Presentation on theme: "Ming Hsu & W. Jake Jacobs Functional Neuroimaging of Place Learning in a Computer- Generated Space."— Presentation transcript:
Ming Hsu & W. Jake Jacobs Functional Neuroimaging of Place Learning in a Computer- Generated Space
Introduction u Our experiment employed the use of a Computer-Generated (C-G) Arena in conjunction with fMRI to study the neural structures involved in human place learning. u The C-G Arena was originally designed after the Morris Water Maze (MWZ), an apparatus instrumental in the development of the cognitive mapping theory.
Introduction cont. u We have previously shown that the C-G Arena is a good representation of the human place learning in real space. u We have also shown that people can learn locations within C-G space by observation. u Thus, we took advantage of this close correspondence to mount an fMRI examination of observational place learning.
Introduction cont. u Following the predictions made by cognitive mapping theory, we expect to find activation in the human hippocampus during observational place learning.
Experiment Design u Subjects were shown a recording of a target being found from various locations in the C- G Arena. u Two experimental conditions were used: l 1. Searches in a room that contains a visible target. l 2. Searches in a room that contains an invisible target (i.e., visible only upon contact).
All trials can be roughly divided into thirds. First 1/3 of the trial consists of panning towards the target, second 1/3 shows movement to the target, and the last 1/3 of the trial shows turning while on target. Experiment Design cont. InvisibleKaleidoscopeVisible InvisibleKaleidoscopeVisibleKaleidoscope InvisibleKaleidoscopeVisibleKaleidoscope InvisibleKaleidoscopeVisibleKaleidoscope 1 211132224333544 4655576668777988 9099101110112121123132 134143145154156165167176177 invisible visiblekaleidoscope
Activation in Perceptual Model Perceptual Model (1) invisible trials - kaleidoscope (2) visible trials - kaleidoscope
Temporal Lobe: Posterior MF: invisible Activation Deactivation Neutral Highest Low Highest MF: visible RD: invisibleRD: visible Activity in temporal lobe appears to be at least an indicator of learning.
Recapitulation uAuActivity in the precentral cortex, and around the intraparietal sulcus during the last 1/3 of the invisible trials is associated with learning. uAuActivity in the prefrontal cortex and temporal cortex in the first 2 invisible trials is also associated with learning.
Conclusions & Hypotheses u “What & Where” System l Ungleider & Mishkin 1982. l Dorsal/Parietal = Where. u Therefore, the time when the relationships between the target and cues are established is the crucial period that determines spatial learning. l Ventral/Occipital = What. l Both streams end in inferotemporal cortex, called in monkeys polysensory cortex.
C&H cont. u Parieto-precentral Network: From vision to motion. l Evidence in monkey and imaging literature. l Unanswered questions within the model. u How visual information gets from parietal to precentral cortex, as motor cortex has only access to “blind” areas of parietal lobe.
C&H cont. u Role of temporal lobe l Temporal activity decreases with familiarity in monkey and imaging studies. l In this task, temporal lobe activity appears to be associated primarily with knowledge of spatial relationships among cues and target--difference between invisible and visible trials. l Possibility of cognitive mapping within MT.
C&H cont. u Role of cerebellum l Abundance of cerebellar activity in imaging studies. l Cognition, or fine motor control, or facilitation of cerebral functions? l Possibility of cerebellum as pathway between parietal and precentral areas.
Future directions/questions u How to get hippocampal activation that argues convincingly for (or against) cognitive mapping? u What exactly is the role of cerebellum in all this? u Further elucidation of the existence and function of these networks.