Friday, June 21, 2013

Mu-Ming Poo, Ph.D. - Neural Plasticity: From Synapse to Perception


This is a video from the NIH (National Institutes of Health) Wednesday Afternoon Lecture Series.

Neuroplasticity is one of the hot topics in neuroscience, with new discoveries being published all of the time - in fact, there is a whole journal devoted to the topic. Here is a little background on neural plasticity from Wikipedia:
Neuroplasticity (from neural - pertaining to the nerves and/or brain and plastic - moldable or changeable in structure), also known as brain plasticity, refers to changes in neural pathways and synapses which are due to changes in behavior, environment and neural processes, as well as changes resulting from bodily injury.[1] Neuroplasticity has replaced the formerly-held position that the brain is a physiologically static organ, and explores how - and in which ways - the brain changes throughout life.[2] 
Neuroplasticity occurs on a variety of levels, ranging from cellular changes due to learning, to large-scale changes involved in cortical remapping in response to injury. The role of neuroplasticity is widely recognized in healthy development, learning, memory, and recovery from brain damage. During most of the 20th century, the consensus among neuroscientists was that brain structure is relatively immutable after a critical period during early childhood. This belief has been challenged by findings revealing that many aspects of the brain remain plastic even into adulthood.[3]  
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Decades of research[6] have now shown that substantial changes occur in the lowest neocortical processing areas, and that these changes can profoundly alter the pattern of neuronal activation in response to experience. Neuroscientific research indicates that experience can actually change both the brain's physical structure (anatomy) and functional organization (physiology). Neuroscientists are currently engaged in a reconciliation of critical period studies demonstrating the immutability of the brain after development with the more recent research showing how the brain can, and does, change.[7]
This presentation is for professionals, but it's good.


Wednesday Afternoon Lecture Series

The cognitive functions of the brain, such as learning and memory, depend on the ability of neural circuits to change their properties of signal processing after the organism has used the circuits. Many of these use-dependent changes (“plasticity”) occur at synapses where signals are transmitted between neurons. Depending on the pattern of neuronal activities, repetitive synaptic transmission could cause long-term potentiation (LTP) or long-term depression (LTD) of the synapse in its efficacy for future transmission. Dr. Poo will summarize his studies on how the timing of neuronal activities spikes in the pre- and post-synaptic neurons and if it determines whether a synapse undergoes LTP or LTD. This phenomenon is known as Spike Timing-Dependent Plasticity (STDP); STDP may provide the mechanism for coding and storing the information on the temporal sequence and interval of sensory signals, two key elements of episodic memory. He will also discuss how neural plasticity shapes the development of neural circuits and offers the potential for functional recovery from injuries and diseases of the adult brain. Finally, to show that higher cognitive functions, such as self-awareness, may originate from experience-dependent neural plasticity, he will present preliminary findings showing that mirror self-recognition, a cognitive function known to be limited only to humans and great apes, could be acquired by rhesus monkeys following training for visual-somatosensory association. 
Author: Mu-Ming Poo, Ph.D., Paul Licht Distinguished Professor in Biology, University of California, Berkeley; Director, Institute of Neuroscience, Chinese Academy of Sciences, Shanghai 
Runtime: 01:09:22
Download: Download Video
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