3Structures of the Brain Facts about human brainweighs about 3 pounds or about 2% of the body’s weightContains 1.1 trillion cells, including 100 billion neuronsNeurons on the average have 5000 connections called synapse from other neurons (Linden, 2007)Brain uses 20-25% of the body’s oxygen and glucose even though it is only 2% of the body’s weight (Lammert, 2008).Brain is always working and performing its functionsBrain uses the same amount of energywhen the body is asleep or when awake it is hard at work thinking (Raichle & Gusnard, 2002).
4The Brain and the MindThe brain interacts with the other systems in the body, which interacts with people and the world around itThe brain is shaped by the mind.In reality the mind is a creation of the brain, the body, the natural world and the human culture and the mind itself (Thompson and Varela, 2001).So it is a simplification to say that the Brain is the primary influence on or the basis of the human mind.
5The Three Human BrainsAggressive Brain: which lies in the primitive portion of the brainEmotional Brain: which entails the Limbic systemAnalytical Brain: which involves these components of the brain:The brain reaches its maximum number of synaptic connections and its greatest metabolic activity around the age of 3 or 4.
7Primary Components of Human Brain (Part 1) The Cerebral Cortex (Described in next slides)Anterior (frontal) Cingulate Cortex (ACC) – Steadies attention and monitors plans. It helps to integrate thinking and feeling (Yamasaki, LaBar, and McCarthy, 2002). A cingulate is a curved bundle of nerve fibersInsula – Senses the internal state of the body, including those “gut feelings” which people experience. It helps a person to become empathic. It is located inside the temporal lobes on each side of the brainThalamus – Major relay station for sensory information. It relays sensory information from the outside world directly to the amygdala to identify the importance of the stimuli
8Primary Components of Human Brain (Part 2) Brain Stem – Sends neuromodulators such as serotonin and dopamine to the rest of the brainCorpus Callosum – Nerve bundle which passes information between the two brain hemispheres - vital for integrated thoughts, feeling and actionThe Pons – (bridge) Connection between the lower brain and the mid-brain. It affects physical arousal, including blood pressure and responsible for heightened physical arousal in anxiety. Nuclei within the pons are important in rapid eye movement (REM) sleep.Cerebellum - Regulates body movement and responsible for body and limb position, relating to balance, posture, walking etc. Integrates information. It is assumed that the Cerebellum plays an important role in dreaming, memory, and other functions.
10The Cerebral Cortex The motor cortex – mediates motor activity The premotor cortex - plans complex motor activityPrefrontal Cortex (PFC) – Makes meaning of sensory input.The orbitofrontal cortex (OFC) - Controls working memoryThe anterior cingulate gyrus (ACG) – Connects directly limbic system
11Prefrontal Cortex (PFC) Makes meaning of sensory inputSets goals, makes plans, directs actions, and shapes emotionsProcesses information, maintains conscious attention, and forms behavioral responsesGuides and sometimes inhibits the limbic systemConducts executive reasoning and is critical for sequencing behaviorHandles working memory
12Prefrontal Cortex’s Components 1. The orbitofrontal cortex (OFC) –Controls working memoryConsolidates long term memoryCompares information with other data coming to it from other information centers of the brain2. The anterior cingulate gyrus (ACG)Connects directly to the structures of the limbic systemFilters and amplifies information from lower regions to and from the prefrontal cortex
13Limbic System Limbic System central to emotion and motivation and memoryincludes cortical as well as subcortical structuresconsists of the structures that ring the upper part of the brainstemBasal Ganglia – Involved with rewards, stimulation seeking and movement. “Ganglia” are masses of tissuesCingulate gyrus – allows shifting of attention, cognitive flexibility, adaptability, and helps the mind move from idea to ideaHippocampus – Forms new memories and idetects threats.Amygdala - Functions as the “alarm bell” for the brain that responds to emotionally charged or negative stimuli (Rasia-Filho, Londero & Archaval, 2000)Hypothalamus - Regulates primal drives such as hunger and sex & activates the pituitary glandsPituitary gland – it makes endorphins and triggers hormones.
16Left Hemisphere of Brain Organizes information, understands sequences & comprehends time in conjunction with activities or events, putting events in sequential order & placing them in timewhere verbal work & making meaning of experience occursForms symbols (language and math) for experienceCreates explanations for experienceInhibits activity of right hemisphere which deals with emotionsModerates emotional information which goes into right side of brainMediates memory, nonverbal, emotional responsiveness of right-side brain functions
17Right Hemisphere of Brain Responsible for recognizing faces, reading emotions, assessing emotional significance of event in conjunction with data from senses which it interpretsSpecialized for nonverbal recognition & emotional memory - vital for quick & accurate response to world in which human livesStrong role in creativity & nonverbal problem solvingCreates novel responses to both practical & emotional situationsComprehends spatial relationshipsAlert for & creates cadence & rhythm in speech, movement, musicRegulates nervous system & hormonal response coming in from senses.
20Role of Brain Hemispheres Left side of brain controls right side of body & right side of brain controls left side of bodyPrevious slide demonstrates: left eye's image is translated on right side of brain & right eye's image is translated on left side of brainImage which person perceives comes after a process in brain in which left & right side images are translated or decoded by left & right side of brain & then made sense for observerAny sight, thought, sound, smell, touch, or taste a person has is simply a series of biochemical electrical impulses which are sent out by senses to brainThis is physiological process by which all senses & thinking are impacted
21Cause of Faulty Perceptions If human has faulty perceptions it can impact the way human thinks, feels and actsAs a result of faulty perceptions which come from obscuring translation of faulty perception can impair problem solving, decision making & conflict resolutionBrain take time to sort out what senses are sending it
22The Evolving BrainInside brain are three levels of development of brainReptilian - Brain stem is “reptilian brain” from which rest of brain has evolved is simplistic, concrete, fast, and motivationally intensePaleomammalian – Limbic SystemNeomammalian - Cortical tissues relatively recent, complex, conceptualizing, slow & motivationally diffuse sit atop subcortical & brain stem structures
25Evolving Brain ImpactModern cortex of brain has great influence over rest of brainIt’s been shaped by evolutionary pressures to develop ever improving abilities to parent, bond, communicate, cooperate love (Dimbar & Shultz, 2007).Cortex is divided into two “hemispheres” connected by corpus callosumIn evolution of brain left hemisphere came to focus on sequential and linguistic processing & right hemisphere focused on holistic & visual-spatial processingTwo hemispheres work closely together & it is often hard to differentiate their different functions as brain operatesMany neural structures in evolving brain were duplicated so that there is one in each hemisphereUsual way of talking about components of brain is to refer to structure as a single entity e.g. cerebellum
26So How Does the Brain Work? Brain Pathway:Power line which connects two brain regionsMade up of interconnected neurons along which signals are transmitted from one brain region to anotherNeuronsBrain has over 100 billion neuronsNeurons on average have 5000 connections called synapse from other neurons (Linden, 2007)Bio-chemical electrical impulses create a cascade of effects based on messages sent to various organ receptors of bodyNeurons process information by receiving, integrating & transmitting information.
27Components of Neurons Cell body – sends out dendrites Axon – when a neuron fires an electrochemical wave ripples down from its axon which is fiber which extends toward other neurons it is sending signals toDendrites - are spikes from neuron which receive neurotransmitters from other neuronsMyelin – fatty substance that insulates axonsTerminal Buton which faces synapse
30Components of Neuron Synapse 1. Terminal Buton:End of a neuron which contains neurotransmittersReferred to as presynaptic2. Receptors:On end of receiving neuron referred as postsynapticThrough which neurotransmitters are transmitted
35NeurotransmittersAll neurotransmitters affect functions throughout bodyBrain is made up of billions of brain cells called NeuronsNeurons transmit information by means of electrical conduction within nerve cells and between nerve cellsMessage once carried through body cell (Axon) crosses space called Synapse to new receiving cellTip of neuron axon-tiny sacs contain neurotransmitter chemicals which are automatically released by sending nerve cellNeurotransmitter chemicals excite receiving cell causing cell to fire to send message through its own body-Axon to next receiving cellOnce message received neurotransmitter is deactivated & taken up from synapse and stored in sacs so as not to cause repeated firing of receiving cell.
39Neurotransmitters (2) Neuromodulators Serotonin: regulates states of consciousness, mood and anxiety, it also regulates sleep & digestion & affects appetite, sleep & sexual behavior. Most antidepressants aim at increasing its effectDopamine: influences emotional behavior & cognition, regulates motor activity & regulates endocrine activity. It is also involved in rewards & attention. It promotes “approach” behaviors for individuals who face stressorsNorepinephrine: Its function is to alert & arouse. It regulates alertness, anxiety & tension & is secreted by adrenal glands in response to stress or arousalAcetylcholine: promotes wakefulness & learning
41Neurotransmitters (3)Neuropeptides – are built from peptides which is a kind of organic moleculeOpiods – buffer stress, provide soothing & reduce pain, & produce pleasure - these include the endorphinesOxytocin – promote nurturing behaviors toward children & bonding in couples. Associated with blissful closeness & love. Women typically have more oxytocin than men.Vasopressin – supports pair bonding & in men it may promote aggressiveness towards sexual rivals
44Other NeurochemicalsCortisol – released by adrenal glands during stress response. It stimulates amygdala & inhibits hippocampusEstrogen – brains of both men & women contain estrogen receptors which affects libido, mood & memory
45The Nervous SystemResponsible for sensing & reacting to environment & coordinating bodily functions of its organ componentsCentral Nervous System (CNS) includes the brain and the spinal cordPeripheral Nervous System (PNS)Autonomic Nervous System (ANS).
47Peripheral Nervous System Affects heart & muscles & directs communications between skin & brainSkin is vital for receiving data about external environment & safety of bodyChanges in pressure, temperature & other environmental factors cause both conscious & automatic adjustments to environment.Norepinephrine activates PNS which then activates heart, muscles & extremitiesAs norepinephrine increases so does heart rate & blood pressure & anxious symptoms such as sweating, flushing & trembling
49Autonomic Nervous System The ANS enervates & controls action of all internal organs. It consists of three parts:Sympathetic nervous system (SNS) which is responsible for arousal of brain & body. It is important in creating physical responses of arousal under stress & traumaParasympathetic nervous system (PSNS) which inhibits arousal. It restores balance to internal organs & stress response systemsDiffuse enteric nervous system which controls digestion & peristaltic action
52Nutritional Care of Brain There are some basic rules of eating to follow to keep the brain healthyEat a well balanced diet on a daily basis – lots of proteins & lots of vegetableEat at least 2 servings of fish a weekLimit fat consumption to 30% of caloric intakeReduce amount of sugar intake on a daily basis-avoid refined sugarsAvoid foods which body is allergic to
53Take Supplements to Help brain Multivitamin/multimineral supplementOmega-3 Fatty Acid – found in fish oil – 500 milligrams a day because it contains both DHA and EPA acids which are very beneficial to brain given that DHA is the predominant structural fatty acid in central nervous systemVitamin E as Gamma –Tocopherol – this is main antioxidant in cellular membranes within brain
54Supplements for Neurotransmitters Serotonin supplements: Iron, Vitamin B-6 and 5-Hydroxytryptophan and TryptophanNorepinephrine and Dopamine supplements: Iron and Vitamin B-6Acetycholine supplement: egg yolks, beef, liver, or dairy fats or use phosphatidylserine, acetyl-l-carnitine or huperzine-A
55Lifestyle Habits to Keep the Brain Healthy (1) 1. Physical Activity and Exercise – 3 times weekly for 45 minutes including some aerobicsImproves cognitive functions & sustains cerebral blood flowEncourages angiogenesis which is development of new blood vesselsIncreases neurogenesis & neuronal growth in hippocampus
56Lifestyle Habits to Keep the Brain Healthy (2) 2. Engaging in intellectually stimulating activities throughout lifeAs people age it buffers against longitudinally-measured cognitive declineHumans need high levels of cognitive activity throughout their adult life to optimize their cognitive functioning later on as they age