Carbamazepine reduces memory induced activation of mesial temporal lobe structures: a pharmacological fMRI-study

BACKGROUND AND PURPOSE: It is not known whether carbamazepine (CBZ; a drug widely used in neurology and psychiatry) influences the blood oxygenation level dependent (BOLD) contrast changes induced by neuronal activation and measured by functional MRI (fMRI). We aimed to investigate the influence of CBZ on memory induced activation of the mesial temporal lobes in patients with symptomatic temporal lobe epilepsy (TLE). MATERIAL AND METHODS: Twenty-one individual patients with refractory symptomatic TLE with different CBZ serum levels and 20 healthy controls were studied using BOLD fMRI. Mesial temporal lobe (MTL) activation was induced by a task that is based on the retrieval of individually familiar visuo-spatial knowledge. The extent of significant MTL fMRI activation was measured and correlated with the CBZ serum level. RESULTS: In TLE patients, the extent of significant fMRI activation over both MTL was negatively correlated to the CBZ serum level (Spearman r = -0.654, P < 0.001). Activation over the supposedly normal MTL, i.e. contralateral to the seizure onset of TLE patients, was smaller than the averaged MTL activation in healthy controls (P < 0.005). Age, duration of epilepsy, side of seizure onset, and intelligence were not correlated to the extent of the significant BOLD-response over both MTL in patients with TLE. CONCLUSIONS: In TLE patients, carbamazepine reduces the fMRI-detectable changes within the mesial temporal lobes as induced by effortful memory retrieval. FMRI appears to be suitable to study the effects of chronic drug treatment in patients with epilepsy

Eye Movements in Ephedrone-Induced Parkinsonism

Patients with ephedrone parkinsonism (EP) show a complex, rapidly progressive, irreversible, and levodopa non-responsive parkinsonian and dystonic syndrome due to manganese intoxication. Eye movements may help to differentiate parkinsonian syndromes providing insights into which brain networks are affected in the underlying disease, but they have never been systematically studied in EP. Horizontal and vertical eye movements were recorded in 28 EP and compared to 21 Parkinson's disease (PD) patients, and 27 age- and gender-matched healthy subjects using standardized oculomotor tasks with infrared videooculography. EP patients showed slow and hypometric horizontal saccades, an increased occurrence of square wave jerks, long latencies of vertical antisaccades, a high error rate in the horizontal antisaccade task, and made more errors than controls when pro-and antisaccades were mixed. Based on oculomotor performance, a direct differentiation between EP and PD was possible only by the velocity of horizontal saccades. All remaining metrics were similar between both patient groups. EP patients present extensive oculomotor disturbances probably due to manganese-induced damage to the basal ganglia, reflecting their role in oculomotor system

Latency and error rate for mixing cost.

<p>Comparison of EP patients with PD and healthy control groups after Bonferroni adjustment: *<i>p</i><0.05; **<i>p</i><0.01; ***<i>p</i><0.001. The symbols represent mean values and error bars standard deviations. EP  =  ephedrone parkinsonism; PD  =  Parkinson's disease.</p

Latencies, average velocities (Vavg), maximal velocities (Vmax), and gains for horizontal (left) and vertical (right) prosaccades.

<p>Comparison of EP patients with PD and healthy control groups after Bonferroni adjustment: *<i>p</i><0.05; **<i>p</i><0.01; ***<i>p</i><0.001. The symbols represent mean values and error bars standard deviations. EP  =  ephedrone parkinsonism; PD  =  Parkinson's disease.</p

Latencies and error rates for horizontal (left) and vertical (right) antisaccades.

<p>Comparison of EP patients with PD and healthy control groups after Bonferroni adjustment: *<i>p</i><0.05; **<i>p</i><0.01; ***<i>p</i><0.001. The symbols represent mean values and error bars standard deviations. EP  =  ephedrone parkinsonism; PD  =  Parkinson's disease.</p