NYU/CNS : Faculty : Core Faculty : Wendy A. Suzuki

Humans and animals have an amazing ability to learn and retain new information for facts and events. This form of memory is termed declarative memory in humans and relational memory in animals. Strong evidence has demonstrated that an interconnected set of brain structures in the medial temporal lobe including the hippocampus and surrounding entorhinal, perirhinal and parahippocampal cortices contribute critically to declarative/relational memory. It remains unclear, however, how the individual brain areas contribute to this form of memory. Do all areas contribute in a unitary way to declarative/relational memory, or is each structure specialized for certain forms of memory? What are the neural mechanisms underlying memory in these areas? How do these areas interact with extra-medial temporal lobe brain areas during the acquisition and retrieval processes?

The major goal the Suzuki Laboratory is to understand the neural signals underlying the formation and representation of declarative/relational memory in the monkey brain. One form of declarative/relational memory we have focused on is associative memory, defined as the ability to associate two unrelated items in memory. We have shown that many cells in the monkey hippocampus signal learning of new associations with dramatic changes in their firing rate (Wirth et al., 2003). Recent functional imaging studies have shown that similar changes in activity are seen in the human medial temporal (Law et al., 2005). We have also shown that hippocampal neurons signal well- learned information with a significantly more selective response compared to novel information (Yanike et al., 2004). Current work is examining how the hippocampus interacts with other brain areas during the associative learning process. Another major goal in the lab is the development of a novel battery of medial temporal lobe-dependent memory tasks to use in our neurophysiological studies. This battery includes tasks of temporal order memory designed to mimic the kind of memory required in episodic memories, a form of declarative/relational memory. We are also in the process of developing a novel family of naturalistic memory tasks based on memory for social interactions that are designed to tap the natural learning and memory tasks that monkeys have evolved to solve. A long-term goal is to understand not only how medial temporal lobe areas contribute to theses tasks, but also how the medial temporal lobe may interact with other brain areas including the prefrontal cortex and striatum during both acquisition and retrieval of declarative/relational information.

E-mail: wendy@cns.nyu.edu

Representative Publications

Suzuki, W.A. and Porteros, A. (2002). Distribution of calbindin D-28k in the entorhinal, perirhinal and parahippocampal cortices of the macaque monkey. J. Comp. Neurol. 451, 392-412.

Suzuki, W.A. and Amaral, D.G. (2003). The perirhinal and parahippocampal cortices of the macaque monkey: Cytoarchitectonic and chemoarchitectonic organization. J. Comp. Neurol. 463, 67-91.

Suzuki, W.A. and Amaral, D.G. (2003). Where are the perirhinal and parahippocampal cortices? A Historical overview of the nomenclature and boundaries applied to the primate medial temporal lobe. Neuroscience 120, 893-906.

Wirth, S., Yanike, M., Frank, L.M., Smith, A.C., Brown, E.N., and Suzuki, W.A. (2003). Single neurons in the monkey hippocampus and learning of new associations. Science 300, 1578-1581.

Smith, A.C., Frank, L.M., Wirth, S., Yanike, M., Hu, D., Kubota, Y., Graybiel, A.M., Suzuki, W.A., and Brown, E.N. (2004) Dynamic analysis of learning in behavioral experiments. J. Neurosci. 24, 447-461.

Lavenex, P., Suzuki, W.A., and Amaral, D.G. (2004) Intrinsic perirhinal and parahippocampal cortices of the macaque monkey: Intrinsic projections and interconnections. J. Comp. Neurol. 472, 371-394.

Yanike, M., Wirth, S., and Suzuki, W.A. (2004) Representation of well-learned information in the monkey hippocampus. Neuron 42, 477-487.

Buckmaster, C.A., Eichenbaum, H., Amaral, D.G., Suzuki, W.A., and Rapp, P.R. (2004) Entorhinal cortex lesions disrupt the relational organization of memory in monkeys. J. Neurosci. 24, 9811-9825.

Law JR, Flanery MA, Wirth S, Yanike M, Smith AC, Frank LM, Suzuki WA, Brown EN and Stark CEL (2005) fMRI activity during the gradual acquisition and expression of paired associate memory. J Neurosci 25, 5720-5729.