consonant strings only activates basic visual recognition o FINDINGS Large

Consonant strings only activates basic visual

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consonant strings (only activates basic visual recognition) o FINDINGS Large individual differences in patterns of activation Overall trends in Wernicke’s/Broca’s but other areas activated too Language is not simply localized - It is difficult to see how a single function could underlie a collection of effects, neural correlates of cog function overlap a lot and our models of the brain need to continue to be improved Magnoetencephalography (MEG) - fMRI has good spatial, but bad temporal compared to ERP - Magnoetencephalography (MEG) = non- invasive brain imaging technique that directly measures neural activity - Advantages: o Has high spatial of fMRI (not as high) AND high temporal of ERP (bc measures magnetic fields produced by brain) o Provides direct measure of neural changes (PET and fMRI are indirect bc linked to blood flow) o Head/skull abnormalities don’t effect the magnetic fields produced by head (unlike the electrical fields produced by ERP) - 2 limitations: o Can only detect signal near cortical surface o Not cost effective / widely available Connectionist Models
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- Connectionism = theory focussed on the way cog processes work at the physiological/neurological (as opposed to info processing) level. It holds that the brain consists of networks of simple units (neurons) communicating with one another o Alternative theory, that the brain consists of interconnected neurons o 2 basic ideas of connectionism 1 – info can be broken down into simple units (neurons) 2 – there are connections between these units - Can understand these neural connections through neural imaging techniques such as o Diffusion tension imaging (DTI) = MRI based neuroimaging technique that makes it possible to visualize the white matter tracts in the brain - Neural network = neurons that are functionally related/connected o Neural connections have different strengths, networks learn by modifying strength of connections so that the proper output occurs in response to a particular input - One assumption… - Hebb rule = connection between two neurons takes place only if both neurons are firing at approx. the same time o When axon of A is near enough to excite B and repeatedly takes part in firing it, some growth process/metabolic change takes place in one/both cells such that A’s efficiency, as one of the cells firing B, is increased - Another assumption is that many connections can be active at same time o Parallel processing = many neural connections can be active at same time – in contrast to serial processing (only 1 neural activity may take place at a time) - Tf connectionist models are called ‘parallel distributed processing models’ - Big dif between connectionism and older info processing is that knowledge is embodied in the connections that make up the network, rather than in a series of info processing stages; connectionist models are good at simulating many cog processes Combining Methods - Cog neuroscience melds all of these methods/theories - Hypotheses about brain mechanisms are made from careful control of behaviour using
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