Single Neurons in the Medial Prefrontal Cortex of the Rat Exhibit Tonic and Phasic Coding During Trace Fear Conditioning

• Published in: Behavioral neuroscience Vol. 119; no. 6; pp. 1496 - 1510
• Main Authors: Gilmartin, Marieke R, McEchron, Matthew D
• Format: Journal Article
• Language: English
• Published: United States American Psychological Association 01-12-2005
• Subjects: Acoustic Stimulation - methods; Action Potentials - physiology; Action Potentials - radiation effects; Analysis of Variance; Animal; Animal behavior; Animal Learning; Animals; Avoidance Learning - physiology; Behavior, Animal; Brain; Brain Mapping; Classical Conditioning; Conditioned Stimulus; Conditioning, Classical - physiology; Fear; Fear & phobias; Female; Male; Medial Prefrontal Cortex; Neurology; Neurons; Neurons - physiology; Prefrontal Cortex; Prefrontal Cortex - cytology; Rats; Rats, Inbred F344; Rats, Sprague-Dawley; Reaction Time - physiology; Reaction Time - radiation effects; Retention (Psychology); Rodents; Time Factors; Unconditioned Stimulus; heart rate; temporal bridging; infralimbic; classical conditioning; prelimbic
• ISSN: 0735-7044; 1939-0084
• DOI: 10.1037/0735-7044.119.6.1496

Trace fear conditioning is a learning task that requires the association of an auditory conditioned stimulus (CS) and a shock unconditioned stimulus (US) that are separated by a 20-s trace interval. Single neuron activity was recorded from the prelimbic and infralimbic areas of the medial prefrontal cortex in rats during trace fear conditioning or nonassociative unpaired training. Prelimbic neurons showed learning-related increases in activity to the CS and US, whereas infralimbic neurons showed learning-related decreases in activity to these stimuli. A subset of prelimbic neurons exhibited sustained increases in activity during the trace interval. These sustained prelimbic responses may provide a bridging code that allows for overlapping representations of CS and US information within the trace fear conditioning circuit.