UVM Sistema Nervioso Sesion 06 Ganglios Basales
•Download as PPTX, PDF•
8 likes•7,522 views
UVM Licenciatura en Terapia de Audición y del Lenguaje Fundamentos del Sistema Nervioso Sesión 06 Ganglios Basales Videos: http://www.youtube.com/watch?v=q7z-373pwuI http://www.youtube.com/watch?v=qLz7w5ow8uw http://www.youtube.com/watch?v=YB9rs4tEAaE
Recommended
More Related Content
What's hot
What's hot (20)
Viewers also liked
Viewers also liked (10)
Similar to UVM Sistema Nervioso Sesion 06 Ganglios Basales
Similar to UVM Sistema Nervioso Sesion 06 Ganglios Basales (20)
More from Iris Ethel Rentería Solís
More from Iris Ethel Rentería Solís (20)
UVM Sistema Nervioso Sesion 06 Ganglios Basales
- 1. Ganglios Basales Dra. Iris Ethel Rentería Solís
- 2. Los ganglios basales Guían los aspectos de la actividad motora gruesa, como caminar, correr, patear, nadar, sonreír, etc.
- 3. Los ganglios basales Guían los aspectos de la actividad motora gruesa, como caminar, correr, patear, nadar, sonreír, etc. Cuando se lesionan los movimientos se vuelven lentos, torpes y pueden acompañarse por temblores o movimientos incontrolables, como en la enfermedad de Parkinson
- 4. Funciones de los ganglios basales Planeación y programación del movimiento Pensamiento abstracto se convierte en acción voluntaria Postura
- 7. Subdivisiones de los ganglios basales A. Neoestriado (o Estriado) Putamen Núcleo Caudado B. Paleoestriado Globus pallidus C. Núcleo Lentiforme Putamen Globus Pallidus D. Arquiestriado Amígdala E. Substantia nigra F. Núcleo Subtalámico
- 9. Cuerpo estriado Núcleo caudado Putamen Globus pallidus
- 10. Núcleo Caudado Cabeza y cola Pared del ventrículo lateral Extremo rostral continúa con el putamen Núcleo accumbens: Porción más ventral del cuerpo caudado. Funciones límbicas
- 11. Putamen Lateral a la cápsula interna y al globo pálido Medial a la cápsula externa, el claustro, la cápsula extrema y la ínsula
- 12. Conexiones del estriado El núcleo caudado y el putamen son las regiones «de entrada» del cuerpo estriado. Reciben fibras aferentes desde la corteza cerebral, los núcleos intralaminares talámicos y la porción compacta de la sustancia negra Las fibras eferentes se dirigen hacia el globo pálido y la porción reticular de la sustancia negra
- 13. Globo pálido Dos divisiones: medial (interno) y lateral (externo) Recibe fibras aferentes desde el estriado y el núcleo subtalámico Medial: Región «de salida» del cuerpo estriado Se proyecta hacia el tálamo (VL, VA) Lateral: Se proyecta hacia el núcleo subtalámico
- 14. Conexiones del globo pálido
- 19. ¿Dónde tenemos los ganglios basales?
- 24. Inhibidor G. Pálido Ext. Tálamo Sustancia Negra Cerebelo, retina, putamen B6 Mendoza Patiño, Nicandro. Farmacología médica / Nicandro Mendoza Patiño, México: Editorial Médica Panamericana: UNAM, Facultad de Medicina, 2008. GABA (Ácido gamma-aminobutírico)
- 25. • EXCITA cuerpo estriado y corteza • Aprendizaje, memoria, visión, audición N-metil-D-aspartato Mendoza Patiño, Nicandro. Farmacología médica / Nicandro Mendoza Patiño, México: Editorial Médica Panamericana: UNAM, Facultad de Medicina, 2008. Glutamato
- 26. L-dihidroxifenilalanina Monoaminooxidasa • INHIBE el cuerpo estriado • Movimiento, atención, aprendizaje y adicciones. Mendoza Patiño, Nicandro. Farmacología médica / Nicandro Mendoza Patiño, México: Editorial Médica Panamericana: UNAM, Facultad de Medicina, 2008. Dopamina
- 27. EXCITADOR de placas neuromusculares Aprendizaje y Memoria Ionotrópico (Nicotínico): Rápidos y corta vida; canales de Na+ Metabotrópico (Muscarínico): Lentos y duraderos ACH ACH ACH Mendoza Patiño, Nicandro. Farmacología médica / Nicandro Mendoza Patiño, México: Editorial Médica Panamericana: UNAM, Facultad de Medicina, 2008. Acetilcolina
- 29. Barrett, Kim. Barman, Susan. Boitano, Scott. Brooks, Heddwen. Fisiología médica. Editorial Lange. 2010 Relación de vías motoras con vías de planeación
- 30. Neuronas y circuitos del los ganglios basales
- 31. Conexiones internas de los ganglios basales: Vía Directa
- 32. Conexiones internas de los ganglios basales: Vía Directa
- 33. Tracto Nigroestriado Movimientos con destreza Conexiones internas de los ganglios basales: Vía Directa
- 34. Conexiones internas de los ganglios basales: Vía Indirecta
- 35. Conexiones internas de los ganglios basales: Vía Indirecta
- 36. Tracto cortico estriado Movimientos coordinados. Glutamato, GABA Conexiones internas de los ganglios basales: Vía Indirecta
- 37. Desinhibición
- 38. Componente motor de los ganglios basales
- 40. BG Efferents
- 41. Conexiones del estriado con la sustancia negra
- 42. Corteza No descarga espontánea, sólo durante el movimiento de extremidades Descargas espontáneas masivas. Inhibe el tálamo Disminución de actividad durante el movimiento debida a la desinhibición por el estriado Actividad durante el movimiento Estriado GPi Tálamo 1 2 3 4 5 Circuito motor
- 43. Canales funcionales de los ganglios basales FUENTE DE IMPULSO CORTICAL NÚCLEO DE ENTRADA A LOS GANGLIOS BASALES NÚCLEO DE SALIDA DE LOS GANGLIOS BASALES NÚCLEOS DE RELEVO EN EL TÁLAMO OBJETIVO EN LA CORTEZA CANAL MOTOR Corteza somatosensorial; corteza motora primaria, corteza premotora Putamen GPi, SNr VL, VA Corteza motora suplementaria; corteza premotora; corteza motora primaria CANAL OCULOMOTOR Corteza parietal posterior; corteza prefrontal Cuerpo del núcleo caudado GPi, SNr VA, MD Campos visuales frontales, campos visuales suplementarios CANAL PREFRONTAL Corteza parietal posterior; corteza premotora Cabeza del núcleo caudado GPi, SNr VA, MD Corteza prefrontal CANAL LÍMBICO Corteza temporal, hipocampo, amígdala Núcleo accumbens; caudado ventral, putamen ventral Pallidum ventral, GPi, SNr MD, VA Circunvolución del cíngulo (anterior); complejo orbitofrontal
- 44. Canales funcionales de los ganglios basales
- 45. Canales funcionales de los ganglios basales
- 46. Desórdenes de los ganglios basales Desórdenes del movimiento voluntario Bradicinesia Movimientos alternantes rápidos Espasmo de intención Anormalidades posturales Desórdenes de la marcha Cambios en el tono Movimientos involuntarios Alteraciones en fonación y articulación
Editor's Notes
- Figure 20-4 The detailed anatomical and functional nature of the input, internal, and output circuits of the basal ganglia. Note the distinction between the direct and indirect pathways. (A) The direct pathway involves projections from the neostriatum to the medial (internal) pallidal segment, which in turn, projects to the thalamus and then to the cerebral cortex. Internal Connections of the Basal GangliaThe anatomical relationships between different components of the basal ganglia are extensive. The most salient of the connections include the following: (1) the projections from the neostriatum to the globus pallidus; (2) the reciprocal relationships between the neostriatum and substantia nigra; and (3) the reciprocal relationships between the globus pallidus and the subthalamic nucleus. In examining these relationships, the overall role of the basal ganglia in motor functions should be kept in mind. Namely, as signals are transmitted through the basal ganglia in response to cortical inputs, they ultimately result in a distinct response transmitted back to the motor areas of the cerebral cortex. Moreover, the circuits within the basal ganglia by which signals are transmitted back to the cerebral cortex may be direct or indirect. The differences between the direct and indirect routes are discussed in the following section.Connections of the Neostriatum with the Globus PallidusThere are two basic projection targets of the neostriatum: the globus pallidus and the substantia nigra. The neostriatum projects to two different regions of the globus pallidus: the medial (internal) pallidal segment and the lateral (external) pallidal segment (Fig. 20-4). GABA mediates the pathway from the neostriatum to the medial pallidal segment; likewise, the pathway from the neostriatum to the lateral pallidal segment also primarily uses GABA as a likely neurotransmitter.Each of these projections forms the initial links of two different circuits within the basal ganglia. Because the primary output of the basal ganglia is from the internal pallidal segment, the projection (neostriatum → globus pallidus (internal) → thalamus → neocortex) is called the direct pathway (Fig. 20-4). In contrast, the external segment of the globus pallidus shares reciprocal projections with the subthalamic nucleus. Thus, this circuit of the basal ganglia can be outlined as follows: neostriatum → globus pallidus (external) → subthalamic nucleus → globus pallidus (internal) → thalamus → neocortex). Because this circuit involves a loop through the subthalamic nucleus, it is called the indirect pathway (Fig. 20-4). The neurotransmitters involved in the reciprocal pathway between the globus pallidus and subthalamic nucleus and the overall functional significance of these pathways are discussed later in this chapter.
- (B) The indirect pathway involves projections from the neostriatum to the lateral pallidal segment (L), which in turn, projects to the subthalamic nucleus. The subthalamic nucleus then projects to the medial pallidal segment (M), and the remaining components of the circuit to the cerebral cortex are similar to that described for the direct pathways. Red arrows depict inhibitory pathways, and blue arrows indicate excitatory pathways. The green pathways represent dopaminergic projections to the neostriatum, which have opposing effects on D1 and D2 receptors (see Fig. 20-5), and the excitatory projection from the subthalamic nucleus (Sth) to the medial pallidal segment. When known, the neurotransmitter for each of the pathways is indicated. Abbreviations: DA, dopamine; GLU, glutamate; CM, centromedian nucleus; VA, ventral anterior nucleus; VL, ventrolateral nucleus; +, excitation; -, inhibition.
- Figure 20-3 Relationship of the cerebral cortex to the putamen and caudate nucleus. The diagram illustrates that the putamen receives fibers from motor regions of the cerebral cortex, while the caudate nucleus receives inputs from association regions (temporal and parietal lobes) as well as inputs from other regions of the frontal lobe, including the prefrontal cortex.The largest afferent source of the basal ganglia arises from the cerebral cortex. In fact, most regions of the cortex contribute projections to the basal ganglia. These include inputs from motor, sensory, association, and even limbic areas of the cortex. While the caudate nucleus and putamen serve as the primary target regions of afferent projections from the cortex, the source of cortical inputs to these regions of the basal ganglia differ. The principal inputs from the primary motor, secondary motor, and primary somatosensory regions of cortex are directed to the putamen. These inputs to the putamen are somatotopically organized, which means that different regions of the putamen receive sensory and motor inputs that are associated with different parts of the body. The caudate nucleus, on the other hand, receives inputs from cortical association regions, frontal eye fields, and limbic regions of cortex (Fig. 20-3). Thus, the putamen appears to be concerned primarily with motor functions, while the caudate nucleus, which appears to receive more varied and integrated cortical inputs, is likely involved with cognitive aspects of movement, eye movements, and emotional correlates of movement (relegated to the ventral aspect of the neostriatum).The neostriatum also receives an indirect source of cortical input. The source of this input is the cen-tromedian nucleus of the thalamus. This nucleus receives afferent fibers primarily from the motor cortex and projects its axons topographically to the putamen as thalamostriate fibers. An additional but highly important source of dopaminergic inputs to the neostriatum is the substantia nigra. The function of this afferent source to the neostriatum is considered later in this chapter.The modular organization of the neostriatum is as follows. The projections from the neocortex and thalamus are not distributed uniformly to the neostriatum. Instead, the projections end in compartments within different parts of the neostriatum. The smaller of these compartments is referred to as a patch or striosome and is surrounded by a larger compartment referred to as a matrix. These two compartments are distinguished from each other because they have different neurochemical properties, contain different receptors, and receive inputs from different cortical regions. The matrix is acetylcholinesterase rich. The striosomes, however, are acetylcholinesterase poor but contain peptides such as somatostatin, substance P, and enkephalin. The striosomes receive their inputs mainly from limbic regions of cortex, and neurons from this region preferentially project to the substantia nigra. In contrast, the neurons of the matrix receive inputs from sensory and motor regions of cortex, and many of them project to the globus pallidus. The overwhelming majority of projection neurons from both of these compartments of the neostriatum are γ-aminobutyric acid (GABA)-ergic. Their significance is considered in the following paragraph.The presumed role of the neostriatum in motor functions can be illustrated by the following example. During active movement of a joint of a finger, the cells within a certain striosomal or matrix compartment become active, while neurons embedded within other compartments become active only after there is passive movement of the same joint. This would suggest that the neurons embedded within given compartments function in a similar manner to those present in functional homogenous regions of the cerebral cortex with respect to movement (i.e., specific regions of motor cortex can be subdivided into distinct functional columns in which the neurons in one column respond to one feature of movement of a limb, whereas those neurons situated in an adjoining column respond to a different feature of movement of that limb;
- Figure 20-5 Key relationships of the substantia nigra. The pars reticulata of the substantia nigra receives an inhibitory (red line) GABAergic input from the neostriatum. In turn, there are two important outputs of the substantia nigra. The first is a dopaminergic (DA) projection to the neostriatum (which is excitatory when acting through D1 receptors and inhibitory when acting through D2 receptors). The second is an inhibitory GABAergic projection from the pars reticulata to the ventral anterior (VA) and ventrolateral (VL) thalamic nuclei as well as to the superior colliculus. +, excitation; -, inhibitionConnections of the Neostriatum with the Substantia NigraThe substantia nigra has two principal components: a region of tightly compacted cells, called the pars compacta, and a region just ventral and extending lateral to the pars compacta, called the pars reticulata (Fig. 20-2B). Fibers arising from the neostriatum project to the pars reticulata. Transmitters identified in this pathway are GABA and substance P. The pathway from the substantia nigra to the neostriatum arises from the pars compacta and uses dopamine as its neurotransmitter (Fig. 20-5). The pars reticulata also gives rise to efferent fibers (which are likely inhibitory) that project to the thalamus, superior colliculus, and locally to the pars compacta. In this manner, the pars reticulata and internal pallidal segment appear to be functionally analogous because both regions provide outputs to the cerebral cortex via the thalamus. Additional functions of these pathways are discussed later in this chapter.
- Figure 8: Potentially converging inputs to the dorsal striatum at the time of an unpredicted biologically salient visual event. A. Phasic sensory: Two separate short-latency representations of the visual event could converge on striatal circuitry: (i) retino-tecto-thalamo-striatal projections will provide a phasic sensory-related glutamatergic input (red arrows) ; and (ii) retino-tecto-nigro-striatal projections will provide a phasic dopaminergic input (orange arrows) . B. Contextual: Striatal neurones are sensitive to experimental context. Multidimensional contextual afferents are likely to originate from cerebral cortex, limbic structures (hippocampus and amygdala) and the thalamus (Blue arrows). C. Motor copy: Branched pathways from motor cortex and subcorticalsensorimotor structures (e.g. superior colliculus) reach the striatum directly (cortex) or indirectly via the thalamus (subcortical structures). Motor-related projections could provide the striatum with a running, multidimensional record (motor efference copy) of commands relating to ongoing goals/actions/movements (green arrows).Reinforcement learningThe basal ganglia have long been associated with the processes of reinforcement learning (Schultz 2006; see also Reward Signals). This should not be surprising since instrumental or operant conditioning (the class of learning most commonly linked to the basal ganglia) can be viewed as the biasing of future action selections by past action outcomes. One of the strongest lines of evidence supporting the involvement of the basal ganglia in reinforcement learning is the electrophysiological data obtained from behaving monkeys. Typically, unexpected biologically significant events including sudden novel stimuli, intense sensory stimuli, primary rewards, and arbitrary stimuli classically conditioned by association with primary rewards evoke a stereotypic sensory response from DA neurones in many species (Schultz 1998). This response comprises a characteristic short latency (70-100 ms), short duration (<200 ms) burst of activity. However, it is the capacity of phasic DA responses to change when experimental conditions are altered that has provoked most interest. The novelty response of DA neurones habituates rapidly when a sensory stimulus is repeated in the absence of behaviourally rewarding consequences. A phasic DA response will emerge following the presentation of a neutral sensory stimulus that predicts a primary reward. Under these conditions the DA responses to the predicted reward gradually diminish. When a predicted reward is omitted, a reliable depression in the spontaneous activity of the DA neurones occurs 70-100 ms after the time of expected reward delivery. It is largely on the basis of these data that the reward-prediction error hypothesis was originally formulated. More recently, additional supporting investigations have established that the phasic DA signal complies with the contiguity, contingency and prediction error tenets of contemporary learning theories (Schultz 2006). This body of evidence provides powerful support for the reward prediction error hypothesis which is now widely accepted by both biological and computational neuroscientists. Within this framework, the hypothesised errors in reward prediction signalled by phasic dopamine activity are presumed teaching signals for appetitive learning and ensure that actions maximising the future acquisition of reward are selected more often. However, recent evidence from studies that have identified sources of short-latency sensory input to midbrain dopaminergicneurones suggests that, in real world conditions where unexpected stimuli are both temporally and spatially unpredictable, the identity of unexpected events (and hence their reward value) will be determined after, rather than before the time of phasicdopaminergicsignalling (Redgrave and Gurney 2006). Although dopamine neurones have reliable responses to reward-related stimuli they also exhibit strong phasic responses to unexpected sensory events that have no obvious appetitive reinforcement consequences (Horvitz 2000). Despite reward-related stimuli coming in all sorts of shapes and sizes, the phasic dopamine signal is highly stereotyped (latency 100 ms, duration 100 ms) and largely independent of animal species, stimulus modality, and perceptual complexity of eliciting events (Schultz 1998). The 100 ms response latency of dopaminergicneurones is reliably shorter than the latency of the gaze-shift that brings the unexpected event onto the fovea for detailed analysis by cortical visual systems. Necessarily this means that dopamine responses are triggered as a consequence of limited pre-attentive, pre-saccadic sensory processing (Redgrave and Gurney 2006). Recent evidence indicates that the sensory inputs to dopaminergicneurones derive largely, if not exclusively as a consequence of early, subcortical sensory processing (Redgrave and Gurney 2006). In the case of vision, the midbrain superior colliculus is configured to indicate where an unexpected event is rather than what it is (Wurtz and Albano 1980). Perhaps it is no coincidence that, in almost all studies showing phasic dopamine signals can signal reward prediction errors (Schultz 2006), the economic values predicted by the conditioned stimuli are correlated with the spatial location of stimulus presentation. It therefore remains to be determined whether dopamine neurones can signal continuous values of reward prediction errors in real world conditions where unexpected events are both temporally and spatially unpredictable.