- Email: [email protected]
120. Changing in effective cerebral connectivity during the acute phase of stroke: An EEG TMS study
e216
Society Proceedings / Clinical Neurophysiology 124 (2013) e189–e223
neuropathies. The key of this method, because of frequent anatomic variants and topographic embedding of terminal nerve fibres, is that maximum care must be placed in the choice of cutaneous regions to stimulate. In our experience, we found some cases in which dSEP confirmed a clinical suspicion of sensitive neuropathy. We studied Genitofemoral, Iliohypogastric, Ilioinguinal, Lateral Femoral Cutaneous, Saphenous, Calcanear nerves. We will present our normative data and some case reports. doi:10.1016/j.clinph.2013.06.146
120. Changing in effective cerebral connectivity during the acute phase of stroke: An EEG TMS study—F. Giambattistelli, L. Tomasevic, F. Vernieri, F. Assenza, A. Pepe, F. Tecchio, P.M. Rossini (Rome) The purpose of this study is to investigate possible changes in effective connectivity of the brain secondary to an acute injury such as cerebral ischemia by using TMS-EEG co-registration. 7 stroke patients with single ischemic stroke in the left middle cerebral artery territory within 10 days and upper arm paresis, and 7 age-matched healthy subjects were enrolled in the study. TMS was performed over the left and right primary motor area during multichannel EEG recording. Stroke patients with no muscular twitch in response to TMS stimulation were excluded. After TMS stimulation of the left affected M1 area a in stroke patients we found a different recruitment then in healthy subjects. In stroke patients, cerebral activations between 20 and 70 ms after the stimulation were steadily bilateral and we found a significantly higher strength in the whole affected hemisphere. This study demonstrated a clear modification in effective cortical connectivity during the acute phases of stroke. The EEG-TMS technique has proven useful in evaluating the modification of synaptic plasticity that occur in the acute phase of stroke, offering the opportunity to acquire information for prediction of the prognosis or new therapeutic approaches. doi:10.1016/j.clinph.2013.06.147
121. Vestibulo-masseteric reflex (VMR) and acoustic-masseteric reflex (AMR): Normative values—F. Ginatempo, E. Ortu, G. Pilurzi, E. Tolu, F. Deriu (Sassari) Our aim was to gain normative values for VMR and AMR, two myogenic potentials recently described in masseter muscles (MM), which normal values for clinical use have not been defined yet. Sixty healthy subjects (aged 13–66 years; 39 females) underwent VMR and AMR recording, during unilateral and bilateral clicks (0.1 ms, 143– 108 dB-SPL, 5 Hz), from active MM, through surface electrodes in a belly-to-tendon double montage (active electrode over MM belly, reference over the mandible angle and zygomatic arch). VMR and AMR onset and peak latencies as well as corrected amplitudes (ratio) were calculated in the averaged unrectified-EMG, according to stimulation/ recording side, electrode montage and sample demographics. VMR and AMR were bilateral and symmetric, with no significant agerelated differences. Following bilateral stimulation, onsets were 8.07 ± 0.98 ms and 12.06 ± 1.90 ms, positive-peaklatencies were 11.2 ± 0.88 ms and 15.37 ± 1.10 ms, ratios were 0.64 ± 0.28 and 0.51 ± 0.26, respectively. Unilateral stimulation induced responses of similar latency but 30–35% smaller (p < 0.001) than bilateral stimulation. The electrode montage with zigomatic reference provided the largest and more consistent responses, with AMR occurring significantly earlier in women than in men (p < 0.01). Availability of normative values for VMR and AMR can offer clinicians an additional tool to test brainstem circuits in normal and pathological conditions.
doi:10.1016/j.clinph.2013.06.148
122. When emotions drive encoding: evidence from ERPs— S. Righi, T. Marzi, V. Orlando, M.P. Viggiano (Florence) The ability to encode together emotional attributes and face identity has a key role in human interactions. Several neuroimaging studies investigated the emotional stimuli encoding but a still open question is the temporal dynamic of the interaction between emotion and memory. We used ERPs with the major goal to investigate whether and when the emotional processing effectiveness drives the encoding. Emotional processing (Early frontal positivity) and subsequent memory (Dm effect) was investigated for faces with either happy, fearful or neutral expressions at encoding. At retrieval all faces were presented with neutral expression and participants were to judge old and new faces. ERP results showed a very early interaction between emotion and successful encoding of faces. Furthermore, the Dm amplitude was modulated as a function of the emotional attributes of the stimuli. All in all, our data suggest that the emotional processing influence encoding through two distinct mechanisms. At an early latency, the effectiveness of saliencerelated processing may benefit memory in a nonspecific way, while later on a valence-related facilitation may enhance memory formation, particularly for fearful faces. doi:10.1016/j.clinph.2013.06.149
123. Visual evoked potential latencies are significantly delayed in a new model of experimental autoimmune encephalomyelitis rat—R. Santangelo, V. Castoldi, M. Cambiaghi, L. Camaleonti, M. Cursi, G. Comi, L. Leocani (Milan) Experimental autoimmune encephalomyelitis (EAE) is a pre-clinical disease model of Multiple Sclerosis (MS). In the present study we used a novel emulsion derived from the spinal cord – spinal cord homogenate (SCH) – to induce disease in Dark-Agouti (DA) rats, monitoring EAE course by using Visual Evoked Potentials (VEPs) to assess their usefulness as neurophysiological biomarker. 19 DA rats were used in the experiment: 7 immunized by injecting SCH (EAE RATS) and 12 controls (CTRL RATS). Flash epidural VEPs from both eyes were recorded 6 times once a week (first one the day before, then at days 6, 13, 20, 27, 34 post immunization). We measured P1 latency and amplitude from N1–P1–N2 complex by acquiring, for each session, the average of 4 waveforms (10 trains each) from each eye. There was significant difference in P1 latency between CTRL RATS and EAE RATS at days 13–20 and 27 post immunization (p < 0,05), while no significant difference was found in P1 amplitude between EAE RATS and CTRL rats (p > 0,05). The present results reveal that VEP P1 latencies are significantly delayed in EAE RATS, thus showing that VEPs could be a useful tool in monitoring disease course also in this new EAE animal model. doi:10.1016/j.clinph.2013.06.150
124. Electrophysiological correlates of individual differences in face ability: A preliminary report—M.T. Turano, T. Marzi, M.P. Viggiano (Florence) The aim of the current study was to investigate the electrophysiological correlates of face processing in different groups of subjects selected on the basis of their poor, low or high face ability, namely Congenital Prosopagnosics, Bad and Good face recognizers. We examined how the Event Related Potentials (ERP) components were
Society Proceedings / Clinical Neurophysiology 124 (2013) e189–e223
neuropathies. The key of this method, because of frequent anatomic variants and topographic embedding of terminal nerve fibres, is that maximum care must be placed in the choice of cutaneous regions to stimulate. In our experience, we found some cases in which dSEP confirmed a clinical suspicion of sensitive neuropathy. We studied Genitofemoral, Iliohypogastric, Ilioinguinal, Lateral Femoral Cutaneous, Saphenous, Calcanear nerves. We will present our normative data and some case reports. doi:10.1016/j.clinph.2013.06.146
120. Changing in effective cerebral connectivity during the acute phase of stroke: An EEG TMS study—F. Giambattistelli, L. Tomasevic, F. Vernieri, F. Assenza, A. Pepe, F. Tecchio, P.M. Rossini (Rome) The purpose of this study is to investigate possible changes in effective connectivity of the brain secondary to an acute injury such as cerebral ischemia by using TMS-EEG co-registration. 7 stroke patients with single ischemic stroke in the left middle cerebral artery territory within 10 days and upper arm paresis, and 7 age-matched healthy subjects were enrolled in the study. TMS was performed over the left and right primary motor area during multichannel EEG recording. Stroke patients with no muscular twitch in response to TMS stimulation were excluded. After TMS stimulation of the left affected M1 area a in stroke patients we found a different recruitment then in healthy subjects. In stroke patients, cerebral activations between 20 and 70 ms after the stimulation were steadily bilateral and we found a significantly higher strength in the whole affected hemisphere. This study demonstrated a clear modification in effective cortical connectivity during the acute phases of stroke. The EEG-TMS technique has proven useful in evaluating the modification of synaptic plasticity that occur in the acute phase of stroke, offering the opportunity to acquire information for prediction of the prognosis or new therapeutic approaches. doi:10.1016/j.clinph.2013.06.147
121. Vestibulo-masseteric reflex (VMR) and acoustic-masseteric reflex (AMR): Normative values—F. Ginatempo, E. Ortu, G. Pilurzi, E. Tolu, F. Deriu (Sassari) Our aim was to gain normative values for VMR and AMR, two myogenic potentials recently described in masseter muscles (MM), which normal values for clinical use have not been defined yet. Sixty healthy subjects (aged 13–66 years; 39 females) underwent VMR and AMR recording, during unilateral and bilateral clicks (0.1 ms, 143– 108 dB-SPL, 5 Hz), from active MM, through surface electrodes in a belly-to-tendon double montage (active electrode over MM belly, reference over the mandible angle and zygomatic arch). VMR and AMR onset and peak latencies as well as corrected amplitudes (ratio) were calculated in the averaged unrectified-EMG, according to stimulation/ recording side, electrode montage and sample demographics. VMR and AMR were bilateral and symmetric, with no significant agerelated differences. Following bilateral stimulation, onsets were 8.07 ± 0.98 ms and 12.06 ± 1.90 ms, positive-peaklatencies were 11.2 ± 0.88 ms and 15.37 ± 1.10 ms, ratios were 0.64 ± 0.28 and 0.51 ± 0.26, respectively. Unilateral stimulation induced responses of similar latency but 30–35% smaller (p < 0.001) than bilateral stimulation. The electrode montage with zigomatic reference provided the largest and more consistent responses, with AMR occurring significantly earlier in women than in men (p < 0.01). Availability of normative values for VMR and AMR can offer clinicians an additional tool to test brainstem circuits in normal and pathological conditions.
doi:10.1016/j.clinph.2013.06.148
122. When emotions drive encoding: evidence from ERPs— S. Righi, T. Marzi, V. Orlando, M.P. Viggiano (Florence) The ability to encode together emotional attributes and face identity has a key role in human interactions. Several neuroimaging studies investigated the emotional stimuli encoding but a still open question is the temporal dynamic of the interaction between emotion and memory. We used ERPs with the major goal to investigate whether and when the emotional processing effectiveness drives the encoding. Emotional processing (Early frontal positivity) and subsequent memory (Dm effect) was investigated for faces with either happy, fearful or neutral expressions at encoding. At retrieval all faces were presented with neutral expression and participants were to judge old and new faces. ERP results showed a very early interaction between emotion and successful encoding of faces. Furthermore, the Dm amplitude was modulated as a function of the emotional attributes of the stimuli. All in all, our data suggest that the emotional processing influence encoding through two distinct mechanisms. At an early latency, the effectiveness of saliencerelated processing may benefit memory in a nonspecific way, while later on a valence-related facilitation may enhance memory formation, particularly for fearful faces. doi:10.1016/j.clinph.2013.06.149
123. Visual evoked potential latencies are significantly delayed in a new model of experimental autoimmune encephalomyelitis rat—R. Santangelo, V. Castoldi, M. Cambiaghi, L. Camaleonti, M. Cursi, G. Comi, L. Leocani (Milan) Experimental autoimmune encephalomyelitis (EAE) is a pre-clinical disease model of Multiple Sclerosis (MS). In the present study we used a novel emulsion derived from the spinal cord – spinal cord homogenate (SCH) – to induce disease in Dark-Agouti (DA) rats, monitoring EAE course by using Visual Evoked Potentials (VEPs) to assess their usefulness as neurophysiological biomarker. 19 DA rats were used in the experiment: 7 immunized by injecting SCH (EAE RATS) and 12 controls (CTRL RATS). Flash epidural VEPs from both eyes were recorded 6 times once a week (first one the day before, then at days 6, 13, 20, 27, 34 post immunization). We measured P1 latency and amplitude from N1–P1–N2 complex by acquiring, for each session, the average of 4 waveforms (10 trains each) from each eye. There was significant difference in P1 latency between CTRL RATS and EAE RATS at days 13–20 and 27 post immunization (p < 0,05), while no significant difference was found in P1 amplitude between EAE RATS and CTRL rats (p > 0,05). The present results reveal that VEP P1 latencies are significantly delayed in EAE RATS, thus showing that VEPs could be a useful tool in monitoring disease course also in this new EAE animal model. doi:10.1016/j.clinph.2013.06.150
124. Electrophysiological correlates of individual differences in face ability: A preliminary report—M.T. Turano, T. Marzi, M.P. Viggiano (Florence) The aim of the current study was to investigate the electrophysiological correlates of face processing in different groups of subjects selected on the basis of their poor, low or high face ability, namely Congenital Prosopagnosics, Bad and Good face recognizers. We examined how the Event Related Potentials (ERP) components were