Joseph E. Steinmetz - US grants

The long-term goal of research proposed in the present application is to delineate neuronal systems and processes involved in simple forms of learning and memory. More specifically, this research seeks to advance our understanding of the involvement of the cerebellum in a simple motor learning task, classical eyelid conditioning in rabbits. Three experiments are proposed that use anesthetized classical conditioning preparations. These preparations involve the pairing of brain microstimulation in place of peripheral conditioning stimuli and recording unit activity from brain stem nuclei known to be involved in generating conditioning responses in place of monitoring overt behavioral responses. The proposed experiments include: (1) An analysis of extracellular single unit cerebellar activity during and after conditioning, (2) Manipulations of the "behavioral" training regimen used during the anesthetized conditioning, and (3) Intracellular recordings coupled with HRP labeling after conditioning. These experiments have been designed to explore similarities and differences in conditioning between awake and anesthetized rabbits, to provide information about changes in the activity of cerebellar neurons induced by the anesthetized conditioning procedures, and to provide some insight into the connectivity between cerebellar and brain stem neurons involved in the conditioning. The further development of this anesthetized conditioning preparation should facilitate the definition and study of cerebellar and brain stem circuits activated during this form of learning. Intracellular analyses of neuronal activity should provide initial information about cellular processes and synaptic mechanisms associated with classical eyelid conditioning. We anticipate that these mechanisms may be generalizable to other motor learning and memory situations and therefore advance our understanding of basic cerebellar and brainstem neuronal function. Results from these experiments should also prove useful for understanding loss of normal function associated with cerebellar pathologies caused by injury or disease. Moreover, advancing our knowledge of cellular and synaptic processes involved in simple motor learning and memory should prove useful for understanding more complex learning and memory processes and the cellular bases of learning impairments and memory loss associated with disease and injury.

In previous research, the PI found evidence that emotions mediate early perception. Specifically, emotions appear to increase a person's perceptual sensitivity to emotion-congruent information in the visual world. The past results indicate that emotions have very specific effects on perception such that happy people are particularly efficient at processing information related to happiness (but not all positive events) and that sad people are particularly efficient at processing information related to sadness (but not all negative events). These past findings will now be extended in several ways: In one series of experiments, the emotion-congruence effect will be explored in the domain of face processing. These experiments will examine the hypotheses that (1) emotions increase the efficiency of perception of emotion-congruent faces, and (2) emotions mediate the perception of the boundaries of facial expression categories such that emotional perceivers can detect the offset of emotion-congruent expressions with greater expertise than can other perceivers. Another series of experiments will explore the roles of emotional feelings and of emotional language in perceptual processes. These experiments will investigate the hypothesis that emotional feelings per se mediate emotion congruence effects. The results from this research can provide the basis for a more precise account of the cognitive representation and processing of emotion. %%% In previous research, the PI found that a person's emotional state can influence very basic perceptual and cognitive processes. The past results indicate that happy people do indeed see the world through rose-colored glasses and that sad people see the dark side of life. In addition, the past results suggest that emotions have very specific effects: happy people are especially good at understanding information related to happiness (but not all positive events) and that sad people are especially good at understanding information related to sadness (but not all negative events). These past findings will now be extended in several ways: One series of experiments will examine the effects of emotion on the accuracy and efficiency of interpreting another person's facial expressions. Another set of experiments will examine whether emotional experience itself influences a person's perceptions of others, or whether emotional language is the more important determinant. The results from this research can provide the basis for a more precise and complete understanding of the cognitive representation and processing of emotion.

DESCRIPTION (adapted from applicant's abstract): How animals learn to choose among alternatives, and how they learn about temporal cues in their environment, are enduring problems for any theory of learning. This project suggests an answer to each question in the form of a dynamic model, and proposes a set of experiments to test the models. The model for choice assumes that in recurrent choice situations, three factors determine how preference for the better alternative is acquired: the overall reward rate, the discriminability of the local reward rates, and the degree of response/reward feedback. In addition, the model predicts that when animals develop partial preferences and show local response patterns, the asymptotic strength of these patterns is also a function of the preceding factors. Five experiments will use pigeons to test the model's predictions concerning the acquisition of molar preference and the molecular organization of behavior. The timing model assumes a serial activation of behavioral states during the interreward interval, a learning process that couples the states with the instrumental response, and a rule mapping the states onto response rate or probability. Four experiments with pigeons will test the model's description of the learning process in three temporal tasks, fixed -- interval schedules, the bisection of temporal intervals, and a psychometric procedure. Taken together, the experiments will help to answer a set of fundamental questions about the processes of choice and timing: How are preferences acquired? How are the molar and the molecular structures of choice related? What do animals learn when rewards are time based? How do learning processes affect temporal judgements? A common feature of the work proposed here is the continual emphasis on the dynamics of behavior and learning.

DESCRIPTION: (Adapted from applicant's abstract): The long-term objective of this research is to advance our understanding of how the cerebellum is involved in encoding classical eyeblink conditioning, a simple, associative, motor learning procedure. Data collected to date have provided strong evidence that populations of neurons in specific regions of the cerebellar cortex and the interpositus nucleus receive convergent input concerning the stimuli used in eyeblink conditioning and change their firing patterns in a manner that is responsible for the acquisition and performance of the learned CR. While the neural network involved in encoding classical eyeblink conditioning has been worked out, there is much less known about how portions of this network interact during learning. The specific objectives of the research proposed here are to use brain recording, lesion and stimulation methods to study relationships between learning-related activity in the cerebellar cortex and learning-related activity in the interpositus nucleus. Four experiments are proposed. First, the interpositus nucleus will be either permanently lesioned with kainic acid or temporarily activated by muscimol and activity in the cerebellar cortex (lobule HVI and the anterior lobe) will be studied during acquisition and performance of eyeblink conditioning. Second, the cerebellar cortex will be either lesioned or inactivated and conditioning related activity in the interpositus nucleus will be examined. Third, double-labeling, tract-tracing techniques will be used to study the pattern of projections between cerebellar cortical areas and the deep cerebellar nuclei. Lastly, stimulation and recording techniques will be used to evaluate whether or not a "rebound from cortical inhibition" mechanism may play a role in promoting neural plasticity associated with conditioning. When completed, this research should provide important new data concerning how cerebellar neural networks are involved in motor learning procedures, and, more generally how neural systems interact to promote behavioral change. This systems-level understanding of how the brain operates during learning is crucial for the development of new treatments and therapies for a variety of pathologies that produce learning and memory deficits, including developmental influences, degenerative diseases and neural injury.

The goal of this research program is to understand the acquisition of motor skills in infancy and early childhood. Specifically, this research is concerned with the dual-nature of skill: how children learn to become both stable in their performance and flexible in their abilities to engage in new tasks. The studies are informed by a dynamic systems perspective and address skill development in terms of dynamics tested and coupled over levels and time scales. This theoretical approach focuses on the multiple, interacting factors that lead to movement. Here we especially consider how perception, motor memory, and task intersect in producing movements of eyes and head, and manual actions of varying complexities. Studies look at changes in real and developmental time and include empirical research, model simulation and robotics. Specific Aim 1 is based on a new model of infant visual habituation. In six experiments, we manipulate the metric parameters contributing to infants' development of visual attention. In Specific Aim 2 we study the dynamics of action memories for simple reaching with hands and with feed in infants and toddlers, and how those memories interact with visual attention. Specific Aim 3 is to study the dynamics of complex motor actions. Infants and toddlers are tested with toys of varying complexity to understand how recent and longer-term experience affect their tendencies to repeat or switch to new actions. In Specific Aim 4 we implement these theoretical models in an autonomous robot to further explore mechanisms of real time behavior and its developmental course. Specific Aim 5 is to continue experiments on infant limb perturbations currently funded and Specific Aim 6 to write a book on development of embodied cognition based on these and previous experimental and modeling work. These studies impact upon our understanding of basic mechanisms of skill development and continue to contribute new theories of clinical intervention in pediatric physical and occupational therapy.