Friday, January 26, 2018
C.R. Gallistel, PhD
Behavioral and Systems Neuroscience
Distinguished Professor Emeritus
How the Brain Really Works
It is generally assumed that the brain’s computational capacities derive mostly from the structure of neural circuits—how it is wired—and from process(es) that rewire circuits in response to experience. The computationally relevant properties ascribed to the neuron itself have not changed in more than a century: it is a leaky integrator with a threshold on its output (Sherrington, 1906). The concepts at the core of molecular biology were undreamed of in Sherrington’s philosophy. They have transformed biological thinking in the last half century. But they play little role in theorizing about how nervous tissue computes. The possibility that the neuron is a full-blown computing machine in its own right, able to store acquired information and to perform complex computations on it, has barely been bruited. I urge us to consider it.
My reasons are: 1) The hypothesis that acquired information is stored in altered synapses is a conceptual dead end. In more than a century, no one has explained even in principle how altered synapses can carry information forward in time in a computationally accessible form. 2) It is easy to suggest several different models for how molecules known to exist inside cells can carry acquired information in a computationally accessible form. 3) The logic gates out of which all computation may be built are known to be implemented at the molecular level inside cells. 4) Implementing memory and computation at the molecular level increases the speed (operations/s), energy efficiency (operations/J), and spatial efficiency (bits/m3) of computation and memory by many orders of magnitude. 5) Recent experimental findings strongly suggest that (at least some) memory resides inside the neuron.
Friday, February 9, 2018
Julia L Evans, PhD
University of Texas, Dallas
Professor, School of Behavioral and Brain Sciences
Director, Child Language and Cognitive Processes Lab
Poles, Bowls and Dinosaur Bones: How Atypical Lexical Representations May Be Derailing Sentence Comprehension for Children with Specific Language Impairment
Rumelhart (1979) argued that comprehension, like perception, should be likened to Hebb’s (1949) paleontologist, who uses his or her beliefs and knowledge about dinosaurs in conjunction with the clues provided by the available bone fragments to construct a full-fledged model of the original. In this talk, I explore studies that suggest that, while real world knowledge is intact in children with SLI, deficits at the lexical level (the bone fragments) may be profoundly influencing sentence comprehension performance in children with SLI.
**Both talks will be given in room 202 Uris Hall @ 12:20pm: refreshments served at 12:10pm.**