Introduction
- History of Auditory Streams
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- Hypothesis
The brain’s ability of efficiently processing input relies on a sophisticated methods - separating streams that compute different aspects of the inputs. One that computes information about the object itself - shape, colour, type - and the other streams computes motion and spatial information - where is the object in realtion to oneself, where is it moving towards?
The discovery of two streams in the brain of the dorsal where and the ventral what stream already occurred in the 1980s, especially for visual inputs. They form a clear pattern starting from the visual cortex and moving anterior into the prefrontal cortex.
The dorsal stream passes through the parietal cortex and terminates in the prefrontal cortex. From there top down attention is directed by the FEF.
The ventral visual stream passes down the temporal lobe passing by FFA and other recognition areas ending in prefrontal cortex. From there top down attention is directed by IFJ.
Today a similar structure is widly accepted for auditory inputs as well. What needs to be researched is whether FEF and IFJ function is attention hubs also for the auditory pathways and not only for visual. This is this research looking into.
The auditory system is commonly described as consisting of two major processing streams similar to the visual system with mainly two pathways. The posterodorsal where-stream and the anteriorventral what-stream.
For clarity in this paper we will use “where”-stream for the posterodorsal stream and “what” for the anteroventral stream due to some areas that could be location-wise assinged to a different stream than its acutal functional connectivity. Therefore we focus on connectivity, because this is more significant for attention than its pure location.
different hemispheres, different tasks
both streams have different functions.
The what stream
The Where-Stream
The function of the where-stream is debated (Hickok & Poeppel (2004) - Cognition), but due to its connection and location to the motor cortey, it is critical for audio-motor integration, similar to visual domain (Hickok & Poeppel (2004) - Cognition). This includes mapping sound onto articulatory-based representations. (Hickok & Poeppel (2004) - Cognition). The suggestion that the dorsal stream has an auditory–motor integration function differs from earlier arguments for a dorsal auditory ‘where’ system (Hickok & Poeppel 2007 - Nature).
On the level of areas
In the auditory cortex the Wernickes area of todays locations of the STG and STS with a strong left-laterilzation are heavily involved in speech processing.
Hypothesis
We propose a similar organisation for the auditory stream where FEF and IFJ are the attention hubs for the corresponding streams.
This position was challenged by two discoveries in the 1970s and 1980s. The first was that deficits in the ability to perceive speech sounds contributed minimally to the auditory comprehension deficit in Wernicke’s aphasia2–7. The second was that destruction of the left STG does not lead to deficits in the auditory comprehension of speech, but instead causes deficits in speech production8. These findings do not rule out a role for the left STG in speech perception, but make it clear that additional regions participate in the process.
see also
Methods
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Created: 2025-11-11 17:02