CAPS 301 Brain Stem, Thalamus, Hypothalamus, Cortex (HUYNH) PDF

CAPS 301 Brain Stem, Thalamus, Hypothalamus, Cortex copyright © Dennis Kunkel Dr. Frank Huynh Department of Cellular and Physiological Sciences University of British Columbia  Learning Objectives By the end of this lecture, you should be a...

CAPS 301 Brain Stem, Thalamus, Hypothalamus, Cortex copyright © Dennis Kunkel Dr. Frank Huynh Department of Cellular and Physiological Sciences University of British Columbia  Learning Objectives By the end of this lecture, you should be able to: 1) identify the major functions of the brain stem 2) identify the major functions of the hypothalamus 3) characterize the anatomy of the lobes of the cerebral cortex 4) identify some of the major functions of the frontal and parietal lobes, namely the primary motor cortex and somatosensory cortex 5) define and describe the motor and sensory homunculi 6) apply the above knowledge to determine what could happen if there was an injury to any of these brain areas  Brain Stem Medulla continuous with spinal cord Table 4-1. Sherwood, 5th Cdn. Ed. Five Major Functions of the Brain Stem 1) Origin of most of the cranial nerves -all except for CNI, II, (XI) -XI has a dual origin, part in brain stem, part in C2-C4 -supply the head and neck with sensory and motor fibres -CNX (vagus nerve) supplies parasympathetic innervation to organs in the thoracic and abdominal cavities Note: Some CN are composed of just sensory fibres, some just motor, some are mixed Five Major Functions of the Brain Stem 2) Control heart function, blood vessel function, respiration, many digestive activities -“vegetative functions” -clusters of cell bodies called centres, located in the medulla, regulate these functions 3) Regulate reflexes involved in equilibrium and posture -vestibular nuclei located in medulla and pons  Five Major Functions of the Brain Stem 4) Activate the ascending reticular activating system (ARAS), which arouses the cerebral cortex reticular formation=network of interconnected neurons running throughout the brain stem and into the thalamus receives and integrates all incoming sensory synaptic input direct attention to important stimuli ascending fibres originating in the reticular formation carry signals upward to arouse and activate the cerebral cortex Fig. 4-19 Sherwood, 5th Cdn. Ed. Five Major Functions of the Brain Stem 5) Regulate sleep -hypothalamus also plays a role in regulating sleep Five Major Functions of the Brain Stem Summary: 1) Cranial nerves 2) Vegetative functions 3) Equilibrium and posture 4) ARAS 5) Sleep  Please download and install the Slido app on all computers you use Which of the following are likely symptoms for a patient that had an ischemic stroke that blocked blood flow to the brain stem? ⓘ Start presenting to display the poll results on this slide.  Learning Objectives By the end of this lecture, you should be able to: 1) identify the major functions of the brain stem 2) identify the major functions of the thalamus and hypothalamus 3) characterize the anatomy of the lobes of the cerebral cortex 4) identify some of the major functions of the frontal and parietal lobes, namely the primary motor cortex and somatosensory cortex 5) define and describe the motor and sensory homunculi 6) apply the above knowledge to determine what could happen if there was an injury to any of these brain areas Thalamus and hypothalamus  Thalamus Preliminary processing of sensory input from brain stem – Screen out insignificant signals “Relay station” – routes important sensory impulses to appropriate areas of the cortex Direct attention to stimuli of interest – Ex. Parents can sleep through outdoor traffic noise but become instantly aware of their baby’s slightest sounds Positively reinforce voluntary motor behavior initiated by the cortex  Hypothalamus Located beneath the thalamus Link between nervous system and endocrine system – Reproductive, metabolic, fluid balance, etc. Brain area most involved with directly regulating internal environment Integrating centre for homeostatic functions (ie. tries to maintain “set point”): – Controls body temperature (receives sensory input and initiates appropriate responses such as sweating or shivering) – Controls thirst and urine output to maintain hydration and blood pressure – Controls food intake/energy expenditure to maintain body weight  Hypothalamus Controls anterior pituitary hormone secretion Produces posterior pituitary hormones Controls uterine contractions and milk ejection Serves as major autonomic nervous system coordinating centre, which means it can control smooth muscle, cardiac muscle, and exocrine gland function Regulates circadian rhythm/sleep-wake cycle  Please download and install the Slido app on all computers you use The primary function of the hypothalamus is: ⓘ Start presenting to display the poll results on this slide.  Learning Objectives By the end of this lecture, you should be able to: 1) identify the major functions of the brain stem 2) identify the major functions of the thalamus and hypothalamus 3) characterize the anatomy of the lobes of the cerebral cortex 4) identify some of the major functions of the frontal and parietal lobes, namely the primary motor cortex and somatosensory cortex 5) define and describe the motor and sensory homunculi 6) apply the above knowledge to determine what could happen if there was an injury to any of these brain areas  Cerebral Cortex Largest portion of human brain R. Cerebral hemisphere L. Cerebral hemisphere Separated in middle by longitudinal fissure L. and R. cerebral hemispheres connected by corpus callosum, which is a thick band of ~300 million neuronal axons travelling between the two hemispheres  Cerebral Cortex Outer shell of grey matter, inner core of white matter Grey matter=cell bodies and dendrites White matter=bundles of axons (=tracts). White because of lipid composition of myelin Fig. 4-28 Sherwood, 5th Cdn. Ed. Lobes of the cerebral cortex Specific deep folds serve as landmarks to divide the lobes One lobe on each side  Frontal Lobes Primary motor cortex – Plan and execute movements together with premotor cortex (located just anterior to the motor cortex) – Large pyramidal neurons with long axons that descend the spinal cord and synapse with alpha-motor neurons that innervate skeletal muscle Fig. 4-23 Sherwood, 5th Cdn. Ed.  Frontal Lobes Primary motor cortex – Neuronal tracts originating in one hemisphere cross over to the other side before terminating on efferent motor neurons – Thus, the motor cortex on each side of the brain primarily controls muscles on the opposite side of the body. Fig. 4-23 Sherwood, 5th Cdn. Ed.  Frontal Lobes Motor homunculus – Stimulation of different areas of the primary motor cortex brings about movement in different regions of the body. – Size of the body part depicts the relative amount of motor cortex devoted to that body part – Areas with requiring complex (lips/tongue for speech) or fine motor control (fingers) require more input from the motor cortex Fig. 4-23 Sherwood, 5th Cdn. Ed.  Frontal Lobes Motor homunculus – The somatotopic map is relatively stable in terms of the major body divisions. – However, under the surface, the neural connections are more plastic. Neuronal activation patterns can change after learning a new skills or re-learning skills after a traumatic injury Fig. 4-23 Sherwood, 5th Cdn. Ed.  Parietal Lobes Somatosensory cortex – Site of initial processing and perception of somaesthetic (touch, pressure, heat, cold, pain) input and proprioceptive input – For the most part, the somatosensory cortex on one side receives sensory input from the other side of the body due to ascending pathways crossing over to the other side before terminating in the cortex. Fig. 4-25 Sherwood, 5th Cdn. Ed.  Parietal Lobes Somatosensory cortex – Simple awareness of sensory input occurs in the thalamus (ie. you are aware you are touching something hot) – Somatosensory cortex localizes the input and perceives the intensity (ie. where on your body is it hot and how hot is it) – Somatosensory cortex projects the sensory input to even higher areas for further elaboration (ie. what is the texture, firmness, shape, position, and location of the hot object you are touching) Fig. 4-25 Sherwood, 5th Cdn. Ed.  Parietal Lobes Sensory homunculus – Stimulation of different areas of the body activate different regions of the somatosensory cortex – Size of the body part depicts the relative amount of somatosensory cortex devoted to that body part – Areas with higher sensitivity (ie. face, tongue, hands) require more of the somatosensory cortex to process the stimuli Fig. 4-25 Sherwood, 5th Cdn. Ed.  Learning Objectives By the end of this lecture, you should be able to: 1) identify the major functions of the brain stem 2) identify the major functions of the thalamus and hypothalamus 3) characterize the anatomy of the lobes of the cerebral cortex 4) identify some of the major functions of the frontal and parietal lobes, namely the primary motor cortex and somatosensory cortex 5) define and describe the motor and sensory homunculi 6) apply the above knowledge to determine what could happen if there was an injury to any of these brain areas  CAPS 301 Brain Stem, Thalamus, Hypothalamus, Cortex copyright © Dennis Kunkel Dr. Frank Huynh Department of Cellular and Physiological Sciences University of British Columbia  Learning Objectives By the end of this lecture, you should be able to: 1) identify the major functions of the brain stem 2) identify the major functions of the hypothalamus 3) characterize the anatomy of the lobes of the cerebral cortex 4) identify some of the major functions of the frontal and parietal lobes, namely the primary motor cortex and somatosensory cortex 5) define and describe the motor and sensory homunculi 6) apply the above knowledge to determine what could happen if there was an injury to any of these brain areas  Brain Stem Medulla continuous with spinal cord Table 4-1. Sherwood, 5th Cdn. Ed. Five Major Functions of the Brain Stem 1) Origin of most of the cranial nerves -all except for CNI, II, (XI) -XI has a dual origin, part in brain stem, part in C2-C4 -supply the head and neck with sensory and motor fibres -CNX (vagus nerve) supplies parasympathetic innervation to organs in the thoracic and abdominal cavities Note: Some CN are composed of just sensory fibres, some just motor, some are mixed Five Major Functions of the Brain Stem 2) Control heart function, blood vessel function, respiration, many digestive activities -“vegetative functions” -clusters of cell bodies called centres, located in the medulla, regulate these functions 3) Regulate reflexes involved in equilibrium and posture -vestibular nuclei located in medulla and pons  Five Major Functions of the Brain Stem 4) Activate the ascending reticular activating system (ARAS), which arouses the cerebral cortex reticular formation=network of interconnected neurons running throughout the brain stem and into the thalamus receives and integrates all incoming sensory synaptic input direct attention to important stimuli ascending fibres originating in the reticular formation carry signals upward to arouse and activate the cerebral cortex Fig. 4-19 Sherwood, 5th Cdn. Ed. Five Major Functions of the Brain Stem 5) Regulate sleep -hypothalamus also plays a role in regulating sleep Five Major Functions of the Brain Stem Summary: 1) Cranial nerves 2) Vegetative functions 3) Equilibrium and posture 4) ARAS 5) Sleep  Please download and install the Slido app on all computers you use Which of the following are likely symptoms for a patient that had an ischemic stroke that blocked blood flow to the brain stem? ⓘ Start presenting to display the poll results on this slide.  Learning Objectives By the end of this lecture, you should be able to: 1) identify the major functions of the brain stem 2) identify the major functions of the thalamus and hypothalamus 3) characterize the anatomy of the lobes of the cerebral cortex 4) identify some of the major functions of the frontal and parietal lobes, namely the primary motor cortex and somatosensory cortex 5) define and describe the motor and sensory homunculi 6) apply the above knowledge to determine what could happen if there was an injury to any of these brain areas Thalamus and hypothalamus  Thalamus Preliminary processing of sensory input from brain stem – Screen out insignificant signals “Relay station” – routes important sensory impulses to appropriate areas of the cortex Direct attention to stimuli of interest – Ex. Parents can sleep through outdoor traffic noise but become instantly aware of their baby’s slightest sounds Positively reinforce voluntary motor behavior initiated by the cortex  Hypothalamus Located beneath the thalamus Link between nervous system and endocrine system – Reproductive, metabolic, fluid balance, etc. Brain area most involved with directly regulating internal environment Integrating centre for homeostatic functions (ie. tries to maintain “set point”): – Controls body temperature (receives sensory input and initiates appropriate responses such as sweating or shivering) – Controls thirst and urine output to maintain hydration and blood pressure – Controls food intake/energy expenditure to maintain body weight  Hypothalamus Controls anterior pituitary hormone secretion Produces posterior pituitary hormones Controls uterine contractions and milk ejection Serves as major autonomic nervous system coordinating centre, which means it can control smooth muscle, cardiac muscle, and exocrine gland function Regulates circadian rhythm/sleep-wake cycle  Please download and install the Slido app on all computers you use The primary function of the hypothalamus is: ⓘ Start presenting to display the poll results on this slide.  Learning Objectives By the end of this lecture, you should be able to: 1) identify the major functions of the brain stem 2) identify the major functions of the thalamus and hypothalamus 3) characterize the anatomy of the lobes of the cerebral cortex 4) identify some of the major functions of the frontal and parietal lobes, namely the primary motor cortex and somatosensory cortex 5) define and describe the motor and sensory homunculi 6) apply the above knowledge to determine what could happen if there was an injury to any of these brain areas  Cerebral Cortex Largest portion of human brain R. Cerebral hemisphere L. Cerebral hemisphere Separated in middle by longitudinal fissure L. and R. cerebral hemispheres connected by corpus callosum, which is a thick band of ~300 million neuronal axons travelling between the two hemispheres  Cerebral Cortex Outer shell of grey matter, inner core of white matter Grey matter=cell bodies and dendrites White matter=bundles of axons (=tracts). White because of lipid composition of myelin Fig. 4-28 Sherwood, 5th Cdn. Ed. Lobes of the cerebral cortex Specific deep folds serve as landmarks to divide the lobes One lobe on each side  Frontal Lobes Primary motor cortex – Plan and execute movements together with premotor cortex (located just anterior to the motor cortex) – Large pyramidal neurons with long axons that descend the spinal cord and synapse with alpha-motor neurons that innervate skeletal muscle Fig. 4-23 Sherwood, 5th Cdn. Ed.  Frontal Lobes Primary motor cortex – Neuronal tracts originating in one hemisphere cross over to the other side before terminating on efferent motor neurons – Thus, the motor cortex on each side of the brain primarily controls muscles on the opposite side of the body. Fig. 4-23 Sherwood, 5th Cdn. Ed.  Frontal Lobes Motor homunculus – Stimulation of different areas of the primary motor cortex brings about movement in different regions of the body. – Size of the body part depicts the relative amount of motor cortex devoted to that body part – Areas with requiring complex (lips/tongue for speech) or fine motor control (fingers) require more input from the motor cortex Fig. 4-23 Sherwood, 5th Cdn. Ed.  Frontal Lobes Motor homunculus – The somatotopic map is relatively stable in terms of the major body divisions. – However, under the surface, the neural connections are more plastic. Neuronal activation patterns can change after learning a new skills or re-learning skills after a traumatic injury Fig. 4-23 Sherwood, 5th Cdn. Ed.  Parietal Lobes Somatosensory cortex – Site of initial processing and perception of somaesthetic (touch, pressure, heat, cold, pain) input and proprioceptive input – For the most part, the somatosensory cortex on one side receives sensory input from the other side of the body due to ascending pathways crossing over to the other side before terminating in the cortex. Fig. 4-25 Sherwood, 5th Cdn. Ed.  Parietal Lobes Somatosensory cortex – Simple awareness of sensory input occurs in the thalamus (ie. you are aware you are touching something hot) – Somatosensory cortex localizes the input and perceives the intensity (ie. where on your body is it hot and how hot is it) – Somatosensory cortex projects the sensory input to even higher areas for further elaboration (ie. what is the texture, firmness, shape, position, and location of the hot object you are touching) Fig. 4-25 Sherwood, 5th Cdn. Ed.  Parietal Lobes Sensory homunculus – Stimulation of different areas of the body activate different regions of the somatosensory cortex – Size of the body part depicts the relative amount of somatosensory cortex devoted to that body part – Areas with higher sensitivity (ie. face, tongue, hands) require more of the somatosensory cortex to process the stimuli Fig. 4-25 Sherwood, 5th Cdn. Ed.  Learning Objectives By the end of this lecture, you should be able to: 1) identify the major functions of the brain stem 2) identify the major functions of the thalamus and hypothalamus 3) characterize the anatomy of the lobes of the cerebral cortex 4) identify some of the major functions of the frontal and parietal lobes, namely the primary motor cortex and somatosensory cortex 5) define and describe the motor and sensory homunculi 6) apply the above knowledge to determine what could happen if there was an injury to any of these brain areas  CAPS 301 Cortex, Cerebellum, Basal Nuclei copyright © Dennis Kunkel Dr. Frank Huynh Department of Cellular and Physiological Sciences University of British Columbia  Learning Objectives By the end of this lecture, you should be able to: 1) identify and characterize other regions of the frontal and parietal lobes that coordinate complex motor functions 2) describe the major functions of the cerebellum 3) describe the major functions of the basal ganglia 4) apply the above knowledge to determine what could happen if there was an injury to any of these brain areas  Other regions controlling motor function Even though signals originating from the primary motor cortex can activate alpha-motor neurons and cause skeletal muscle contraction, this doesn’t mean the primary motor cortex is the only part of the CNS that controls motor function. The motor cortex itself doesn’t initiate voluntary movement. It also doesn’t necessarily coordinate multiple movements. The decisions about whether/when/how to move are made in higher cortical centres.  Coordinating motor function Need higher processing centres to coordinate movement, like a skilled Primary motor cortex Pulling on a single string or puppeteer. an unskilled puppeteer pulling on many strings doesn’t produce meaningful movement. alpha-motor neurons Higher motor areas Fig. 4-24a Sherwood, 5th Cdn. Ed.  Supplementary motor area Medial surface of each frontal lobe, anterior to the primary motor cortex Programming complex sequences of movements – Ex. movements requiring simultaneous use of both hands and feet Lesion here does not result in paralysis but interferes with performance of complex, integrated movements  Premotor cortex/posterior parietal cortex Lateral surface of each frontal lobe, anterior to the primary motor cortex Orients body and arms toward a specific target In order to inform the primary motor cortex which muscles to contract to achieve the desired movement, must first receive info about the body’s current position in relation to the target Sensory input is provided by the posterior parietal cortex, just posterior to the primary somatosensory cortex.  Premotor cortex/posterior parietal cortex If either of these regions is damaged, a person cannot process complex sensory information to accomplish purposeful movement in a spatial context – Ex. Cannot successfully eat using utensils  Higher motor areas Just because these areas are able to coordinate more complex motor movements, this doesn’t necessarily mean these brain areas initiate voluntary movements. Ex. Picking up an apple to eat – Your primary motor cortex, supplementary motor area, premotor cortex, and posterior parietal cortex all coordinate to pick up the apple – But initiation of this action depends on motivation and behaviour Are you hungry? Do you just love apples? Stress eating?  Please download and install the Slido app on all computers you use A lesion to which of the following regions would likely result in the MOST difficulty picking up a pencil? ⓘ Start presenting to display the poll results on this slide.  Learning Objectives By the end of this lecture, you should be able to: 1) identify and characterize other regions of the frontal and parietal lobes that coordinate complex motor functions 2) describe the major functions of the cerebellum 3) describe the major functions of the basal ganglia 4) apply the above knowledge to determine what could happen if there was an injury to any of these brain areas Cerebellum  Cerebellum Three functionally distinct parts spinocerebellum cerebrocerebellum vestibulocerebellum  Cerebellum Vestibulocerebellum – Maintaining balance and control eye movements – Vestibulo-ocular reflex can be modulated by the cerebellum – Hard to maintain gaze if vestibulocerebellum is damaged Cerebrocerebellum – initiation of highly skilled movements, especially the planning and execution of complex spatial and temporal sequences of movement (including speech) – Storage of procedural memories (muscle memory) Ex. not having to think when walking or tying your shoe laces  Cerebellum Spinocerebellum – Enhances muscle tone – Coordinates skilled, voluntary movements – Ensure accurate timing of various muscle contractions to coordinate movements involving multiple joints – Coordinates signals coming down from motor cortex with sensory signals coming from peripheral receptors and then can make adjustments in order to ensure that the intended outcome happens Ex. If trying to pick up a pencil, cerebellum helps you stop forward movement of your hand when you approach the pencil, rather than overshooting  Cerebellum Cerebellar damage – Poor balance – Decreased muscle tone, but no paralysis – Unable to perform rapid movements smoothly – Unable to start/stop skeletal muscle action quickly – Intention tremor (oscillating to-and-fro movements of a limb as it approaches its intended destination Tremor that happens when engaging in intentional movements and not when just at rest Ex. Reaching for pencil, but you overshoot, then rebound excessively, repeat this process until you successfully grab the pencil https://www.youtube.com/watch?v=DPijQriVgvA  Learning Objectives By the end of this lecture, you should be able to: 1) identify and characterize other regions of the frontal and parietal lobes that coordinate complex motor functions 2) describe the major functions of the cerebellum 3) describe the major functions of the basal ganglia 4) apply the above knowledge to determine what could happen if there was an injury to any of these brain areas  Basal Nuclei Masses of grey matter located deep within the cerebral white matter  Basal Nuclei Variety of functions: motor control, cognition, emotions, learning Functions related to motor function – Inhibit muscle tone – Selecting and maintaining purposeful motor activity while suppressing useless or unwanted patterns of movement – Monitor and coordinate slow, sustained contractions, especially those related to posture and support – No direct influence on efferent motor neurons, but can modify motor pathways  Basal Nuclei Highly interconnected with other brain regions – Ex. Interconnected loop between basal nuclei, motor regions in cerebral cortex, and thalamus Thalamus positively reinforces voluntary motor behaviour initiated by cortex Basal ganglia inhibit parts of thalamus to eliminate antagonistic or unnecessary movements  Learning Objectives By the end of this lecture, you should be able to: 1) identify and characterize other regions of the frontal and parietal lobes that coordinate complex motor functions 2) describe the major functions of the cerebellum 3) describe the major functions of the basal ganglia 4) apply the above knowledge to determine what could happen if there was an injury to any of these brain areas  Please download and install the Slido app on all computers you use Parkinson's Disease (PD) is associated with a deficiency of dopamine in the basal nuclei. Because the basal nuclei lack enough dopamine, they are unable to perform their normal roles. Thus, which motor disturbances can occur in PD? ⓘ Start presenting to display the poll results on this slide.  Learning Objectives By the end of this lecture, you should be able to: 1) identify and characterize other regions of the frontal and parietal lobes that coordinate complex motor functions 2) describe the major functions of the cerebellum 3) describe the major functions of the basal ganglia 4) apply the above knowledge to determine what could happen if there was an injury to any of these brain areas  CAPS 301 Limbic System copyright © Dennis Kunkel Dr. Frank Huynh Department of Cellular and Physiological Sciences University of British Columbia  Learning Objectives By the end of this lecture, you should be able to: 1) identify the parts of the limbic system 2) identify the basic functions of the limbic system 3) characterize the role of the hypothalamus and higher cortical centres in mediating the physical responses associated with emotions 4) identify three major neurotransmitters implicated in mediating emotions 5) examine the role of neurotransmitters in depression and smart phone addiction  Limbic System ring of interconnected structures includes parts of cerebral cortex, basal ganglia, thalamus, hypothalamus associated with emotions, basic survival and sociosexual behavioral patterns motivation, learning  Emotions Feelings and moods (anger, happiness, sadness) plus the physical responses associated with them Physical responses can be specific behavioural patterns (eg. preparing for attack when angered) or observable expressions (laughing, crying, blushing)  Basic Behavioural Patterns Behaviours aimed at individual survival (attacking, fleeing, searching for food) and perpetuating the species (sociosexual behaviours conducive to mating)  Basic Behavioural Patterns Role of hypothalamus – involuntary internal responses appropriate for specific emotions – eg. increased heart rate, respiratory rate, elevation of blood pressure that happens when angered  Basic Behavioural Patterns Role of higher cortex – Complex behavioural activities (fight, flight, mate) requires higher cortical connections that connect the limbic system and hypothalamus with motor centres to exert the appropriate physical behaviours – Simplest example: happiness → smile – These behaviours appear to be preprogrammed in the cortex since individuals blind from birth still have normal facial expressions  Basic Behavioural Patterns Role of higher cortex – Higher centres can reinforce, modify, or suppress basic behavioural responses – Prefrontal and limbic association areas - Conscious learned control of innate behavioural patterns  Basic Behavioural Patterns Limbic system and hypothalamus: Anger – elevated BP, increased HR, elevated RR, increased blood flow to muscles Prefrontal and amygdala limbic association Fast track Slow track areas (crude, (rational, instinctive) based on past experience)  Basic Behavioural Patterns Reward and punishment centres – Gratifying behaviours tend to be reinforced, while unpleasant experiences are suppressed – Reward and punishment centres in the limbic system give rise to pleasant or unpleasant sensations – Reward centres are most abundant in brain regions responsible for which behaviours?  Neurotransmitters in pathways for emotions and behaviour Underlying mechanisms responsible for emotions and motivated behaviour are still largely unknown Specific neurotransmitters have been implicated – Norepinephrine, dopamine, serotonin  Neurotransmitters in pathways for emotions and behaviour Norepinephrine – reward, alertness, focus Dopamine – reward, pleasure Serotonin – happiness, focus, calmness Activity 1) Which of these neurotransmitters have been implicated in depression? Identify two popular classes of drugs used to treat depression and briefly describe their mechanisms. 2) Why can’t you put your phone down? Which neurotransmitter(s) are involved? Could a drug help? How would you design it? Fill in your answers here: https://docs.google.com/document/d/1K_KYSNQM9ZB- qlC68r65XjfnhjM107dSCP0s9YuUyGU/edit?usp=sharing If you or someone you know is struggling with depression: – Call or text 9-8-8 – Find help here  Learning Objectives By the end of this lecture, you should be able to: 1) identify the parts of the limbic system 2) identify the basic functions of the limbic system 3) characterize the role of the hypothalamus and higher cortical centres in mediating the physical responses associated with emotions 4) identify three major neurotransmitters implicated in mediating emotions 5) examine the role of neurotransmitters in depression and smart phone addiction