Increased excitability of the human corticospinal system with hyperventilation

Seyal, Masud; Mull, Brendan; Gage, B.

doi:10.1016/s0924-980x(98)00022-8

Cited by 27 publications

(21 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Subjects were instructed to hyperventilate briskly until a PET CO 2 of 15 Torr was reached. This was the case after approximately 2-3 min, which is in accordance with previous observations (27). Subjects could then reduce their efforts but were still required to maintain a mean PET CO 2 of 15 Torr until a period of 10 min of HV was over.…”

Section: Experimental Setup and Stimulation Proceduressupporting

confidence: 88%

“…This negative finding was probably due to the study protocol that resulted in a low change of the mean PET CO 2 (22.5 Torr). Seyal et al (27) demonstrated a direct relationship between PET CO 2 levels and the MEP amplitude. They found a negligible change in the MEP amplitude to 30 or 20 Torr, whereas a PET CO 2 of ϳ15 Torr significantly enhanced the MEP amplitude and shortened the MEP (27) argued plausibly that the use of very high TMS intensities in the study of Priori et al (25) most likely accounted for the lack of HV-induced change in MEP amplitude.…”

Section: Effects Of Hv On Mt and S-r Curvesmentioning

confidence: 97%

“…Seyal et al (27) demonstrated a direct relationship between PET CO 2 levels and the MEP amplitude. They found a negligible change in the MEP amplitude to 30 or 20 Torr, whereas a PET CO 2 of ϳ15 Torr significantly enhanced the MEP amplitude and shortened the MEP (27) argued plausibly that the use of very high TMS intensities in the study of Priori et al (25) most likely accounted for the lack of HV-induced change in MEP amplitude. This explanation is supported by our findings that HV decreased MT and that the absolute increase of mean MEP amplitudes was more prominent at lower TMS intensities.…”

Section: Effects Of Hv On Mt and S-r Curvesmentioning

confidence: 97%

“…Since it has to be considered that changes in the Pa CO 2 and changes in the brain tissue and cerebrospinal fluid do not occur simultaneously, the level of the PETCO 2 may not play the only role; rather, the duration of HV and the time point at which the motor-evoked potential (MEP) or phosphene testing is conducted may also play a role. We therefore designed our study protocol according to previous TMS studies [i.e., 15 Torr/10 min compared with 22.5 Torr/3 min in Kong et al (16); Ͻ15 Torr/10 min in Priori et al (25); 15 Torr/3 min in Seyal et al (27)] to most likely detect significant effects of HV. Subjects were instructed to hyperventilate briskly until a PET CO 2 of 15 Torr was reached.…”

Section: Experimental Setup and Stimulation Proceduresmentioning

confidence: 99%

See 3 more Smart Citations

Excitability of human motor and visual cortex before, during, and after hyperventilation

Sparing¹,

Dafotakis²,

Buelte³

et al. 2007

Journal of Applied Physiology

View full text Add to dashboard Cite

Sparing R, Dafotakis M, Buelte D, Meister IG, Noth J. Excitability of human motor and visual cortex before, during, and after hyperventilation. J Appl Physiol 102: 406 -411, 2007. First published September 21, 2006; doi:10.1152/japplphysiol.00770.2006.-In humans, hyperventilation (HV) has various effects on systemic physiology and, in particular, on neuronal excitability and synaptic transmission. However, it is far from clear how the effects of HV are mediated at the cortical level. In this study we investigated the effects of HV-induced hypocapnia on primary motor (M1) and visual cortex (V1) excitability. We used 1) motor threshold (MT) and phosphene threshold (PT) and 2) stimulus-response (S-R) curves (i.e., recruitment curves) as measures of excitability. In the motor cortex, we additionally investigated 3) the intrinsic inhibitory and facilitatory neuronal circuits using a short-interval paired-pulse paradigm. Measurements were performed before, during, and after 10 min of HV (resulting in a minimum end-tidal PCO2 of 15 Torr). HV significantly increased motor-evoked potential (MEP) amplitudes, particularly at lower transcranial magnetic stimulation (TMS) intensities. Pairedpulse stimulation indicated that HV decreases intracortical inhibition (ICI) without changing intracortical facilitation. The results suggest that low PCO 2 levels modulate, in particular, the intrinsic neuronal circuits of ICI, which are largely mediated by neurons containing ␥-aminobutyric acid. Modulation of MT probably resulted from alterations of Na ϩ channel conductances. A significant decrease of PT, together with higher intensity of phosphenes at low stimulus intensities, furthermore suggested that HV acts on the excitability of M1 and V1 in a comparable fashion. This finding implies that HV also affects other brain structures besides the corticospinal motor system. The further exploration of these physiological mechanisms may contribute to the understanding of the various HV-related clinical phenomenona. partial pressure of carbon dioxide; phosphenes; threshold; pairedpulse transcranial magnetic stimulation; intracortical facilitation; intracortical inhibition HYPERVENTILATION (HV) (or hyperpnea) is the state of breathing faster or deeper than necessary, thereby reducing the CO 2 concentration of the blood below normal. What is usually referred to as HV is, in fact, hypocapnia. Since a reduction of arterial PCO 2 (Pa CO 2 ) below the normal level (40 Torr) is obtained by increasing the alveolar ventilation, HV became synonymous with hypocapnia (32). HV is known to have various effects on human physiology (for a review, see Ref. 6).For instance, a reduction in Pa CO 2 increases the excitability of sensory and motor axons in the peripheral nervous system (21,23,28).The aim of the present study was to investigate further the neural mechanisms of the HV-induced changes in cortical excitability. As measures of primary motor cortex (M1) excitability, motor threshold (MT), stimulus-response (S-R) curves (i.e., recruitment curves), intra...

show abstract

Section: Experimental Setup and Stimulation Proceduressupporting

confidence: 88%

Section: Effects Of Hv On Mt and S-r Curvesmentioning

confidence: 97%

Section: Effects Of Hv On Mt and S-r Curvesmentioning

confidence: 97%

Section: Experimental Setup and Stimulation Proceduresmentioning

confidence: 99%

See 2 more Smart Citations

Excitability of human motor and visual cortex before, during, and after hyperventilation

Sparing¹,

Dafotakis²,

Buelte³

et al. 2007

Journal of Applied Physiology

View full text Add to dashboard Cite

show abstract

“…This alteration in pH results in reduced blood flow particularly to the brain, 36,58,135 poorer oxygen delivery to the tissues, 135 increased muscle tension, 135 and increased nervous system excitability. 93,117 Chronic pain has been associated with nervous system sensitization, 12 which may be at least partially explained by the increase in excitability associated with hypocapnia.…”

mentioning

confidence: 99%

Developing Biologically-Based Assessment Tools for Physical Therapy Management of Neck Pain

MacDermid

Gross²,

Galea³

et al. 2009

J Orthop Sports Phys Ther

View full text Add to dashboard Cite

Basic One‐ and Two‐Dimensional NMR Spectroscopy. Fourth, Completely Revised and Updated Edition. By Horst Friebolin.

Schnell

2005

ChemPhysChem

View full text Add to dashboard Cite

Increased excitability of the human corticospinal system with hyperventilation

Cited by 27 publications

References 12 publications

Excitability of human motor and visual cortex before, during, and after hyperventilation

Excitability of human motor and visual cortex before, during, and after hyperventilation

Developing Biologically-Based Assessment Tools for Physical Therapy Management of Neck Pain

Basic One‐ and Two‐Dimensional NMR Spectroscopy. Fourth, Completely Revised and Updated Edition. By Horst Friebolin.

Contact Info

Product

Resources

About