lightofdarkness
April 7th, 2005, 07:44 AM
From:
Brainstem origins for cortical ?what?and ?where? pathways in the auditory system
Nina Kraus and Trent Nicol
"Over the past 20 years, increasing attention has been paid to the functional organization of sensory systems. Across
modalities, sensory systems route different aspects of the input into discrete processing streams; in other words, a
particular stimulus, whether a seen object, a heard sound or a felt touch, is not processed in the brain as a unit.
Rather, different qualities of the stimulus (e.g. what it is, where it is coming from, and who or what is producing it)
are processed separately, yet simultaneously, by different neural mechanisms before the stimulus is consciously
perceived as a whole. Here, we present a novel way of looking at the origin of well-known what/where cortical
processing streams ? one that postulates a subcortical precursor to specialized speech processing in the cortex.
In 1983, a seminal article published in [TRENDS in Neurosciences] described two parallel processing streams in the visual system, the ventral and dorsal pathways [1]. These streams are responsible for object identification (e.g. color and shape)
and object location (e.g. position and motion), respectively, and have popularly become known as ?what? and ?where?
pathways. This separation, evident early in parvocellular and magnocellular ganglion cells in the retina [2], continues
throughout the afferent pathway via the thalamus to visual cortex. Evolutionarily, the dorsal ?where? pathway developed first [3]. It is also more responsive to multimodal stimulation than the ventral ?what? pathway [4,5]."
What the 2nd part indicates is ---- "yin", the undifferentiated/integrated came first and so validating the notion, when we focus on the natural binary sequence of the I Ching, that the realm of yin serves as a realm of POTENTIALS out of which come the ACTUALS in the form of YANG line patterns, the assertion of a 'thing' post the integration of elements to form a pattern that is the labelled.
Our reality, as a species, is YIN oriented, unconscious (stimulus/response, autopilot), reactive, social, driven by context to elicit instincts as responses. - note the "where" being sensitive to 'multimodal' aka 'multicontext' stimulation. The development of the 'what' is more single context in perspective. more 'precise' but can be too precise, so focused on the trees it misses the forest.
If we move from the dorsal/ventral dichotomy in each hemisphere to the right-brain/left-brain dichotomy the SAME pattern of development is shown - right brain is more developed at birth than left brain (in most). As differentiation of senses, an so general particularisation, takes over so the 'yang' side starts to dominate, to assert universals (such as handedness, discrete labels etc) - we move from general to particular.
Genetic diversity, hormones, or just local social context can the 'favour' a particular perspective to be favoured over all of the possible perspectives available on this dimension from yin to yang, integrating to differentiating etc etc.
If we move to the abstract realm of "Small World Networks", this development of YIN to YANG is dominating the universe as a whole in ITS development - IOW 'in here' reflects 'out there' rather well. With that development comes the ability to refuse to go on the ride any more - this allows for stratification to develop - but that development will STILL follow a yin-to-yang path, just localised in the particular, originating, context.
The IC binary sequence reflects this overall dynamic, rooted in the neuron (inputs (yin) to outputs (yang)) and all the way up into our collectives. As such, the micro and the macro is 'revealed' in the IC through the use of analogy/metaphor.
Chris.
Brainstem origins for cortical ?what?and ?where? pathways in the auditory system
Nina Kraus and Trent Nicol
"Over the past 20 years, increasing attention has been paid to the functional organization of sensory systems. Across
modalities, sensory systems route different aspects of the input into discrete processing streams; in other words, a
particular stimulus, whether a seen object, a heard sound or a felt touch, is not processed in the brain as a unit.
Rather, different qualities of the stimulus (e.g. what it is, where it is coming from, and who or what is producing it)
are processed separately, yet simultaneously, by different neural mechanisms before the stimulus is consciously
perceived as a whole. Here, we present a novel way of looking at the origin of well-known what/where cortical
processing streams ? one that postulates a subcortical precursor to specialized speech processing in the cortex.
In 1983, a seminal article published in [TRENDS in Neurosciences] described two parallel processing streams in the visual system, the ventral and dorsal pathways [1]. These streams are responsible for object identification (e.g. color and shape)
and object location (e.g. position and motion), respectively, and have popularly become known as ?what? and ?where?
pathways. This separation, evident early in parvocellular and magnocellular ganglion cells in the retina [2], continues
throughout the afferent pathway via the thalamus to visual cortex. Evolutionarily, the dorsal ?where? pathway developed first [3]. It is also more responsive to multimodal stimulation than the ventral ?what? pathway [4,5]."
What the 2nd part indicates is ---- "yin", the undifferentiated/integrated came first and so validating the notion, when we focus on the natural binary sequence of the I Ching, that the realm of yin serves as a realm of POTENTIALS out of which come the ACTUALS in the form of YANG line patterns, the assertion of a 'thing' post the integration of elements to form a pattern that is the labelled.
Our reality, as a species, is YIN oriented, unconscious (stimulus/response, autopilot), reactive, social, driven by context to elicit instincts as responses. - note the "where" being sensitive to 'multimodal' aka 'multicontext' stimulation. The development of the 'what' is more single context in perspective. more 'precise' but can be too precise, so focused on the trees it misses the forest.
If we move from the dorsal/ventral dichotomy in each hemisphere to the right-brain/left-brain dichotomy the SAME pattern of development is shown - right brain is more developed at birth than left brain (in most). As differentiation of senses, an so general particularisation, takes over so the 'yang' side starts to dominate, to assert universals (such as handedness, discrete labels etc) - we move from general to particular.
Genetic diversity, hormones, or just local social context can the 'favour' a particular perspective to be favoured over all of the possible perspectives available on this dimension from yin to yang, integrating to differentiating etc etc.
If we move to the abstract realm of "Small World Networks", this development of YIN to YANG is dominating the universe as a whole in ITS development - IOW 'in here' reflects 'out there' rather well. With that development comes the ability to refuse to go on the ride any more - this allows for stratification to develop - but that development will STILL follow a yin-to-yang path, just localised in the particular, originating, context.
The IC binary sequence reflects this overall dynamic, rooted in the neuron (inputs (yin) to outputs (yang)) and all the way up into our collectives. As such, the micro and the macro is 'revealed' in the IC through the use of analogy/metaphor.
Chris.