15 research outputs found
Low-level carbon monoxide exposure affects BOLD fMRI response.
Blood oxygen level dependent (BOLD) fMRI is a common technique for measuring brain activation that could be affected by low-level carbon monoxide (CO) exposure from, e.g. smoking. This study aimed to probe the vulnerability of BOLD fMRI to CO and determine whether it may constitute a significant neuroimaging confound. Low-level (6βppm exhaled) CO effects on BOLD response were assessed in 12 healthy never-smokers on two separate experimental days (CO and air control). fMRI tasks were breath-holds (hypercapnia), visual stimulation and fingertapping. BOLD fMRI response was lower during breath holds, visual stimulation and fingertapping in the CO protocol compared to the air control protocol. Behavioural and physiological measures remained unchanged. We conclude that BOLD fMRI might be vulnerable to changes in baseline CO, and suggest exercising caution when imaging populations exposed to elevated CO levels. Further work is required to fully elucidate the impact on CO on fMRI and its underlying mechanisms
Low-level carbon monoxide exposure affects BOLD fMRI signal
Blood Oxygen Level Dependent (BOLD) fMRI is a common technique for measuring brain
activation that could be affected by low-level carbon monoxide (CO) exposure from e.g. smoking.
This study aimed to probe the vulnerability of BOLD fMRI to CO and determine whether it may
constitute a significant neuroimaging confound. Low-level (6ppm exhaled) CO effects on BOLD
response were assessed in 12 healthy never-smokers on two separate experimental days (CO
and air control). fMRI tasks were breath-holds (hypercapnia), visual stimulation and fingertapping.
BOLD fMRI response was lower during breath holds, visual stimulation and fingertapping in the
CO protocol compared to the air control protocol. Behavioural and physiological measures
remained unchanged. We conclude that BOLD fMRI might be vulnerable to changes in baseline
CO, and suggest exercising caution when imaging populations exposed to elevated CO levels.
Further work is required to fully elucidate the impact on CO on fMRI and its underlying
mechanisms
Debating pharmacological options for dyspnoea relief: The need for full, accurate and balanced critical appraisal of the evidence
The pedunculopontine region and breathing in Parkinsonβs disease
Objective. Respiratory abnormalities such as upper airway obstruction are common in Parkinson's disease (PD) and are an important cause of mortality and morbidity. We tested the effect of pedunculopontine region (PPNr) stimulation on respiratory maneuvers in human participants with PD, and separately recorded PPNr neural activity reflected in the local field potential (LFP) during these maneuvers. Methods.
Nine patients with deep brain stimulation electrodes in PPNr, and seven in globus pallidus interna (GPi) were studied during trials of maximal inspiration followed by forced expiration with stimulation OFF and ON. Local field potentials (LFPs) were recorded in the unstimulated condition. Results. PEFR increased from 6.41 Β± 0.63 L/sec in the OFF stimulation state to 7.5 L Β± 0.65 L/sec in the ON stimulation state (z = β2.666, df = 8, P = 0.024). Percentage improvement in PEFR was strongly correlated with proximity of the stimulated electrode contact to the mesencephalic locomotor region in the rostral PPN (r = 0.814, n = 9, P = 0.008). Mean PPNr LFP power increased within the alpha band (7β11 Hz) during forced respiratory maneuvers (1.63 Β± 0.16 ΞΌV2/Hz) compared to resting breathing (0.77 Β± 0.16 ΞΌV2/Hz; z = β2.197, df = 6, P = 0.028). No changes in alpha activity or spirometric indices were seen with GPi recording or stimulation. Percentage improvement in PEFR was strongly positively correlated with increase in alpha power (r = 0.653, n = 14 (7 PPNr patients recorded bilaterally), P = 0.0096). Interpretation. PPNr stimulation in PD improves indices of upper airway function. Increased alphaβband activity is seen within the PPNr during forced respiratory maneuvers. Our findings suggest a link between the PPNr and respiratory performance in PD
Simple contrivance βclampsβ end-tidal P CO 2 and P O 2 despite rapid changes in ventilation
VIII ΡΠΊΠΎΠ½ΠΎΠΌΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΡΡΠ΅Π½ΠΈΡ : ΠΌΠ°ΡΠ΅ΡΠΈΠ°Π»Ρ Π½Π°ΡΡΠ½ΠΎ-ΠΏΡΠ°ΠΊΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΊΠΎΠ½ΡΠ΅ΡΠ΅Π½ΡΠΈΠΈ, ΠΏΠΎΡΠ²ΡΡΠ΅Π½Π½ΠΎΠΉ 110- Π»Π΅ΡΠΈΡ ΡΠΊΠΎΠ½ΠΎΠΌΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΡ Π² Π‘ΠΈΠ±ΠΈΡΠΈ ΠΈ 45-Π»Π΅ΡΠΈΡ ΡΠΊΠΎΠ½ΠΎΠΌΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠ°ΠΊΡΠ»ΡΡΠ΅ΡΠ° Π’ΠΠ£ "ΠΠ½Π½ΠΎΠ²Π°ΡΠΈΠΎΠ½Π½ΡΠ΅ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΠΈ ΡΠ°Π·Π²ΠΈΡΠΈΡ ΡΠΊΠΎΠ½ΠΎΠΌΠΈΠΊΠΈ Π ΠΎΡΡΠΈΠΈ", Π’ΠΎΠΌΡΠΊ, 21-22 Π½ΠΎΡΠ±ΡΡ 2008 Π³.
Π ΡΠ±ΠΎΡΠ½ΠΈΠΊΠ΅ ΠΏΡΠ±Π»ΠΈΠΊΡΡΡΡΡ Π΄ΠΎΠΊΠ»Π°Π΄Ρ ΡΠΊΠΎΠ½ΠΎΠΌΠΈΡΡΠΎΠ² Π ΠΎΡΡΠΈΠΈ: ΠΏΡΠΎΡΠ΅ΡΡΠΎΡΠΎΠ², ΠΏΡΠ΅ΠΏΠΎΠ΄Π°Π²Π°ΡΠ΅Π»Π΅ΠΉ, Π°ΡΠΏΠΈΡΠ°Π½ΡΠΎΠ², ΠΏΡΠ°ΠΊΡΠΈΠΊΠΎΠ², Ρ ΠΊΠΎΡΠΎΡΡΠΌΠΈ ΠΎΠ½ΠΈ Π²ΡΡΡΡΠΏΠΈΠ»ΠΈ Π½Π° ΡΡΠ°Π΄ΠΈΡΠΈΠΎΠ½Π½ΡΡ
ΡΠΊΠΎΠ½ΠΎΠΌΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΡΠ΅Π½ΠΈΡΡ
Π² Π’ΠΎΠΌΡΠΊΠΎΠΌ Π³ΠΎΡΡΠ΄Π°ΡΡΡΠ²Π΅Π½Π½ΠΎΠΌ ΡΠ½ΠΈΠ²Π΅ΡΡΠΈΡΠ΅ΡΠ΅ 21 - 22 Π½ΠΎΡΠ±ΡΡ 2008 Π³. Π Π΄ΠΎΠΊΠ»Π°Π΄Π°Ρ
Π°Π½Π°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π»ΠΈΡΡ Π°ΠΊΡΡΠ°Π»ΡΠ½ΡΠ΅ ΠΏΡΠΎΠ±Π»Π΅ΠΌΡ ΠΈΠ½Π½ΠΎΠ²Π°ΡΠΈΠΎΠ½Π½ΠΎΠ³ΠΎ ΡΠ°Π·Π²ΠΈΡΠΈΡ ΡΠΊΠΎΠ½ΠΎΠΌΠΈΠΊΠΈ Π ΠΎΡΡΠΈΠΈ, Π² ΡΠΎΠΌ ΡΠΈΡΠ»Π΅ Π‘ΠΈΠ±ΠΈΡΠΈ, Π° ΡΠ°ΠΊΠΆΠ΅ Π²ΠΎΠΏΡΠΎΡΡ ΡΠΊΠΎΠ½ΠΎΠΌΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΡ ΠΊΠ°ΠΊ ΠΎΡΠ½ΠΎΠ²Π½ΠΎΠ³ΠΎ ΡΡΠ»ΠΎΠ²ΠΈΡ ΠΈΠ½Π½ΠΎΠ²Π°ΡΠΈΠΎΠ½Π½ΠΎΠ³ΠΎ ΡΠ°Π·Π²ΠΈΡΠΈΡ. ΠΠ»Ρ ΠΏΡΠ΅ΠΏΠΎΠ΄Π°Π²Π°ΡΠ΅Π»Π΅ΠΉ ΡΠΊΠΎΠ½ΠΎΠΌΠΈΡΠ΅ΡΠΊΠΈΡ
Π΄ΠΈΡΡΠΈΠΏΠ»ΠΈΠ½ Π² ΡΠΈΡΡΠ΅ΠΌΠ΅ Π²ΡΡΡΠ΅Π³ΠΎ ΠΏΡΠΎΡΠ΅ΡΡΠΈΠΎΠ½Π°Π»ΡΠ½ΠΎΠ³ΠΎ ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΡ, ΡΠΏΡΠ°Π²Π»Π΅Π½ΡΠ΅ΡΠΊΠΈΡ
ΡΡΡΡΠΊΡΡΡ, ΡΡΡΠ΄Π΅Π½ΡΠΎΠ² Π²ΡΠ·ΠΎΠ² ΠΈ Π²ΡΠ΅Ρ
ΠΈΠ½ΡΠ΅ΡΠ΅ΡΡΡΡΠΈΡ
ΡΡ ΡΠΎΡΠΈΠ°Π»ΡΠ½ΠΎ-ΡΠΊΠΎΠ½ΠΎΠΌΠΈΡΠ΅ΡΠΊΠΈΠΌ ΡΠ°Π·Π²ΠΈΡΠΈΠ΅ΠΌ Π ΠΎΡΡΠΈΠΈ.ΠΠ°Π³Π». Ρ ΡΠΈΡΡΠ». ΡΠΊΡΠ°Π½
Image_1_Blunted perception of breathlessness in three cases of low grade insular-glioma.JPEG
Better understanding of breathlessness perception addresses an unmet clinical need for more effective treatments for intractable dyspnoea, a prevalent symptom of multiple medical conditions. The insular-cortex is predominantly activated in brain-imaging studies of dyspnoea, but its precise role remains unclear. We measured experimentally-induced hypercapnic air-hunger in three insular-glioma patients before and after surgical resection. Tests involved one-minute increments in inspired CO2, raising end-tidal PCO2 to 7.5βmmHg above baseline (38.5βΒ±β5.7βmmHg), whilst ventilation was constrained (10.7βΒ±β2.3βL/min). Patients rated air-hunger on a visual analogue scale (VAS). Patients had lower stimulusβresponse (2.8βΒ±β2 vs. 11βΒ±β4 %VAS/mmHg; pβ=β0.004), but similar threshold (40.5βΒ±β3.9 vs. 43.2βΒ±β5.1βmmHg), compared to healthy individuals. Volunteered comments implicated diminished affective valence. After surgical resection; sensitivity increased in one patient, decreased in another, and other was unable to tolerate the ventilatory limit before any increase in inspired CO2.We suggest that functional insular-cortex is essential to register breathlessness unpleasantness and could be targeted with neuromodulation in chronically-breathless patients. Neurological patients with insula involvement should be monitored for blunted breathlessness to inform clinical management.</p
Measuring dyspnoea: new multidimensional instruments to match our 21st century understanding
Image_2_Blunted perception of breathlessness in three cases of low grade insular-glioma.JPEG
Better understanding of breathlessness perception addresses an unmet clinical need for more effective treatments for intractable dyspnoea, a prevalent symptom of multiple medical conditions. The insular-cortex is predominantly activated in brain-imaging studies of dyspnoea, but its precise role remains unclear. We measured experimentally-induced hypercapnic air-hunger in three insular-glioma patients before and after surgical resection. Tests involved one-minute increments in inspired CO2, raising end-tidal PCO2 to 7.5βmmHg above baseline (38.5βΒ±β5.7βmmHg), whilst ventilation was constrained (10.7βΒ±β2.3βL/min). Patients rated air-hunger on a visual analogue scale (VAS). Patients had lower stimulusβresponse (2.8βΒ±β2 vs. 11βΒ±β4 %VAS/mmHg; pβ=β0.004), but similar threshold (40.5βΒ±β3.9 vs. 43.2βΒ±β5.1βmmHg), compared to healthy individuals. Volunteered comments implicated diminished affective valence. After surgical resection; sensitivity increased in one patient, decreased in another, and other was unable to tolerate the ventilatory limit before any increase in inspired CO2.We suggest that functional insular-cortex is essential to register breathlessness unpleasantness and could be targeted with neuromodulation in chronically-breathless patients. Neurological patients with insula involvement should be monitored for blunted breathlessness to inform clinical management.</p