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Steven M Platek

Publications and source records attributed to Steven M Platek.

16 recordsLinked to original sources
PubMed2006

Self-face recognition and theory of mind in patients with schizophrenia and first-degree relatives.

OBJECTIVE: The hypothesized relationship between theory of mind (ToM) and self-face recognition as well as its potential genetic associations has not been previously explored in patients with schizophrenia and in first-degree relatives with schizotypal personality traits. METHOD: Ten patients diagnosed with schizophrenia, 10 of their first-degree relatives and 10 healthy controls were included. To assess self-face recognition (SFR), participants were presented images of faces of themselves and others and asked to make rapid 'unfamiliar', 'familiar' and 'self' judgments. As a measure of ToM, subjects were administered the Revised Mind in the Eyes Test (MET [Baron-Cohen, S., Wheelwright, S., Hill, J., Raste, Y., and Plumb, I., 2001. The "Reading the Mind in the Eyes" Test revised version: a study with normal adults, and adults with Asperger syndrome or high-functioning autism. J Child Psychol Psychiatry 42(2), 241-251.]). Schizotypal characteristics in relatives and controls were assessed using a modified version of the Schizotypal Personality Questionnaire (SPQ [Raine, A., 1991. The SPQ: a scale for the assessment of schizotypal personality based on DSM-III-R criteria. Schizophrenia Bulletin 17(4), 555-564.]). RESULTS: Patients took longer and were less accurate on the SFR task than their relatives who in turn performed worse than healthy controls. Specific ToM deficits in schizophrenia were replicated. There was a relationship between accuracy rates on the MET and SFR tasks. High levels of schizotypal traits such as social anxiety, constricted affect and no close friends were important for both tasks. CONCLUSIONS: Face recognition deficits and ToM deficits in schizophrenia are apparent. The critical influence of high levels of select schizotypal traits is also highlighted. A deficit in relatives of schizophrenia patients raises the possibility that ToM and face recognition deficits may be candidate endophenotypes for schizophrenia. Support for the hypothesized link between ToM and face recognition is provided.

Adult↗
PubMed2006

Neural substrates for functionally discriminating self-face from personally familiar faces.

Understanding the neurobiological substrates of self-recognition yields important insight into socially and clinically critical cognitive functions such as theory of mind. Experimental evidence suggests that right frontal and parietal lobes preferentially process self-referent information. Recognition of one's own face is an important parameter of self-recognition, but well-controlled experimental data on the brain substrates of self-face recognition is limited. The goal of this study was to characterize the activation specific to self-face in comparison with control conditions of two levels of familiarity: unknown unfamiliar face and the more stringent control of a personally familiar face. We studied 12 healthy volunteers who made "unknown," "familiar," and "self" judgments about photographs of three types of faces: six different novel faces, a personally familiar face (participant's fraternity brother), and their own face during an event-related functional MRI (fMRI) experiment. Contrasting unknown faces with baseline showed activation of the inferior occipital lobe, which supports previous findings suggesting the presence of a generalized face-processing area within the inferior occipital-temporal region. Activation in response to a familiar face, when contrasted with an unknown face, invoked insula, middle temporal, inferior parietal, and medial frontal lobe activation, which is consistent with an existing hypothesis suggesting familiar face recognition taps neural substrates that are different from those involved in general facial processing. Brain response to self-face, when contrasted with familiar face, revealed activation in the right superior frontal gyrus, medial frontal and inferior parietal lobes, and left middle temporal gyrus. The contrast familiar vs. self produced activation only in the anterior cingulate gyrus. Our results support the existence of a bilateral network for both perceptual and executive aspects of self-face processing that cannot be accounted for by a simple hemispheric dominance model. This network is similar to those implicated in social cognition, mirror neuron matching, and face-name matching. Our findings also show that some regions of the medial frontal and parietal lobes are specifically activated by familiar faces but not unknown or self-faces, indicating that these regions may serve as markers of face familiarity and that the differences between activation associated with self-face recognition and familiar face recognition are subtle and appear to be localized to lateral frontal, parietal, and temporal regions.

Brain↗
PubMed2006

Brain mapping of deception and truth telling about an ecologically valid situation: functional MR imaging and polygraph investigation--initial experience.

PURPOSE: To examine the neural correlates during deception and truth telling by using a functional magnetic resonance (MR) imaging technique and an ecologically valid task and to compare the results with those of a standard polygraph examination. MATERIALS AND METHODS: All subjects gave written informed consent for this HIPAA-approved study, which was approved by the institutional review board of Drexel University. Eleven healthy subjects (five female and six male subjects; mean age, 28.9 years) were randomly assigned to the group of guilty subjects or the group of nonguilty subjects. Each group consisted of two separate functional MR imaging conditions: "lie-only condition" and "truth-only condition." The lie-only condition was used to compare brain activity during a known lie to control questions and a subjective lie to relevant questions. The truth-only condition was used to compare brain activity during a known truthful response to control questions and a subjective truthful response to relevant questions. Functional MR images were acquired with an echo-planar sequence, and statistical analysis was performed. Physiologic responses were measured with a standard four-channel polygraph instrument. RESULTS: During the deception process, specific areas of the frontal lobe (left medial and left inferior frontal lobes), temporal lobe (right hippocampus and right middle temporal gyrus), occipital lobe (left lingual gyrus), anterior cingulate, right fusiform gyrus, and right sublobar insula were significantly active. During the truth telling process, specific areas of the frontal (left subcallosal gyrus or lentiform nucleus) and temporal (left inferior temporal gyrus) lobes were significantly active. The polygraph examination revealed 92% accuracy in deceptive subjects and 70% accuracy in truthful subjects. CONCLUSION: Specific areas of the brain involved in deception or truth telling can be depicted with functional MR imaging.

Adult↗
PubMed2005

Integrated zone comparison polygraph technique accuracy with scoring algorithms.

The Integrated Zone Comparison Technique (IZCT) was utilized with computerized polygraph instrumentation as part of a blind study in the detection of deception. Three scoring algorithms: ASIT Poly Suite (Academy for Scientific Investigative Training's Horizontal Scoring and Algorithm for Chart Interpretation), PolyScore 5.5, and the Objective Scoring System (OSS) were assessed in the interpretation of the charts generated. Where "Inconclusives" were excluded, accuracy for the IZCT with all three algorithms was 100%. When "Inconclusives" were counted as errors, overall accuracy for the IZCT with ASIT Poly Suite was 90% and accuracy with PolyScore and the Objective Scoring System was 72%.

Algorithms↗
PubMed2005

Sex differences in the neural correlates of child facial resemblance: an event-related fMRI study.

Detection of genetic relatedness (i.e. kinship) impacts the social, parental, and sexual behavior of many species. In humans, self-referent phenotype matching based on facial resemblance may indicate kinship. For example, faces that resemble ours are perceived as more trustworthy and attractive. Sex differences in behavioral reactions to facial resemblance among children have also been demonstrated and are consistent with evolutionary theory suggesting that resemblance might serve as a paternity cue. Using event-related fMRI, we show that specific regions of the brain are implicated in processing facial resemblance and a sex difference in cortical response to facial resemblance expressed in children. We found a consistent activation in the fusiform gyrus across all face conditions, which is consistent with previous research on face processing. There were no sex differences in overall response to faces in the fusiform gyrus, and also to faces that did not resemble subjects. When resemblance was not modeled, females showed greater activation to child faces than males. Consistent with parental investment theory and theories of sexual selection, males showed greater cortical activity than females in response to children's faces that resembled them. These data suggest natural selection may have crafted a sexually differentiated neuro-sensory module implicated in detection of facial resemblance that may serve as a kin detection and paternity cue. This process may capitalize on neural substrates involved in self-referent processing and familiarity detection.

Adult↗
PubMed2005

Contagious yawning and the brain.

Contagious yawning, the onset of a yawn triggered by seeing, hearing, reading, or thinking about another person yawn is a well-documented phenomenon. The mechanisms that drive contagious yawning are as yet unknown, but there is recent evidence of a link between contagious yawning and self-processing (S.M. Platek, S.R. Critton, T.E. Myers, G.G. Gallup Jr., Contagious yawning: the role of self-awareness and mental state attribution, Cogn. Brain Res. 17 (2003) 223-227.) that is negatively impacted by schizotypal personality traits. The neural substrates involved in contagious yawning, however, are unknown. Here, using fMRI, we show that viewing someone yawn evokes unique neural activity in the posterior cingulate and precuneus. Because of the role these areas play in self-processing (e.g., self-referential processing, theory of mind, autobiographical memory), our findings provide further support for the hypothesis that contagious yawning may be part of a neural network involved in empathy.

Cognition↗
PubMed2004

Where am I? The neurological correlates of self and other.

Although still controversial, there is growing evidence that information about the self is processed in the right hemisphere, specifically the right frontal lobe. It has also been hypothesized that self-awareness and mental state attribution (inferences about the mental experience of others) are part of a similar neurocognitive process [Am. J. Primatol. 2 (1982) 237]. Here we measured blood oxygen level-dependent (BOLD) activity when viewing self-faces and when thinking about the mental states of others. We found significant activation in right superior, middle, and inferior frontal gyri when activation associated with self-face processing was compared with activation associated with familiar famous face processing. Mental state attribution, as measured by a computerized version of the Mind in the Eyes--Revised Test, was associated with activation in the right superior and middle frontal gyri, medial superior frontal gyrus, and left middle frontal gyrus and superior temporal gyrus/temporal pole. Self-face recognition and mental state attribution were colocalized to the middle and superior frontal gyri in the right hemisphere. These data support a model developed over two decades ago by Gallup [Am. J. Primatol. 2 (1982) 237] that posits that self-awareness and mental state attribution are part of a shared neurocognitive suite of processing and that neural architecture implicated in processing knowledge about the self is called upon when inferring knowledge in others.

Brain↗
PubMed2004

Cross-modal self-recognition: the role of visual, auditory, and olfactory primes.

Three priming experiments were conducted to determine how information about the self from different sensory modalities/cognitive domains affects self-face recognition. Being exposed to your body odor, seeing your name, and hearing your name all facilitated self-face recognition in a reaction time task. No similar cross-modal facilitation was found among stimuli from familiar or novel individuals. The finding of a left-hand advantage for self-face recognition was replicated when no primes were presented. These data, along with other recent results suggest the brain processes/represents information about the self in highly integrated ways.

Adult↗
PubMed2003

A left-hand advantage for self-description: the impact of schizotypal personality traits.

Consistent with the possibility that the right hemisphere is responsible for processing information about the self, subjects responded faster with their left hand to adjectives that were self-descriptive. However, those who scored high on the Schizotypal Personality Questionnaire (SPQ) did not show a left-hand advantage. These data add to a growing body of evidence that implicates the right hemisphere in processing information about the self and supports the hypothesis that self-processing may be impaired in schizophrenic-like populations.

Adult↗
PubMed2003

Contagious yawning: the role of self-awareness and mental state attribution.

Contagious yawning is a common, but poorly understood phenomenon. We hypothesized that contagious yawning is part of a more general phenomenon known as mental state attribution (i.e. the ability to inferentially model the mental states of others). To test this hypothesis we compared susceptibility to contagiously yawn with performance on a self-face recognition task, several theory of mind stories, and on a measure of schizotypal personality traits. Consistent with the hypothesis, susceptibility to contagiously yawn was positively related to performance on self-face recognition and faux pas theory of mind stories, and negatively related to schizotypal personality traits. These data suggest that contagious yawning may be associated with empathic aspects of mental state attribution and are negatively affected by increases in schizotypal personality traits much like other self-processing related tasks.

Adult↗
PubMed2003

Self-face processing in a callosotomy patient.

Self-face recognition is reserved for humans, apes and possibly dolphins and is thought to be a marker of self-awareness. Previous data have indicated that self-face recognition may be mediated via frontal right hemisphere circuits within the brain. Testing patient M.L., who underwent a total callosotomy, we found that when searching for the self-face in a series of morphs (composite facial images made up of his own and a famous face in inversely varying percentages) the patient made (i) more true-positive and (ii) fewer false-positive responses when responding with the right hemisphere (i.e. indicating with the left hand). There was no hand difference when searching for familiar faces. These data imply a right hemisphere processing advantage for self-faces.

Adult↗
PubMed2002

Self-face recognition is affected by schizotypal personality traits.

The right cortical hemisphere appears to be important for processing self-face images and we have hypothesized that self-face processing is compromised in schizophrenia. As a way of testing this hypothesis, we investigated how reaction times to one's own face varied as a function of scores on the Schizotypal Personality Questionnaire (SPQ). Left-hand reaction times to self-face images were positively correlated to scores on the SPQ. In addition, people who scored 20 or below on the SPQ showed shorter reaction times to self-face images than stranger faces when responding with their left-hand, whereas those who scored 21 or above on the SPQ showed a left-hand disadvantage. These results imply that self-face processing in the right hemisphere is impaired in individuals with schizotypal traits. Our data are the first to show that traits associated with a schizophrenic spectrum disorder in a non-clinical population may compromise self-face recognition.

Adult↗
PubMed2002

Does semen have antidepressant properties?

In a sample of sexually active college females, condom use, as an indirect measure of the presence of semen in the reproductive tract, was related to scores on the Beck Depression Inventory. Not only were females who were having sex without condoms less depressed, but depressive symptoms and suicide attempts among females who used condoms were proportional to the consistency of condom use. For females who did not use condoms, depression scores went up as the amount of time since their last sexual encounter increased. These data are consistent with the possibility that semen may antagonize depressive symptoms and evidence which shows that the vagina absorbs a number of components of semen that can be detected in the bloodstream within a few hours of administration.

Condoms↗