The Journal of Neuroscience, December 15, 2004, 24(50):11356-11367; doi:10.1523/JNEUROSCI.3907-04.2004
Previous Article | Next Article 
Behavioral/Systems/Cognitive
Inferior Olive Oscillations Gate Transmission of Motor Cortical Activity to the Cerebellum
Sarah P. Marshall and
Eric J. Lang
Department of Physiology and Neuroscience, New York University, School of Medicine, New York, New York 10016
Inferior olivary (IO) neurons display spontaneous oscillatory activity, yet the importance of these oscillations for shaping the responses of this system to its afferents is uncertain. We used multiple electrode recording of crus 2a Purkinje cell complex spikes (CSs) in ketamine-xylazine-anesthetized rats to investigate olivocerebellar responses to activation of motor cortico-olivary pathways. Trains of electrical stimuli were applied to the motor cortex at frequencies between 4 and 30 Hz. Various frequency-response curves were observed, with the most common types being unimodal with a maximum at 9.5 ± 2.3 Hz and bimodal with peaks at 8.9 ± 1.0 and 15.1 ± 1.3 Hz. To determine whether IO oscillatory properties underlie the resonance peaks in the frequency-response curves, apamin and charybdotoxin were injected into the IO. These toxins, which weaken and enhance spontaneous IO oscillations, respectively, had corresponding effects on the sharpness of resonance peaks. Next, the variation of CS entrainment patterns with frequency was investigated to characterize the nature of the IO oscillator. Low-frequency (4 Hz) stimulation was relatively ineffective in entraining CS activity. Between 4 and 30 Hz, two predominant entrainment patterns emerged. For low-frequency (4-6 Hz) and high-frequency (17-30 Hz) ranges, a 1:2 entrainment dominated, whereas in the intermediate range (6-17 Hz), 1:1 entrainment was most prevalent. These results indicate that IO neurons respond as nonlinear oscillators to afferent signals.
Key words: oscillator; complex spike; Purkinje cell; cerebellum; motor cortex; gating
Received Jan 20, 2004;
revised November 8, 2004;
accepted November 8, 2004.
This article has been cited by other articles:

|
 |

|
 |
 
E. J. Lang, I. Sugihara, and R. Llinas
Olivocerebellar modulation of motor cortex ability to generate vibrissal movements in rat
J. Physiol.,
February 15, 2006;
571(1):
101 - 120.
[Abstract]
[Full Text]
[PDF]
|
 |
|