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Adult neurogenesis occurs in primate sensorimotor cortex following cervical dorsal rhizotomy.

ABSTRACT: Adult neurogenesis remains controversial in the cerebral cortex. We have previously shown in monkeys and rats that reactive neurogenesis occurs in the spinal dorsal horn 6-8 weeks after a cervical dorsal rhizotomy. Here, in three monkeys with the same lesion, we asked whether it also occurs coincidentally in the corresponding primary somatosensory and motor cortex, where significant topographic and neuronal reorganization is known to occur. Monkeys (male Macaca fascicularis) were given 5-bromo-2-deoxyuridine (BrdU) injections 2-3 weeks after the rhizotomy, and were perfused 4-6 weeks later. Cells colabeled for BrdU and five different neuronal markers were observed within the primary somatosensory and motor cortex, and their distributions were compared bilaterally. Cells colabeled with BrdU and the astrocytic marker glial fibrillary acidic protein (GFAP) were also quantified for comparison. A significant number of BrdU/NeuN- and BrdU/calbindin-colabeled cells were observed in topographically reorganized cortex. Small numbers of BrdU/GFAP-colabeled cells were also consistently observed bilaterally, but these cells were never colabeled with any of the neuronal markers. Of the cells colabeled with BrdU and a neuronal marker, at least half had an inhibitory phenotype. However, excitatory pyramidal neurons were also identified with classic pyramidal morphology. Cortical neurogenesis was not observed in other cortical regions. It was also not observed in the primary sensorimotor, prefrontal, or posterior parietal cortex in an additional control monkey (male Macaca fascicularis) that had no surgical intervention. Our findings provide evidence for reactive endogenous cortical neurogenesis after a dorsal rhizotomy, which may play a role in functional recovery.

SUBMITTER: Vessal M

PROVIDER: S-EPMC2897730 | biostudies-literature | 2010 Jun

REPOSITORIES: biostudies-literature

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Adult neurogenesis occurs in primate sensorimotor cortex following cervical dorsal rhizotomy.

Vessal Mani M Darian-Smith Corinna C

The Journal of neuroscience : the official journal of the Society for Neuroscience 20100601 25

Adult neurogenesis remains controversial in the cerebral cortex. We have previously shown in monkeys and rats that reactive neurogenesis occurs in the spinal dorsal horn 6-8 weeks after a cervical dorsal rhizotomy. Here, in three monkeys with the same lesion, we asked whether it also occurs coincidentally in the corresponding primary somatosensory and motor cortex, where significant topographic and neuronal reorganization is known to occur. Monkeys (male Macaca fascicularis) were given 5-bromo-2 ...[more]

PMID: 20573907

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Project description:BackgroundSelective dorsal rhizotomy (SDR) is a neurosurgical procedure that reduces lower limb spasticity, performed in some children with spastic diplegic cerebral palsy. Effective pain management after SDR is essential for early rehabilitation. This study aimed to describe the anaesthetic and early pain management, pain and adverse events in children following SDR.MethodsThis was a retrospective cohort study. Participants were all children who underwent SDR at a single Australian tertiary hospital between 2010 and 2020. Electronic medical records of all children identified were reviewed. Data collected included demographic and clinical data (pain scores, key clinical outcomes, adverse events and side effects) and medications used during anaesthesia and postoperative recovery.Results22 children (n=8, 36% female) had SDR. The mean (SD) age at surgery was 6 years and 6 months (1 year and 4 months). Common intraoperative medications used were remifentanil (100%), ketamine (95%), paracetamol (91%) and sevoflurane (86%). Postoperatively, all children were prescribed opioid nurse-controlled analgesia (morphine, 36%; fentanyl, 36%; and oxycodone, 18%) and concomitant ketamine infusion. Opioid doses were maximal on the day after surgery. The mean (SD) daily average pain score (Wong-Baker FACES scale) on the day after surgery was 1.4 (0.9), decreasing to 1.0 (0.5) on postoperative day 6 (POD6). Children first attended the physiotherapy gym on median day 7 (POD8, range 7-8). Most children experienced mild side effects or adverse events that were managed conservatively. Common side effects included constipation (n=19), nausea and vomiting (n=18), and pruritus (n=14). No patient required return to theatre, ICU admission or prolonged inpatient stay.ConclusionsMost children achieve good pain management following SDR with opioid and ketamine infusions. Adverse events, while common, are typically mild and managed with medication or therapy. This information can be used as a baseline to improve postoperative care and to support families' understanding of SDR before surgery.

Project description:Classic in vitro studies have described spike-timing-dependent plasticity (STDP) at a synapse: the connection from neuron A to neuron B is strengthened (or weakened) when A fires before (or after) B within an optimal time window. Accordingly, more recent in vivo works have demonstrated behavioral effects consistent with an STDP mechanism; however, many relied on single-unit recordings. The ability to modify cortical connections becomes useful in the context of injury, when connectivity and associated behavior are compromised. To avoid the need for long-term, stable isolation of single units, one could control timed activation of two cortical sites with paired electrical stimulation. We tested the hypothesis that STDP could be induced via prolonged paired stimulation as quantified by cortical evoked potentials (EPs) in the sensorimotor cortex of awake, behaving monkeys. Paired simulation between two interconnected sites produced robust effects in EPs consistent with STDP, but only at 2/15 tested pairs. The stimulation protocol often produced increases in global network excitability or depression of the conditioned pair. Together, these results suggest that paired stimulation in vivo is a viable method to induce STDP between cortical populations, but that factors beyond activation timing must be considered to produce conditioning effects.SIGNIFICANCE STATEMENT Plasticity of neural connections is important for development, learning, memory, and recovery from injury. Cellular mechanisms underlying spike-timing-dependent plasticity have been studied extensively in vitro Recent in vivo work has demonstrated results consistent with the previously defined cellular mechanisms; however, the output measure in these studies was typically an indirect assessment of plasticity at the neural level. Here, we show direct plasticity in recordings of neuronal populations in awake, behaving nonhuman primates induced by paired electrical stimulation. In contrast to in vitro studies, we found that plastic effects were only produced between specific cortical areas. These findings suggest that similar mechanisms drive plasticity in vitro and in vivo, but that cortical architecture may contribute significantly to site-dependent effects.

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Adult neurogenesis occurs in primate sensorimotor cortex following cervical dorsal rhizotomy.

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Adult neurogenesis occurs in primate sensorimotor cortex following cervical dorsal rhizotomy.

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