David Baxter PhD
Late Founder
Brain potentials implicate temporal lobe abnormalities in criminal psychopaths
by Kat Lambrou
Wed, 10/08/2008
Electrophysiological data were collected from 80 incarcerated men who were divided according to levels of psychopathy. The men were given several tests of neurocognitive processes. Differences were found when the two groups were compared, with psychopathic men exhibiting abnormalities in attention and orienting. The researchers concluded this data as support for the idea that psychopathy may be related to problems in the paralimbic system.
Psychopathy is defined as a ?personality disorder? characterized by longstanding social, emotional and behavior problems. Psychopathic individuals have difficulty with empathy, often times have difficulty controlling impulses and show no remorse for others.
Neurobiological differences between psychopathic and non-psychopathic men has been shown in other research, as well. These have included lower skin conductivity in psychopathic men in relation to noxious stimuli (Blair, Jones, Clark & Smith, 1997). Other studies found psychopathic males may pay too much attention to stimuli that is of immediate interest and disregard other stimuli (Jutai & Hare, 1983; Jutai et al, 1987; Newman, Schmitt & Voss, 1997). Furthermore, studies of brain injured patients, and patients who have had their amygdala removed, show temporal lobe abnormalities resulting in similar cognitive difficulties, (Johnson, 1993; Yamaguchi & Knight, 1993).
The researchers offer a comprehensive explanation of their results in context of other related research. They postulate alternative explanations for their findings and ultimately conclude that the medial and anterior lateral temporal lobe are important players in understanding psychopathy. The medial and anterior lateral temporal lobes are part of the paralimbic system, and limbic structures such as the amygdala and hippocampus are encompassed by the larger paralimbic system (Mesulum, 2000).
The article concludes that, ?psychopathy may be associated with abnormalities in the paralimbic system (Kiehl et al, 2006).? This idea raises additional questions about whether the paralimbic system is inherently compromised in individuals who develop psychopathy or whether the system is damaged as a result of life experiences psychopathic individuals endure. For example, early life experiences of abuse and trauma may affect the physical development of the limbic system. Would trauma (psychological and/or physical) result in irreparable changes in the limbic system? Similarly, an individual who embarks on a life of criminal activity is likely to encounter further trauma and difficult life experiences. Would these further disrupt the functioning of the limbic system? Conversely, are the limbic system difficulties present at birth in individuals who develop high levels of psychopathy? The authors describe their findings as part of a growing body of research suggesting the links between the paralimbic system and psychopathology.
References
Blair, R.J.R., Jones, L., Clark, F. & Smith, M. (1997). The psychopathic individual: A lack of responsiveness to distress cues? Psychophysiology, 34, 192-198.
Johnson, R.J. (1993). On the neural generators of the P300 component of the event-related potential. Psychophysiology, 30, 90-97.
Jutai, J.W. & Hare, R.D. (1983). Psychopathy and selective attention during performance of a complex perceptual-motor task. Psychophysiology, 20, 146-151.
Jutai, J.W., Hare, R.D. & Connolly, J.F. (1987). Psychopathy and event-related potentials (ERP?s) associated with attention to speech stimuli. Personality and Individual Differences, 8, 175-184.
Mesulam, M.M. (Ed.). (2000). Principles of behavior and cognitive neurology. (2nd ed.). New York: Oxford University Press.
Newman, J.P., Schmitt, W.A. & Voss, W.D. (1997). The impact of motivationally neutral cues on psychopathic individuals: Assessing the generality of the response modulation hypothesis. Journal of Abnormal Psychology, 106, 563-575.
Yamaguchi, S., & Knight, R.T. (1993). Association cortex contributions to the human P3. In W. Haschke, A.I. Roitbak, & E.J. Speckman (Eds.), Slow potential changes in the human brain (pp.71-84). Boston: Birkhauser.
by Kat Lambrou
Wed, 10/08/2008
Electrophysiological data were collected from 80 incarcerated men who were divided according to levels of psychopathy. The men were given several tests of neurocognitive processes. Differences were found when the two groups were compared, with psychopathic men exhibiting abnormalities in attention and orienting. The researchers concluded this data as support for the idea that psychopathy may be related to problems in the paralimbic system.
Psychopathy is defined as a ?personality disorder? characterized by longstanding social, emotional and behavior problems. Psychopathic individuals have difficulty with empathy, often times have difficulty controlling impulses and show no remorse for others.
Neurobiological differences between psychopathic and non-psychopathic men has been shown in other research, as well. These have included lower skin conductivity in psychopathic men in relation to noxious stimuli (Blair, Jones, Clark & Smith, 1997). Other studies found psychopathic males may pay too much attention to stimuli that is of immediate interest and disregard other stimuli (Jutai & Hare, 1983; Jutai et al, 1987; Newman, Schmitt & Voss, 1997). Furthermore, studies of brain injured patients, and patients who have had their amygdala removed, show temporal lobe abnormalities resulting in similar cognitive difficulties, (Johnson, 1993; Yamaguchi & Knight, 1993).
The researchers offer a comprehensive explanation of their results in context of other related research. They postulate alternative explanations for their findings and ultimately conclude that the medial and anterior lateral temporal lobe are important players in understanding psychopathy. The medial and anterior lateral temporal lobes are part of the paralimbic system, and limbic structures such as the amygdala and hippocampus are encompassed by the larger paralimbic system (Mesulum, 2000).
The article concludes that, ?psychopathy may be associated with abnormalities in the paralimbic system (Kiehl et al, 2006).? This idea raises additional questions about whether the paralimbic system is inherently compromised in individuals who develop psychopathy or whether the system is damaged as a result of life experiences psychopathic individuals endure. For example, early life experiences of abuse and trauma may affect the physical development of the limbic system. Would trauma (psychological and/or physical) result in irreparable changes in the limbic system? Similarly, an individual who embarks on a life of criminal activity is likely to encounter further trauma and difficult life experiences. Would these further disrupt the functioning of the limbic system? Conversely, are the limbic system difficulties present at birth in individuals who develop high levels of psychopathy? The authors describe their findings as part of a growing body of research suggesting the links between the paralimbic system and psychopathology.
References
Blair, R.J.R., Jones, L., Clark, F. & Smith, M. (1997). The psychopathic individual: A lack of responsiveness to distress cues? Psychophysiology, 34, 192-198.
Johnson, R.J. (1993). On the neural generators of the P300 component of the event-related potential. Psychophysiology, 30, 90-97.
Jutai, J.W. & Hare, R.D. (1983). Psychopathy and selective attention during performance of a complex perceptual-motor task. Psychophysiology, 20, 146-151.
Jutai, J.W., Hare, R.D. & Connolly, J.F. (1987). Psychopathy and event-related potentials (ERP?s) associated with attention to speech stimuli. Personality and Individual Differences, 8, 175-184.
Mesulam, M.M. (Ed.). (2000). Principles of behavior and cognitive neurology. (2nd ed.). New York: Oxford University Press.
Newman, J.P., Schmitt, W.A. & Voss, W.D. (1997). The impact of motivationally neutral cues on psychopathic individuals: Assessing the generality of the response modulation hypothesis. Journal of Abnormal Psychology, 106, 563-575.
Yamaguchi, S., & Knight, R.T. (1993). Association cortex contributions to the human P3. In W. Haschke, A.I. Roitbak, & E.J. Speckman (Eds.), Slow potential changes in the human brain (pp.71-84). Boston: Birkhauser.
