RESUMO
Enhancements in motor performance have been demonstrated in response to intense stimuli both in healthy subjects and in the form of 'paradoxical kinesis' in patients with Parkinson's disease. Here we identify a mid-latency evoked potential in local field potential recordings from the region of the subthalamic nucleus, which scales in amplitude with both the intensity of the stimulus delivered and corresponding enhancements in biomechanical measures of maximal handgrips, independent of the dopaminergic state of our subjects with Parkinson's disease. Recordings of a similar evoked potential in the related pedunculopontine nucleus - a key component of the reticular activating system - provide support for this neural signature in the subthalmic nucleus being a novel correlate of ascending arousal, propagated from the reticular activating system to exert an 'energizing' influence on motor circuitry. Future manipulation of this system linking arousal and motor performance may provide a novel approach for the non-dopaminergic enhancement of motor performance in patients with hypokinetic disorders such as Parkinson's disease.
Assuntos
Estimulação Encefálica Profunda/métodos , Potenciais Evocados/fisiologia , Atividade Motora/fisiologia , Doença de Parkinson/terapia , Núcleo Subtalâmico/fisiologia , Estimulação Acústica , Adulto , Idoso , Antiparkinsonianos/uso terapêutico , Sinais (Psicologia) , Eletromiografia , Potenciais Evocados/efeitos dos fármacos , Feminino , Força da Mão/fisiologia , Humanos , Levodopa/uso terapêutico , Masculino , Pessoa de Meia-Idade , Atividade Motora/efeitos dos fármacos , Doença de Parkinson/fisiopatologia , Estimulação Luminosa , Psicoacústica , Tempo de Reação/efeitos dos fármacos , Tempo de Reação/fisiologiaRESUMO
We investigate the clinical outcome from stimulation of the mamillothalamic tract in two patients with intractable epilepsy secondary to hypothalamic hamartomas. One patient has a left-sided and the other a right-sided tumor. Both patients presented with a history of gelastic and complex partial seizures resistant to multiple antiepileptic drugs. Both patients underwent insertion of a single deep brain-stimulating electrode ipsilateral to the site of the tumor, lying adjacent to the mamillothalamic tract. Postoperatively they both had a significant reduction in seizure frequency, with one patient being seizure free for the last 10 months. An improvement in mood was reported by the patient's primary carers and demonstrated on quality of life questionnaires.