Penfield’s Homunculus and Other Grotesque Creatures from the Land of If

Nuncius ◽  
2012 ◽  
Vol 27 (1) ◽  
pp. 141-162 ◽  
Author(s):  
Claudio Pogliano

The neurosurgeon Wilder Graves Penfield (1891-1976) helped to develop a surgical treatment for epilepsy and used his results to investigate the functional organization of the brain. He was instrumental in founding the Montreal Neurological Institute at McGill University, which he directed from 1934 to 1960. There he studied, with his collaborators, the effects of stimulation and surgical ablation on different parts of the brain in order to localize their somatosensory functions. To visualize the results of this research, Hortense Pauline Cantlie drew images of a homunculus whose proportions reflected the extent of the cortical areas controlling different parts of the body. These images were published by Penfield in 1937; a modified version followed in 1950, opening the way for such developments as the diagrams of mammalian brains drawn by the neurophysiologist Clinton N. Woolsey in 1958. This article will reconstruct the history of Penfield’s map of the human brain, which was utilized in medical texts for many decades, but which eventually would be severely criticized.

2020 ◽  
Author(s):  
Nicholas N. Foster ◽  
Laura Korobkova ◽  
Luis Garcia ◽  
Lei Gao ◽  
Marlene Becerra ◽  
...  

ABSTRACTThe cortico-basal ganglia-thalamic loop is one of the fundamental network motifs in the brain. Revealing its structural and functional organization is critical to understanding cognition, sensorimotor behavior, and the natural history of many neurological and neuropsychiatric diseases. Classically, the basal ganglia is conceptualized to contain three primary information output channels: motor, limbic, and associative. However, given the roughly 65 cortical areas and two dozen thalamic nuclei that feed into the dorsal striatum, a three-channel view is overly simplistic for explaining the myriad functions of the basal ganglia. Recent works from our lab and others have subdivided the dorsal striatum into numerous functional domains based on convergent and divergent inputs from the cortex and thalamus. To complete this work, we generated a comprehensive data pool of ∼700 injections placed across the striatum, external globus pallidus (GPe), substantia nigra pars reticulata (SNr), thalamic nuclei, and cortex. We identify 14 domains of SNr, 36 in the GPe, and 6 in the parafascicular and ventromedial thalamic nuclei. Subsequently, we identify 6 parallel cortico-basal ganglia-thalamic subnetworks that sequentially transduce specific subsets of cortical information with complex patterns of convergence and divergence through every elemental node of the entire cortico-basal ganglia loop. These experiments reveal multiple important novel features of the cortico-basal ganglia network motif. The prototypical sub-network structure is characterized by a highly interconnected nature, with cortical information processing through one or more striatal nodes, which send a convergent output to the SNr and a more parallelized output to the GPe; the GPe output then converges with the SNr. A domain of the thalamus receives the nigral output, and is interconnected with both the striatal domains and the cortical areas that filter into its nigral input source. This study provides conceptual advancement of our understanding of the structural and functional organization of the classic cortico-basal ganglia network.


Author(s):  
Dharnaben A. Patel ◽  
Dhruv J. Patel ◽  
N. D. Kantharia

Background: Diabetes Mellitus is a chronic metabolic disorder characterized by hyperglycemia, polyuria, hyperlipidemia etc, resulting from defects in insulin secretion, insulin action or both. It affects various organs of the body including the brain. Cognitive function is the thinking process of the brain. In any chronic disease evaluation of cognitive function is justified as it may affect various common day to day activities.Methods: It is a prospective, observational and non-interventional study. Thirty diabetic patients who were recently started on insulin i.e. within 7 days were enrolled in the study based on inclusion and exclusion criteria. Thirty non diabetic healthy individuals served as a control. Cognitive function was accessed by Adenbrooke’s Cognitive Examination (ACE III) at the time of enrollment.Results: The results were analysed using paired t-test. Attention, Memory and Visiospatial ability was significantly reduced in diabetic patients compared to control. Verbal fluency and language was also reduced but the change was not significant. Total ACE III score was significantly reduced in diabetic patients compared to control.Conclusions: Cognitive function is significantly reduced in Diabetic patients recently started on insulin. Hyperglycemia could be the possible reason of cognitive decline. Proper understanding of the natural history of Diabetes and the pathogenesis of cognitive decline as well as control of Diabetes can help to prevent development of cognitive dysfunction.


eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Shigehiro Namiki ◽  
Michael H Dickinson ◽  
Allan M Wong ◽  
Wyatt Korff ◽  
Gwyneth M Card

In most animals, the brain controls the body via a set of descending neurons (DNs) that traverse the neck. DN activity activates, maintains or modulates locomotion and other behaviors. Individual DNs have been well-studied in species from insects to primates, but little is known about overall connectivity patterns across the DN population. We systematically investigated DN anatomy in Drosophila melanogaster and created over 100 transgenic lines targeting individual cell types. We identified roughly half of all Drosophila DNs and comprehensively map connectivity between sensory and motor neuropils in the brain and nerve cord, respectively. We find the nerve cord is a layered system of neuropils reflecting the fly’s capability for two largely independent means of locomotion -- walking and flight -- using distinct sets of appendages. Our results reveal the basic functional map of descending pathways in flies and provide tools for systematic interrogation of neural circuits.


2003 ◽  
Vol 33 (1) ◽  
pp. 53-54 ◽  
Author(s):  
Bello B Shehu ◽  
Nasiru J Ismail

A 37-year-old woman, Para 5+0 presented with a 1 year history of recurrent convulsions and progressive weakness of the right side of the body. She had been treated for postpartum eclampsia in her last delivery but symptoms recurred 3 months later. Evaluation including computerized tomography scan of the brain suggested a parieto-temporal meningioma, which was completely excised at craniotomy. Histology confirmed this to be a meningioma. The patient was well at 8 months of follow up. The growth of meningiomas may increase during pregnancy due to presence of receptors for progestational hormones in the tumour and the meningioma may become symptomatic in pregnancy, presenting as eclampsia. Close follow up of patients with eclampsia is necessary to identify neurological features that may lead to a diagnosis of meningioma. Early diagnosis is essential if a good outcome is to be ensured.


2009 ◽  
Vol 5 (1) ◽  
pp. 186-207 ◽  
Author(s):  
Yuseok Kim ◽  
Shin Dongwon

Abstract This paper examines the characteristics of the illustrations in Heo Jun’s Dong’ui’bo’gam (Treasured Collections of an Eastern Physician), which are the sole distinctively Korean pictorial representations in the history of Korean medical texts. Those anatomical images differ from earlier East Asian anatomical charts in three important ways. First, they embody the view that Daoist practices for preserving health and vitality (yangsheng) are closer to the essence of life than is medicine. Second, unlike existing medical texts, which mainly focused on the organs inside the body and the channels on the surface of the body, they emphasise building up systematic outer ‘bodily form’. Third, they reflect Heo Jun’s regard for the anatomical content of the earlier Inner Canon and the Classic of Difficulties rather than the contributions of positivistic anatomy from and after the Song and Yuan Dynasties, and the diagrams of the five zang- organs are devised in accord with such a view. In my view, these three points in Treasured Collections of an Eastern Physician (hereafter Treasured Collection), the most influential medical book since its publication, provides clues to understanding the very conservative character of traditional Korean medicine in the seventeenth century and thereafter.


2020 ◽  
Vol 18 (1) ◽  
pp. 5-22
Author(s):  
Petr D. Shabanov ◽  
Andrei A. Lebedev ◽  
Eugenii R. Bychkov ◽  
Nikanor V. Lavrov ◽  
Vitalii I. Morozov

The purpose of the review was to analyze the neurochemical and neurophysiological mechanisms of the ghrelin system and the role of ghrelin in body functions and behavior. The focus is on the participation of ghrelin in the mechanisms of reinforcement and the formation of addictive behavior. At the beginning of the review a history of the first works on the field of ghrelin and its receptor was described. Then, genetic control, molecular precursor of ghrelin, molecular forms of ghrelin and ghrelin receptor were represented. In particular, the distribution of the ghrelin receptor, ghrelin-producing cells in the brain and its participation in various physiological functions of the body were shown. The hypothalamic functions of ghrelin were discussed: energy balance, regulation of glucose metabolism, stimulation of eating behavior, regulation of hypophys-pituitary axis (HPA) system. The connection of ghrelin with the brain CRH system was demonstrated. In particular, activation of HPA was described as a possible mechanism through which ghrelin regulates a number of physiological processes. Extrahypothalamic action of ghrelin was shown on the basis of the mechanisms of reinforcement and addiction. On the basis of their own data and literary, it was concluded that action of alcohol and psychoactive drugs are reduced after the ghrelin receptors blockade. In particular, it has been demonstrated that alcoholization of mothers affects the activity of the ghrelin system during the prenatal and early postnatal periods of development in the offspring of rats. It was shown the participation of ghrelin in memory and learning. The further perspective of the study and practical application of ghrelin-based pharmacological agents was analyzed.


Nature ◽  
2021 ◽  
Vol 598 (7879) ◽  
pp. 188-194
Author(s):  
Nicholas N. Foster ◽  
Joshua Barry ◽  
Laura Korobkova ◽  
Luis Garcia ◽  
Lei Gao ◽  
...  

AbstractThe cortico–basal ganglia–thalamo–cortical loop is one of the fundamental network motifs in the brain. Revealing its structural and functional organization is critical to understanding cognition, sensorimotor behaviour, and the natural history of many neurological and neuropsychiatric disorders. Classically, this network is conceptualized to contain three information channels: motor, limbic and associative1–4. Yet this three-channel view cannot explain the myriad functions of the basal ganglia. We previously subdivided the dorsal striatum into 29 functional domains on the basis of the topography of inputs from the entire cortex5. Here we map the multi-synaptic output pathways of these striatal domains through the globus pallidus external part (GPe), substantia nigra reticular part (SNr), thalamic nuclei and cortex. Accordingly, we identify 14 SNr and 36 GPe domains and a direct cortico-SNr projection. The striatonigral direct pathway displays a greater convergence of striatal inputs than the more parallel striatopallidal indirect pathway, although direct and indirect pathways originating from the same striatal domain ultimately converge onto the same postsynaptic SNr neurons. Following the SNr outputs, we delineate six domains in the parafascicular and ventromedial thalamic nuclei. Subsequently, we identify six parallel cortico–basal ganglia–thalamic subnetworks that sequentially transduce specific subsets of cortical information through every elemental node of the cortico–basal ganglia–thalamic loop. Thalamic domains relay this output back to the originating corticostriatal neurons of each subnetwork in a bona fide closed loop.


Author(s):  
Brooke Holmes

This article attempts to characterize a secular tradition of medicine, and focuses on approaches to the body and theories of causation. It seems that, just like the street philosophers, magicians were more individualistic and charismatic than the writers of systematic treatises, and yet they too sometimes relied on texts. It is important to remain open to possible connections between magic and medicine. For example, in the course of medical history, dissection and investigation of the interior of the body gradually became more prominent; similarly, ancient curses, spells, and binds became increasingly specific about the body parts and internal organs they targeted. The wider context of society is relevant here: magical and medical texts are affected by the history of torture, and of vivisection.


1990 ◽  
Vol 64 (3) ◽  
pp. 767-781 ◽  
Author(s):  
T. Drew ◽  
S. Rossignol

1. The present article described the various patterns of movement evoked in the limbs and neck by microstimulation (33-ms trains, 330 Hz, 0.2-ms pulses at less than or equal to 35 microA) of the medullary reticular formation (MRF) of seven chronically implanted, unanesthetized, intact cats. Altogether 878 loci were stimulated in 83 penetrations. However, as stimulation in the more lateral regions of the MRF was less effective, the results are based on stimulation in 592 loci made in 56 penetrations at distances of between 0.5 and 2.5 mm lateral to the midline. 2. Of these 592 loci, movement of one or more parts of the body was evoked from a total of 539 (91%) sites. Most of these movements were compound in nature, involving movement of one or more limbs as well as the head. Discrete movements were observed only with respect to the head; limb movements were always accompanied by head movement. In addition, hindlimb movements were always accompanied by forelimb movements, although the inverse was generally not true. 3. The most common effects of the stimulation were as follows: a turning of the head to the ipsilateral side (79% of stimulated sites); flexion of the ipsilateral elbow (41%); and extension of the contralateral elbow (45%). Effects in the hindlimbs were more variable and less frequent, with the majority of the effective loci causing flexion of the ipsilateral knee (9%) together with extension of the contralateral knee (8%). In total, including both flexion and extension, 18% of the stimulated sites caused movement of the ipsilateral hindlimb and 11% of the contralateral hindlimb. 4. Although movements of the head were obtained from the whole extent of the brain stem, movements of the forelimbs showed a dorsoventral organization with flexion of the ipsilateral elbow being evoked from the more dorsal regions of the brain stem, whereas contralateral elbow extension was evoked more frequently from the ventral regions. There was a large area of overlap from which movements of both limbs could be obtained simultaneously. Movements of the hindlimbs were more frequently evoked from central and ventral areas of the brain stem and from the most rostral aspect of the explored region. 5. In examining the combinations of movements evoked by the MRF stimulation, it was found that the most commonly evoked pattern was movement of the head to the stimulated side together with flexion of the ipsilateral forelimb and extension of the contralateral forelimb (26.5% of sites).(ABSTRACT TRUNCATED AT 400 WORDS)


2016 ◽  
Vol 31 (7) ◽  
pp. 953-984 ◽  
Author(s):  
Daniela Silva Adaya ◽  
Lucinda Aguirre-Cruz ◽  
Jorge Guevara ◽  
Emma Ortiz-Islas

The blood–brain barrier is the interface between the blood and brain, impeding the passage of most circulating cells and molecules, protecting the latter from foreign substances, and maintaining central nervous system homeostasis. However, its restrictive nature constitutes an obstacle, preventing therapeutic drugs from entering the brain. Usually, a large systemic dose is required to achieve pharmacological therapeutic levels in the brain, leading to adverse effects in the body. As a consequence, various strategies are being developed to enhance the amount and concentration of therapeutic compounds in the brain. One such tool is nanotechnology, in which nanostructures that are 1–100 nm are designed to deliver drugs to the brain. In this review, we examine many nanotechnology-based approaches to the treatment of neurodegenerative diseases. The review begins with a brief history of nanotechnology, followed by a discussion of its definition, the properties of most reported nanomaterials, their biocompatibility, the mechanisms of cell–material interactions, and the current status of nanotechnology in treating Alzheimer’s, Parkinson’s diseases, and amyotrophic lateral sclerosis. Of all strategies to deliver drug to the brain that are used in nanotechnology, drug release systems are the most frequently reported.


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