Anterior Cingulate Cortex and the Medial Pain System

A PET activation study of dynamic mechanical allodynia in patients with mononeuropathy

“…A study of primates with a damaged primary somatosensory cortex and a case report of a patient with a tumor affecting the secondary somatosensory cortex have revealed clear de®cits in pain discrimination (Kenshalo et al, 1991;Greenspan and Win®eld, 1992) which supports the hypothesis that the lateral pain system plays an important role in the sensory/discriminative aspects of pain processing (Kenshalo et al, 1980;Kenshalo and Isensee, 1983;Albe-Fessard et al, 1985;Chung et al, 1986;Friedman and Murray, 1986;Vogt et al, 1993;Apkarian and Shi, 1994;Willis, 1995). Several functional imaging studies of phasic heat pain, tonic pain and electrically induced pain support the involvement of S1, S2 and the thalamus in pain processing (Talbot et al, 1991;Casey et al, 1994;Coghill et al, 1994;Hsieh, 1995; (Talairach and Tournoux, 1988).…”

“…Peyron et al (1998) suggested that the absence of ACC activation could be a speci®c feature for patients with allodynia after Wallenberg infarct, which may also be the case for allodynia after peripheral nerve damage. The lack of activation in the medial pain system, in contrast to the massive activations in the lateral pain system (7±9% rCBF increase in S1), was still an unexpected ®nding since the patient descriptions of dynamic mechanical allodynia usually include affective components (Hansson, 1994) and since the medial system is considered to be involved in processing the affective and evaluative part of the pain experience (Albe-Fessard et al, 1985;Vogt et al, 1993;Craig et al, 1994;Talbot et al, 1995;Willis, 1995;Rainville et al, 1997).…”

“…It is currently believed that the lateral pain system is more involved in sensory-discriminative aspects of pain processing whereas the medial system is more involved in processing the affective-motivational component (Albe-Fessard et al, 1985;Vogt et al, 1993;Willis, 1995). Functional neuroimaging studies have identi®ed several networks, which are involved in pain processing in man.…”

Alterations of Thalamic Activity in Schizophrenia and in Response to Antipsychotic Drugs Studies in the Legacy of Seymour S. Kety

“…The regions showing activation share reciprocal innervation with prefrontal cortex, amygdala and nucleus accumbens, each of which, in turn, are innervated by dopamine and other monoamine neurons (Groenwegen 1988;Su and Bentivoglio 1990;Vogt et al 1993;Lavin and Grace 1998). However, the thalamus, too, in human as in rat, shows evidence of dopamine and other monoamine innervation (Nieuwenhuys et al 1988;Farde et al 1997).…”

“…Thalamic nuclei responding to antipsychotic drugs in animal studies are heavily interconnected to other brain regions suspected of mediating the symptoms of psychosis, including the amygdala, prefrontal cortex, cingulate cortex, hippocampus and nucleus accumbens (Groenwegen 1988;Su and Bentivoglio 1990;Vogt et al 1993). Comparable thalamic regions in human brain are in mediodorsal thalamus, which includes the mediodorsal thalamic nucleus as well as midline or intralaminar nuclei including the central medial nucleus.…”