Special Issue: Cognition in Neuropsychiatric Disorders
Cognition in schizophrenia: core
psychological and neural mechanisms
Deanna M. Barch and Alan Ceaser
Departments of Psychology, Psychiatry and Radiology, Washington University in St. Louis, Box 1125, One Brookings Drive,
St. Louis, MO 63130, USA
The challenge in understanding cognitive impairment in
schizophrenia is that people with this illness have def-
icits in an array of domains. Here, we briefly review
evidence regarding the pattern of deficits within three
domains: context processing, working memory and epi-
sodic memory. We suggest that there may be a common
mechanism driving deficits in these domains – an im-
pairment in the ability to actively represent goal infor-
mation in working memory to guide behavior, a function
we refer to as proactive control. We suggest that such
deficits in proactive control reflect impairments in dor-
solateral prefrontal cortex, its interactions with other
brain regions, such as parietal cortex, thalamus and
striatum, andthe influenceof neurotransmitter systems,
such as dopamine, GABA and glutamate.
Centrality of cognition in schizophrenia
When we think of the core symptoms of illness, such as
schizophrenia, we think of people who hear voices, see
visions and have false beliefs about reality (i.e., delusions).
However, clinicians have long recognized that abnormali-
ties in cognitive function are a key component of schizo-
phrenia, one of the most debilitating psychiatric disorders.
As such, the last three decades have witnessed a relative
explosion of research on cognition in schizophrenia, much
of it couched within the framework of understanding the
cognitive neuroscience of schizophrenia. This emphasis on
cognition in schizophrenia is in part due to the growing
body of research suggesting that cognitive function in
schizophrenia is one of the most critical determinants of
quality of life and function in schizophrenia, potentially
more so than the severity of other symptoms of schizophre-
nia, such as hallucinations or delusions .
The challenge we face in understanding the nature of
cognitive impairments in schizophrenia is that, at least on
the surface, individuals with this illness appear to have
deficits in a diverse array of domains, such as working
memory, language function, executive function, episodic
memory, processing speed, attention, inhibition and sen-
sory processing [2,3]. While it is certainly possible that this
seemingly diverse array of impairments reflects dissocia-
ble deficits, each with its own psychological and neural
pathophysiology, this explanation does little to help us
conceptualize the nature of cognitive dysfunction in this
illness, or in other psychotic disorders (Box 1). Instead,
a number of researchers have argued that a common
mechanism contributing to cognitive impairments across
a range of domains in schizophrenia is an inability to
actively represent goal information in working memory
needed to guide behavior and that this deficit reflects
impairments in the function of the dorsolateral prefrontal
cortex prefrontal cortex (DLPFC), its interactions with
other brain regions, such as the parietal cortex, the thala-
mus and the striatum, and the influence of neurotransmit-
In the sections below, we provide a discussion of the
evidence for such impairment in schizophrenia, and how
it manifests in domains typically referred to as executive
control, working memory and episodic memory.
Context: information that can be used to modify the interpretation of an event
or the response of an individual to stimuli in their environment. Context is
information that must be ‘actively’ held in mind so that it can be used to
mediate task appropriate behavior. Context information can be a specific prior
stimulus, the result of processing a sequence of prior stimuli, or more abstract
information, such as task instructions. Language processing provides a useful
example of context information, as in the following sentence: ‘In order to keep
pigs, you need a pen.’ In this sentence, the first clause serves as context that
biases towards the appropriate meaning of the word ‘pen’ (a fenced enclosure)
for this sentence, rather than the more common meaning of the word ‘pen’ (a
writing instrument). This is a case in which the result of processing the first
part of the sentence (e.g., a sequence of prior stimuli) creates a contextual
representation that can bias future behavior (e.g., the semantic interpretation
of the word ‘pen’) .
Episodic memory: the ability to learn and then subsequently retrieve
information about new ‘episodes’ in one’s life. Episodes can refer to events,
experiences, situations, or new associations, and can be linguistic or non-
linguistic in content.
Executive control: a collection of processes involved in supporting a range of
functions thought to be critical for effective cognitive function, including
processes, such as goal maintenance, set-shifting and inhibition.
Neurotransmitter system: types of chemicals in the brain that support
communication between neurons across synapses. Some examples include
the dopamine, serotonin, acetylcholine, glutamate and norepinephrine sys-
Proactive control: a form of cognitive processing, in which goal relevant
information is actively maintained in a form that biases attention, perception
and action towards the achievement of that goal .
Psychosis: a mental disturbance in which thoughts, emotions and perceptions
lose touch with reality. Individuals experiencing psychosis can have delusions,
hallucinations, and disorganized speech and behavior, as well as other types of
alterations (e.g., cognitive and motivational impairments). The psychiatric
disorder referred to as schizophrenia involves psychosis, but psychosis can
also occur in other psychiatric disorders, such as major depression and bipolar
Working memory: the ability to temporarily maintain and manipulate
Corresponding author: Barch, D.M. (email@example.com).
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