On the use of isofluorane as an anaesthetic for visual neurophysiology

Tigwell, D.A.; Sauter, Jörg J.

doi:10.1007/bf02259146

Cited by 11 publications

(8 citation statements)

References 35 publications

(21 reference statements)

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“…Halothane suppressed the later components of firing more than the initial component -both within the time frame of our early response. In contrast, Tigwell and Sauter 14 found reliable neuron responses in monkey striate cortex at isoflurane concentrations 0.5 to 0.9 %. Villeneuve and Casanova 45 compared the concentration-dependent effects of halothane/nitrous oxide and isoflurane/nitrous oxide on cat striate cortex neuron responses and found that isoflurane produced a greater suppression than did halothane.…”

Section: Discussionmentioning

confidence: 81%

“…Likewise, Chapin et al 5 found that 0.75% halothane depressed the long-latency (300 ms) excitatory firing of rat somatosensory cortical neurons following cutaneous stimulation of the forepaw while short-latency responses within 50 ms were little affected. At variance with these findings, Tigwell and Sauter 14 reported that the sustained response up to 300 ms of monkey striate cortex neurons was preserved under anesthesia with 0.5 – 0.9% isoflurane + 73% nitrous oxide. While the exact reason for this discrepancy is unclear, it may have been due to the presentation of a prolonged visual stimulus as opposed to flash.…”

Section: Discussionmentioning

confidence: 95%

“…Although numerous investigations have been devoted to the subject, the effect of inhalational agents on the responsiveness of central nervous system neurons to sensory stimuli has been controversial 1–14. Volatile anesthetics differ in their potency and regional effects on central nervous system neurons 15 and it is difficult to extrapolate the effect of one agent to that of another.…”

Section: Introductionmentioning

confidence: 99%

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Desflurane Selectively Suppresses Long-latency Cortical Neuronal Response to Flash in the Rat

Hudetz¹,

Vizuete

Imas

2009

Anesthesiology

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Background The effect of inhalational anesthetics on sensory-evoked unit activity in the cerebral cortex has been controversial. Desflurane has desirable properties for in vivo neurophysiologic studies but its effect on cortical neuronal activity and neuronal responsiveness is not known. We studied the effect of desflurane on resting and visual evoked unit activity in rat visual cortex in vivo. Methods Desflurane was administered to adult albino rats at steady-state concentrations at 2%, 4%, 6% and 8%. Flashes from a light emitting diode were delivered to the left eye at 5-second intervals. Extracellular unit activity within the right visual cortex was recorded using a 49-electrode array. Individual units were identified using principal components analysis. Results At 2% desflurane 578 active units were found. Of these, 75% increased their firing rate in response to flash. Most responses contained early (0–100ms) and late (150–1000ms) components. With increasing desflurane concentration, the number of units active at baseline decreased (−13%), the number of early responding units increased (+31%), and number of late responding units decreased (−15%). Simultaneously, baseline firing rate decreased (−77%), the early response was unchanged, and the late response decreased (−60%). Conclusions The results indicate that visual cortex neurons remain responsive to flash stimulation under desflurane anesthesia but the long-latency component of their response is attenuated in a concentration-dependent manner. Suppression of the long-latency response may be related to a loss of cortico-cortical feedback and loss of consciousness.

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Section: Discussionmentioning

confidence: 81%

Section: Discussionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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Desflurane Selectively Suppresses Long-latency Cortical Neuronal Response to Flash in the Rat

Hudetz¹,

Vizuete

Imas

2009

Anesthesiology

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“…The effect of anesthetic agents on spontaneous and stimulus-evoked neuronal activity has been studied extensively in vitro and in vivo 8-13,15,29,30 . Much less is known about the interaction of neurons in an intact network as influenced by anesthesia in vivo .…”

Section: Discussionmentioning

confidence: 99%

Critical Changes in Cortical Neuronal Interactions in Anesthetized and Awake Rats

et al. 2015

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Background Neuronal interactions are fundamental for information processing, cognition and consciousness. Anesthetics reduce spontaneous cortical activity; however, neuronal reactivity to sensory stimuli is often preserved or augmented. How sensory stimulus-related neuronal interactions change under anesthesia has not been elucidated. Here we investigated visual stimulus-related cortical neuronal interactions during stepwise emergence from desflurane anesthesia. Methods Parallel spike trains were recorded with 64-contact extracellular microelectrode arrays from the primary visual cortex of chronically instrumented, unrestrained rats (N=6) at 8%, 6%, 4%, 2% desflurane anesthesia and wakefulness. Light flashes were delivered to the retina by transcranial illumination at 5-15s randomized intervals. Information theoretical indices, integration and interaction complexity, were calculated from the probability distribution of coincident spike patterns and used to quantify neuronal interactions before and after flash stimulation. Results Integration and complexity showed significant negative associations with desflurane concentration (N=60). Flash stimulation increased integration and complexity at all anesthetic levels (N=60); the effect on complexity was reduced in wakefulness. During stepwise withdrawal of desflurane, the largest increase in integration (74%) and post-stimulus complexity (35%) occurred prior to reaching 4% desflurane concentration – a level associated with the recovery of consciousness according to the rats' righting reflex. Conclusions Neuronal interactions in the cerebral cortex are augmented during emergence from anesthesia. Visual flash stimuli enhance neuronal interactions in both wakefulness and anesthesia; the increase in interaction complexity is attenuated as post-stimulus complexity reaches plateau. The critical changes in cortical neuronal interactions occur during transition to consciousness.

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“…and xylazine (0.5-1.0 mg/kg, I.M. ), with supplementary doses given as needed to maintain surgical levels of anesthesia (White et al, 1982), or with approximately 2% isoflurane as an inhalation anesthetic (see Tigwell and Sauter, 1992). Under aseptic conditions, portions of dorsolateral visual cortex were exposed along the lunate and inferior occipital sulci.…”

mentioning

confidence: 99%

Topographic patterns of V2 cortical connections in macaque monkeys

Stepniewska

Kaas

1996

J. Comp. Neurol.

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Patterns of connections of dorsal and ventral portions of the second visual area (V2) were used to evaluate and extend current theories of cortical organization and processing streams in macaque monkeys. Injections of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) and up to four different fluorochromes in V2 labeled neurons and terminations in V2 and in 1) caudal (DLc) and rostral (DLr) subdivisions of dorsolateral cortex between V2 and the middle temporal area (MT); 2) regions we define as dorsomedial (DM) and dorsointermediate (DI) areas; 3) MT, medial superior temporal area (MST), and fundal superior temporal area (FST); 4) the dorsal part of inferior temporal (TEO) cortex; and 5) two locations in posterior parietal cortex. The largest extrastriate connection zone was DLc, which occupied the caudal one-third to one-half of the fourth visual area (V4) region of other proposals. Based on the connection pattern, foveal vision in DLc is represented adjacent to foveal vision in V2, with the lower quadrant represented dorsally and the upper quadrant ventrally, as in V2, but within a much less extensive region of cortex. The sparser connections of DLr formed a more compressed but parallel visuotopic pattern. A third visuotopic pattern of connections was located in a moderately myelinated region of cortex just rostral to dorsomedial V2. Whereas the region would include parts of dorsal visual area 3 (V3), V3a, and possibly other areas of other proposals, we interpret the connection pattern as reflecting a dorsomedial visual area, DM, with foveal vision represented caudolaterally and other parts of the lower and upper quadrants represented more medially and rostrally. A fourth pattern of label in dorsointermediate cortex suggested the location and organization of another visual area (DI). Most of a fifth connection pattern with MT was congruent with the known visuotopic organization of MT area, but visuotopically mismatched foci of connections were observed as well. Sparser foci of label in MST suggested a rostrodorsal representation of foveal vision, with paracentral vision represented more caudally. Separate dorsal and ventral foci of label in FST were consistent with previous evidence for dorsal (FSTd) and ventral (FSTv) visual areas. Finally, connections with TEO and posterior parietal cortex were sparse. Our results suggest that much of visual cortex organization is similar in New and Old World monkeys.

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On the use of isofluorane as an anaesthetic for visual neurophysiology

Cited by 11 publications

References 35 publications

Desflurane Selectively Suppresses Long-latency Cortical Neuronal Response to Flash in the Rat

Desflurane Selectively Suppresses Long-latency Cortical Neuronal Response to Flash in the Rat

Critical Changes in Cortical Neuronal Interactions in Anesthetized and Awake Rats

Topographic patterns of V2 cortical connections in macaque monkeys

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