Chris Frith

Meeting of minds: the medial frontal cortex and social cognition.

Social interaction is a cornerstone of human life, yet the neural mechanisms underlying social cognition are poorly understood. Recently, research that integrates approaches from neuroscience and social psychology has begun to shed light on these processes, and converging evidence from neuroimaging studies suggests a unique role for the medial frontal cortex. We review the emerging literature that relates social cognition to the medial frontal cortex and, on the basis of anatomical and functional characteristics of this brain region, propose a theoretical model of medial frontal cortical function relevant to different aspects of social cognitive processing.

The Cognitive Neuropsychology of Schizophrenia

The Nature of Schizophrenia. Brain Abnormalities in Schizophrenia. Linking the Mind and the Brain. Behavioural Abnormalities. Positive Symptoms, Abnormal Experiences. Communication in Schizophrenia. Schizophrenia as a Disorder of Self-Awareness. Appendices. References. Author Index. Subject Index.

Empathic neural responses are modulated by the perceived fairness of others

The neural processes underlying empathy are a subject of intense interest within the social neurosciences. However, very little is known about how brain empathic responses are modulated by the affective link between individuals. We show here that empathic responses are modulated by learned preferences, a result consistent with economic models of social preferences. We engaged male and female volunteers in an economic game, in which two confederates played fairly or unfairly, and then measured brain activity with functional magnetic resonance imaging while these same volunteers observed the confederates receiving pain. Both sexes exhibited empathy-related activation in pain-related brain areas (fronto-insular and anterior cingulate cortices) towards fair players. However, these empathy-related responses were significantly reduced in males when observing an unfair person receiving pain. This effect was accompanied by increased activation in reward-related areas, correlated with an expressed desire for revenge. We conclude that in men (at least) empathic responses are shaped by valuation of other peoples social behaviour, such that they empathize with fair opponents while favouring the physical punishment of unfair opponents, a finding that echoes recent evidence for altruistic punishment.

The Neural Basis of Mentalizing

Mentalizing refers to our ability to read the mental states of other agents and engages many neural processes. The brains mirror system allows us to share the emotions of others. Through perspective taking, we can infer what a person currently believes about the world given their point of view. Finally, the human brain has the unique ability to represent the mental states of the self and the other and the relationship between these mental states, making possible the communication of ideas.

Willed action and the prefrontal cortex in man: a study with PET.

We used positron emission tomography to contrast changes in cerebral blood flow associated with willed and routine acts. In the six tasks used, volunteers had to make a series of responses to a sequence of stimuli. For the routine acts, each response was completely specified by the stimulus. For the willed acts, the response was open-ended and therefore volunteers had to make a deliberate choice. Willed acts in the two response modalities studied (speaking a word, or lifting a finger) were associated with increased blood flow in the dorsolateral prefrontal cortex (Brodmann area 46). Willed acts were also associated with decreases in blood flow, but the location of these decreases was modality dependent.

Central cancellation of self-produced tickle sensation

A self-produced tactile stimulus is perceived as less ticklish than the same stimulus generated externally. We used fMRI to examine neural responses when subjects experienced a tactile stimulus that was either self-produced or externally produced. More activity was found in somatosensory cortex when the stimulus was externally produced. In the cerebellum, less activity was associated with a movement that generated a tactile stimulus than with a movement that did not. This difference suggests that the cerebellum is involved in predicting the specific sensory consequences of movements, providing the signal that is used to cancel the sensory response to self-generated stimulation.

Dysconnection in Schizophrenia: From Abnormal Synaptic Plasticity to Failures of Self-monitoring

Over the last 2 decades, a large number of neurophysiological and neuroimaging studies of patients with schizophrenia have furnished in vivo evidence for dysconnectivity, ie, abnormal functional integration of brain processes. While the evidence for dysconnectivity in schizophrenia is strong, its etiology, pathophysiological mechanisms, and significance for clinical symptoms are unclear. First, dysconnectivity could result from aberrant wiring of connections during development, from aberrant synaptic plasticity, or from both. Second, it is not clear how schizophrenic symptoms can be understood mechanistically as a consequence of dysconnectivity. Third, if dysconnectivity is the primary pathophysiology, and not just an epiphenomenon, then it should provide a mechanistic explanation for known empirical facts about schizophrenia. This article addresses these 3 issues in the framework of the dysconnection hypothesis. This theory postulates that the core pathology in schizophrenia resides in aberrant N-methyl-D-aspartate receptor (NMDAR)–mediated synaptic plasticity due to abnormal regulation of NMDARs by neuromodulatory transmitters like dopamine, serotonin, or acetylcholine. We argue that this neurobiological mechanism can explain failures of self-monitoring, leading to a mechanistic explanation for first-rank symptoms as pathognomonic features of schizophrenia, and may provide a basis for future diagnostic classifications with physiologically defined patient subgroups. Finally, we test the explanatory power of our theory against a list of empirical facts about schizophrenia.

Experiencing Oneself vs Another Person as Being the Cause of an Action: The Neural Correlates of the Experience of Agency

The present study is aimed at identifying the neural correlates of two kinds of attribution: experiencing oneself as the cause of an action (the sense of agency) or experiencing another person as being the cause of that action. The experimental conditions were chosen so that they differed only in their requirement to attribute an action to another person or to oneself. The same motor task and the same visual stimuli were used in the experimental conditions. Subjects used a joystick to drive a circle along a T-shaped path. They were told that the circle would be driven either by themselves or by the experimenter. In the former case subjects were requested to drive the circle, to be aware that they drove the circle, and thus to mentally attribute the action seen on the screen to themselves. In the latter case they were also requested to perform the task, but they were aware that action seen on the screen was driven by the experimenter. In accord with previous studies, the results showed that being aware of causing an action was associated with activation in the anterior insula, whereas being aware of not causing the action and attributing it to another person was associated with activation in the inferior parietal cortex. These two regions are involved in the perception of complex representations of the self and of its interactions with the external world. We suggest that the anterior insula is concerned with the integration of all the concordant multimodal sensory signals associated with voluntary movements. The inferior parietal cortex, in contrast, represents movements in an allocentric coding system that can be applied to the actions of others as well as the self.

A PET study of word finding

We have used PET in conjunction with psychological activations to identify cortical areas involved in the intrinsic activation of word representations. In four normal subjects intrinsic generation of a word (verbal fluency) was associated with an increase in left dorsolateral prefrontal cortical activity (BA 46) and a bilateral decrease in activity in auditory and superior temporal cortices. Conversely, when subjects made lexical decisions about words that were heard, there was an increase in superior temporal activity with no change in area 46. We suggest that the superior temporal regions are the site of stored word representations and that inhibitory modulation of these areas by the left prefrontal cortex is the basis of intrinsic word generation.

Exploring ‘theory of mind’ in people with schizophrenia

Mentalizing ability was studied in 46 symptomatic schizophrenic patients and 44 non-symptomatic controls. Subjects heard six stories and simultaneously were shown simple cartoon pictures depicting the action sequencing occurring in the stories. All the stories involved false belief or deception, so that it was necessary to infer the mental states of the characters in order to understand their behaviour. After each story, subjects were asked one memory/reality question (concerning an event in the story) and one question that depended on the ability to infer the mental state of one of the characters. Patients with paranoid delusions were impaired on the questions concerning mental states. Patients with behavioural signs (i.e. negative features or incoherence) were also impaired on the mental state questions, but this difficulty was associated with memory impairments. Patients with symptoms of passivity (e.g. delusions of control) and patients in remission did not differ from normal controls. These results are consistent with the hypothesis that certain of the positive symptoms of schizophrenia reflect an impairment in the ability to infer the mental states of others.