ABSTRACT
Reports on social cognition in patients with developmental amnesia resulting from bilateral hippocampal lesions are rare, although the link between social cognition and temporal lobe structures is well established. We present the case of a 23-year-old male epilepsy patient, BM, with developmental amnesia due to perinatal cerebral hypoxia. The patient was examined with neuroimaging and neuropsychological methods and compared to IQ-matched patients with epilepsy to control for effects of epilepsy. In addition, we used a test battery that evaluates emotion recognition and theory of mind to study his social cognition abilities. Structural high-resolution magnetic resonance imaging showed bilateral hippocampal atrophy. The comparison to controls showed that, in addition to the well-documented memory disorders in developmental amnesia, BM showed remarkable deficits in 9 out of 17 social cognitive tasks assessing emotion recognition and theory of mind. In contrast, BM's performance on tasks of executive functions was largely preserved. The relevance of deficits in social cognition for patients with developmental amnesia is discussed.
Subject(s)
Amnesia , Cognitive Dysfunction , Epilepsy , Hippocampus/pathology , Hypoxia/complications , Infant, Newborn, Diseases , Social Cognition , Adult , Amnesia/diagnosis , Amnesia/etiology , Amnesia/pathology , Amnesia/physiopathology , Atrophy , Cognitive Dysfunction/diagnosis , Cognitive Dysfunction/etiology , Cognitive Dysfunction/pathology , Cognitive Dysfunction/physiopathology , Epilepsy/diagnosis , Epilepsy/etiology , Epilepsy/pathology , Epilepsy/physiopathology , Female , Hippocampus/diagnostic imaging , Humans , Infant, Newborn , Magnetic Resonance Imaging , Male , Pregnancy , Pregnancy, Twin , Young AdultABSTRACT
OBJECTIVE: To explore motor excitability changes induced by disobedience and feigning-like behaviour. METHODS: Healthy subjects participated in motor imagery tasks. They imagined either a maximum muscle relaxation (condition 1) or a pinch grip (condition 2). In other trials, they were instructed to disobey the command to imagine a pinch grip. Instead, they should either imagine a maximum muscle relaxation (condition 3) or think of something else which they could choose freely (condition 4). Transcranial magnetic stimulation was used to explore motor excitability during the different tasks. Motor evoked potential amplitudes were expressed as percentage of the task-free control condition (condition 5). RESULTS: Imagination of a pinch grip enhanced motor excitability, imagery of maximum muscle relaxation reduced motor excitability below the level of the control condition. In conditions 3 and 4, motor excitability was lower than in condition 2. However, motor excitability in condition 3 was higher than in condition 1. CONCLUSIONS: Healthy subjects successfully disobeyed the motor imagery command but failed to maintain the down-regulation of motor excitability when trying to imagine maximum muscle relaxation. SIGNIFICANCE: The results help to interpret the down-regulation of motor excitability found in patients with motor conversion disorder.
