RESUMEN
The olfactory bulb (OB) is the first relay station in the olfactory system. In the OB, mitral/tufted cells (M/Ts), which are the main output neurons, play important roles in the processing and representation of odor information. Recent studies focusing on the function of M/Ts at the single-cell level in awake behaving mice have demonstrated that odor-evoked firing of single M/Ts displays transient/long-term plasticity during learning. Here, we tested whether the neural activity of M/Ts and sniffing patterns are dependent on anticipation and reward in awake behaving mice. We used an odor discrimination task combined with in vivo electrophysiological recordings in awake, head-fixed mice, and found that, while learning induced plasticity of spikes and beta oscillations during odor sampling, we also found plasticity of spikes, beta oscillation, sniffing pattern, and coherence between sniffing and theta oscillations during the periods of anticipation and/or reward. These results indicate that the activity of M/Ts plays important roles not only in odor representation but also in salience-related events such as anticipation and reward.
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Objective To explore the significance of multiple microelectrode guided technique in determining the sensory?motor area of the sub?thalamic nucleus(STN)in deep brain stimulation(DBS)surgeries. Methods A total of 22 electrophysiological recording data of STNs recorded by multiple microelectrode was retrospectively analyzed ,while another 20 electrophysiological recording data of STNs recorded by a single micro?electrode was recruited as the control group. Results A total of 64 microelectrodes were used in 22 STNs guided by multiple electrophysiological recording electrodes. Sensory or motor activated potentials were recorded in 21 sides(95.5%),while regular discharge was recorded in one side. The average length of typical STN activity on the optimal channel of multiple electrophysiological recording electrodes was 5.58±0.53 mm,and the average length of sensory or motor activated potentials was 3.27±1.54 mm. In contrast,the average length of typical STN activity recorded by single microelectrode was 5.02±1.01 mm. However,sensory or motor activated potentials were recorded in 13 sides(65.0%)with the average length of 1.36±0.98 mm. Among the 22 STNs guided by multiple electrophysiological recording electrodes,the final implanted target was consistent with the initially selected anatomic target in 13 sides(coincidence rate,59.1%). In 9 sides,the electrophysiological target was inconsistent with the initially selected anatomic target. Conclusion STN DBS performed with multiple electrophysiological recording electrodes resulted in better outcomes of recording of the average length of typical STN activity or the average length of sensory or motor activated potentials of STN ,final confirmation of STN sensory motor area and determination of the optimal channel of implantation. Application of multiple electrophysiological recording electrodes provides a premise for the precise electrode placement in STN DBS surgeries.
RESUMEN
Awake craniotomy is a brain surgery performed on awake patients and is indicated for certain intracranial pathologies. These include procedures that require an awake patient for electrocorticographic mapping or precise electrophysiological recordings, resection of lesions located close to or in the motor and speech of the brain, or minor intracranial procedures that aim to avoid general anaesthesia for faster recovery and earlier discharge. This type of brain surgery is quite new and has only recently begun to be performed in a few neurosurgical centres in Malaysia. The success of the surgery requires exceptional teamwork from the neurosurgeon, neuroanaesthesiologist, and neurologist. The aim of this article is to briefly describe the history of awake craniotomy procedures at our institution.
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CraneotomíaRESUMEN
The intracranial blood vessels of the dura and the pia receive sensory afferent innervations from trigeminal nerve which has been believed to play a critical role in the mediation of vascular headache such as migraine. The purpose of this study was to discover the mechanism by which the interaction between trigeminal ganglion neurons and the function of cerebral blood vessels. Using electrophysiological recording, we studied the responses of trigeminal ganglion neurons to electrical stimulation of middle meningeal artery(MMA), superior sagittal sinus(SS) and transverse sinus(TS) in rats. Sumatriptan is a highly selective agonist for 5-HT1D receptor subtype which mediates vasoconstriction of cerebral blood vessels. We observed responses to electrical stimulation in trigeminal ganglion neurons and meningeal blood flow(MBF) after intravenous injection of sumatriptan. The results were as follows: 1) The presumed mean conduction velocities of the cells activated MMA, SS and TS by electrical stimulation were approximately 1.5, 2.9 and 2.9m/s, respectively. These were presumed to be nociceptive small myelinated or unmylinated sensory fibers. 2) The action potential discharges of trigeminal ganglion neurons on MMA, SS and TS in the experimental control groups were 671+/-39.49, 856+/-63.95 and 494+/-21.54microV, respectrely. The action potential discharges of sumatriptan groups on MMA, SS and TS(393+/-20.10, 562+/-32.26 and 262+/-18.94microV, respectively) were significantly decreased compared to that of the experimental control groups. 3) The mean MBF of normal control group was 63.29+/-7.54ml/100g/min. The mean MBF of the experimental control groups on MMA, SS and TS were 97.13+/-9.91, 104.28+/-12.54 and 91.82+/-6.41ml/100g/min, respectively(p<0.05). MBF of sumatriptan group before stimulation was significantly decreased(compared to normal: 37.17+/-4.76ml/100g /min vs 63.29+/-7.54ml/100g/min). The mean MBF of sumatriptan groups on MMA, SS and TS were 57.11+/-4.48, 66.56+/-6.23 and 56.07+/-5.00ml/100g/min, respectively. Compared to that of the experimental control groups, the MBF of the sumatriptan groups were significantly decreased. In conclusion, the activation of trigeminal sensory afferents by the electrical stimulation of the dural vessel may create vasodilatation and increase cerebral blood flow which may lead to vascular headaches via trigeminal ganglion to brain stem This pathway can be important for understanding the neural mechanism for the development of pharmacological and surgical approach to alleviate vascular headache.