Classical Conditioning Flashcards

Study Notes

Air Puff Conditioning

Air puff to the cornea serves as an unconditioned stimulus, triggering an eye blink response in humans and nictitating membrane response in rabbits.
Sensory information from the cornea follows the trigeminal nerve to the cranial motor nucleus, leading to eyelid closure.
Reflex pathways remain constant, allowing for the conditioned stimulus to evoke an eyeblink response.

Purkinje Cells Function

Purkinje cells are crucial for neural plasticity involved in conditioning processes.

Cerebellum Access Mechanisms

Conditioned stimulus access to the cerebellum occurs via mossy fibers interacting with granule cells, activating parallel fiber systems, allowing communication with Purkinje cells.
The reflex pathway remains accessible for the unconditioned stimulus but activates only after conditioning.

Reflex Pathway Activation

After learning, the conditioned stimulus gains access to the reflex response pathway.

Inhibition Before Conditioning

Prior to conditioning, the conditioned stimulus (tone) can only partially activate interpositus neurons due to strong GABAergic inhibition from Purkinje cells.
The unconditioned stimulus (air puff) generates the eye blink response by bypassing this inhibition.

Timing of Stimulus Pairing

Learning necessitates that the conditioned stimulus must be paired with the unconditioned stimulus within a critical time frame of approximately 200 milliseconds, targeting Purkinje cell dendrites.

Anatomical Pathways

The conditioned stimulus pathway involves the Pontine nucleus, mossy fibers, granule cells, and Purkinje cells.
The unconditioned stimulus pathway includes the inferior olive and climbing fibers leading to the eye blink response.
Purkinje cells release GABA and inhibit Nucleus Interpositus (Int) activity while being postsynaptic to climbing fibers.

Conditioning Process

The conditioned stimulus is represented by a tone.
The unconditioned stimulus is identified as the air puff.

Purkinje Cells Overview

Purkinje cells serve as the exclusive inhibitory output neurons of the cerebellum, projecting to cerebellar nuclei and influencing motor systems.

Long-Term Depression Mechanism

Convergence of conditioned (mossy fibers) and unconditioned (climbing fibers) stimuli leads to long-term depression (LTD) of synapses:
- Upon activation, glutamate released at Purkinje dendrites causes calcium release from internal stores.
- Calcium inactivation of glutamate receptors occurs slowly, making them temporarily susceptible.
- If the unconditioned stimulus is applied timely, it can lead to internalization of glutamate receptors, resulting in LTD. Delayed application results in loss of susceptibility, preventing LTD.

Eye Blink Conditioning Circuit Dynamics

The circuit begins with the tone engaging auditory pathways, leading to granule and Purkinje cell activation, but inhibition prevents conditioned responses until learning occurs.
Ultimately, successful timing of tone followed by air puff leads to conditioned eyeblink responses.

Description

This quiz covers key concepts related to classical conditioning using the air puff eye model. You will learn about unconditioned stimuli, reflex responses, and the physiological mechanisms involved in eye blinks. Perfect for students studying psychology and behavioral responses.