Lucy Morley

Facial fear processing and psychotic symptoms in schizophrenia: functional magnetic resonance imaging study

BACKGROUND The recognition of negative facial affect is impaired in people with schizophrenia. The neural underpinnings of this deficit and its relationship to the symptoms of psychosis are still unclear. AIMS To examine the association between positive and negative psychotic symptoms and activation within the amygdala and extrastriate visual regions of patients with schizophrenia during fearful and neutral facial expression processing. METHOD Functional magnetic resonance imaging was used to measure neural responses to neutral and fearful facial expressions in 11 patients with schizophrenia and 9 healthy volunteers during an implicit emotional task. RESULTS No association between amygdala activation and positive symptoms was found; the activation within the left superior temporal gyrus was negatively associated with the negative symptoms of the patients. CONCLUSIONS Our results indicate an association between impaired extrastriate visual processing of facial fear and negative symptoms, which may underlie the previously reported difficulties of patients with negative symptoms in the recognition of facial fear.

Using the Stroop task to investigate the neural correlates of symptom change in schizophrenia

This study examined brain activation during a cognitive inhibition task in patients with schizophrenia following changes in their positive symptoms. A Stroop task was used during functional magnetic resonance imaging in 11 patients with schizophrenia (patient group) and 9 healthy volunteers (control group). At baseline, the patient group showed significantly attenuated activation within the anterior cingulate gyrus, left pre-/postcentral gyrus and inferior frontal junction. At follow-up, there was a significant increase in activation in the left inferior frontal junction associated with a decrease in positive symptoms, suggesting this region plays a role in the development of these symptoms.

An fMRI study of prefrontal dysfunction and symptomatic recovery in schizophrenia

Smee C, Krabbendam L, O’Daly O, Prins A‐M, Nalesnik N, Morley L, Samson G, Shergill S. An fMRI study of prefrontal dysfunction and symptomatic recovery in schizophrenia.

Exploring psychotic symptoms: a comparison of motor related neuronal activation during and after acute psychosis

BackgroundDelusions and hallucinations are classic positive symptoms of schizophrenia. A contemporary cognitive theory called the ‘forward output model’ suggests that the misattribution of self-generated actions may underlie some of these types of symptoms, such as delusions of control – the experience of self-generated action being controlled by an external agency. In order to examine the validity of this suggestion, we performed a longitudinal functional magnetic resonance imaging (fMRI) study examining neuronal activation associated with motor movement during acute psychosis.MethodsWe studied brain activation using fMRI during a motor task in 11 patients with schizophrenia and 9 healthy controls. The patient group was tested at two time points separated by 6–8 weeks.ResultsAt initial testing, the patient group had a mean Positive and Negative Syndrome Scale score of 56.3, and showed significantly increased activation within the left inferior parietal lobe (IPL) compared to controls. Patients reported significantly decreased positive symptoms at 6–8 week followup and IPL activation had returned to normal. Our results demonstrate that first-rank positive symptoms are associated with hyperactivation in the secondary somatosensory cortex (IPL).ConclusionsThese findings lend further credence to the theory that a dysfunction in the sensory feedback system located in the IPL, and which is thought to underlie our sense of agency, may contribute to the aetiology of delusions of control.

Prefrontal cortical dysfunction in schizophrenia: an fMRI study

Background Prefrontal cortical dysfunction has been implicated in the pathophysiology of schizophrenia [1], although functional neuroimaging studies have reported mixed findings. A major concern is that alterations in the prefrontal activation in patients may be related to differences in task demand and performance [2]. This study manipulated task demand during an established frontal task to examine these issues.

Differential activation of fusiform gyrus during fearful face processing in schizophrenia

Background The crucial role of the fusiform or occipitotemporal gyrus in face recognition has been supported by findings from neuropsychological, brain lesion as well as functional neuroimaging studies. These findings suggest a crucial role of this region in finely discriminating and processing invariant aspects of the human face information as well as the emotional facial expressions. Recent functional neuroimaging studies suggest a direct role of the fusiform gyrus in the processing of fearful facial expressions; it has been demonstrated that this region shows statistically significant greater activation during the processing of fearful compared with neutral faces. In addition, increasing activation of the fusiform gyrus with increasing intensity of facial fear has been demonstrated.

Fearful emotional processing enhances activation of temporal cortices

Background The amygdala plays a central role in fear-related learning and activation during the processing of fearful facial expressions is a consistent finding from several functional neuroimaging studies. However, perception of fearful facial expressions also elicits greater activation of the vision-related regions of the temporal cortex. It has been proposed that the enhanced neuronal activation of temporal visual cortices may arise via its connectivity with the amygdala and represent an amygdala-mediated system to increase perceptual sensitivity for the threat-related facial expressions. We examined the functional connectivity between task-induced amygdala and temporal visual cortices activation, using functional imaging.