Eduard Minks

ARE SUBTHALAMICUS NUCLEUS, INTERNAL GLOBUS PALLIDUS AND THALAMUS INVOLVED IN THINKING?

Introduction The aim was to compare evoked potentials (EP) from the P300 paradigm against mismatch negativity (MMN) paradigm, both recorded in the subthalamic nucleus (STN), internal globus pallidus (GPi) and thalamus (Th) and thus electrophysiologically isolate conscious cognition component in these structures. Methods We included 8 patients in Deep brain stimulation program and recorded EP (patients with Parkinsons disease, Generalized dystonia, Essential tremor, Epilepsy). The two four-contacts intracerebral electrodes were implanted into the left and right STN, GPi or Th bilaterally. We computed local potentials on the left and right electrode and we studied the latency of cognitive response (from 200 to 400 ms). Results In the comparison of infrequent stimuli related P300 and MMN a significant difference was found in 14 from 16 electrodes. Comparing frequent answers we found significant difference in 13 from 16 electrodes. Conclusion The difference between evoked potentials of MMN and P300 protocols in 200–400 ms latency suggests that STN, GPi and Th are involved in conscious cognitive processes at the time of stimuli application.

10. Electrophysiological correlate of auditory processing initiative on an unconscious level in the nucleus subthalamicus

Superior temporal sulcus (STS) is a brain structure, which has been related to many cognitive functions recently. It can be presumed that it is a part of many cognitive functions and that in particular situation, its relationship with other brain areas is relevant. Our work aimed to its effective connectivity during processing of potentially relevant unusual events. Twenty healthy volunteers were investigated by functional magnetic resonance during visual oddball task – they were instructed to react to different visual stimuli, randomly dislocated among frequent ones. Further processing was done by SPM5 programme. Next step was psychophysiological interaction analysis, method of effective connectivity. We have detected two areas related to target stimuli detection in STS. The anterior area had increased connectivity with mesiotemporal cortices, the posterior one with anterior cingulate cortex. We have found decreased connectivity of the anterior area with dorsolateral prefrontal cortex and the posterior area with parietal cortex – attention related structures. We can hypothesize that STS in detection of rare events is not related to attention, but to later stages of stimuli processing. This hypothesis is supported by association of STS and mesiotemporal areas.

Correspondence on ‘‘Outcome Measures Used in Studies of Botulinum Toxin in Childhood Cerebral Palsy: A Systematic Review’’

Used outcome measures and scales in the treatment of spasticity in cerebral palsy with botulinum toxin: systematic overview of the current literature

P11-5 Is the cerebellum potential target for stimulation in Parkinson disease? The effect of 1Hz rTMS over the cerebellum on the upper limb motor tasks

Introduction: Spinocerebellar ataxia type 1 (SCA1) is a neurodegenerative disorder of autosomal dominant inheritance, genetically and clinically heterogeneous, caused by CAG repeat expansion. The regions most affected by the disease include the cerebellum and brainstem, the spinocerebellar and pyramidal tracts, the anterior horn and posterior columns. Trunk and limb ataxia, dysarthria, gaze palsy, axonal neuropathy are the dominant signs.AIM: to assess alterations of excitability and inhibition in motor cortex and corticospinal projections in presymptomatic SCA1 gene carriers. Methods: Transcranial magnetic stimulation (TMS) was performed in 20 (12 female) SCA1 gene carriers and 20 healthy volunteers matched for age, sex and height. Cortical excitability threshold (MT) at rest, silent period (SP) during voluntary contractions, central motor conduction time (CMCT) and amplitude of motor evoked potentials (MEPs) from abductor digiti minimi (ADM) and extensor digitorum brevis (EDB) muscles were obtained. Exclusion of ataxia was made by the Scale for the Assessment and Rating of Ataxia (SARA). Results: Age at study entry of SCA1 persons was 25.6±4.7. MT was in normal range in all but three SCA1 cases. The silent period from ADM was significantly longer as compared to controls (83±37 vs. 119±27 msec, p < 0.01). A similar prolongation was found in SP from EDB (219±30 vs. 135.5±37). SP did not correlate with the CAG repeat number. MEP amplitude was decreased in 27% of SCA1 subjects for upper and lower limbs. CMCT was significantly prolonged in 30% of cases to cervical level and in 50% to lumbar spinal cord segments. Conclusions: This study provides evidence for alterations of inhibitory cortical circuits and cerebellar excitation of the motor cortex and corticospinal pathway in the SCA1 gene carriers before the onset of overt clinical symptoms.