Automated assessment of conditioning parameters for context and cued fear in mice.
1. Learn Mem. 2002 Mar-Apr;9(2):89-96.
Automated assessment of conditioning parameters for context and cued fear in
mice.
Contarino A(1), Baca L, Kennelly A, Gold LH.
Author information:
(1)The Scripps Research Institute, Department of Neuropharmacology, La Jolla,
California 92037, USA.
A behavioral technique often used to evaluate the cognitive performance of rats
and mice is the fear conditioning paradigm. During conditioned fear experiments,
freezing responses shown by rodents after exposure to environmental stimuli
previously paired to an aversive experience provide a behavioral index of the
animal’s associative abilities. The present study examined the ability of a
computer-controlled automated Freeze Monitor system for recording immobility
behavior in mice. The sensitivity of the automated procedure to detect group
differences caused by the application of various training protocols was also
evaluated. Statistical analyses revealed significant positive correlations
between immobility scores obtained with the automated apparatus and hand-scored
data collected by a continuous or a time-sampling method. Behavioral patterns
recorded by the computerized system were very similar to those obtained by the
hand-scoring methods adopted. In particular, during context testing, exposure to
environmental stimuli previously paired with a mild foot shock (unconditioned
stimulus [US]) evoked increased immobility behavior in mice conditioned with the
US compared with levels of immobility displayed by mice previously confined to
the same contextual stimuli without receiving the US. Moreover, although during
conditioned stimulus (CS) testing, mice previously exposed to the US displayed
high levels of immobility when confined to environmental cues much different from
those paired with the US (contextual fear generalization), both hand-scored and
automated results revealed the effect of CS-US pairing (increased immobility)
only in mice trained to associate the two stimuli (paired group) but not in mice
exposed to both CS and US separated by a 40-sec time interval (unpaired group) or
in mice receiving only the US (US group) during conditioning sessions. Overall,
the results show associative conditioning measured in an automated apparatus and
highlight the utility of obtaining both latency as well as beam interruption
parameters.
DOI: 10.1101/lm.43002
PMCID: PMC155931
PMID: 11992019 [Indexed for MEDLINE]