Biomedical subjects

K Kirkpatrick-Steger

Publications and source records attributed to K Kirkpatrick-Steger.

4 recordsLinked to original sources

PubMed1996

The what and the where of the pigeon's processing of complex visual stimuli.

Eight pigeons were trained on a go-no go visual discrimination involving 1 S+ and 15 S- s. The 16 discriminative stimuli were black-and-white line drawings created by the factorial combination of 4 different geometric shapes (wedge, cylinder, cone, handle) in 4 different spatial locations (right, left, above, below) in relation to a common shape (cube). All of the pigeons readily learned this complex visual discrimination. Each bird's pecking behavior was controlled by both attributes of the line drawings, but somewhat stronger stimulus control was exerted by the location of the added component than by its shape. Across all 8 pigeons, there was an inverse relation between stimulus control by component shape and component location. These results document pigeons' joint processing of "what" and "where" information in visual discrimination learning.

Animals↗

PubMed1995

Pigeons show same-different conceptualization after training with complex visual stimuli.

Eight pigeons were first trained to peck 1 button in the presence of 16 distinct 4 x 4 arrays of identical pictures and to peck a 2nd button in the presence of 16 distinct 4 x 4 arrays of nonidentical pictures. Later, they were tested with 16 other same and 16 other different stimulus arrays involving untrained pictures. Performance to the testing arrays greatly exceeded chance levels, thus suggesting same-different conceptualization by pigeons.

Animals↗

PubMed1992

Effects of MDA upon differential serial compound conditioning and reflex modification of the rabbit's nictitating membrane response.

The present investigations sought to determine the effects of 3,4-methylenedioxyamphetamine (MDA) on: 1) differential conditioning of the rabbit's nictitating membrane response to the serial compounds A-X-US (tone-light-reinforced compound) and B-X (white noise-light-unreinforced compound) by examining differential responding to A and B and their conditional control over responding to X within the compounds (Experiment 1); and 2) the ability of the compound stimuli and their components to modify the amplitude of the unconditioned nictitating membrane response (Experiment 2). Experiment 1 revealed that MDA decremented differential responding to the serial compounds and their A and B components, while enhancing conditioned responding to the X component. In addition, Experiment 2 indicated that MDA attenuated reflex modification to the compounds and their A and B components, but facilitated reflex modification to X alone. The results of these experiments indicated that MDA operated to alter the intensity, distinctiveness, and persistence (short-term memory) of stimulus representations.

3,4-Methylenedioxyamphetamine↗

PubMed1991

Effects of MDA on classical conditioning of the rabbit nictitating membrane response.

In Experiment 1, classical conditioning of the rabbit's nictitating membrane response (NMR) was accomplished by pairing tone and light conditioned stimuli (CSs) with a shock unconditioned stimulus (UCS). MDA impaired the acquisition of conditioned responses (CR) to a tone-CS, while significantly enhancing CR acquisition to a light-CS. Experiment 2, employing explicitly unpaired CS, UCS training, revealed no reliable effects of MDA upon nonassociative processes. Subsequent efforts determined if MDA's CR acquisition effects resulted from alterations in sensory processing of the CS, UCS, and/or UCR motor functioning. Specifically, it was determined that MDA: (a) increased the tone-CS intensity threshold for eliciting CRs (Experiment 3); (b) attenuated the tone-induced reflex modification of the unconditioned NMR (Experiment 4); and (c) enhanced UCR frequency at varying UCS intensities (Experiment 5). It was concluded that MDA's effect upon CR acquisition reflected the drug's effect upon CS and UCS/UCR processing and thereby altered the ability of these components of conditioning to enter into associative learning.

3,4-Methylenedioxyamphetamine↗