Synesthesia is defined as the perception of a certain stimulus, which is called the inducer, that automatically results in an internally generated sensation, which is called the concurrent (van Leeuwen, 2013). It is an uncommon condition but there are many different types of synesthesia. The most common type is synesthesia is grapheme-colour (GC) synesthesia. GC synesthesia is when letters induce the perception of colours (Ramachandran & Hubbard, 2001). Just as there are different types of synesthesia, there are individual differences between synesthetes such as the types of inducers that elicit the concurrent or the perception of the inducer. There are two major distinctions that synesthetes are classified into the projector-associator and
…show more content…
A GC projector synesthete will describe experiencing the concurrent colours as being projected onto the world, such as being projected onto the text, while a GC associator synesthete will describe as seeing the concurrent colours in their head (van Leeuwen, 2013). The distinction between higher-lower distinction classifies synesthetes based on the level of processing of the inducer and the type of inducer that elicits the concurrent (van Leeuwen, 2013). For lower GC synesthetes, the concurrent colours are elicited at an early processing stage, such as the shape of the grapheme, while the concept or meaning of the grapheme elicits the colours for high GC synesthetes (van Leeuwen, 2013). Since there are various types of synesthesia as well as individual differences between synesthetes, it is difficult to determine the mechanisms of synesthesia. The purpose of the current review is to present the two controversial theories on the neural mechanisms of synesthesia and provide evidence for …show more content…
However, looking at case studies of brain damage that induces synesthesia also supports the CA model of understanding the neural mechanisms of synesthesia. The onset and causes of synesthesia is another topic of controversial synesthetic findings, but there is evidence that brain damage can induce synesthesia. Ro et al. (2007) studied the case of a woman with lesions in the ventrolateral nucleus of the thalamus, which is involved in motor functions. After the lesions of this thalamic regions, she developed auditory-tactile synesthesia, where a tone includes the synthetic experience of touch sensation (Ro et al., 2007). They suggest that she developed synesthesia due to the neuroplasticity of the brain which rewired the brain and resulted in greater connections between the auditory and somatosensory regions of the brain (Ro et al., 2007). A DTI was used to show the altered connections from the damaged thalamus (Ro et al., 2007). These results show the role of VL in normal sensory processing and that reorganization of the rain can alter connectivity to change the process of perception (Ro et al., 2007). This study on injury induced synesthesia supports the CA model because it is the increased connectivity from neuroplasticity of the brain that induced the synesthetic experience this patient
A GC projector synesthete will describe experiencing the concurrent colours as being projected onto the world, such as being projected onto the text, while a GC associator synesthete will describe as seeing the concurrent colours in their head (van Leeuwen, 2013). The distinction between higher-lower distinction classifies synesthetes based on the level of processing of the inducer and the type of inducer that elicits the concurrent (van Leeuwen, 2013). For lower GC synesthetes, the concurrent colours are elicited at an early processing stage, such as the shape of the grapheme, while the concept or meaning of the grapheme elicits the colours for high GC synesthetes (van Leeuwen, 2013). Since there are various types of synesthesia as well as individual differences between synesthetes, it is difficult to determine the mechanisms of synesthesia. The purpose of the current review is to present the two controversial theories on the neural mechanisms of synesthesia and provide evidence for …show more content…
However, looking at case studies of brain damage that induces synesthesia also supports the CA model of understanding the neural mechanisms of synesthesia. The onset and causes of synesthesia is another topic of controversial synesthetic findings, but there is evidence that brain damage can induce synesthesia. Ro et al. (2007) studied the case of a woman with lesions in the ventrolateral nucleus of the thalamus, which is involved in motor functions. After the lesions of this thalamic regions, she developed auditory-tactile synesthesia, where a tone includes the synthetic experience of touch sensation (Ro et al., 2007). They suggest that she developed synesthesia due to the neuroplasticity of the brain which rewired the brain and resulted in greater connections between the auditory and somatosensory regions of the brain (Ro et al., 2007). A DTI was used to show the altered connections from the damaged thalamus (Ro et al., 2007). These results show the role of VL in normal sensory processing and that reorganization of the rain can alter connectivity to change the process of perception (Ro et al., 2007). This study on injury induced synesthesia supports the CA model because it is the increased connectivity from neuroplasticity of the brain that induced the synesthetic experience this patient