Jason G.
Fleischer |
|||||
| J: |
Research Fellow in Theoretical Neurobiology |
T: |
+1 (858) 626-2069 |
||
| P: |
The Neurosciences Institute 10640 John Jay Hopkins Dr. San Diego, CA 92121 USA |
E: |
|||
| Curriculum
Vitae
Research Info Publications
|
|||||
| RESEARCH |
|||||
|
Neuroscience
Robotics
Robotics is a natural complement to computational neuroscience. Neural models that are embodied in real world devices receive more varied inputs than simulated models, and the consequences of an embodied model's actions are less predictable --- what some dismiss as the inherent "noisiness" of the real world may in fact be a key component in how biological neural systems learn. This is one of the reasons why I feel that neural models that have physical bodies are more convincing than those that are implemented in simulation. And neuroscience models can in turn help build more capable robots. A better understanding of how animals learn motor control and cognitive abilities will produce a new set of tools for building robots that need those same skills. My work is part of the Brain-Based
Device (BBD) program here at The Neurosciences
Institute. BBDs are large-scale neural models with an emphasis on realistic neuroanatomy and
neurophysiology. A BBD's simulated nervous system is embodied in a robotic
device, which interacts with the environment while engaged in a
behavioral task. |
|||||
| Neuroscience | |||||
|
My main research interest is in the computational modelling of
medial temporal lobe (MTL) function. The MTL, including the
hippocampus, is a brain region that is known to be involved in
memory formation in humans and other mammals. One of the most
striking features of hippocampal activity is the existence of
place fields, where a cell's discharge rate is strongly correlated
with the animal's location. Some place fields occur regardless of
context, and others depend on the path the animal took in the past
or will take in the future. Place fields in animals have been
also been shown to be dependent on multiple sensory modalities.
I have been building, testing, and analyzing the Darwin X and XI BBDs, which have models of MTL plus selected cortical areas (~100K simulated neuronal units, 1.2M synapses) and perform maze-navigation tasks. Activity in the simulated hippocampus has been shown to be place specific, journey dependent and multimodal in its responses. Analysis of the neural pathways leading to place activity have pointed to differential involvement of the perforant path versus the trisynaptic loop in early versus late training place fields, and in journey-dependent versus -independent place fields. When lesioning sensory streams to the simulated MTL, changes in the pathways leading to place activity during the lesion are larger in the entorhinal cortex than in the hippocampus, which is consistent with pattern-completion theories of hippocampal function. The work with Darwin X and XI has shown that BBDs simulating anatomical and physiological details of the MTL and surrounding regions can support the formation of spatial memory, episodic memory, and associative memory. The results using these models may have heuristic value in analyzing findings from studies of behaving animals. |
|||||
| Robotics | |||||
| I have been working on a soccer-playing robot based
on the Segway scooter that
implements a neural simulation for visual processing and uses
algorithms based on psychophysical data to perform obstacle avoidance
and ball-handling. The Neurosciences Institute ran demonstrations in
conjunction with Carnegie Mellon University, who also have a Segway
robot, at both the 2004 and 2005 RoboCup American Open
tournaments (BBC
news blurb). This is part of a newly-proposed RoboCup league where
each team consists of both human players, mounted on Segway scooters,
and Segway robots. This new league highlights the problem of
human-robot interaction, which has become an important research topic
since robots are becoming more common in the everyday world.
Previously I have worked in the area of AI robotics,
investigating issues of reliable landmark detection using predictive
sensor models, symbol grounding on robotic agents, and route
communication between robots.
|
|||||
| PUBLICATIONS |
|||||
| Journal
Articles |
|||||
| Full-text | |||||
| Full-text | |||||
| Full-text | |||||
| Full-text | |||||
| Invited Book Chapters |
|||||
|
|||||
| Full-text |
|||||
|
|||||
| Full-text |
|||||
| Refereed
Conference Papers |
|||||
|
|||||
| Full-text |
|||||
|
|||||
| Full-text |
|||||
|
|||||
| Full-text |
|||||
|
|||||
| Full-text |
|||||
|
|||||
| Full-text |
|||||
|
|||||
| Full-text |
|||||
| Posters |
|||||
| Abstract, Poster | |||||
| Theses |
|||||
|
|||||
| Abstract, Full-text |
|||||
|
|||||
| Abstract, Full-text |
|||||