involving the thalamus and could therefore serve as convenient biomarkers, and
eventually provide robust targets for efficient therapies.
Bish et al.’s (2004) report of thalamic reductions in children with chromo-
some 22q11.2 deletion syndrome fits well in this context. Chromosome 22q11.2
deletion syndrome (22q) encompasses DiGeorge and velocardiofacial (VCFS)
syndromes. It is a congenital condition resulting from a deletion at chromosome
22q11.2 and has a prevalence of at least one in 4,000 live births. According to
Bish et al. (2004), the most systematically observed m anifestations of 22q include
cleft palate, heart defects, T-cell abnormalities, and neonatal hypocalcemia, as
well as facial dysmorphisms and mild to moderate cognitive deficits. Along with
an overall delay in early cognitive, psychomotor, and language development and
an overall IQ typically in the range 70–85, a subset of deficits are evident in
the areas of visuospatial and numerical performance. Children with 22q also
show an extremely high incidence of psychopathology, especially schizophrenia,
as they reach adulthood. That we find thalamic damage (especially affecting the
pulvinar) in these children suggests that it would be a serious mistake to ignore
the role of the thalamus in language and cognition.
The point of this section is not to provide a comprehensive catalog of cases
of thalamic damage associated with cognitive/language disorders. Rather, we
want to use the evidence just reviewed to shed light on what it is that the
thalamus does to make human linguistic cognition possible in the first place.
In other words, our intention is to follow a long tradition of studies exploiting
atypical situations to understand the norm.
The majority of the disorders mentioned in this section are routinely character-
ized as disorders of information processing, ‘dysregulation’ syndromes, or, even
more frequently, ‘disconnection syndromes’ (see, e.g., Schmahmann and Pandya
2008). They are viewed as dysfunction s in the coordination of distributed neural
activity between and within functionally specialized regions of the brain. In the
relevant literature, the guiding idea is that connectivity in some sense determines
behavior, and that as soon as a node in the relevant network fails, the whole net-
work is affected; the ‘traffic’ stops, or at the very least is severely affected. In this
context, the thalamus appears like a central pacemaker (Buzsáki 1991) or “universal
synchronizer” (Ghosh et al. 2014) , a “mediator” among networks (Barron et al.
2015), pretty much like the conductor of an orc hestra: if one of the players fails,
the conductor’s job is affected. If the conductor fails, the jobs of all the players
are affected. This may be a good place to recall Patterson’s (1987) remark: “if
one were to single out a brain structure that displayed the possibility for central
‘timing’ functions in brain, it would most likely be the thalamus”.
For disorders like schizophrenia and autism, seen as ‘information-processing
impairments’, it is common to find talks of an imbalance between inhibition
and excitation (Yizhar et al. 2011). The central idea here is that for the type
of cognition we are interested in to emerge, there must be a suitable, perhaps
even optimal, mix between local and long-distance connections, with the traffic
(information flow) being regulated by a suitable balance of excitation and inhi-
bition (with inhibition mostly coming from the thalamus, a point we return to
The central role of the thalamus 239