scholarly journals Learning-related neuronal activity in the ventral lateral geniculate nucleus during associative cerebellar learning

2014 ◽  
Vol 112 (9) ◽  
pp. 2234-2250 ◽  
Author(s):  
Alireza Kashef ◽  
Matthew M. Campolattaro ◽  
John H. Freeman
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Neuronal Activity ◽  
Sensory Input ◽  
Eyeblink Conditioning ◽  
Training Sequence ◽  
Single Unit Activity ◽  
Behavioral Training ◽  
Eyelid Closure ◽  
Lateral Geniculate

During delay eyeblink conditioning, rats learn to produce an eyelid-closure conditioned response (CR) to a conditioned stimulus (CS), such as a light, which precedes and coterminates with an unconditioned stimulus (US). Previous studies have suggested that the ventral lateral geniculate nucleus (LGNv) might play an important role in visual eyeblink conditioning by supplying visual sensory input to the pontine nuclei (PN) and also receiving feedback from the cerebellum. No prior study has investigated LGNv neuronal activity during eyeblink conditioning. The present study used multiple tetrodes to monitor single-unit activity in the rat LGNv during pre-exposure (CS only), unpaired CS/US, and paired CS-US training conditions. This behavioral-training sequence was used to investigate nonassociative- and associative-driven neuronal activity in the LGNv during training. LGNv neuronal activity habituated during unpaired training and then recovered from habituation during subsequent paired training, which may indicate that the LGNv plays a role in attention to the CS. The amplitude of LGNv neuronal activity correlated with CR production during paired but not unpaired CS/US training. Cerebellar feedback to the LGNv may play a role in modulating LGNv activity and attention to the CS during paired training. Based on the present findings, we hypothesize that the role of LGNv in visual eyeblink conditioning goes beyond simply routing visual CS information to the PN and involves modulation of attention.

Role of intrathalamic inhibition on the spatial frequency tuning of neurons in the lateral geniculate nucleus of the cat

2009 ◽  
Vol 65 ◽  
pp. S106
Author(s):  
Akihiro Kimura ◽  
Satoshi Shimegi ◽  
Shin-ichiro Hara ◽  
Masahiro Okamoto ◽  
Hiromichi Sato
Keyword(s):  
Spatial Frequency ◽  
Lateral Geniculate Nucleus ◽  
Frequency Tuning ◽  
Spatial Frequency Tuning ◽  
Lateral Geniculate

Effects of ouabain on neuronal thermosensitivity in hypothalamic tissue slices

1989 ◽  
Vol 257 (1) ◽  
pp. R21-R28
Author(s):  
M. C. Curras ◽  
J. A. Boulant
Keyword(s):  
Firing Rate ◽  
Neuronal Activity ◽  
Unit Activity ◽  
Single Unit ◽  
Single Unit Activity ◽  
Tissue Slices ◽  
Temperature Changes ◽  
Cold Sensitive ◽  
Hypothalamic Tissue

To determine the role of the electrogenic Na+-K+ pump in neuronal thermosensitivity, single-unit activity was recorded in rat hypothalamic tissue slices before, during, and after perfusions containing 10(-5) or 10(-6) M ouabain, a specific pump inhibitor. Most neurons were recorded in the preoptic-anterior hypothalamus. Some neurons were also tested with high magnesium-low calcium perfusions to determine ouabain's effects on neuronal activity during synaptic blockade. When the neurons were characterized according to thermosensitivity, 24% were warm sensitive, 8% were cold sensitive, and 68% were temperature insensitive. Ouabain increased the firing rate of 60% of all neurons. Ouabain did not reduce the thermosensitivity of cold-sensitive and warm-sensitive neurons; however, temperature-insensitive neurons became more warm sensitive during ouabain perfusion. This increase in warm sensitivity did not occur with ouabain plus high Mg2+-low Ca2+ perfusion, suggesting that Ca2+ is important in this response. These results indicate that the Na-K pump is not responsible for the thermosensitivity of hypothalamic cold-sensitive or warm-sensitive neurons; however, this pump may be actively employed by many neurons that remain insensitive to temperature changes.

A quantitative electron-microscopical study of the postnatal development of the lateral geniculate nucleus in normal kittens and in kittens with eyelid suture

1980 ◽  
Vol 210 (1179) ◽  
pp. 211-234 ◽  
Keyword(s):  
Electron Microscope ◽  
Postnatal Development ◽  
Lateral Geniculate Nucleus ◽  
Normal Development ◽  
Microscopical Study ◽  
Electron Microscopical Study ◽  
Synaptic Organization ◽  
Eyelid Closure ◽  
Lateral Geniculate ◽  
Electron Microscopical

The postnatal development of the lateral geniculate nucleus has been studied quantitatively with the electron microscope in normal kittens and in kittens with eyelid closure. The maturation of the synaptic organization of glomeruli in the normal kitten occurs during the period of susceptibility to eyelid closure and is due predominantly to a logarithmic increase in the number of symmetric presynaptic dendritic synapses. In contrast, the pro­portion of symmetric synapses falls with age in non-glomerular neuropil over this period. Unilateral and bilateral eyelid suture do not interfere with the normal development of the lateral geniculate nucleus.

scholarly journals Assessing the role of inferior olivary sensory signaling in the expression of conditioned eyeblinks using a combined glutamate/GABAA receptor antagonist protocol

2012 ◽  
Vol 107 (1) ◽  
pp. 273-282 ◽  
Author(s):  
Svitlana Zbarska ◽  
Vlastislav Bracha
Keyword(s):  
Receptor Antagonist ◽  
Eyeblink Conditioning ◽  
Behavioral Outcomes ◽  
Training Session ◽  
Eyelid Closure ◽  
Glutamate Antagonist ◽  
Learning Hypothesis ◽  
Gabaa Receptor Antagonist ◽  
Inferior Olivary

The inferior olive (IO) is a major component of the eyeblink conditioning neural network. The cerebellar learning hypothesis assumes that the IO supplies the cerebellum with a “teaching” unconditioned stimulus input required for the acquisition of the conditioned response (CR) and predicts that inactivating this input leads to the extinction of CRs. Previous tests of this prediction attempted to block the teaching input by blocking glutamatergic sensory inputs in the IO. These tests were inconclusive because blocking glutamate neurotransmission in the IO produces a nonspecific tonic malfunction of cerebellar circuits. The purpose of the present experiment was to examine whether the behavioral outcomes of blocking glutamate receptors in the IO could be counterbalanced by reducing GABA-mediated inhibition in the IO. We found that injecting the IO with the glutamate antagonist γ-d-glutamylglycine (DGG) abolished previously learned CRs, whereas injecting the GABAA receptor antagonist gabazine at the same site did not affect CR incidence but shortened CR latencies and produced tonic eyelid closure. To test whether the glutamate antagonist-induced behavioral deficit could be offset by elevating IO activity with GABAA antagonists, rabbits were first injected with DGG and then with gabazine in the same training session. While DGG abolished CRs, follow-up injections of gabazine accelerated their recovery. These findings suggest that the level of IO neuronal activity is critical for the performance of CRs, and that combined pharmacological approaches that maintain spontaneous activity at near normal levels hold tremendous potential for unveiling the role of IO-mediated signals in eyeblink conditioning.

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