1985 |
Holland, Peter C |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Pavlovian Serial Compound Conditioning @ University of Pittsburgh At Pittsburgh
The Pavlovian conditioning of stimulus compounds has received extensive empirical and theoretical treatment in the past decade. Most investigators have been concerned only with the associations formed between the individual stimulus elements and the unconditioned stimulus. The proposed research examines other sources of responding in Pavlovian serial conditioning in rats. The first set of experiments investigates variables affecting the formation of associations among the elements of stimulus compounds. The use of an appetitive conditioning preparation involving direct behavioral observation of the subjects makes possible a separation of the roles of element-US and both mediated ("S-S") and unmediated ("S-R") within-compound associations in generating conditioned responding to serial compounds. A second set of experiments examines compound conditioning within simple conditional discriminations. Those experiments are especially concerned with the ability of stimuli in feature-positive and feature-negative discriminations to modulate the action of other associative units, independent of the participation of those stimuli in associations with the US or other stimulus elements.
|
0.945 |
1995 — 1999 |
Holland, Peter C |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Amygdala Systems and Associative Learning
Recent studies indicate a role for the amygdala in the modulation of attentional processes during .associative learning in rats. Lesions of the amygdala central nucleus (CN) present the normal conditioning of orienting responses (ORs) to conditioned stimuli (CSs) paired with food unconditioned stimuli (USs), and interfere with the enhancement of CS associability normally observed when contingencies between the CS and other events are altered. For its primary focus, the proposed research would more fully characterize the behavioral determinants and nature of CN-mediated attentional changes and would investigate the neural circuitry involved in those changes. The experiments in specific aim 1 are based on well-developed behavioral theories of learning and are designed to determine the procedural conditions necessary for activating the CN- mediated incremental CS processing system. The studies in specific aim 2 address the neural circuitry for implementation of amygdala attentional functions, concentrating on a CN-nigral-striatal system for the conditioned OR and CN regulation of basal forebrain corticipetal pathways for enhancement of CS associability. A second focus (specific aim 3) is the exploration of the relation between CN systems underlying attentional regulation and amygdala circuitry responsible for changes in the motivational significance or value of CSs in conditioning (a function more traditionally ascribed to the amygdala). A final set of experiments (specific aim 4) would consider the relation between amygdala circuitry involved in enhancements of attention and hippocampal circuitry implicated in reductions in attention (for example, in latent inhibition). The research would use behavioral techniques, simple and crossed (asymmetrical) lesion procedures with specific neuro- and immunotoxins, and measurements of corticipetal activation using high-affinity choline uptake and c-fos mapping to accomplish these specific aims. The proposed behavioral and neurobiological studies may provide new insights into cognitive functions of the amygdala, as well as relations between cognitive and motivational functions in associative learning.
|
0.97 |
2001 — 2005 |
Holland, Peter C |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Role of Amygdala Systems in Associative Learning @ Johns Hopkins University
Previous research in this project investigated behavioral and neural bases of two changes in attentional processing in associative learning mediated by the amygdala central nucleus (CN): the potentiation of orienting to conditioned stimuli (CSs) paired with food unconditioned stimuli (USs), and the enhancement of CS associability that occurs when contingencies between the CS and other events are altered. The proposed research extends that work by investigating the relation of these attentional changes to other aspects of attention, and by continuing systems analysis of these functions. The project will use a variety of behavioral procedures, asymmetrical lesion techniques, transient, reversible inactivation procedures, and electrophysiological recording methods, with rat subjects, to address four specific aims. The first aim is to distinguish between CN-systems effects on the acquisition and expression of conditioned orienting and associability changes. The second aim is to examine cortical neural encoding of attentional changes in associative learning that depend on CN and its regulation of the basal forebrain cholinergic system. The third aim is to examine the roles of CN attentional systems in performance of selective attention tasks. The fourth aim is to examine cortical activity during performance of selective attention tasks. This research may provide a basis for new insights into cognitive functions of the amygdala, as well as the integration of cognitive and emotional function. In addition, it may have wide clinical implications, because the neural systems to be studied are involved in a number of pathological conditions, for example, Alzheimer's disease (learning and attention deficits often signal the onset of more complete dementia), schizophrenia (deficits in focusing attention on relevant events and ignoring extraneous events), and various affective disorders (inappropriate assignment of motivational value to life events).
|
1 |
2002 — 2006 |
Holland, Peter C |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Associatively-Activated Event Representations @ Johns Hopkins University
DESCRIPTION (provided by applicant): Most contemporary learning theorists describe conditioning in terms of the acquisition of associations between internal representations of the conditioned stimulus (CS) and the unconditioned stimulus (US). These associations allow presentation of the CS to activate the US representation, so that the CS can substitute for the US in a variety of behavioral, emotional, and cognitive functions originally controlled by the US alone. The proposed research would explore the nature and function of CS-evoked event representations, especially their ability to activate perceptual or memorial images of the US, allowing the formation of new associations with that US, even in its absence. The research would determine the conditions under which various functions of CS-activated event representations are displayed, and would explore a number of limitations on those functions. Although the proposed research is primarily intended to address questions about fundamental behavioral properties of learning and memory, it also has clinical relevance For example, food aversions mediated by evoked cognitive images rather than physical illness may contribute to eating disorders. Similarly, implicitly conditioned imagery may contribute to the establishment and display of inappropriate emotional behavior in some cases of anxiety and reaction to trauma. Likewise, many clinical therapeutic treatments involve patients' use of techniques of imagery in which activation of images of emotionally significant events is placed under the control of explicit prompts through conditioning-like procedures. The proposed research provides a basis for the understanding of basic processing of imaginal events in associative learning.
|
1 |
2007 — 2014 |
Holland, Peter C |
R37Activity Code Description: To provide long-term grant support to investigators whose research competence and productivity are distinctly superior and who are highly likely to continue to perform in an outstanding manner. Investigators may not apply for a MERIT award. Program staff and/or members of the cognizant National Advisory Council/Board will identify candidates for the MERIT award during the course of review of competing research grant applications prepared and submitted in accordance with regular PHS requirements. |
Amygdala Systems in Associative Learning @ Johns Hopkins University
Most behavioral and psychological function depends on learning. Abnormalities in basic learning processes have been identified in many psychopathologies, including schizopiirenia, autism, impulse control and eating disorders, and a range of affective disorders. Many of the genes identified in association studies as linked to these pathologies are plasticity-related and hence linked to basic learning processes. Thus, better understanding of these processes may be critical to understanding the origins of psychopathology. In our last project period we identified a number of key aspects of amygdala system function in the modulation of attention and incentive in associative learning. In the next project period, we will focus on the interface of learning, memory ahd attention by investigating how violations of learned outcome expectancies can enhance attention to the events present at the time of surprise, such that those events may more readily enter into new associations in tine future. This research will extend our prior work in significant new directions, within three Specific Aims. Research under the first aim will identify brain domains for initial processing of surprise (prediction error), maintenance of altered cue associability information in memory, and the ultimate expression of altered learning rates. Research under a second aim will examine the nature of associability memory. The violation of outcome expectancies today alters the associability (ease of entering into new learning) of cues tomorrow. Thus, there must be some relatively permanent memory of this altered cue associability. We will explore 'associability memory' within a broader perspective of post-trial information processing, including questions of consolidation, replay, and reconsolidation. Finally, research under a third aim will use unit recording and optogenetic silencing and hijacking (stimulation) techniques to examine neuronal coding of prediction and prediction error underlying the enhancement of cue associability.
|
1 |