Ipsilateral median somatosensory evoked potentials recorded from human somatosensory cortex

1997 ◽  
Vol 104 (3) ◽  
pp. 189-198 ◽  
Author(s):  
Soheyl Noachtar ◽  
Hans O. Lüders ◽  
Dudley S Dinner ◽  
George Klem
Keyword(s):  
Evoked Potentials ◽  
Somatosensory Cortex ◽  
Somatosensory Evoked Potentials

Human proprioceptive adaptations during states of height-induced fear and anxiety

2011 ◽  
Vol 106 (6) ◽  
pp. 3082-3090 ◽  
Author(s):  
Justin R. Davis ◽  
Brian C. Horslen ◽  
Kei Nishikawa ◽  
Katie Fukushima ◽  
Romeo Chua ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Somatosensory Cortex ◽  
Somatosensory Evoked Potentials ◽  
Emotional Experience ◽  
Afferent Feedback ◽  
Triceps Surae ◽  
Feedback Gain ◽  
Postural Threat ◽  
Fear And Anxiety ◽  
Stimulation Of

Clinical and experimental research has demonstrated that the emotional experience of fear and anxiety impairs postural stability in humans. The current study investigated whether changes in fear and anxiety can also modulate spinal stretch reflexes and the gain of afferent inputs to the primary somatosensory cortex. To do so, two separate experiments were performed on two separate groups of participants while they stood under conditions of low and high postural threat. In experiment 1, the proprioceptive system was probed using phasic mechanical stimulation of the Achilles tendon while simultaneously recording the ensuing tendon reflexes in the soleus muscle and cortical-evoked potentials over the somatosensory cortex during low and high threat conditions. In experiment 2, phasic electrical stimulation of the tibial nerve was used to examine the effect of postural threat on somatosensory evoked potentials. Results from experiment 1 demonstrated that soleus tendon reflex excitability was facilitated during states of height-induced fear and anxiety while the magnitude of the tendon-tap-evoked cortical potential was not significantly different between threat conditions. Results from experiment 2 demonstrated that the amplitudes of somatosensory-evoked potentials were also unchanged between threat conditions. The results support the hypothesis that muscle spindle sensitivity in the triceps surae muscles may be facilitated when humans stand under conditions of elevated postural threat, although the presumed increase in spindle sensitivity does not result in higher afferent feedback gain at the level of the somatosensory cortex.

scholarly journals Somatosensory cortical excitability changes precede those in motor cortex during human motor learning

2019 ◽  
Vol 122 (4) ◽  
pp. 1397-1405 ◽  
Author(s):  
Hiroki Ohashi ◽  
Paul L. Gribble ◽  
David J. Ostry
Keyword(s):  
Motor Cortex ◽  
Motor Learning ◽  
Evoked Potentials ◽  
Somatosensory Cortex ◽  
Somatosensory Evoked Potentials ◽  
Motor Skill ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Human Motor ◽  
Motor Cortical

Motor learning is associated with plasticity in both motor and somatosensory cortex. It is known from animal studies that tetanic stimulation to each of these areas individually induces long-term potentiation in its counterpart. In this context it is possible that changes in motor cortex contribute to somatosensory change and that changes in somatosensory cortex are involved in changes in motor areas of the brain. It is also possible that learning-related plasticity occurs in these areas independently. To better understand the relative contribution to human motor learning of motor cortical and somatosensory plasticity, we assessed the time course of changes in primary somatosensory and motor cortex excitability during motor skill learning. Learning was assessed using a force production task in which a target force profile varied from one trial to the next. The excitability of primary somatosensory cortex was measured using somatosensory evoked potentials in response to median nerve stimulation. The excitability of primary motor cortex was measured using motor evoked potentials elicited by single-pulse transcranial magnetic stimulation. These two measures were interleaved with blocks of motor learning trials. We found that the earliest changes in cortical excitability during learning occurred in somatosensory cortical responses, and these changes preceded changes in motor cortical excitability. Changes in somatosensory evoked potentials were correlated with behavioral measures of learning. Changes in motor evoked potentials were not. These findings indicate that plasticity in somatosensory cortex occurs as a part of the earliest stages of motor learning, before changes in motor cortex are observed. NEW & NOTEWORTHY We tracked somatosensory and motor cortical excitability during motor skill acquisition. Changes in both motor cortical and somatosensory excitability were observed during learning; however, the earliest changes were in somatosensory cortex, not motor cortex. Moreover, the earliest changes in somatosensory cortical excitability predict the extent of subsequent learning; those in motor cortex do not. This is consistent with the idea that plasticity in somatosensory cortex coincides with the earliest stages of human motor learning.

scholarly journals Functional Magnetic Resonance Imaging and Somatosensory Evoked Potentials in Rats with a Neonatally Induced Freeze Lesion of the Somatosensory Cortex

2004 ◽  
Vol 24 (12) ◽  
pp. 1409-1418 ◽  
Author(s):  
Wolfram Schwindt ◽  
Michael Burke ◽  
Frank Pillekamp ◽  
Heiko J. Luhmann ◽  
Mathias Hoehn
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Evoked Potentials ◽  
Somatosensory Cortex ◽  
Somatosensory Evoked Potentials ◽  
Magnetic Resonance Images ◽  
Projection Area ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging

Brain plasticity is an important mechanism for functional recovery from a cerebral lesion. The authors aimed to visualize plasticity in adult rats with a neonatal freeze lesion in the somatosensory cortex using functional magnetic resonance imaging (fMRI), and hypothesized activation outside the primary projection area. A freeze lesion was induced in the right somatosensory cortex of newborn Wistar rats (n = 12). Sham-operated animals (n = 7) served as controls. After 6 or 7 months, a neurologic examination was followed by recording of somatosensory evoked potentials (SSEPs) and magnetic resonance experiments (anatomical images, fMRI with blood oxygen level–dependent contrast and perfusion-weighted imaging) with electrical forepaw stimulation under α-chloralose anesthesia. Lesioned animals had no obvious neurologic deficits. Anatomical magnetic resonance images showed a malformed cortex or hyperintense areas (cysts) in the lesioned hemisphere. SSEPs were distorted and smaller in amplitude, and fMRI activation was significantly weaker in the lesioned hemisphere. Only in a few animals were cortical areas outside the primary sensory cortex activated. The results are discussed in respect to an apparent absence of plasticity, loss of excitable tissue, the excitability of the lesioned hemisphere, altered connectivity, and a disturbed coupling of increased neuronal activity to the hemodynamic response.

Cortical somatosensory evoked potentials. II. Effects of excision of somatosensory or motor cortex in humans and monkeys

1991 ◽  
Vol 66 (1) ◽  
pp. 64-82 ◽  
Author(s):  
T. Allison ◽  
C. C. Wood ◽  
G. McCarthy ◽  
D. D. Spencer
Keyword(s):  
Motor Cortex ◽  
Evoked Potentials ◽  
Median Nerve ◽  
Somatosensory Cortex ◽  
Somatosensory Evoked Potentials ◽  
Sensorimotor Cortex ◽  
Surgical Excision ◽  
Cortical Surface ◽  
Focal Seizures ◽  
Hand Area

1. To clarify the generators of human short-latency somatosensory evoked potentials (SEPs) thought to arise in sensorimotor cortex, we studied the effects on SEPs of surgical excision of somatosensory or motor cortex in humans and monkeys. 2. Normal median nerve SEPs (P20-N30, N20-P30, and P25-N35) were recorded from the cortical surface of a patient (G13) undergoing a cortical excision for relief of focal seizures. All SEPs were abolished both acutely and chronically after excision of the hand area of somatosensory cortex. Similarly, excision of the hand area of somatosensory cortex abolished corresponding SEPs (P10-N20, N10-P20, and P12-N25) in monkeys. Excision of the crown of monkey somatosensory cortex abolished P12-N25 while leaving P10-N20 and N10-P20 relatively unaffected. 3. After excision of the hand area of motor cortex, all SEPs were present when recorded from the cortical surface of a patient (W1) undergoing a cortical excision for relief of focal seizures. Similarly, all SEPs were present in monkeys after excision of the hand area of motor cortex. 4. Although all SEPs were present after excision of motor cortex in monkeys, variable changes were observed in SEPs after the excisions. However, these changes were not larger than the changes observed after excision of parietal cortex posterior to somatosensory cortex. We concluded that the changes were not specific to motor cortex excision. 5. These results support two major conclusions. 1) Median nerve SEPs recorded from sensorimotor cortex are produced by generators in two adjacent regions of somatosensory cortex: a tangentially oriented generator in area 3b, which produces P20-N30 (human) and P10-N20 (monkey) [recorded anterior to the central sulcus (CS)] and N20-P30 (human) and N10-P20 (monkey) posterior to the CS; and a radially oriented generator in area 1, which produces P25-N35 (human) and P12-N25 (monkey) recorded from the postcentral gyrus near the CS. 2) Motor cortex makes little or no contribution to these potentials.

Localization of the face area of human sensorimotor cortex by intracranial recording of somatosensory evoked potentials

1993 ◽  
Vol 79 (6) ◽  
pp. 874-884 ◽  
Author(s):  
Gregory McCarthy ◽  
Truett Allison ◽  
Dennis D. Spencer
Keyword(s):  
Evoked Potentials ◽  
Median Nerve ◽  
Somatosensory Cortex ◽  
Somatosensory Evoked Potentials ◽  
Content Type ◽  
Face Area ◽  
The Face ◽  
Hand Area ◽  
Fine Print ◽  
Stimulation Of

✓ The authors describe a method of localizing the sensory and motor peri-rolandic cortex representing the face and intraoral structures. Somatosensory evoked potentials (SEP's) to stimulation of the chin, lips, tongue, and palate were recorded in 37 patients studied intraoperatively under general anesthesia or following chronic implantation of cortical surface electrodes. Localization by trigeminal SEP recording was validated by SEP localization of the hand area with median nerve stimulation, and by cortical stimulation of the hand and face areas. The following conclusions were drawn regarding the implementation of face area localization: 1) in general agreement with the results of cortical stimulation in humans and single-unit recordings in monkeys, there is a medial-to-lateral representation in somatosensory cortex of the hand, chin, upper lip, lower lip, tongue, and palate; 2) the chin and lip representations overlap, are adjacent to the hand area, and provide little additional localizing information if the hand area has been identified; 3) stimulation of the tongue and palate evokes reliable, large-amplitude SEP's useful for localization; 4) palatal SEP's allow localization near the sylvian sulcus; 5) for any type of trigeminal stimulation, the largest SEP's are recorded from the somatosensory cortex and provide the most consistent criterion for its identification; and 6) polarity inversion of potentials across the sulcus (a reliable localizing criterion for median nerve SEP's) is a less reliable criterion for trigeminal SEP's.

Differences between primary somatosensory cortex- and vertex-derived somatosensory-evoked potentials in the rat

2004 ◽  
Vol 1030 (2) ◽  
pp. 256-266 ◽  
Author(s):  
Peter J. Stienen ◽  
Walter E. van den Brom ◽  
Harry N.M. de Groot ◽  
Anjop J. Venker-van Haagen ◽  
Ludo J. Hellebrekers
Keyword(s):  
Evoked Potentials ◽  
Somatosensory Cortex ◽  
Somatosensory Evoked Potentials ◽  
Primary Somatosensory Cortex

Hemispheric Mapping of Secondary Somatosensory Cortex in the Rat

2007 ◽  
Vol 97 (1) ◽  
pp. 200-207 ◽  
Author(s):  
Alexander M. Benison ◽  
David M. Rector ◽  
Daniel S. Barth
Keyword(s):  
High Resolution ◽  
Evoked Potentials ◽  
Somatosensory Cortex ◽  
Somatosensory Evoked Potentials ◽  
Body Representation ◽  
Rat Cortex ◽  
Face Representation ◽  
Secondary Somatosensory Cortex ◽  
The Face ◽  
Somatosensory Areas

This study used high-resolution hemispheric mapping of somatosensory evoked potentials to determine the number and organization of secondary somatosensory areas (SII) in rat cortex. Two areas, referred to as SII and PV (parietoventral), revealed complete (SII) or nearly complete (PV) body maps. The vibrissa and somatic representation of SII was upright, rostrally oriented, and immediately lateral to primary somatosensory cortex (SI), with a dominant face representation. Vibrissa representations in SII were highly organized, with the rows staggered rostrally along the mediolateral axis. Area PV was approximately one fifth the size of SII, and located rostral and lateral to auditory cortex. PV had a rostrally oriented and inverted body representation that was dominated by the distal extremities, with little representation of the face or vibrissae. These data support the conclusion that in the rat, as in other species, SII and PV represent anatomically and functionally distinct areas of secondary somatosensory cortex.

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