduced in the Group ≥ 10 criteria compared to the Group < 10. Moreover, adolescents included in the Group ≥ 10 showed lower conflict when attention was cued to the target location (valid trials) but showed normal interference when there was no overpowering focus of attention (invalid trials). The results found with ANOVA after splitting the sample into two categorical groups were also observed in a complementary correlation analysis keeping intact the continuous nature of such variables. These findings are consistent with the notion that dysfunctional features of personality disorders may represent the psychological manifestations of a neuropsychological abnormality in attention and executive functioning. Finally, we discuss the implications of this attentional anomaly for dysfunctional personality traits and behaviour.     

Does the use of mobile phones affect human short‐term memory or attention?

The effect of acute exposure to low‐level radio frequency electromagnetic fields (REF) generated by mobile phones on short‐term memory and attention was assessed in two experiments. Most of the tests manipulated task difficulty or what might be termed cognitive load. This manipulation is important since previous studies have argued that exposure to mobile phones might affect cognitive functions only under conditions which tax the cognitive system. All participants were exposed to REF (half were exposed to GSM—Global System for Mobile Communication—signals and the other half were exposed to unmodulated signals) in one testing session, while in a separate session participants were exposed to sham signals. To investigate potential lateralised effects, the mobile phone was positioned on the left side of the head for half of the participants and on the right side for the other half. No significant effect of exposure to REF was detected in any of the six tasks used in either the low or high cognitive load conditions. This study used much larger sample sizes than is typical for this type of research and REF exposure was administered under double‐blind conditions. Overall, the results indicate that acute exposure to REFs emitted by mobile phones do not have a strong impact on cognitive functions. Copyright © 2007 John Wiley & Sons, Ltd.     

Methodological evolution and clinical application of C.G. Jung's Word Association Experiment: a follow-up study

We became interested in the clinical application of the Word Association Experiment (AE) when we decided to use Jung's theory of complexes in the psycho-diagnostic evaluation and treatment of patients applying to our Psychotherapy Out-patients Unit (Psychiatric Clinic, Milan University). In psychopathological situations, complexes with a particularly high emotional charge become autonomous and disturbing, inhibiting the ego's functions. The representations and affective states corresponding to these complexes become dominant, conditioning the expression of symptoms and the subject's relational modes. In this experimental study we started out from the basic theory that our psycho-therapeutic work should lead to a progressive change in the patient's initial complex set up. Jung's Word Association Experiment allows us to identify those words which indicate and stimulate a specific activation of the complexes for each subject via specific markers of complexes. We therefore decided to determine whether AE, administered during the first phase of clinical-diagnostic evaluation and after one year of treatment, revealed any changes occurring in the patients' set up of complexes.     

Exploring the relationship between umbilical blood cord donation and the impact of social distance on altruism and trust

Allogeneic umbilical cord blood (UCB) donation is a pro-social behaviour directed to strangers that has a certain cost for the donor. Although the promotion of such behaviour is an important goal for many countries' health systems, little is known about the reasons that would lead to it. With this study, we explored how the impact of social closeness on altruism and trust could be related to UCB donation in a sample of new-mothers (N = 167). Participants played hypothetical Dictator and Trust games with socially close (e.g., parents) or distant (e.g., strangers) others. They donated more money to parents and siblings compared to cousins, friends and strangers and they trusted more parents, siblings and friends than cousins and strangers. Interestingly, the lower the impact of social closeness on altruism (i.e., generosity towards socially distant others), the higher the intention and the actual probability of UCB donation. A mediation analysis has shown that the relationship between social closeness on altruism and UCB donation was mediated by objective intention to donate (i.e., having followed all the procedures needed). These findings show that other-oriented motivations towards distant others might have important practical implications in identifying the targets of interventions for the promotion of UCB donation.     

See what I mean? An ERP study of the effect of background knowledge on novel object processing

Two event-related potential (ERP) experiments were used to examine the representation of object feature information and background knowledge in semantic memory. Participants were trained on novel object categories with three features and were tested with new exemplars that were complete or were missing one to two features that were essential or nonessential to object function. In both a category membership judgment task (Experiment 1) and a parts detection task (Experiment 2), the N400, a functionally specific measure of semantic access, was graded with feature number but was insensitive to knowledge-based feature importance. A separable ERP effect related to knowledge was seen in Experiment 1 as an enhanced frontocentral negativity (beginning ∼300 msec) to exemplars missing a nonessential versus an essential feature, but this effect did not manifest when background knowledge was less task relevant (Experiment 2). Thus, similarity- and knowledge-based effects are separable, and the locus of knowledge effects varies with task demands but does not seem to arise from facilitated semantic access.