Ablation of the inferior olive prevents H-reflex down-conditioning in rats

We evaluated the role of the inferior olive (IO) in acquisition of the spinal cord plasticity that underlies H-reflex down-conditioning, a simple motor skill. The IO was chemically ablated before a 50-day exposure to an operant conditioning protocol that rewarded a smaller soleus H-reflex. In normal rats, down-conditioning succeeds (i.e., H-reflex size decreases at least 20%) in 80% of animals. Down-conditioning failed in every IO-ablated rat ( P < 0.001 vs. normal rats). IO ablation itself had no long-term effect on H-reflex size. These results indicate that the IO is essential for acquisition of a down-conditioned H-reflex. With previous data, they support the hypothesis that IO and cortical inputs to cerebellum enable the cerebellum to guide sensorimotor cortex plasticity that produces and maintains the spinal cord plasticity that underlies the down-conditioned H-reflex. They help to further define H-reflex conditioning as a model for understanding motor learning and as a new approach to enhancing functional recovery after trauma or disease.

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The inferior olive is essential for long-term maintenance of a simple motor skill

Journal of Neurophysiology ◽

10.1152/jn.00085.2016 ◽

2016 ◽

Vol 116 (4) ◽

pp. 1946-1955 ◽

Cited By ~ 4

Author(s):

Xiang Yang Chen ◽

Yu Wang ◽

Yi Chen ◽

Lu Chen ◽

Jonathan R. Wolpaw

Keyword(s):

Motor Skill ◽

Inferior Olive ◽

Neuronal Loss ◽

H Reflex ◽

Initial Value ◽

Simple Motor ◽

Cerebellar Plasticity ◽

Cortical Inputs ◽

Term Maintenance

The inferior olive (IO) is essential for operant down-conditioning of the rat soleus H-reflex, a simple motor skill. To evaluate the role of the IO in long-term maintenance of this skill, the H-reflex was down-conditioned over 50 days, the IO was chemically ablated, and down-conditioning continued for up to 102 more days. H-reflex size just before IO ablation averaged 62(±2 SE)% of its initial value ( P < 0.001 vs. initial). After IO ablation, H-reflex size rose to 75–80% over ∼10 days, remained there for ∼30 days, rose over 10 days to above its initial value, and averaged 140(±14)% for the final 10 days of study ( P < 0.01 vs. initial). This two-stage loss of down-conditioning maintenance correlated with IO neuronal loss ( r = 0.75, P < 0.01) and was similar to the loss of down-conditioning that follows ablation of the cerebellar output nuclei dentate and interpositus. In control (i.e., unconditioned) rats, IO ablation has no long-term effect on H-reflex size. These results indicate that the IO is essential for long-term maintenance of a down-conditioned H-reflex. With previous data, they support the hypothesis that IO and cortical inputs to cerebellum combine to produce cerebellar plasticity that produces sensorimotor cortex plasticity that produces spinal cord plasticity that produces the smaller H-reflex. H-reflex down-conditioning appears to depend on a hierarchy of plasticity that may be guided by the IO and begin in the cerebellum. Similar hierarchies may underlie other motor learning.

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Long-term effect of bilateral ovariectomy on endothelial function in aortic rings of spontaneously hypertensive rats: role of nitric oxide

Gynecological Endocrinology ◽

10.1080/713602798 ◽

2001 ◽

Vol 15 (2) ◽

pp. 158-164 ◽

Cited By ~ 2

Author(s):

A. Riveiro ◽

A. Mosquera ◽

C. Calvo ◽

M. Alonso ◽

M. Macía ◽

...

Keyword(s):

Nitric Oxide ◽

Endothelial Function ◽

Spontaneously Hypertensive Rats ◽

Term Effect ◽

Hypertensive Rats ◽

Spontaneously Hypertensive ◽

Bilateral Ovariectomy ◽

Long Term Effect

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The Effect of Chronic Methamphetamine Treatment on Schizophrenia Endophenotypes in Heterozygous Reelin Mice: Implications for Schizophrenia

Biomolecules ◽

10.3390/biom10060940 ◽

2020 ◽

Vol 10 (6) ◽

pp. 940

Author(s):

Camilla Hume ◽

Shelley Massey ◽

Maarten van den Buuse

Keyword(s):

Locomotor Activity ◽

Social Behaviour ◽

Social Preference ◽

Term Effect ◽

Spontaneous Locomotor Activity ◽

Brain Dopamine ◽

Locomotor Hyperactivity ◽

Long Term Effect

Reelin has been implicated in the development of schizophrenia but the mechanisms involved in this interaction remain unclear. Chronic methamphetamine (Meth) use may cause dopaminergic sensitisation and psychosis and has been proposed to affect brain dopamine systems similarly to changes seen in schizophrenia. We compared the long-term effect of chronic Meth treatment between heterozygous reelin mice (HRM) and wildtype controls (WT) with the aim of better understanding the role of reelin in schizophrenia. Meth pretreatment induced sensitisation to the effect of an acute Meth challenge on locomotor activity, but it had no effect on baseline PPI or sociability and social preference. In all behavioural models, HRM did not significantly differ from WT at baseline, except spontaneous exploratory locomotor activity which was higher in HRM than WT, and sociability which was enhanced in HRM. Locomotor hyperactivity sensitisation was not significantly different between HRM and WT. Chronic Meth treatment reduced spontaneous locomotor activity to the level of WT. No deficits in PPI or social behaviour were induced by chronic Meth pretreatment in either strain. In conclusion, these data do not support a role of reelin in schizophrenia, at least not in HRM and in the methamphetamine sensitisation model.

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