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Per Brodal

Publications and source records attributed to Per Brodal.

7 recordsLinked to original sources
PubMed2005

[The neurobiology of pain].

The nociceptive system enables us to respond in time to external threats that otherwise would produce tissue damage. By monitoring tissue composition the system also contributes to bodily homeostasis. Nociceptors signal mechanical stress, extreme temperatures, cell injury and inflammation. Powerful modulation of nociceptive signals occurs in the spinal dorsal horn, so that their further transmission to the brain can be enhanced or inhibited. A vast array of transmitters and receptors are responsible for complex synaptic interactions in the dorsal horn. Synaptic plasticity alters neuronal excitability for hours to months (years?), contributing to hyperalgesia and chronic pain. Descending monoaminergic connections from the brain stem can inhibit or facilitate the signal transmission from nociceptors. These systems are partly controlled by ascending signals from the dorsal horn, partly by descending connections from amygdala, hypothalamus and the cerebral cortex. The latter are thought to contribute to context-dependent pain modulation. The subjective experience of pain correlates with increased activity in a cortical network including the insula, the cingulate gyrus and some other areas. The activity of the network is also positively correlated with expectation of pain, and negatively correlated with expectation of pain relief--independent of nociceptor stimulation.

Central Nervous System↗
PubMed2004

A novel infraclavicular brachial plexus block: the lateral and sagittal technique, developed by magnetic resonance imaging studies.

UNLABELLED: A new infraclavicular brachial plexus block method has the patient supine with an adducted arm. The target is any of the three cords behind the pectoralis minor muscle. The point of needle insertion is the intersection between the clavicle and the coracoid process. The needle is advanced 0 degrees -30 degrees posterior, always strictly in the sagittal plane next to the coracoid process while abutting the antero-inferior edge of the clavicle. We tested the new method using magnetic resonance imaging (MRI) in 20 adult volunteers, without inserting a needle. Combining 2 simulated needle directions by 15 degrees posterior and 0 degrees in the images of the volunteers, at least one cord in 19 of 20 volunteers was contacted. This occurred within a needle depth of 6.5 cm. In the sagittal plane of the method the shortest depth to the pleura among all volunteers was 7.5 cm. The MRI study indicates that the new infraclavicular technique may be efficient in reaching a cord of the brachial plexus, often not demanding more than two needle directions. The risk of pneumothorax should be minimal because the needle is inserted no deeper than 6.5 cm. However, this needs to be confirmed by a clinical study. IMPLICATIONS: A new infraclavicular brachial plexus block method was investigated using magnetic resonance imaging without inserting needles in the volunteers. The study suggests two needle directions for performance of the block and that the risk of lung injury should be minimal. Expectations need to be confirmed by a clinical study.

Adult↗
PubMed2002

Distribution of local anesthetic in axillary brachial plexus block: a clinical and magnetic resonance imaging study.

BACKGROUND: There is an unsettled discussion about whether the distribution of local anesthetic is free or inhibited when performing brachial plexus blocks. This is the first study to use magnetic resonance imaging (MRI) to help answer this question. METHODS: Thirteen patients received axillary block by a catheter-nerve stimulator technique. After locating the median nerve, a total dose of 50 ml local anesthetic was injected via the catheter in four divided doses of 1, 4, 15, and 30 ml. Results of sensory and motor testing were compared with the spread of local anesthetic as seen by MRI scans taken after each dose. The distribution of local anesthetic was described with reference to a 20-mm diameter circle around the artery. RESULTS: Thirty minutes after the last dose, only two patients demonstrated analgesia or anesthesia in the areas of the radial, median, and ulnar nerve. At that time, eight of the patients had incomplete spread of local anesthetic around the artery, as seen by MRI. Their blocks were significantly poorer than those of the five patients with complete filling of the circle, although incomplete blocks were also present in the latter group. CONCLUSION: This study demonstrated that MRI is useful in examining local anesthetic distribution in axillary blocks because it can show the correlation between MRI distribution pattern and clinical effect. The cross-sectional spread of fluid around the brachial-axillary artery was often incomplete-inhibited, and the clinical effect often inadequate.

Adult↗
PubMed1989

Demonstration of a Mamillo-Ponto-Cerebellar Pathway.

The pathway from the mamillary complex to the cerebellum via the pontine nuclei has been studied using several anterograde and retrograde tracing techniques in the cat. We have also compared the pontine terminal regions of fibres from the mamillary complex and from the cingulate gyrus. Implantations of crystalline horseradish peroxidase wheat germ agglutinin (HRP-WGA) in the mamillary complex and lesions of the cingulate gyrus were combined in the same animal with injections of HRP-WGA, rhodamine-B-isothiocyanate (RITC), and Fluoro-Gold in different parts of the cerebellar hemisphere. Fibres from both the mamillary complex and the cingulate gyrus terminate mainly within a transversely oriented, c-shaped band in the ipsilateral, rostral pontine nuclei. Within this band the terminal fields of fibres from the mamillary complex and the cingulate gyrus form a mosaic-like pattern of partly overlapping patches. Pontine regions receiving a mamillary input project mainly to the ventral paraflocculus, and to a lesser degree to the dorsal paraflocculus, but apparently not to the uvula or crus II. Judging from the literature it seems highly unlikely that other parts of the cerebellar hemispheres received projections from these pontine regions. Fibres from the ventral paraflocculus were shown to terminate in the parvicellular part of the lateral cerebellar nucleus only. The present findings would seem to imply that inputs from the mamillary complex and a related cortical region, the cingulate gyrus, are partly integrated, partly kept separate at the precerebellar level. This would ensure that small groups of cells in the rostral pontine nuclei receive a specific set of afferents. Conceivably, the information transmitted to the cerebellum by these groups of pontine cells might be related to functions of the mamillary complex, such as learning, motivation, and spatial memory.

Journal Article↗