strongly associated with the parietal lobe (dorsal pulvinar). This strikes us as
particularly relevant, as the pulvinar has been claimed to be crucially involved in
cortico-cortical information management (Theyel et al. 20 10, Saalmann et al.
2012). As a matter of fact, the most conspicuous cortical region linked to parietal
bulging, the precuneus (Bruner et al. 20 14a, b), is most strongly connected to
the pulvinar (Cavanna and Trim ble 2006 and references therein).
The notion of co-evolution strengthens our belief that the thalamus is key
in the domain of human cognition. A recent study by Bohsali et al. ( 2015) has
revealed significant structural connectivity between Broca’s area and the thalamus,
specifically the pulvinar. As is well known, Broca’s area has undergone a spec-
tacular enlargement in recent human evolution (Schenker et al. 20 10), which
must have been associated with a comparable recruitment and expansion of the
thalamic nuclei to which Broca’s area is connected. Interestingly, there is inde-
pendent evidence for a significant expansion of the pulvinar in our species. The
pulvinar nucleus of the thalamus is known to have expanded greatly in primate
evolution, with its expansion linked to cortical areas associated with integration
of visual information, attention, and movement planning. But in humans, higher-
order association nuclei like the pulvinar and the medio-dorsal nucleus have
been said to be disproportionately large (Striedter 2005: 331 ) (see also Arm-
strong 1981). Su ch an enlargement is often related to an evolutionary novelty:
in human development alone, the pulvinar receives extra GABAergic cells migrat-
ing from a telencephalic structure known as the ganglionic eminence (Rakic
and Sidman 19 69, Letinic and Rakic 2 001).
Interestingly as well, there is indirect evidence of a recruitment of thalamic
nuclei like the pulvinar for linguistic purposes. Taken into account the reduction
of the visual cortex in humans, especially in Homo sapiens (Pearce et al. 2013) ,
one could hypothesize that the pulvinar, classically associated with visual atten-
tion, was recruited for purposes of linguistic cognition, as we wish to suggest
in the present paper.
A final consideration leading to a reappraisal of the role of the thalamus is
more pragmatic, as it pertains to technological considerations. There may indeed
have been a technological reason why early biological concepts of language were
predominantly corticocentric. The thalamus lies deep inside the brain, and is
therefore far less easily accessible than the more surfacy cortical regions. How-
ever, as reviewed in Klostermann et al. (2013), the emergence of new technical
possibilities is slowly correcting for the cortical bias. For instance, David et al.
(2011) provide the first demonstration in cognitive neuroscience that subcortical-
cortical loops can be empirically investigated using noninvasive electrophysiologi-
cal recordings. Specifically, they show that “a hidden source, modeling
magnetically silent deep nuclei, is required to explain the[ir] data best”. Based
on data from intracranical recordings with similar language material in Wahl
et al. (2008), the so-called “deep source” in David et al. (2011) is assumed to
correspond to the thalamus and the respective thalamocortical loops. While it
remains true that subcortical structures like the basal ganglia and the cerebellum
continue to figure more prominently in this new, less cortico-centric paradigm
234 Constantina Theofanopoulou and Cedric Boeckx