Sean Mullan

Bio: Sean Mullan is an academic researcher. The author has contributed to research in topics: Feeling & Temporal cortex. The author has an hindex of 1, co-authored 1 publications receiving 209 citations.

Illusions of Comparative Interpretation and Emotion: Production by Epileptic Discharge and by Electrical Stimulation in the Temporal Cortex

Abstract: "We now consider," wrote Hughlings Jackson1in 1880, "certain psychical states during the onset of epileptic seizures which are much more elaborate than crude sensations." "I speak first," he continued, "of certain highly elaborate mental states, sometimes called 'intellectual aurae.'... The state is often like that occasionally experienced by healthy people as a feeling of 'reminiscence.'... It is sometimes called 'dreamy feelings' or is described as 'dreams mixing up with present thoughts,' 'double consciousness,' 'feeling of being somewhere else,' 'as if I went back to all that occurred in my childhood.' These are all voluminous mental states and yet of different kinds; no doubt they ought to be classified." In recent years we have studied these "psychical states" clinically, as Jackson did. They may appear in the onset of an epileptic seizure that originates in temporal regions of the brain, and they may, in fact, constitute the only clinical

Disconnexion syndromes in animals and man

Abstract: As I have pointed out earlier, when I met Oliver Zangwill in 1961 at a meeting on dyslexia in Baltimore, he listened patiently to the exposition of my ideas on the significance of the cortico-cortical connections for the higher functions. A short time later, while on a trip to Boston, he suggested to me that I should prepare an extended account of these ideas. This paper would never have been written without Professor Zangwill’s urging, and I am grateful to him for having brought me to a more careful review of the older literature and a more precise statement of my own ideas. Although Russell Brain, who was then the editor of Brain, had some misgivings about the section on philosophical implications he agreed to take the manuscript unchanged.

The role of the limbic system in experiential phenomena of temporal lobe epilepsy

Abstract: Experiential phenomena occurring in spontaneous seizures or evoked by brain stimulation were reported by 18 of 29 patients with medically intractable temporal lobe epilepsy who were investigated with chronic, stereotaxically implanted intracerebral electrodes. The phenomena mainly consisted of perceptual (visual or auditory) hallucinations or illusions, memory flashbacks, illusions of familiarity, forced thinking, or emotions. Experiential phenomena did not occur unless a seizure discharge or electrical stimulation involved limbic structures. For such phenomena to occur, seizure discharge or electrical stimulation did not have to implicate temporal neocortex. This was true even for perceptual experiential phenomena. Many experiential responses elicited by electrical stimulation, particularly when applied to the amygdala, were not associated with electrical afterdischarge. Limbic activation by seizure discharge or electrical stimulation may add an affective dimension to perceptual and mnemonic data processed by the temporal neocortex, which may be required for endowing them with experiential immediacy.

Brain organization for language from the perspective of electrical stimulation mapping

Abstract: A model for the organization of language in the adult humans brain is derived from electrical stimulation mapping of several language-related functions: naming, reading, short-term verbal memory, mimicry of orofacial movements, and phoneme identification during neurosurgical operations under local anesthesia. A common peri-Sylvian cortex for motor and language functions is identified in the language dominant hemisphere, including sites common to sequencing of movements and identification of phonemes that may represent an anatomic substrate for the “motor theory of speech perception.” This is surrounded by sites related to short-term verbal memory, with sites specialized for such language functions as naming or syntax at the interface between these motor and memory areas. Language functions are discretely and differentially localized in association cortex, including some differential localization of the same function, naming, in multiple languages. There is substantial individual variability in the exact location of sites related to a particular function, a variability which can be partly related to the patient's sex and overall language ability and which may depend on prior brain injury and, perhaps subtly, on prior experience. A common “specific alerting response” mechanism for motor and language functions is identified in the lateral thalamus of the language–dominant hemisphere, a mechanism that may select the cortical areas appropriate for a particular language function.

Progress in Sensory Physiology

Abstract: 1 Introductory Remarks- 2 Plasticity in the Peripheral Somatosensory Nervous System- 21 Aspects of Plasticity in the Peripheral Nervous System- 22 Survival and Loss of Sensory Neurons After Lesions of the Peripheral Nervous System- 221 Effect of Crush or Transection of Peripheral Nerve on Neurons of Sensory Ganglia- 222 Trophic Dependence of Immature Sensory Neurons on the Periphery- 223 Effect of Peripheral Nerve Transection on Different Types of Sensory Neurons in Dorsal Root Ganglia- 224 Effect of Peripheral Nerve Section on Fibre Composition of Dorsal Roots- 225 Fate of the Lost neurons- 226 Sensory Cell Loss After Chemical Lesions of Afferent Fibres- 23 Collateral Sprouting of Primary Afferent Fibres in the Periphery- 231 Collateral Reinnervation of the Skin in Adult Mammals- 232 Collateral Sprouting in Neonates- 233 Effect of Neural Activity on Collateral Sprouting- 234 Collateral Sprouting of Trigeminal Afferents- 235 Collateral Sprouting and Sensory Recovery in Man- 236 Fate of Collateral Sprouts After Regeneration of Original Nerve- 24 Regeneration of Somatic Sensory Afferent Fibres- 241 Numbers of Axons in Nerves Regenerating After Crush or Transection- 242 Size of Regenerated Axons- 243 Effect of Denervation on Specialized Cutaneous Mechanoreceptors- 244 Reinnervation of Cutaneous Receptors by Regenerating Sensory Fibres- 25 Modality Specificity of Somatosensory Nerve Regeneration- 251 Regeneration of Myelinated Afferent Fibres to Hairy Skin- 252 Regeneration of Myelinated Afferent Fibres to Glabrous Skin- 253 Regeneration of Unmyelinated Afferent Fibres- 26 Major Conclusions- 3 Plasticity and the Mystacial Vibrissae of Rodents- 31 General Account of Pathway- 32 Normal Development of the Vibrissae and Their Neural Connections to the Cerebral Cortex- 33 Effects of Lesions and Manipulations in Prenatal, Neonatal and Developing Animals- 331 Damage of the Infraorbital Nerve- 332 Lesions to One or More Vibrissae- 333 The Effects of Supernumerary Vibrissae- 334 The Effects of Lesioning Unmyelinated Afferents- 335 Hyper- and Hypostimulation of Vibrissa Afferents- 336 Cortical Alterations- 34 Plasticity in the Vibrissa System of Adult Animals- 341 The SI Cortex- 342 The Ventral Posterior Medial Nucleus- 35 Major Conclusions- 4 Plasticity and the Spinal Dorsal Horn (with Notes on Homologous Regions of the Trigeminal Nuclei)- 41 Experimental Strategies for Demonstration of Plasticity in the Dorsal Horn of the Spinal Cord and Trigeminal Nuclei- 42 Overview of Dorsal Horn Organization- 421 Laminar Cytoarchitectonic Organization- 422 Laminar Organization of the Termination of Primary Afferent Fibres- 423 Microanatomical Organization of Low-Threshold Cutaneous Afferents- 424 Relation of Functional Properties to Lamination of the Dorsal Horn- 425 Inhibitory Receptive Fields- 43 Somatotopic Organization of the Dorsal Horn- 431 Dorsal Horn Neurons- 432 Somatotopy and Lamination- 433 Relation of Primary Afferent Projections to Dorsal Horn Somatotopy- 434 Relation Between Dorsal Horn Cell Dendritic Morphology and Receptive Field- 44 Effect of Lesions on Somatotopic Organization- 441 Dorsal Rhizotomy- 442 Chronic Spinal Lesions- 443 Peripheral Nerve Transection or Crush- 45 Mechanisms Underlying the Somatotopic Reorganization of Dorsal Horn Neurons- 451 Physiological and Pharmacological Evidence for the Existence of Normally Ineffective- Afferent Connections- 452 Spontaneous Changes of Receptive Fields- 453 Plasticity of Receptive Fields Induced by Afferent Activity- 454 Involvement of Unmyelinated Afferents in the Somatotopic Reorganization After Peripheral Nerve Injury- 455 Sprouting of Primary Afferent Fibres and Other Neurons as a Basis for Somatotopic Reorganization- 46 Plasticity of the Developing Dorsal Hor- 461 Development of Dorsal Horn Neurons and Primary Afferents- 462 Functional Plasticity in Development- 463 Somatotopic Reorganization Following Neonatal Peripheral Nerve Lesions- 464 Anatomical Plasticity of Neonatal Afferent Projections- 47 Major Conclusions- 5 Plasticity and the Dorsal Column Nuclei- 51 Advantages of the Dorsal Column Nuclei for Studies of Plasticity- 52 Organization of the Dorsal Column Nuclei- 521 Cytoarchitectonics- 522 Ascending Afferent Pathways- 523 Responses of Neurons to Natural Stimulation- 524 Core and Shell Organization- 525 Somatotopic Organization- 53 Alterations of Inputs to the Nuclei- 531 Section of Ascending Pathways- 532 Effects of Dorsal Rhizotomy- 533 Peripheral Nerve Section- 54 Evidence for Ineffective Afferent Connections- 541 Projections of Dorsal Roots and Peripheral Nerves- 542 Projections of Single Afferent Fibres- 543 Dendritic Spread of Cuneate Neurons- 544 Electrical Stimulation and Widefield Neurons- 545 Pharmacological Alterations of Receptive Fields- 55 Recovery from Sensorimotor Deficits Following Dorsal Column Lesions- 56 Plasticity of the DCN During Development- 561 Effects of Prenatal Lesions- 562 Effect of Neonatal Destruction of Unmyelinated Afferents- 57 Major Conclusions- 6 Plasticity and the Somatosensory Thalamus- 61 Experimental Strategies and Plasticity in the Ventral Posterior Nuclei of the Thalamus- 62 Anatomical Organization of Inputs and Outputs of the Ventral Posterior Nuclei- 621 Primate and Cat- 622 Raccoon- 623 Rat- 63 Responses of Neurons to Cutaneous Stimulation and the Effects of Anaesthetics and Other Drugs- 64 Somatotopic Organization of the VPL and VPM- 65 Effects of Alteration of Input on Somatotopic Organization- 651 Reversible Blockade of Afferents and the Immediate Expression of New Inputs- 652 Chronic Lesion of Afferent Pathways and Sprouting of Thalamic Afferents- 66 Major Conclusions- 7 Plasticity and the Somatosensory Cerebral Cortex- 71 Experimental Strategies and Cortical Plasticity- 72 Plasticity in the Cortex of Adult and Developing Primates- 721 Multiple Representations- 722 Thalamic Input and Intracortical Connectivity- 723 Responses of Cortical Neurons to Natural Stimulation- 724 Somatotopic Representation of the Hand in Areas 3b and 1- 725 Anatomy and Innervation of the Monkey Hand- 726 Anaesthetics and the Representation of the Hand- 727 Injury and Subsequent Regeneration of Peripheral Nerves- 728 Section and Ligation of Peripheral Nerves- 729 Effects of Repeated Stimulation on Cortical Representations- 7210 Cortical Damage- 73 Plasticity in the Cortex of Adult and Developing Cats- 731 Somatotopic Organization, Cytoarchitectonics and Neuronal Responses- 732 Thalamic Input and Ineffective Thalamocortical Connections- 733 Effects of Anaesthetics and Other Drugs- 734 Cordotomy and Section of Ascending Tracts- 735 Blockage of Primary Afferent Input in Specific Dorsal Roots- 736 Damage to Peripheral Nerves and Effects of Usage on Cortical Representation- 737 Cortical Damage- 74 Plasticity in the Cortex of Adult and Infant Raccoons- 741 Somatotopic Organization and Cytoarchitectonics- 742 Neuronal Responses in SI Cortex and the Effects of Anaesthetics- 743 Ineffective Afferent Connections- 744 Effects of Amputation on Cortical Somatotopy- 75 Plasticity in the Cortex of Adult and Developing Rodents- 751 Somatotopic Organization and Cytoarchitectonics- 752 Section and Ligation of Peripheral Nerves in the Adult- 753 Effects of Perinatal Nerve Section or Limb Amputation- 754 Pharmacological Mechanisms Underlying Somatotopic Reorganization- 755 Cortical Damage- 76 Major Conclusions- 8 Concluding Remarks- 81 Plasticity During Development- 811 Disruption of a Growing System and the Influence of the Periphery- 812 The Influence of Afferent Axons and the Target Tissue- 82 Evaluation of Experimentally Induced Plasticity in Adult Animals- 821 Plasticity in the Peripheral Nervous System- 822 Somatotopic Organization in Intact Animals as a Baseline for Assessing Altered Connections- 823 Somatotopic-Artifacts in Regions Deprived of Their Normal Input- 824 Plasticity and the Level of the Neuraxis- 83 The Case for Ineffective Connections- 831 Elucidation of Sub-Threshold Inputs- 832 Somatotopically Inappropriate Projections of Afferent Axons- 84 Spatial Extent of Immediate and Long-Term Changes in Somatotopic Organization- 841 Distance Limits of Somatotopic Reorganization- 842 Sprouting and Synaptogenesis in the Mature System- 843 Recovery of Function- 85 Normal Physiological Mechanisms and Plasticity- 851 Inhibitory Receptive Fields and Partial Deafferentation- 852 Neurotransmitters and Neural Systems That Regulate Sensory Input- 86 Role of Plasticity in the Mature Somatosensory System- References

Stimulation and Regional Ablation of the Amygdaloid Complex with Reference to Functional Representations

Abstract: Stimulation and ablation of the amygdaloid nuclear complex result in a variety of somatic, visceral, endocrine and behavioral effects. Since this brain area is a very heterogeneous structure, with a number of rather distinct subdivisions, and since differences in structure obviously implies functional differences, it is reasonable that attempts have been made to correlate structure and patterns of responses.