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- 3. 2 MIN NEUROSCIENCE: BASALGANGLIA https://www.youtube.com/watch?v=OD2KPSGZ1No
- 4. BASAL GANGLIA OVERVIEW ▸ The basalganglia consists of a number of subcortical nuclei ▸ The grouping of these nuclei is related to function rather than anatomy – its components are not part of a single anatomical unit, and are spread deep within the brain ▸ It is part of a basic feedback circuit, receiving information from several sources including the cerebral cortex
- 5. BASAL GANGLIA OVERVIEW ▸ Thebasal ganglia feeds this information back to the cortex, via the thalamus ▸ In doing so, it acts to modulate and refine cortical activity – such as that controlling descending motor pathways ▸ Although widely used, the term basal ganglia is a misnomer, as ganglia are collection of cell bodies outside of the central nervous system ▸ Since a collection of subcortical cell bodies inside the nervous system are known as nuclei, the name basal nuclei is more accurate
- 6. BASAL GANGLIA NUCLEI OFTHE BASAL GANGLIA ▸ The anatomy of the basal ganglia is complex since it is spread throughout the forebrain ▸ Its components can be divided into ▸ input nuclei ▸ output nuclei ▸ intrinsic nuclei ▸ Input nuclei receive information, which is then relayed to intrinsic nuclei for processing, and further passed to output nuclei
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- 8. BASAL GANGLIA NUCLEI OFTHE BASAL GANGLIA ▸ In the telencephalon, the caudate nucleus (CN) and the putamen (Pu) are collectively called neostriatum, and their functions are closely related ▸ The most rostral aspect of the neostriatum, where the caudate nucleus and the putamen join together, is termed nucleus accumbens (Acb), which is part of a functionally separate domain named ventral striatum ▸ The globus pallidus is divided in an external (GPe) and an internal (GPi) domains, which are functionally different ▸ The subthalamic nucleus (StN) lies in the diencephalon ▸ In the mesencephalon, the substantia nigra is divided into two parts; the pars compacta (SNc) and the pars reticularis (SNr)
- 9. BASAL GANGLIA NUCLEI OFTHE BASAL GANGLIA - CAUDATE NUCLEUS ▸ The caudate nucleus forms the lateral wall of the lateral ventricle and follows the telencephalic expansion during development ▸ It has a characteristic ventricular C-shape when fully developed ▸ It can be identified as the collection of gray matter on the wall of the lateral ventricles ▸ During development, the caudate nucleus is separated from the putamen by descending white matter fibres, which at this level are known as internal capsule
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- 11. BASAL GANGLIA NUCLEI OFTHE BASAL GANGLIA - LENTIFORM NUCLEUS ▸ Lentiform Nucleus = Globus Pallidus and Putamen ▸ The lentiform nucleus is comprised of globus pallidus and the putamen ▸ Although anatomically related, they share no functional relationship ▸ It can be identified as a collection of gray matter laying deep within the hemispheres ▸ The putamen forms the lateral aspect of the lentiform nucleus ▸ On its concave inner surface lies the most exterior of the globus pallidus, the GPe, and the most internal structure is the GPi
- 12. BASAL GANGLIA NUCLEI OFTHE BASAL GANGLIA - LENTIFORM NUCLEUS ▸ The putamen is separated from the GPe by the lateral medullary lamina, and the medial medullary lamina separates the GPe from the GPi ▸ Note that, laterally to the putamen, there is another collection of white matter fibres known as the external capsule ▸ A thin bundle of grey matter can be seen lateral to the external capsule: this is the claustrum, once thought to be part of the basal ganglia ▸ More lateral to the claustrum is the extreme capsule, which are white matter tracts separating the claustrum from the neocortical insula
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- 14. BASAL GANGLIA NUCLEI OFTHE BASAL GANGLIA Substantia Nigra ▸ The substantia nigra is conspicuous in gross specimens and can be seen in cuts through the midbrain, having a dark appearance due to the neuromelanin present in the cells of the SNc Subthalamic Nucleus ▸ The subthalamic nucleus, as the name implies, lies inferior to the thalamus, and right above the substantia nigra
- 15. BASAL GANGLIA FUNCTION ▸ Insimple terms, the basal ganglia provide a feedback mechanism to the cerebral cortex, modulating and refining cortical activation ▸ Its main function is related to motor refinement, acting as a tonically active break, preventing unwanted movements to start ▸ Much of this involves reducing the excitatory input to the cerebral cortex ▸ This prevents excessive and exaggerated movements
- 16. BASAL GANGLIA FUNCTION ▸ Thebasal ganglia also plays an important role in modulating cognitive and emotional responses ▸ The putamen receives almost exclusive inputs from motor and somatosensory cortices and projects back to motor areas, and is thus related to the motor loop ▸ The caudate nucleus receives input from cortical association areas and projects to prefrontal areas ▸ In contrast, the ventral striatum (including the Acb) receives limbic inputs and is thus related to emotions
- 17. BASAL GANGLIA VASCULATURE ▸ Thearterial supply to the basal ganglia comes mainly from the middle cerebral artery, a continuation of the internal carotid artery ▸ The main artery is named lenticulostriate artery and, as the name implies, provides most of the circulation to the striatum and the lenticular nucleus ▸ There is also a small amount of supply from the anterior cerebral artery and the anterior choroidal artery, both of which are also branches of the internal carotid artery, supplying the more anterior aspect of the ganglia, (i.e. the head of the caudate nucleus and the nucleus accumbens) ▸ This particularly large artery is referred to as medial striate artery (of Heubner)
- 18. BASAL GANGLIA VASCULATURE ▸ Thesubstantia nigra and the subthalamic nucleus are more posterior and thus receive its vasculature from branches of the posterior cerebral and posterior communicating arteries ▸ The venous drainage is via striate branches of the internal cerebral vein, which drain into the great cerebral vein
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- 20. BASAL GANGLIA REVIEW QUESTIONS ▸This is a coronal section of the cerebrum ▸ Which of the following labels corresponds to an intrinsic nuclei of the basal ganglia?
- 21. BASAL GANGLIA REVIEW QUESTIONS ▸'C' corresponds to the external globus pallidus, which an intrinsic nuclei of the basal ganglia
- 22. BASAL GANGLIA REVIEW QUESTIONS ▸In the basal ganglia, which structures collectively form the neostriatum? ▸ Caudate nucleus and subthalamic nucleus ▸ Substantia nigra and subthalamic nucleus ▸ Putamen and globus pallidus ▸ Putamen and caudate nucleus
- 23. BASAL GANGLIA REVIEW QUESTIONS ▸The caudate nucleus and the putamen are collectively known as the neostriatum
- 24. BASAL GANGLIA REVIEW QUESTIONS ▸Which structure separates the caudate nucleus from the putamen? ▸ Lateral ventricle ▸ Internal capsule ▸ Globus pallidus ▸ Claustrum
- 25. BASAL GANGLIA REVIEW QUESTIONS ▸Descending white matter fibres, known as the internal capsule, separate the caudate nucleus from the putamen
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- 28. DEEP BRAIN STRUCTURES THALAMUS ▸LOCATION ▸ Surrounding the third ventricle, just above the midbrain ▸ STRUCTURES ▸ Many nuclei ▸ BLOOD SUPPLY ▸ Posterior communicating artery ▸ Anterior choroidal artery (a branch of the internal carotid artery)
- 29. DEEP BRAIN STRUCTURES THALAMUS ▸FUNCTIONS ▸ Sensory relay station: ▸ The thalamus receives sensory input of all sensory modalities ▸ Sensory input is "filtered" ▸ The thalamus sends processed signals to other areas of the cortex ▸ Emotion and memory: ▸ The thalamus is part of the Papez circuit, which is involved in emotion and memory ▸ Motor relay station: ▸ Receives input from the motor cortex and basal ganglia and sends signals to the descending motor tracts
- 30. DEEP BRAIN STRUCTURES THALAMUS ▸Lesion ▸ associated with motor and sensory deficits involving multiple areas of the body ▸ thalamic pain syndrome ▸ pain perceived without an appropriate stimulus
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- 34. 2 MIN NEUROSCIENCE: HYPOTHALAMUS& PITUITARY GLAND https://www.youtube.com/watch?v=TVhm2rBGhB0
- 35. DEEP BRAIN STRUCTURES HYPOTHALAMUS ▸FUNCTIONS ▸ Involved in homeostasis and instinctive actions ▸ Eg. eating, drinking, sleeping, and sex ▸ STRUCTURE ▸ Like the thalamus, it is divided into several nuclei controlling various functions
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- 40. CNS GLANDS PITUITARY GLAND:OVERVIEW ▸ The pituitary gland, also known as the hypophysis, is a major gland of the endocrine system ▸ It secretes hormones that control the actions of other endocrine organs and various tissues around the body
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- 42. CNS GLANDS PITUITARY GLAND:ANATOMICAL POSITION AND RELATIONS ▸ The pituitary gland is a pea-sized oval structure, suspended from the underside of the brain by the pituitary stalk (known as the infundibulum) ▸ It sits within a small depression in the sphenoid bone, known as the sella turcica (‘’Turkish saddle’’) ▸ The superior surface of the gland is covered by a reflection of the dura mater – the diaphragma sellae ▸ This membrane has a central opening which allows passage of the infundibulum
- 43. CNS GLANDS PITUITARY GLAND:ANATOMICAL POSITION AND RELATIONS ▸ The gland has several key anatomical relations: ▸ Anteriorly – sphenoid sinus (the pituitary gland is accessed surgically via the sphenoid sinus, known as a trans-sphenoidal approach) ▸ Posteriorly – posterior intercavernous sinus, dorsum sellae (posterior wall of the sella turcica), basilar artery and the pons ▸ Superiorly – diaphragma sellae (fold of dura mater that covers the pituitary gland), optic chiasm ▸ Inferiorly – sphenoid sinus ▸ Laterally – cavernous sinus
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- 46. CNS GLANDS PITUITARY GLAND:ANATOMICAL STRUCTURE ▸ Anatomically, the pituitary gland is a ‘’two-in-one’’ structure consisting of the anterior pituitary and the posterior pituitary ▸ These parts have different embryonic origins and function very differently Anterior Lobe ▸ The anterior lobe (adenohypophysis) is derived from an outpouching of the roof of the pharynx, called Rathke’s pouch ▸ It is composed of glandular epithelium and secretes a number of hormones
- 47. CNS GLANDS PITUITARY GLAND:ANATOMICAL STRUCTURE ▸ The anterior lobe can be further divided into three parts: ▸ Pars anterior – the largest part, responsible for hormone secretion ▸ Pars intermedia – a thin epithelial layer that separates the pars anterior from the posterior lobe ▸ Pars tuberalis – an upwards extension of the pars anterior that surrounds the anterolateral aspect of the infundibulum
- 48. CNS GLANDS PITUITARY GLAND:ANATOMICAL STRUCTURE ▸ The release of hormones is under the control of the hypothalamus, which communicates with the gland via neurotransmitters secreted into the hypophyseal portal vessels ▸ These vessels ensure that the hypothalamic hormones remain concentrated, rather than being diluted in the systemic circulation
- 49. CNS GLANDS PITUITARY GLAND:ANATOMICAL STRUCTURE Posterior Lobe ▸ The posterior lobe (neurohypophysis) consists of nervous tissue ▸ It arises from the embryonic forebrain, and is, in essence, an extension of the hypothalamus ▸ Upon stimulation, the posterior lobe secretes two hormones – ADH (responsible for control of blood osmolarity), and oxytocin (involved in parturition and milk secretion) ▸ Both of these substances are produced in the supraoptic and paraventricular nuclei of the hypothalamus and then subsequently stored in the posterior pituitary gland, ready for release
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- 51. CNS GLANDS PITUITARY GLAND:VASCULATURE ▸ The vasculature of the pituitary gland is complex and unique ▸ The anterior lobe and posterior lobe have the same venous drainage (anterior and posterior hypophyseal veins) ▸ But they have an individual arterial supply
- 52. CNS GLANDS PITUITARY GLAND:VASCULATURE - ANTERIOR PITUITARY ▸ The anterior pituitary gland receives arterial supply from the superior hypophyseal artery (a branch of the internal carotid artery) ▸ This vessel first forms a capillary network around the hypothalamus ▸ Blood from this network is then transported to a secondary capillary plexus surrounding the anterior pituitary ▸ Known as the hypothalamo-hypophysial portal system, this structure allows the hypothalamus to communicate with the anterior pituitary via the release of neurotransmitters into the bloodstream
- 53. CNS GLANDS PITUITARY GLAND:VASCULATURE - POSTERIOR PITUITARY ▸ The infundibulum and posterior pituitary gland receive a rich blood supply from many arteries ▸ Of these, the major vessels are ▸ superior hypophyseal artery ▸ infundibular artery ▸ inferior hypophyseal artery
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- 55. CNS GLANDS REVIEW QUESTIONS ▸Which of the following structures is located inferiorly to the pituitary gland? ▸ Sphenoid sinus ▸ Cavernous sinus ▸ Optic chiasm ▸ Basilar artery
- 56. CNS GLANDS REVIEW QUESTIONS ▸The sphenoid sinus is located inferiorly to the pituitary gland
- 57. CNS GLANDS REVIEW QUESTIONS ▸What structure can become compressed in a pituitary adenoma, leading to problems with vision? ▸ Basilar artery ▸ Cavernous sinus ▸ Optic chiasm ▸ Pons
- 58. CNS GLANDS REVIEW QUESTIONS ▸Optic chiasm - leading to bitemporal hemianopia
- 59. CNS GLANDS REVIEW QUESTIONS ▸What part of the anterior pituitary gland is mainly responsible for hormone secretion? ▸ Hypothalamus ▸ Pars tuberalis ▸ Pars intermedia ▸ Pars anterior
- 60. CNS GLANDS REVIEW QUESTIONS ▸Pars anterior – the largest part, responsible for hormone secretion
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- 62. 2 MIN NEUROSCIENCE: PINEALGLAND https://www.youtube.com/watch?v=R0VPDd0JwCE
- 63. CNS GLANDS PINEAL GLAND:OVERVIEW ▸ The pineal gland is a small endocrine gland located within the brain ▸ Its main secretion is melatonin, which regulates the circadian rhythm of the body ▸ It is also thought to produce hormones that inhibit the action of other endocrine glands in the body
- 64. CNS GLANDS PINEAL GLAND:ANATOMICAL STRUCTURE AND POSITION ▸ The pineal gland is small glandular body, approximately 6mm long ▸ It is shaped like a pine cone, from which its name is derived ▸ There are two types of cells present within the gland: ▸ Pinealocytes – hormone secreting cells ▸ Glial cells – supporting cells ▸ In middle age, the gland commonly becomes calcified, and can be subsequently identified on radiographs and CT scans of the head
- 65. CNS GLANDS PINEAL GLAND:ANATOMICAL STRUCTURE AND POSITION ▸ The pineal gland is a midline structure, located between the two cerebral hemispheres ▸ It is attached by a stalk to the posterior wall of third ventricle ▸ In close proximity to the gland are the superior colliculi of the midbrain – paired structures that play an important role in vision
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- 67. CNS GLANDS PINEAL GLAND:VASCULATURE ▸ The arterial supply to the pineal gland is profuse, second only to the kidney ▸ The posterior choroidal arteries are the main supply ▸ They are a set of 10 branches that arise from the posterior cerebral artery ▸ Venous drainage is via the internal cerebral veins
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- 69. CNS GLANDS REVIEW QUESTIONS ▸Which of these substances is produced by the pineal gland? ▸ Melatonin ▸ Calcitonin ▸ Serotonin ▸ Thyrotropin-releasing hormone
- 70. CNS GLANDS REVIEW QUESTIONS ▸The pineal gland produces melatonin, which regulates the circadian rhythm of the body
- 71. CNS GLANDS REVIEW QUESTIONS ▸The pineal gland is attached by a stalk to the posterior wall of which ventricle? ▸ First ▸ Second ▸ Third ▸ Fourth
- 72. CNS GLANDS REVIEW QUESTIONS ▸It is attached by a stalk to the posterior wall of third ventricle
- 73. CNS GLANDS REVIEW QUESTIONS ▸The posterior choroidal arteries originate from which main artery? ▸ Anterior cerebral artery ▸ Middle cerebral artery ▸ Posterior cerebral artery ▸ Posterior communicating arteries
- 74. CNS GLANDS REVIEW QUESTIONS ▸posterior choroidal arteries (main supply) are a set of 10 branches that arise from the posterior cerebral artery
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- 76. 2 MIN NEUROSCIENCE: LIMBICSYSTEM https://www.youtube.com/watch?v=LNs9ruzoTmI
- 77. DEEP BRAIN STRUCTURES LIMBICSYSTEM ▸ The limbic system is a set of structures in the brain that deal with emotions and memory ▸ A set of brain structures located on both sides of the thalamus, immediately beneath the medial temporal lobe of the cerebrum primarily in the forebrain ▸ It regulates autonomic or endocrine function in response to emotional stimuli and also is involved in reinforcing behavior
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- 79. References ▸ These slidereflect a summary of the contents of TeachMeAnatomy.info and are to be used for educational purposes only in compliance with the terms of use policy. Specific portions referenced in this summary are as follows: ▸ https://teachmeanatomy.info/neuroanatomy/structures/meninges/ ▸ https://teachmeanatomy.info/neuroanatomy/vessels/ventricles/ ▸ https://teachmeanatomy.info/neuroanatomy/structures/basal-ganglia/ ▸ https://teachmeanatomy.info/neuroanatomy/structures/pineal-gland/ ▸ https://teachmeanatomy.info/neuroanatomy/structures/pituitary- gland/ Additional sources are referenced on the slide containing that specific content.