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19. Visual cortex representation of the vertical meridian
Abstracts / Clinical Neurophysiology 127 (2016) e323–e341
16. Presynaptic and postsynaptic inhibition in the human dorsal column nuclei—M. Valeriani, A. Insola, P. Mazzone (Roma, Italy)
The study aimed to investigate the site of the movement related inhibition of the human dorsal column nuclei. Median nerve somatosensory evoked potentials (SEPs) were recorded from 18 patients suffering from Parkinson’s disease, who underwent electrode implantation in the pedunculopontine (PPTg) nucleus. SEPs were recorded at rest and during movement of the thumb of the stimulated wrist. The PPTg electrode recorded a triphasic potential generated in the cuneate nucleus. The PPTg potential was subtended by 2 high frequency oscillation (HFO) components: (1) an earlier one with 1000 Hz frequency, and (2) a later one with 1700 Hz frequency. Movement reduced both HFO components. We suggest that the 1000 Hz and 1700 Hz HFO bursts are generated at pre- and postsynaptical level, respectively. Therefore, movement exerts both pre- and post-synaptic inhibition on the dorsal column nuclei.
e327
described in the companion paper (Troni et al.,1966) were recorded during a sustained (80 min) fatigue task. The task consisted in continuous finger extension to maintain a fixed position at half of maximal range of motion (basal position) while supporting a load (30– 50 g) hanging on distal phalanx. The sequence of the 3 motor tasks was superimposed to the fatigue task. Fatigue was monitored using a 10 points Visual Analogic Scale (VAS). A significant increase in amplitude of all post-movement components was observed in Bt- and Ex-MRCPs, associated with a substantial stability of pre-movement components (early- and late-BP) throughout the experimental session. A similar trend was initially observed for Re-MRCP, later followed by a progressive reduction in amplitude of both late-BP and post-movement components. The post-movement changes of Bt- and Ex-MRCP can hardly be attributed to fatigue because of early occurrence and temporal stability. The late and progressive deterioration of Re-MRCP strongly indicates a fatigue effect. doi:10.1016/j.clinph.2016.10.030
doi:10.1016/j.clinph.2016.10.028
17. Simultaneous recording of motor related cortical potentials to different basal components of voluntary movements— W. Troni, F. Boretto, A. Di Sapio, F. Melillo, R. Morese, M.C. Valentini (Torino, Italy)
The purpose of the paper was to compare motor related cortical potentials (MRCPs) to basic components of voluntary movements in prolonged recording sessions. EEG activity (27 electrodes placed over the sensorimotor cortex) was recorded in 10 normal volunteers instructed to perform a sequence of 3 simple self-paced movements with the right index finger, separated by an interval of at least 3–4 s: (1) rapid, ballistic-type (Bt-) extension with immediate automated return to resting position; (2) rapid extension (Ex-) to reach and maintain a defined target followed by (3) relaxation (Re-) with passive return to resting position. A prolonged recording session (80 min) provided, for each task, a sequence of 4 MRCPs resulting from the average of 4 successive blocks of 40–80 artefact-free EEG epochs (3 s before and 1 s after onset of individual movements derived from the mechanogram). Recording breaks of about 10–20 s, without interruption of motor task, were interposed at intervals of 3–4 min. Pre- and post-movement components were stable in all MRCPs throughout the recording session. All potentials showed a similar onset and duration of pre-movement components with a similar scalp distribution. Clear-cut differences were observed in the postmovement components probably reflecting different afferent patterns from peripheral effectors.
19. Visual cortex representation of the vertical meridian— S. Rinalduzzi, S.J. Jones, E.M. Vingolo, F. Fattapposta, A. Currà (Roma, Italy, London, UK, Terracina, Italy)
Two neural mechanisms warrant transmission of visual information to both hemispheres: the corpus callosum, most represented at secondary visual cortices (V2–V3–V4–V5); the 0.5 deg wide band of nasal retina near the fovea, which contains ganglion cells projecting to ipsilateral LGN/striate cortex intermingled with cells that project contralaterally. We investigated visual projections at the vertical meridian of the visual field to the visual cortex, by studying visual evoked potentials (VEPs) in ten healthy subjects. With binocular viewing of the pattern reversal checkerboard, we used either left/right hemifield stimulation either upper/lower hemifield stimulation. Alternating right and left hemifield stimulation with extension of edges across the vertical meridian (binding recordings) and complementary reversal (unbinding recordings) was used for test recordings. Alternating upper and lower hemifield stimulation were used as control recordings. N75 did not differ in binding/unbinding and control recordings. P100 and N145 amplitude were higher - and P100 latency shorter – during binding than unbinding recordings. Control recordings showed no difference between upper/ lower hemifield stimulation. These findings suggest that visual stimuli with extension of edges across the vertical meridian are mainly represented at the level of visual peristriate areas. doi:10.1016/j.clinph.2016.10.031
doi:10.1016/j.clinph.2016.10.029
18. Simultaneous recording of motor related cortical potentials to different basal components of voluntary movements during a sustained fatigue task—W. Troni, F. Boretto, A. Di Sapio, F. Melillo, R. Morese, M.C. Valentini (Torino, Italy)
Our aim was to study the effects of a sustained fatigue task on Motor Related Cortical Potentials (MRCPs) to basic components of voluntary movements. In 10 normal volunteers MRCPs to Ballistic, Extension movements and Relaxation of the right index finger, according to the method
20. Habituation of somatosensory evoked potentials in dystonia— A. Cardillo, M. Gorini, A. Alibardi, D. Greco, S. Rinalduzzi, F. Pierelli, F. Fattapposta, L. Marinelli, A. Currà (Terracina, Italy, Roma, Italy, Latina, Italy, Genova, Italy)
Dystonia is a disorder of both motor and sensory function, clinically characterized by involuntary movements, abnormal postures, and abnormal sensory discrimination. Whereas most data on the physiology of motor cortices are consistent with a general frame of reduced inhibition and maladaptative plasticity, electrophysiological data in sensory cortices are controversial. Habituation refers to
16. Presynaptic and postsynaptic inhibition in the human dorsal column nuclei—M. Valeriani, A. Insola, P. Mazzone (Roma, Italy)
The study aimed to investigate the site of the movement related inhibition of the human dorsal column nuclei. Median nerve somatosensory evoked potentials (SEPs) were recorded from 18 patients suffering from Parkinson’s disease, who underwent electrode implantation in the pedunculopontine (PPTg) nucleus. SEPs were recorded at rest and during movement of the thumb of the stimulated wrist. The PPTg electrode recorded a triphasic potential generated in the cuneate nucleus. The PPTg potential was subtended by 2 high frequency oscillation (HFO) components: (1) an earlier one with 1000 Hz frequency, and (2) a later one with 1700 Hz frequency. Movement reduced both HFO components. We suggest that the 1000 Hz and 1700 Hz HFO bursts are generated at pre- and postsynaptical level, respectively. Therefore, movement exerts both pre- and post-synaptic inhibition on the dorsal column nuclei.
e327
described in the companion paper (Troni et al.,1966) were recorded during a sustained (80 min) fatigue task. The task consisted in continuous finger extension to maintain a fixed position at half of maximal range of motion (basal position) while supporting a load (30– 50 g) hanging on distal phalanx. The sequence of the 3 motor tasks was superimposed to the fatigue task. Fatigue was monitored using a 10 points Visual Analogic Scale (VAS). A significant increase in amplitude of all post-movement components was observed in Bt- and Ex-MRCPs, associated with a substantial stability of pre-movement components (early- and late-BP) throughout the experimental session. A similar trend was initially observed for Re-MRCP, later followed by a progressive reduction in amplitude of both late-BP and post-movement components. The post-movement changes of Bt- and Ex-MRCP can hardly be attributed to fatigue because of early occurrence and temporal stability. The late and progressive deterioration of Re-MRCP strongly indicates a fatigue effect. doi:10.1016/j.clinph.2016.10.030
doi:10.1016/j.clinph.2016.10.028
17. Simultaneous recording of motor related cortical potentials to different basal components of voluntary movements— W. Troni, F. Boretto, A. Di Sapio, F. Melillo, R. Morese, M.C. Valentini (Torino, Italy)
The purpose of the paper was to compare motor related cortical potentials (MRCPs) to basic components of voluntary movements in prolonged recording sessions. EEG activity (27 electrodes placed over the sensorimotor cortex) was recorded in 10 normal volunteers instructed to perform a sequence of 3 simple self-paced movements with the right index finger, separated by an interval of at least 3–4 s: (1) rapid, ballistic-type (Bt-) extension with immediate automated return to resting position; (2) rapid extension (Ex-) to reach and maintain a defined target followed by (3) relaxation (Re-) with passive return to resting position. A prolonged recording session (80 min) provided, for each task, a sequence of 4 MRCPs resulting from the average of 4 successive blocks of 40–80 artefact-free EEG epochs (3 s before and 1 s after onset of individual movements derived from the mechanogram). Recording breaks of about 10–20 s, without interruption of motor task, were interposed at intervals of 3–4 min. Pre- and post-movement components were stable in all MRCPs throughout the recording session. All potentials showed a similar onset and duration of pre-movement components with a similar scalp distribution. Clear-cut differences were observed in the postmovement components probably reflecting different afferent patterns from peripheral effectors.
19. Visual cortex representation of the vertical meridian— S. Rinalduzzi, S.J. Jones, E.M. Vingolo, F. Fattapposta, A. Currà (Roma, Italy, London, UK, Terracina, Italy)
Two neural mechanisms warrant transmission of visual information to both hemispheres: the corpus callosum, most represented at secondary visual cortices (V2–V3–V4–V5); the 0.5 deg wide band of nasal retina near the fovea, which contains ganglion cells projecting to ipsilateral LGN/striate cortex intermingled with cells that project contralaterally. We investigated visual projections at the vertical meridian of the visual field to the visual cortex, by studying visual evoked potentials (VEPs) in ten healthy subjects. With binocular viewing of the pattern reversal checkerboard, we used either left/right hemifield stimulation either upper/lower hemifield stimulation. Alternating right and left hemifield stimulation with extension of edges across the vertical meridian (binding recordings) and complementary reversal (unbinding recordings) was used for test recordings. Alternating upper and lower hemifield stimulation were used as control recordings. N75 did not differ in binding/unbinding and control recordings. P100 and N145 amplitude were higher - and P100 latency shorter – during binding than unbinding recordings. Control recordings showed no difference between upper/ lower hemifield stimulation. These findings suggest that visual stimuli with extension of edges across the vertical meridian are mainly represented at the level of visual peristriate areas. doi:10.1016/j.clinph.2016.10.031
doi:10.1016/j.clinph.2016.10.029
18. Simultaneous recording of motor related cortical potentials to different basal components of voluntary movements during a sustained fatigue task—W. Troni, F. Boretto, A. Di Sapio, F. Melillo, R. Morese, M.C. Valentini (Torino, Italy)
Our aim was to study the effects of a sustained fatigue task on Motor Related Cortical Potentials (MRCPs) to basic components of voluntary movements. In 10 normal volunteers MRCPs to Ballistic, Extension movements and Relaxation of the right index finger, according to the method
20. Habituation of somatosensory evoked potentials in dystonia— A. Cardillo, M. Gorini, A. Alibardi, D. Greco, S. Rinalduzzi, F. Pierelli, F. Fattapposta, L. Marinelli, A. Currà (Terracina, Italy, Roma, Italy, Latina, Italy, Genova, Italy)
Dystonia is a disorder of both motor and sensory function, clinically characterized by involuntary movements, abnormal postures, and abnormal sensory discrimination. Whereas most data on the physiology of motor cortices are consistent with a general frame of reduced inhibition and maladaptative plasticity, electrophysiological data in sensory cortices are controversial. Habituation refers to