Luigi Trojano

Selective motor imagery defect in patients with locked-in syndrome

Recent studies indicate that motor imagery is subserved by activation of motor information. However, at present it is not clear whether the sparing of motor efferent pathways is necessary to perform a motor imagery task. To clarify this issue, we required patients with a selective, severe de-efferentation (locked-in syndrome, LIS) to mentally manipulate hands and three-dimensional objects. Compared with normal controls, LIS patients showed a profound impairment on a modified version of the hand-laterality task and a normal performance on mental rotation of abstract items. Moreover, LIS patients did not present visuomotor compatibility effects between anatomical side of hands and spatial location of stimuli on the computer screen. Such findings confirmed that the motor system is involved in mental simulation of action but not in mental manipulation of visual images. To explain LIS patients inability in manipulating hand representations, we suggested that the pontine lesion, both determined a complete de-efferentation, and affected a component of the motor system, which is crucial for mental representation of body parts, probably the neural connections between parietal lobes and cerebellum.

Relationship between apathy and cognitive dysfunctions in de novo untreated Parkinson's disease: a prospective longitudinal study.

Apathy may be either a symptom of major depression or a behavioral disturbance occurring in concomitance with depression or alone in Parkinsons disease (PD). The aim of the present study was to determine the progression of cognitive impairment in drug‐naïve untreated PD patients with or without clinically significant apathy.

Cognitive neuroscience of drawing: contributions of neuropsychological, experimental and neurofunctional studies.

From at least 30,000 years ago, humans pictured animals, such as rhinoceroses, horses, and lions, on the walls of the caves in which they lived. In spite of controversies over the level of cognitive evolution underlying such cave paintings (see Humphrey, 1998), drawing is a distinguishing skill of human beings. It is one sign of the striking evolution of the human brain to its sophisticated symbolic and communicative abilities, and despite the ever-changing conventions of artistic representation, artists and painters may provide deep insights into principles governing brain processes, such as visual processing (Cavanagh, 2005). Yet, drawing has received little attention in the neurosciences, possibly because so many processes are involved. Only a few authors have attempted to formalise the processing stages involved in drawing. Based on single case neuropsychological studies, they have tried to identify cognitive mechanisms responsible for drawing disorders (Farah, 1984; Roncato et al., 1987; Van Sommers, 1989; Grossi, 1991). The cognitive models for drawing developed so far differ from each other in formal characteristics, depth of analysis and theoretical aspects, but they all share the idea that drawing involves a wide range of cognitive and neural processing capabilities. These include visuo-spatial skills, attentional mechanisms, different mental representations of space, conceptual knowledge, motion planning and control mechanisms, as well as spatial manipulation abilities (for review, see Grossi and Trojano, 1999).

Observation of another's action but not eye gaze triggers allocentric visual perspective

In the present paper, we investigated whether observation of bodily cues—that is, hand action and eye gaze—can modulate the onlookers visual perspective taking. Participants were presented with scenes of an actor gazing at an object (or straight ahead) and grasping an object (or not) in a 2 × 2 factorial design and a control condition with no actor in the scene. In Experiment 1, two groups of subjects were explicitly required to judge the left/right location of the target from their own (egocentric group) or the actors (allocentric group) point of view, whereas in Experiment 2 participants did not receive any instruction on the point of view to assume. In both experiments, allocentric coding (i.e., the actors point of view) was triggered when the actor grasped the target, but not when he gazed towards it, or when he adopted a neutral posture. In Experiment 3, we demonstrate that the actors gaze but not action affected participants attention orienting. The different effects of others grasping and eye gaze on observers behaviour demonstrated that specific bodily cues convey distinctive information about other peoples intentions.

Differential neuropsychological profiles in Parkinsonian patients with or without vascular lesions

The purpose of this study is to compare the neuropsychological profile of patients affected by parkinsonism and vascular lesions to that in patients with PD alone (PD) and to evaluate whether the brain vascular lesion load is associated with neuropsychological variables. Thirty‐six nondemented patients with parkinsonism were divided into 3 groups of 12 patients each, according to both clinical history and the presence of brain vascular lesions and/or dopaminergic denervation as revealed by magnetic resonance and dopamine transporter imaging, respectively. The first group had vascular lesions without dopaminergic denervation (VP group); the second group had vascular lesions and dopaminergic denervation (DD) (VP+DD group); and the third group consisted of patients with dopaminergic denervation (PD group) without vascular lesions. All patients underwent neurological and neuropsychological assessments. The groups differed in disease duration, age at onset, and cerebrovascular risk factors. The VP and VP+DD groups performed worse than the PD group on frontal/executive tasks. Regardless of the presence of dopaminergic denervation, cerebrovascular lesions in hemispheric white matter, basal ganglia, and cerebellum have an important effect in determining early onset and severity of cognitive impairment in patients with parkinsonism.

Representational neglect in "invisible" drawing from memory

We describe the case of a patient with right hemisphere damage and left unilateral neglect. The patient was asked to draw from memory common objects, either with or without visual feedback. In the conditions without visual feedback the patient was either blindfolded or he made invisible drawings using a pen with the cap on, the drawings being recorded with carbon paper underneath. Results showed more neglect without than with visual feedback, contrary to previously published cases. This patients pattern of performance may result from the contribution of a deficit of spatial working memory. Alternatively or in addition, the patient, who was undergoing cognitive rehabilitation for neglect, may have found easier to compensate for his neglect with visual feedback, which allowed him to visually explore the left part of his drawings.

Striatal [123I] FP-CIT SPECT demonstrates dopaminergic deficit in a sporadic case of Creutzfeldt-Jakob disease.

Backgroundu2002–u2002 The frequent occurrence of movement disorders such as myoclonus, parkinsonism and dystonia, strongly suggests an involvement of the dopaminergic system in sporadic Creutzfeldt‐Jakob disease (sCJD), but this issue has not been specifically addressed yet.

Avoiding or approaching eyes? Introversion/extraversion affects the gaze-cueing effect

We investigated whether the extra-/introversion personality dimension can influence processing of others’ eye gaze direction and emotional facial expression during a target detection task. On the basis of previous evidence showing that self-reported trait anxiety can affect gaze-cueing with emotional faces, we also verified whether trait anxiety can modulate the influence of intro-/extraversion on behavioral performance. Fearful, happy, angry or neutral faces, with either direct or averted gaze, were presented before the target appeared in spatial locations congruent or incongruent with stimuli’s eye gaze direction. Results showed a significant influence of intra-/extraversion dimension on gaze-cueing effect for angry, happy, and neutral faces with averted gaze. Introverts did not show the gaze congruency effect when viewing angry expressions, but did so with happy and neutral faces; extraverts showed the opposite pattern. Importantly, the influence of intro-/extraversion on gaze-cueing was not mediated by trait anxiety. These findings demonstrated that personality differences can shape processing of interactions between relevant social signals.

Mixed transcortical aphsia. On relative sparing of phonological short-term store in a case

A case of Mixed Transcortical Aphasia is reported. The patient showed completely impaired verbal comprehension and speech production, with preservation of automatic speaking and singing; repetition was relatively spared. A detailed study of word and nonword repetition is reported, in order to demonstrate that the patients residual repetition ability is based on relative sparing of short-term phonological store.

Subthreshold depression and subjective cognitive complaints in Parkinson's disease

Subthreshold depression (SubD) is characterized by clinically relevant depressive symptoms not meeting criteria for major depression. The possible association of SubD with subjective cognitive complaints and/or objective cognitive impairments was investigated in a sample of consecutive, non‐demented Parkinsons disease (PD) outpatients.