The in the neurological study of the

The Visual Word Form Area (VWFA), located in the left
fusiform gyrus, responds exclusively in language to the perception of visual words
as opposed to the perception of speech. It has been thoroughly established in
previous literature that this region possesses a unique specialization for word
forms. Currently, the VWFA is essential to studying the neural basis of
reading. However, this region is of special interest in the study of
neuroscience since it is “highly unlikely that evolution has created a brain
system specialized for reading” (Hirshorn et al., 2016). The lack of an
evolutionary basis poses the new question of how the brain processes
information that is learned through prolonged exposure and experience (Hirshorn
et al., 2016). With no underlying evolutionary foundation yet connected to the
VWFA and a lack of a similar region in other species, research on the VWFA will
provide insight into human’s capacity for written language, whereas variations
of verbal language are evident throughout the animal kingdom. Advances in the neurological
study of the language in the brain has resulted in a modern debate around the
role of the VWFA in language processing. It has been established that this is
the predominant functional region involved in processing the identity of words
based on lower-order shapes. However, the exact processes of the VWFA in
relation to the language system as a whole are in dispute, breeding the Visual
Word Form Hypothesis: the VWFA is responsible for discerning the identity of
words before any semantic or phonology processes are resolved. Given its
specificity, the left fusiform gyrus, specifically the Visual Word Form Area,
is responsible for the pre-lexical identification of words but does not have
the capacity for lexical representations.

            In
order to discern the role of the VWFA in pre-lexical and lexical
representations, a 2002 study, conducted by researchers Dehaene et al., used a
basic visual and audio based task performed concurrently with fMRI scanning in
“the visual word form area: a prelexical representation of visual words in the
fusiform gyrus.” Subjects were presented two consecutive words or pseudo-words
(strings of letters than follow orthology and could plausibly be real words),
both of which were either written or spoken. The subject was responsible for
determining if the stimulus had been repeated. The audio case served as a
baseline control to discern the extent of the WFVA’s role in pre-lexical and
lexical representations. The study’s results “are compatible with the hypothesis
that this area is involved in a visual and prelexical representation” (Dehaene
et al., 2002). These results confirm the role of the VWFA in visual word
processing as being broadly specialized for all identifying the amalgamation of
lower order shapes: “no differential activation was found in the VWFA as a
function of the semantic category of the stimuli,” as well as “meaningless
pseudo-words evoked very strong activation in this area” (Dehaene et al.,
2002). This proves the VWFA’s role in pre-lexical visual word identification
since the VWFA responds equally to visual word forms regardless of the
underlying semantics or phonology (that are vastly different for a word and a
pseudo-word). This study used an fMRI procedure that reaffirmed the VWFA’s
responsiveness to visual word forms as well as the equal processing of words
and pseudo-words demonstrating a blindness to lexical (semantic and phonology)
information.

            Building
upon the work of Dehaene et al. (2002), Hirshorn et al. (2016) attempts to
further discern the role of the VWFA in their study, “Decoding and disrupting
left midfusiform gyrus activity during word reading.” Using intracranial
electroencephalography (iEEG) in four patients, images were presented to
subjects representing varying visual stimuli, such as bodies, phase-scrambled
objects, and words to measure activity in the left midfusiform gyrus (lmFG).
Furthermore, in Hirshorn et al. 2016, two subjects then had electrical
stimulation directly along the left midfusiform gyrus to enable researchers to
determine the impact of disrupting lmFG activity. After lmFG stimulation,
subjects “showed the characteristics of acquired alexia —
specifically letter-by-letter reading and longer naming times” which indicates
that the lmFG is responsible for the processes involved in word identification (Hirshorn
et al., 2016). In the stimulation experiments, the researchers observed that
“disruption of lmFG function impairs both skilled identification of visual
words and sublexical components of words” (Hirshorn et al., 2016). The
diminished ability to read in patients with stimulated lmFG demonstrates the
role of the lmFG specifically as a sublexical component. After images are
processed in the visual system, visual data is converted into inferential lexical-based
data in the lmFG. Interpretation of the EEG results specified that not only
does the lmFG process pre-lexical identification, but that it exists in two
distinct stages. The first stage is “an early stage that allows for
category-level word decoding and gist-level representation” and the second
stage “supports precise word individuation” (Hirshorn et al., 2016). This
two-step process reaffirms the VWFA and left fusiform gyrus’ role in
identification of lower-level shapes. With the evidence presented by Hirshorn
et al., (2016), it can be concluded that the left midfusiform gyrus is
responsible for pre-lexical processes. Although gist-level guesses can be made
in the lmFG, which lead to a lexical conclusion, the predictions themselves are
a result of further pre-lexical analysis.

            Both
studies conclude that the VWFA is responsible for the coding of visually
presented words and can be cross-analyzed to further specify the role and
discern the underlying processes of the VWFA. The two distinct processes in the
lmFG found in Hirshorn et al. (2016) can directly be related to Dehaene et al.
(2002). The “greater activation to pseudo-words than to words” found by Dehaene
et al. (2002) may be a result of the first stage of processing that Hirshorn et
al.’s (2016) uncovered, where gist-level representations are formed (Dehaene et
al., 2002). Since pseudo-words are unrecognizable but familiar, the VWFA
activates more in the Hirshom et al.’s gist-level stage as it attempts to
identify the pseudo-word, which may be similar to preexisting words and the
orthographic rules known by the subject, but does not actually have any basis
to make a gist-level interpretation upon (since there is no conclusion to reach
since it does not actually exist).

Pairing the temporal results from
Hirshorn et al. (2016) with the qualitative conclusions of Dehaene et al.
(2002) supports the hypothesis claiming that the left fusiform gyrus and more
specifically, the Verbal Word Form Area, are responsible for pre-lexical
interpretation but not lexical representation. Overall, there is far more
research to be conducted on the VWFA. Directly, there are more insights into
language processing to be found. However on a broader scale, since it the
process of reading is not rooted in as an evolutionary factor, future research
may provide understanding on processes in which there is no evolutionary basis,
only extensive experience and exposure.