pathways to the amygdala: Effects of lesions of the posterior intralaminar thalamus on foot-shock-induced c-Fos expression in the subdivisions of the later amygdala.
Control pups learned to avoid the unconditioned stimulus
by running into the other compartment during the unconditioned stimulus
on almost all experimental days and recorded a high success rate of avoidance response (Fig.
Four research assistants were involved, one of whom had volunteered to be videotaped and exposed to an eliciting stimulus; we initially needed to determine an effective unconditioned stimulus
(US) with which to elicit the startle reflex, with the designated volunteer out of the room.
(1999) Renewal to the signal value of an unconditioned stimulus
. Learning and Motivation, 30, 15-34.
However, reflex relations may be temporarily weakened by repeated presentation of the unconditioned stimulus
. Such a process is known as habituation.
2002)in which a neutral conditioned stimulus is paired with a fear-inducing unconditioned stimulus
, so that animals come to exhibit a conditioned fear response to the conditioned stimulus.
consolidated memory; CR, conditioned response; CS, conditioned stimulus; LLD, long-lasting depolarization; LTM, long-term memory; NSW, natural seawater; PKC, protein kinase C; Ro-32, Ro-32-0432, or bisindolylmaleimide-XI; RTE, random training event; STM, short-term memory; TE, training event; UCR, unconditioned response; US, unconditioned stimulus
In classical experiments, one must remove an unconditioned stimulus
from time to time in order to recognize the conditioned response.
For each trial, a 5-sec conditioned stimulus (CS), consisting of a buzzer and light, was followed by a 5-sec unconditioned stimulus
(UCS), which included a scrambled shock of 0.2 mA delivered through the floor grid.
An unconditioned stimulus
elicits an unlearned response, while a conditioned stimulus paired with the unconditioned
One set was tested on the shuttle-box and the number of avoidances to unconditioned stimulus
(US) was noted.
conditioned stimuli for shock (unconditioned stimulus
) result in appropriate conditioned responses (CRs) of avoidance and opiate release (Drugan & Maier, 1983).
Pavlovian conditioning pairs a neutral stimulus, (CS) with another, unconditioned stimulus
(UCS) that has some beneficial or harmful effect which produces a response (UCR).
The bell sound was the condition stimulus; the smell and/or the sight of food was the unconditioned stimulus
. Pairing the conditioned stimulus (bell sound) with the unconditioned stimulus
(smell or sight of food) eight or nine times brought about salivation to the sound of the tuning forks.
Several investigators now suggest that imprinting is a form of associative learning Hollis et al., 1991), perhaps a variant of Pavlovian conditioning (Bolhuis et al., 1990; Suboski, 1990), in which the imprinting object provides both the conditioned and biologically significant unconditioned stimulus
. Consider a young female zebra finch (Taenicopygia guttata) that has to learn to recognize what adult males look like, and does so by imprinting on her father Immelmann, 1972; Clayton, 1989).