Blockade of GABAA receptors in the interpositus nucleus modulates expression of conditioned excitation but not conditioned inhibition of the eyeblink response

Brian C Nolan; Daniel A Nicholson; John H Freeman Jr

doi:10.1007/BF02734250

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Blockade of GABAA receptors in the interpositus nucleus modulates expression of conditioned excitation but not conditioned inhibition of the eyeblink response

Journal article

Open access

Peer reviewed

Blockade of GABAA receptors in the interpositus nucleus modulates expression of conditioned excitation but not conditioned inhibition of the eyeblink response

Brian C Nolan, Daniel A Nicholson and John H Freeman Jr

Integrative physiological and behavioral science, Vol.37(4), pp.293-310

10/2002

DOI: 10.1007/BF02734250

PMCID: PMC1393457

PMID: 12645845

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https://www.ncbi.nlm.nih.gov/pmc/articles/1393457View

Open Access

Abstract

The cerebellum and related brainstem structures are essential for excitatory eyeblink conditioning. Recent evidence indicates that the cerebellar interpositus and lateral pontine nuclei may also play critical roles in conditioned inhibition (CI) of the eyeblink response. The current study examined the role of GABAergic inhibition of the interpositus nucleus in retention of CI. Male Long-Evans rats were implanted with a cannula positioned just above or in the anterior interpositus nucleus before training. The rats were trained with two different tones and a light as conditioned stimuli, and a periorbital shock as the unconditioned stimulus. CI training consisted of four phases: 1) excitatory conditioning (8 kHz tone paired with shock); 2) feature-negative discrimination (2 kHz tone paired with shock or 2 kHz tone concurrent with light); 3) summation test (8 kHz tone or 8 kHz tone concurrent with light); and 4) retardation test (light paired with shock). After reaching a criterion level of performance on the feature-negative discrimination (40% discrimination), 0.5 microl picrotoxin (a GABAA receptor antagonist) was infused at one of four concentrations, each concentration infused during separate test sessions. Picrotoxin transiently impaired conditioned responses during trials with the excitatory stimulus (tone) in a dose-dependent manner, but did not significantly impact responding to the inhibitory compound stimulus (tone-light). The results suggest that expression of conditioned inhibition of the eyeblink conditioned response does not require GABAergic inhibition of neurons in the anterior interpositus nucleus.

Cues

Blinking - drug effects

Brain Stem - anatomy & histology

Conditioning, Classical - drug effects

GABA-A Receptor Antagonists

Acoustic Stimulation

Rats, Long-Evans

Rats

Male

Brain Stem - physiology

Conditioning, Classical - physiology

Brain Stem - drug effects

Blinking - physiology

GABA Antagonists - pharmacology

Animals

Discrimination Learning - drug effects

Picrotoxin - pharmacology

Photic Stimulation

Electroshock

Details

Title: Subtitle: Blockade of GABAA receptors in the interpositus nucleus modulates expression of conditioned excitation but not conditioned inhibition of the eyeblink response
Creators: Brian C Nolan - Department of Psychology, University of Iowa, Iowa City 52242, USA
Daniel A Nicholson
John H Freeman Jr
Resource Type: Journal article
Publication Details: Integrative physiological and behavioral science, Vol.37(4), pp.293-310
DOI: 10.1007/BF02734250
PMID: 12645845
PMCID: PMC1393457
NLM abbreviation: Integr Physiol Behav Sci
ISSN: 1053-881X
eISSN: 2168-7846
Publisher: United States
Grant note: NS38890 / NINDS NIH HHS R01 NS038890 / NINDS NIH HHS R01 MH065483 / NIMH NIH HHS
Language: English
Date published: 10/2002
Academic Unit: Psychological and Brain Sciences; Iowa Neuroscience Institute
Record Identifier: 9984065862102771

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