Biological Basis of Behaviour PDF

54 I. Parts of the Nervous System II. The Brain and Spinal Cord 1. Spinal Cord 2. Identifying the hemispheres and the lobes of the brain 3. Brain Imaging 55 1  ¡ By the end of t...

54 I. Parts of the Nervous System II. The Brain and Spinal Cord 1. Spinal Cord 2. Identifying the hemispheres and the lobes of the brain 3. Brain Imaging 55 1  ¡ By the end of this section you will be able to: Describe the difference between the central and peripheral nervous systems Explain the difference between the somatic and autonomic nervous systems Differentiate between the sympathetic and parasympathetic divisions of the autonomic nervous system 56 57 2  Peripheral Nervous System (PNS) - Nervous tissue in the rest of the body 58 ¡ Nervous System ¡ CNS and PNS ¡ CNS § Brain § Spinal cord ¡ PNS § Somatic and autonomic NS 59 3  ¡ Homeostasis is a state of equilibrium, or balance, in which biological conditions (such as body temperature) are maintained at optimal levels. ¡ Sympathetic NS § Involved in preparing the body for stress-related activities ¡ Parasympathetic NS § Associated with returning the body to routine, day-to-day operations 60 I. Parts of the Nervous System II. The Brain and Spinal Cord 1. Spinal Cord 2. Identifying the hemispheres and the lobes of the brain 3. Brain Imaging 62 4  ¡ Learning Objectives By the end of the chapter you should be able to: § Explain the functions of the spinal cord § Identify the hemispheres and lobes of the brain § Describe the types of techniques available to clinicians and researchers to image or scan the brain 63 ¡ Connects the brain to the outside world ¡ Organized in 30 segments, corresponding with the vertebrae § Sensory nerves bring messages in § Motor nerves send messages out to the muscles and organs ¡ Some reflexes are controlled solely by the spinal cord and do not need to communicated with the brain 64 5  A. Hindbrain B. Midbrain C. Forebrain 66 ¡ Hindbrain Structures § Medulla § Pons § Cerebellum 67 6  Pons 1) Medulla Bodily functions (breathing, heart rate) 2) Pons (means bridge) Sleep, waking and dreaming, movement 68 3. Cerebellum ¡ Means “lesser brain” ¡ Balance and coordination ¡ Fine motor movements ¡ Higher cognitive tasks ¡ Some memory function ¡ Cerebellar damage § Clumsy, § Uncoordinated, § Difficulty walking 69 7  “Older Brain Structures” makes reference to regions of the brain that are shared by most species (vertebrates), and are therefore believed to have evolved earliest. “Older Brain Structures” are highly involved in rudimentary survival “Reptilian Brain” functions (breathing, heart rate etc.) 70 A. Hindbrain B. Midbrain C. Forebrain 72 8  Midbrain Structures 1. Reticular formation 2. Ventral Tegmental Area (VTA) 3. Substantia nigra 73 1. Reticular Formation Spans hindbrain-midbrain-forbrain Pons Reticular activating system (RAS) Sleep/wake, arousal, alertness and motor activity 74 9  2. Ventral tegmental area (VTA) 3. Substantia nigra (SN) Both regions contain cell bodies that produce the neurotransmitter dopamine Critical for movement. ¡ Damage to SN most associated with Parkinson’s disease VTA associated with reward and addiction 75 A. Hindbrain B. Midbrain C. Forebrain 76 10  ¡ The surface of the brain, known as the cerebral cortex, ¡ Gyri (gyrus, sing.) are pattern of folds or bumps, known as gyri ¡ Sulci (sulcus, sing.) are the grooves, ¡ The most prominent sulcus, known as the longitudinal fissure, is the deep groove that separates the brain into two halves or hemispheres 77 Organization of the Cortex Lobes of the cortex and our Divided Brain 78 11  Cortical regions can broadly be broken down into: 1) Primary cortical areas 2) Association areas 79 1) Primary cortical regions These regions are the first cortical areas to receive sensory information, or initiate motor movement (motor cortex). Project information on to the association areas 80 12  2) Associational cortical regions Process and integrate information sent from primary cortices 81 Each brain hemisphere is divided into four lobes, separated by prominent fissures. 1) Frontal lobes (forehead) 2) Parietal lobes (top to rear head) 3) Occipital lobes (back head) 4) Temporal lobes (side of head). 82 13  Frontal lobe – front of brain § Contains primary and association motor cortices that plan, sequence, and execute motor movements § Broca’s area (usually left frontal lobe): production of language 83 Frontal lobe – front of brain § Involved in social judgment, rational decision making, ability to set goals, make plans, carry through plans § Involved in the inhibition of behaviour 84 14 85 86 15  Parietal lobes § Somatosensory cortex receives input about pressure, temperature, pain, touch from all over the body § Posterior parietal cortex is involved in directing movement in space (e.g., reaching out and touch an object - visually guided movement) 87 Temporal lobe § Contains primary auditory cortex (hearing) § Amygdala (emotion) § Hippocampus (memory) § Visual association cortices associated with face and object recognition § Wernicke’s area: comprehension of language 88 16  Occipital lobe (vision) § Contains the primary and association visual cortices § Select regions process the qualities of colour, motion, shape, spatial location § Damage can lead to inability to perceive colour, motion, or recognize objects (visual agnosia) 89 91 17  Your TWO Brains: Mysteries of the Split-Brain Patients s pt n ce C o U R FO Dr. Michael Gazzaniga 92 #1 t t cep Lef n e : e Co ag her gu p n is La em H 93 18  ¡ Broca’s area- production of language § damage leads to Broca’s aphasia § ‘Tan’, a stroke patient who could only say ‘tan’ ¡ Wernickes area- language comprehension § - Damage causes receptive aphasia 94 ¡ Right-handed people – Typically language processes are found in the left hemisphere- spatial, right ¡ Left-handed people – 40% dominant left hemisphere (language) – 40% right hemisphere – 20% mixed 95 19  VOCABULARY Contralateral = opposite side Ipsilateral = same side 2 l p t # ntro e o onc a l c nt C e r e a lat vem r nt f mo nytimes.com o C o 96 The two hemispheres communicate with one another across the corpus callosum Corpus Callosum s 3 f er t# ns ep tra e o nc um rom her C f p os n is c a l l at io h e m s m o rpu for re t Co i n he isp m he 97 20  Information from right v.f. goes to the left hemisphere and transferred to right via the c.c. and vice versa CONCEPT #4 Visual information from one visual field ends up in the contralateral (opposite) visual cortex. The c.c. transfers this info across. 98 99 21  Intractable epilepsy - generalized seizures In severe cases the corpus callosum is severed (commisurotomy) Do not have motor impairment 100 Information from the right v.f. STILL goes to the left hemisphere. - Left v.f. to right hemisphere No information is transferred to the other hemisphere!!! Information is trapped in that hemisphere. 101 22  E: Name what you see E: Name what you see S: “fork” S: “nothing” 103 E: Name what you see E: Name what you see S: “fork” S: “nothing” 104 23  E: Name what you see E: Name what you see S: “fork” S: “nothing” 105 E: Name what you saw E: Name what you see S: “fork” S: “nothing” 106 24  E: Name what you saw E: Name what you see S: “fork” S: “nothing” 107 E: Name what you see E: Name what you see S: “fork” S: “nothing” 108 25  E: Name what you see E: Name what you see S: “fork” S: “nothing” 109 E: Name what you see E: Name what you see S: “fork” S: “nothing” 110 26  E: Name what you see E: Name what you saw S: “fork” S: “nothing” 111 E: Name what you see E: Name what you saw S: “fork” S: “nothing” 112 27 113 114 28  Left hemisphere can concoct stories or reasons about what the right hemisphere is doing Reports that the two hemispheres can be at odds. Believes left hemisphere is the master hemisphere 115 ¡ The brain’s capacity for modification ¡ Because of neuroplasticity, our brains are constantly changing and adapting e.g. learning and memory forms new synapses ¡ Children’s brains are more plastic than adult brains ¡ Rewiring after brain injury, developmental incidents and amputation 116 29  Thalamus ¡ Traffic officer” ¡ Gateway for all sensory information (except olfaction) ¡ Sends sensory information onto higher order cortical regions 119 Hypothalamus The hypothalamus lies below (hypo) the thalamus Directs several maintenance activities like ¡ Eating ¡ Drinking Helps govern the endocrine system via ¡ Body temperature the pituitary gland. ¡ Emotions 120 30  The “Limbic System” It includes the hippocampus, amygdala, and hypothalamus Associated with: § Emotions such as fear, aggression and drives for food and sex. § MEMORY!!!! 121 Human brains are difficult to access Technology has provided many tools that allow us to access images of the brain in living beings 122 31  Clinical observations have shed light on a number of brain disorders. Tom Landers/ Boston Globe 123 Computerized Tomography CT scans take a number of x- rays through a body structure The x-rays pass through tissues of different densities at different rates, allowing a computer to construct an overall image Relatively high resolution images Good for obtaining structural information 124 32  PET (positron emission tomography) Scan a visual display of brain activity that detects a radioactive form of glucose while the brain performs a given task. Lower resolution images Good for obtaining functional TEST STATE CONTOL information (Relaxed) Subtracted Result 125 MRI (magnetic resonance imaging) uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of brain tissue. Top images: MRI, show ventricular enlargement in a schizophrenic patient. Bottom images: fMRI shows brain regions when a participants lies. 126 33  An amplified recording of the electrical waves sweeping across the brain’s surface, measured by electrodes placed on the scalp. AJ Photo/ Photo Researchers, Inc. 127 34