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Alex Martin, Ph.D.


NIH Researcher Offers “Food for Thought”

DALLAS, Feb. 10, 2014 – Dr. Alex Martin, a senior investigator at the National Institutes of Health, visited the Center for Vital Longevity today for a Science Luncheon talk on perception and how representations of familiar objects are distributed across the brain in locations that are largely predictable from brain-to-brain.

Dr. Martin has spent a career conducting functional brain imaging studies on the neural substrate of cognition at his NIMH laboratory, which is studying the different neural systems related to memory, language and perception.

Dr. Martin explained that there are dedicated neural circuits for perceiving and knowing about animate and inanimate objects. The cognitive processes involved in imagining an object based on a representation and processes involved in actually seeing the object rely on some of the same neural circuitry, he said.

“Memory is not smeared across the cortex,” he said, but rather stored in defined, predictable areas. Object properties are stored throughout the brain, with specific sensory and motor-based information stored in their corresponding sensory and motor systems.

To a lunch-time audience consisting of post-doctoral researchers, Center faculty and students, as well as guests from the Richardson campus, Dr. Martin shared results from functional magnetic resonance imaging studies involving subjects who viewed pictures of food while being imaged.

He and other researchers have found that the same cortical and subcortical regions of the brain lit up as when presented with real food, but that firing was “context-dependent”: Whether or not the brain fired strongly depended literally on the concentration of glucose in the blood, among other factors.

This gives rise, he joked, “to a neurobiological explanation of why it’s a bad idea to go shopping when hungry” – one buys too many groceries, and very likely goes for foods overly rich in carbohydrates.
Dr. Martin also explained the concept of repetition priming – a form of implicit learning that is not dependent on conscious retrieval of prior events.

His further studies at the NIH will concentrate on characterizing changes in neural activity associated with perceptual skill learning. The aim is to provide a model system for studying how the brain can adapt to new information and learning over time.