Colloquia are located in:
Dale Melbourne Herklotz Conference Center
Center for the Neurobiology of Learning and Memory
(building 506 on the campus map)
The CNLM Colloquium Series is supported by the Thomas Henry Curtis Fund.
CNLM Colloquium Series 2016
February 9, 2016, 4 p.m.
Jay McClelland, Ph.D.
Department of Psychology and Center for Mind, Brain, and Computation, Stanford University
Integrating Rapid Neocortical Consolidation into Complimentary Learning Systems Theory
Since the 1950’s, it has been known that the medial temporal lobes in the brain play a special role in learning and memory. These findings have led, through the work and thinking of David Marr and many others, to a theory of the roles of hippocampus and neocortex in memory called the complementary learning systems theory (McClelland, McNaughton, & O’Reilly, 1995). Our theory postulated two distinct learning systems, one in the medial temporal lobes that supports the rapid learning of arbitrary new information, and one in the neocortex and other structures that supports the gradual discovery of structured representations that encode knowledge of the natural and man-made world, as well as the knowledge underlying cognitive skills and the knowledge underlying language and communication. In this talk, I examine evidence from recent studies showing that new information can sometimes be integrated rapidly into the neocortex, challenging our theory as previously presented. I present new simulations based on our theory, showing that new information that is consistent with knowledge previously acquired by a cortex-like artificial neural network can be learned rapidly without interfering with existing knowledge. These results match the pattern observed in the recent studies, and provide a mechanism for understanding when and how rapid integration of new information can occur.
CNLM Colloquium Series 2015
December 10, 1 p.m.
Robert T. Knight, M.D.
University of California, Berkeley
Frontal Cortex Physiology and Human Behavior
Thursday, November 19, 4p.m.
Sheri J.Y. Mizumori, Ph.D.
University of Washington
Hippocampal neural activity reflects the economy of choices
Hippocampal neural activity patterns are context-dependent, and this may aid in the formation of episodic memories. Distinguishing contexts requires an ability to recall features of a learned context, then compare the predicted features to those actually experienced. We studied how hippocampus represents predicted context information. Hippocampal place cells and theta activity were recorded during the performance of a maze-based probability discounting task in which predictive information about the probability of reward was systematically varied. Place fields redistributed (or remapped) around the goal location, but only during low probability trials that ended with reward delivery. Also around the goal location, theta power increased in proportion to the expected probability of reward, and not sensory or behavioral modulation. Theta power further dynamically varied as specific econometric information was obtained ‘on the fly’ during task performance. Behavioral economic information may define a ‘decision context’ that guides hippocampal context-dependent representations and learning during navigation.
Thursday, May 14, 4 p.m.
Warren H. Meck, Ph.D.
Functional and Neural Mechanisms of Interval Timing
The ability of the brain to process time in the seconds-to-minutes range is a fascinating problem given that the basic electrophysiological properties of neurons operate on a millisecond time scale. Neuropsychological studies of humans and other animals with damage to the basal ganglia have indicated that these structures play an important role in timing and time perception. Parkinson’s disease patients, for example, show evidence of a slowed internal clock and the “coupling” of durations stored in temporal memory when tested off of their dopaminergic medication. These studies have shown that the normal cognitive functions of the basal ganglia are heavily dependent upon dopamine-regulated neuronal firing in the cortex and striatum. Moreover, the electrophysiological properties of striatal medium spiny neurons within the basal ganglia suggest that these neurons may serve as a coincidence detectors of cortical and thalamic oscillatory input in order to provide the basis for duration discrimination in the seconds-to- minutes range. Recent findings obtained from ensemble recording in the prefrontal/cingulate cortex and the anterior dorsal striatum of rats performing in peak-interval timing procedures indicate that striatal neurons are able to encode specific durations in their firing rate in a “perceptron-like” manner. These findings correspond well with fMRI data obtained from human participants performing similar timing tasks and lend support to the striatal beat-frequency model of interval timing.
CNLM Colloquium Series 2014
Thursday, January 16, 11am
Charles Limoli, Ph.D.
University of California, Irvine
Radiation- and chemotherapy-induced cognitive dysfunction: Causes, consequences and treatments
Exposure of the CNS to treatments used to control the advance of cancer has been known to compromise cognitive function. Depending on disease state, treatments specifics and socioeconomic factors, cognitive outcomes vary in onset and severity. With increasing numbers of cancer patients surviving long-term, cognitive health is becoming an increasing concern, and to date, no satisfactory treatments exist for ameliorating the progressive and often debilitating cognitive side effects caused by radiotherapy and chemotherapy. This talk will cover the various mechanisms underlying treatment associated cognitive dysfunction and discuss the potential of using stem cell based strategies for the long-term treatment of this serious unmet medical need.
Thursday, March 13, 11am
Aryeh Routtenberg, Ph.D.
Is mamallian NMDA-dependent long-lasting memory conserved in C. elegans?
The N-methyl-D-aspartate receptor (NMDA-R) is associated with memory formation in both vertebrate and invertebrate nervous systems suggesting evolutionary conservation of this receptor mechanism. While considerable information exists concerning vertebrate NMDA-R and memory, evidence for its role in invertebrates is sparse; hence its linkage to mammalian mechanisms remains poorly understood. To begin to address this issue, we studied the formation of long-term associative memory as regulated by NMDAR and its subunit NMR-1 in the nematode, Caenorhabditis elegans (C. elegans).
Thursday, March 20, 11am
Loren Frank, Ph.D.
University of California, San Francisco
Neural substrates of memory retrieval and decision-making
The hippocampus is a brain structure known to be critical for forming and retrieving memories for the experiences of daily life, but the specific patterns of neural activity that support memory formation and retrieval remain unclear. In this talk I will discuss work from my laboratory that links a specific pattern of hippocampal place cell activity to the ability to use past experience to guide behavior. We have shown that hippocampal replay events can reactivate patterns of brain activity from a previous experience in awake animals and that disrupting these events interferes with learning and memory-guided decision-making. Further, we have found that the intensity of replay activity is predictive of whether an upcoming choice will be correct or incorrect. Our results suggest that the awake replay of place cell sequences plays a role in deliberative proceeses that are important for memory-guided decision making.