Chapter 7.1 Flashcards
primary sensory cortex
the area of sensory cortex that receives most of its input directly from the thalamic relay nuclei of that system.
secondary sensory cortex
comprises the areas of the sensory cortex that receive most of their input from the primary sensory cortex of that system or from other areas of the secondary sensory cortex of the same system.
association cortex
is any area of cortex that receives input from more than one sensory system. Most input to the areas of association cortex comes via areas of secondary sensory cortex.
hierarchical organization
sensory systems; a system whose members can be assigned to specific levels or ranks in relation to one another. Organized on the basis of the specificity and complexity of their function. Going from receptors, to thalamic nuclei, to primary sensory cortex, to secondary sensory cortex, to associated cortex, one finds neurons that respond optimally to stimuli of greater and greater specificity and complexity. Each level receives most of its input from lower levels and adds another layer of analysis before passing it on up the hierarchy.
The higher the level of damage in the hierarchy
the more specific and complex the deficit
sensation
the process of detecting the presence of stimuli.
perception
the higher-order process of integrating, recognizing, and interpreting complete patterns of sensations.
functional segregation
rather than functional homogeneity; characterizes the organization of sensory systems. Each of the three levels of the cerebral cortex – primary, secondary, and association – in each sensory system contains functionally distinct areas that specialize in different kinds of analysis.
serial system
information flows among the components over just one pathway.
paralle system
information flows through the components over multiple pathways.
parallel processing
the simultaneous analysis of a signal in different ways by the multiple parallel pathways of a neural network.
Two different parallel streams of analysis in our sensory systems:
one capable of influencing our behavior without our conscious awareness and one that influences our behavior by engaging out conscious awareness.
Sensory systems are characterized by a division of labor:
multiple specialized areas, at multiple levels, are interconnected by multiple parallel pathways.
One possible solution to the binding problem is that
there is a single area of the cortex at the top of the sensory hierarchy that receives signals from all other areas of the sensory stem and puts them together to form perceptions: however, there are no areas of the cortex to which all the areas of a single sensor system report.
It seems then that perceptions must be
a product of the combined activity of different interconnected cortical areas.
