## 4 Discussion
However, there is a right hemispheric dominance (although occurring bilaterally) for digits compared to words, which obviously consist of another class of symbols (i.e., letters, not digits). This finding is also consistent with the results reported by [PERSON] et al. [41] (see above). The researchers employed intracranial electrophysiological recordings in epileptic patients with a history of seizures, for which the patients had undergone implantation of electrodes. It is noteworthy that the pathological status of the subjects may have influenced the results, yet it is nevertheless striking to observe an enhanced cerebral response to visually presented numerals in comparison to morphologically similar stimuli, including letters, false fonts, symbols, number words, and words in the inferior temporal and occipto-temporal regions (all of which are situated in close proximity). In conclusion, our findings regarding the earliest neurophysiological effect are in accordance with prior studies indicating that the inferior occipto-temporal cortical region (potentially encompassing occipto-parietal aspects) predominantly responds to visual digit presentations. It is of particular significance that our novel data provide a temporal marker for the differentiation in neural processing between digits and other linguistic elements, including words, non-words, and number words. This difference becomes apparent approximately 200 ms after a stimulus is presented and reaches its maximum at around 230 ms. Although the respective lateralisation remains uncertain, it is proposed that this region in the left hemisphere is more specialised for the conversion of letter symbols to meaning, whereas the corresponding area in the right hemisphere is more specialised for the initialisation of the conversion of digits into their meaning, which is a certain quantity. At a later stage of the processing hierarchy, approximately 70 ms later (at around 300 ms post-stimulus onset), number words evoked the most negative-going brain potentials at the left temporo-parietal region, followed by non-words, words, and digits, which were observed to elicit the smallest brain potential amplitude in this region and at this time point. As previously stated, this region is functionally analogous to the language comprehension area. In this context, the approximately 70 ms prior high brain activity level related to digits has already been sent to more frontal brain areas. However, number words (consisting of letters) appear to be strongly processed here. It appears that the aforementioned area is activated by meaningful letter strings yet lacks the requisite neural representations, thereby hindering the activation of the requisite neural circuits. Consequently, it requires assistance from other, more frontal cortical brain areas. It must be acknowledged that these observations are, at this stage, purely speculative. However, the high temporal and acceptable spatial resolutions of an EEG system allow for such hypotheses to be formulated. Finally, and most intriguingly, the processing of digits as symbols for quantities is most pronounced in the left inferior fronto-temporal brain region, beginning at approximately 400 ms post-stimulus onset and reaching its peak at around 450 ms at the F7 electrode location. It seems plausible to suggest that the earlier increase in brain activity in the occipito-parietal (or temporo-parietal) cortical region elicited by digits ultimately resulted in this pronounced left inferior frontal activity level. This region appears to have developed a specialisation for quantity processing at the cognitive level, at least in the adult human brain. It is noteworthy that at this juncture and in this region, number words evoked the most substantial brain potential amplitudes among all letter-string stimuli. This is indicative of neurophysiological evidence that number words are also capable of triggering mental representations of quantities, albeit to a lesser extent than digits.