Posterior pedunculopontine tegmental nucleus may be involved in visual complaints with intractable epilepsy

Abstract

Understanding the neural basis of vision remains a fundamental goal of neuroscience and has as much importance to studies of visual processing as to clinical studies of the visual disorders. Evidence suggests that the pedunculopontine tegmental nucleus (PPTg) may be an available therapeutic target for treatment of intractable epilepsy and Parkinson's disease [ 1 Liu T.T. Feng J. Bu H.L. Liu C. Guan X.H. Xiang H.B. Stimulation for the compact parts of pedunculopontine nucleus: an available therapeutic approach in intractable epilepsy. Epilepsy Behav. 2013; 29: 252-253 Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar , 2 Alam M. Schwabe K. Krauss J.K. The pedunculopontine nucleus area: critical evaluation of interspecies differences relevant for its use as a target for deep brain stimulation. Brain. 2011; 134: 11-23 Crossref PubMed Scopus (122) Google Scholar , 3 Liu C. Ye D.W. Guan X.H. Li R.C. Xiang H.B. Zhu W.Z. Stimulation of the pedunculopontine tegmental nucleus may affect renal function by melanocortinergic signaling. Med Hypotheses. 2013; 81: 114-116 Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar ]. Jenkinson et al. reported a case of induced oscillopsia caused by deep brain stimulation (DBS) of PPTg using infrared eye tracking [ [4] Jenkinson N. Brittain J.S. Hicks S.L. Kennard C. Aziz T.Z. On the origin of oscillopsia during pedunculopontine stimulation. Stereotact Funct Neurosurg. 2012; 90: 124-129 Crossref PubMed Scopus (15) Google Scholar ]. It is known that visual symptoms are common in Parkinson's disease (PD), and the detection of visual symptoms is important for differential diagnosis and patient management [ [5] Urwyler P. Nef T. Killen A. Collerton D. Thomas A. Burn D. et al. Visual complaints and visual hallucinations in Parkinson's disease. Parkinsonism Relat Disord. 2013; https://doi.org/10.1016/j.parkreldis.2013.12.009 Abstract Full Text Full Text PDF PubMed Scopus (58) Google Scholar ]. It has been shown previously that there is strong cholinergic innervation from PPTg to lateral geniculate nucleus (LGN), and LGN receives as much as 40% of its input from PPTg [ 6 Erisir A. Van Horn S.C. Bickford M.E. Sherman S.M. Immunocytochemistry and distribution of parabrachial terminals in the lateral geniculate nucleus of the cat: a comparison with corticogeniculate terminals. J Comp Neurol. 1997; 377: 535-549 Crossref PubMed Scopus (108) Google Scholar , 7 Van Horn S.C. Erisir A. Sherman S.M. Relative distribution of synapses in the A-laminae of the lateral geniculate nucleus of the cat. J Comp Neurol. 2000; 416: 509-520 Crossref PubMed Scopus (175) Google Scholar ]. There are several reports that in vivo activation of pedunculopontine tegmental nucleus (PPTg) neurons enhances visual responses in LGN without changing receptive field size by making these neurons more excitable [ 8 Uhlrich D.J. Tamamaki N. Murphy P.C. Sherman S.M. Effects of brain stem parabrachial activation on receptive field properties of cells in the cat's lateral geniculate nucleus. J Neurophysiol. 1995; 73: 2428-2447 PubMed Google Scholar , 9 Kobayashi Y. Isa T. Sensory-motor gating and cognitive control by the brainstem cholinergic system. Neural Netw. 2002; 15: 731-741 Crossref PubMed Scopus (79) Google Scholar ]. Otherwise, some clinical studies point to a hyperexcitability of the visual cortex in patients with idiopathic generalized epilepsies [ 10 Brigo F. Bongiovanni L.G. Nardone R. Trinka E. Tezzon F. Fiaschi A. et al. Visual cortex hyperexcitability in idiopathic generalized epilepsies with photosensitivity: a TMS pilot study. Epilepsy Behav. 2013; 27: 301-306 Abstract Full Text Full Text PDF PubMed Scopus (28) Google Scholar , 11 Brazzo D. Di Lorenzo G. Bill P. Fasce M. Papalia G. Veggiotti P. et al. Abnormal visual habituation in pediatric photosensitive epilepsy. Clin Neurophysiol. 2011; 122: 16-20 Abstract Full Text Full Text PDF PubMed Scopus (20) Google Scholar , 12 Seshia S.S. Carmant L. Visual-sensitive epilepsies: classification and review. Can J Neurol Sci. 2005; 32: 298-305 PubMed Google Scholar , 13 Zifkin B.G. Kasteleijn-Nolst Trenite D. Reflex epilepsy and reflex seizures of the visual system: a clinical review. Epileptic Disord. 2000; 2: 129-136 PubMed Google Scholar , 14 Specchio N. Kasteleijn-Nolst Trenite D.G. Piccioli M. Specchio L.M. Trivisano M. Fusco L. et al. Diagnosing photosensitive epilepsy: fancy new versus old fashioned techniques in patients with different epileptic syndromes. Brain Dev. 2011; 33: 294-300 Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar ]. Thereby, we postulate that PPTg may be involved in visual complaints in patients with intractable epilepsy.