Somatosensory evoked potentials and blood lactate levels.

We compared, in 20 subjects, the effects of high blood lactate levels on amplitude and latency of P1, N1, P2 and N2 components of lower limb somatosensory evoked potential (SEP), an useful, noninvasive tool for assessing the transmission of the afferent volley from periphery up to the cortex. SEPs were recorded from CPz located over the somatosensory vertex and referenced to FPz with a clavicle ground. Measurements were carried out before, at the end as well as 10 and 20 min after the conclusion of a maximal exercise carried out on a mechanically braked cycloergometer.

Relationship of high blood lactate levels with latency of visual-evoked potentials.

We studied, in healthy adult subjects, the association of high blood lactate levels, induced with an exhaustive exercise (12 subjects) or an intravenous infusion (four subjects) of a lactate solution (3 mg/kg in 1 min), with amplitude and latency of visual-evoked potentials. Amplitude of N75, P100, and N145 components did not show significant changes, whereas latency of P100 was reduced at exercise's end and that of N145 increased 10 min after the conclusion. Therefore, an increase of blood lactate induced by an exhaustive exercise or an intravenous infusion appears to induce an improvement in the conduction time between eye and striate cortex, while it seems to evoke a worsening of intracortical communication between striate and extrastriate areas.

Rhodium-catalyzed hydroformylation of ketal-masked β-isophorone: computational explanation for the unexpected reaction evolution of the tertiary Rh-alkyl via an exocyclic β-elimination derivative.

Ketal-masked β-isophorone (7,9,9-trimethyl-1,4-dioxaspiro[4.5]dec-7-ene) is an interesting case study of Rh-catalyzed hydroformylations not only for the competition between secondary and tertiary rhodium alkyls but also for the unexpected isomerization of the tertiary Rh-alkyl to the exocyclic olefin which undergoes hydroformylation, yielding the acetaldehyde derivative (2) of 7,9,9-trimethyl-1,4-dioxaspiro[4.5]decane.

Effects of repetitive transcranial magnetic stimulation in performing eye-hand integration tasks: four preliminary studies with children showing low-functioning autism.

This report, based on four studies with children with low-functioning autism, aimed at evaluating the effects of repetitive transcranial magnetic stimulation delivered on the left and right premotor cortices on eye-hand integration tasks; defining the long-lasting effects of high-frequency repetitive transcranial magnetic stimulation; and investigating the real efficacy of high-frequency repetitive transcranial magnetic stimulation by comparing three kinds of treatments (high-frequency repetitive transcranial magnetic stimulation, a traditional eye-hand integration training, and both treatments combined). Results showed a significant increase in eye-hand performances only when high-frequency repetitive transcranial magnetic stimulation was delivered on the left premotor cortex; a persistent improvement up to 1 h after the end of the stimulation; better outcomes in the treatment combining high-frequency repetitive transcranial magnetic stimulation and eye-hand integration training. Based on these preliminary findings, further evaluations on the usefulness of high-frequency repetitive transcranial magnetic stimulation in rehabilitation of children with autism are strongly recommended.

Changes in cortical excitability and blood lactate after a fatiguing hand-grip exercise.

Excitability of primary hand motor cortex (PHMC), evaluated with transcranial magnetic stimulation by using the "1 mV resting motor threshold" method, and capillary blood lactate were measured at the end, as well as 5 and 10 min after a fatiguing hand-grip exercise. The relation between blood lactate and the amplitudes of motor-evoked potentials showed a significant direct proportionality. Blood lactate seems to exert a protective role on PHMC against fatigue reduction during extremely intensive isometric exercises.