2 The thalamus at the center
A series of considerations have led us to reanalyze and reemphasize the impor-
tance of the thalamus as a region-of-interest for the neurobiology of language.
We will discuss several such considerations in this section, from conceptual to
empirical and technical. The order in which we discuss these considerations
should not be construed as reflecting the intrinsic importance we attach to each.
All of them are important to making the thalamus as central as we think it is.
There is a lot of evidence from a range of fields that humans are unique – or,
to put it in the context of an evolutionary continuum, far better than other
species – in transcending the signature limits of core knowledge systems, going
beyond modular boundaries (Boeckx 201 1a, b and references therein). This
ability, which has all the characteristics of a phase transition, is at the heart of
cognitive novelty, and subsequently, material and cultural innovation, leading
to the establishment of a new cognitive phenotype. Hauser (20 09) referred to
this as ‘humaniqueness’, which he defines as follows: the ability to “create and
easily understand symbolic representations of computation and sensory input”,
to “apply the same rule or solution to one problem to a different and new situ-
ation”, and to “combine and recombine different types of information and
knowledge in order to gain new understanding”.
Boeckx (2013 a, b) and Theofanopoulou and Boeckx (submitted) put forth
the idea that cross-modular conceptual combinations, of the sort made possible
by the core combinatorial rules of the language faculty, takes the form of cross-
frequency oscillation synchrony and coherence across distant, local brain net-
works, allowing for the binding of features distributed across core knowledge
systems. We think that this linking capacity (to be refined in subsequent sec-
tions) could be performed by the thalamus. As a matter of fact, a capacity of
long-distance synchrony and modulation has routinely been attributed to the
thalamus in other cognitive domains, such as vision (Saalmann et al. 2012,
Saalmann a nd Kastner 2011), so we think that it makes sense that this capacity
of the thalamus would have been recruited in the context of linguistic cogni-
tion. Indeed, it can be said that the central role of the thalamus is already firmly
established in cognitive functions such as consciousness, attention, working
memory or the central executive role, for which a crucial role for language is
often recognized. As a result, we think that a rapprochement between language
and the thalamus makes sense.
The latter point is further reinforced by considerations such as Chomsky’s
renewed emphasis on the idea that language serves as an internal “instrument
of thought” (Chomsky 2012, Berwick et al. 2013). As he writes (Chomsky
2012: 11), “probably 99.9% of [the] use [of language] is internal to the mind.
You can’t go a minute without talking to yourself. It takes an incredible act of
will not to talk to yourself”. With passages like this one, Chomsky seems to be
suggesting that language is crucially involved in cognitive behaviors like mind
wandering, foresight, internal planning and mentation, etc. This gains particular
relevance in a neurobiological context, as many of these cognitive traits are
232 Constantina Theofanopoulou and Cedric Boeckx