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Biomedical subjects

Julian Paul Keenan

Publications and source records attributed to Julian Paul Keenan.

7 recordsLinked to original sources
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

Where in the brain is the self?

Localizing the self in the brain has been the goal of consciousness research for centuries. Recently, there has been an increase in attention to the localization of the self. Here we present data from patients suffering from a loss of self in an attempt to understand the neural correlates of consciousness. Focusing on delusional misidentification syndrome (DMS), we find that frontal regions, as well as the right hemisphere appear to play a significant role in DMS and DMS related disorders. These data are placed in the context of neuroimaging findings.

Awareness↗
PubMed2005

Hemispheric asymmetry and deception detection.

Previous research has indicated a possible right hemisphere advantage in deception detection including a possible left ear advantage in decoding deceptive statements. In this study, 32 undergraduate students listened to 112 true and false statements presented unilaterally to both the left and right ears. The participants responded using their left or right hand, indicating whether the statements they heard were true or false. It was found that there was a significant (p < .004) advantage for the left ear in detecting whether a statement was true or false. These findings replicate and extend previous research indicating a left ear/right hemisphere advantage in deception detection.

Adolescent↗
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↗
PubMed2003

The effects of gender on the neural substrates of pitch memory.

Imaging studies have indicated that males and females differ anatomically in brain regions thought to underlie language functions. Functional studies have corroborated this difference by showing gender differences in terms of language processing with females relying on less lateralized processing strategies than males. Gender differences in musical functions might show similar differences in functional asymmetries, although no detailed study has been performed. The current study employed a pitch memory task while acquiring functional magnetic resonance images to investigate possible differences in hemispheric processing between males and females. Gender differences were found in the time course of activation (during the first four imaging time points after the end of the auditory stimulus-"perceptual phase"-and the subsequent three imaging time points after the end of the auditory stimulus-"memory phase") in both anterior and posterior perisylvian regions. Male subjects had greater lateralized activations (left > right) in anterior and posterior perisylvian regions during the "perceptual" as well as during the "memory" phase. There was a trend for males to have more cerebellar activation than females. Females showed more prominently posterior cingulate/retrosplenial cortex activation compared to males. Although activation patterns differed, there was no difference in the behavioral performance between both genders. These data indicate that similar to language studies, males rely more on left lateralized hemispheric processing even for basic pitch tasks.

Acoustic Stimulation↗
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↗