4 The divisions of the brain Telencephalon Diencephalon Mesencephalon Metencephalon MyelencephalonCortex Thalamus Tectum Pons MedullaBasal ganglia Hypothalamus Tegmentum CerebellumHippocampusAmygdala
5 Subcortical organisation PS1003: Introduction to Biological Psychology1 : Brain structure and functionSubcortical organisationCerebral CortexHippocampusLearning & memoryCorpus CallosumConnection the two cortical hemispheresCerebellumMovement, balance, postureBasal gangliaControl of behavioural patternsBrainstemControl of autonomic functionHypothalamus : Hunger, thirst, circadian rhythms, emotion, body temperatureBrain stem : Breathing, heart rate blood pressureThalamusInterface between the cortex and the rest of the nervous systemHypothalamusHomeostasis, emotionControl of endocrine (hormone) systemSpinal cordNerves going to and from the rest of the body
6 The lobes of the cerebral cortex PrecentralgyrusPostcentralgyrusCentralSulcus(or fissure)ParietallobeFrontal lobeOccipitallobeCerebellumLateral (Sylvian)fissureTemporal lobe
7 Comparative Brain Structure (cortical) Adult Cortex Surfacebrain as % Areaweight Brain wt. (cm2)RatCatChimpanzee ,000Human 1, ,500Sulci (fissures) – infoldings of the surfaceGyri – the bumps on the cortical surface
8 Understanding cortical function Brain damaged patientsAssess cognitive deficitLocate area of brain damage (post-mortem, neuroimaging)Functional neuroimagingFunctional MRI measurements during task performanceMeasure areas activated by different aspects of the task
9 Sensory areas of the cortex Primary somatosensory cortexSomatosensory association cortexMultimodal association cortexPrimary auditory cortexAuditory association cortexPrimary visual cortexVisual association cortexPrimary olfactory cortexOlfactory association cortexWe will explore the visual system in more detail in lecture 4
10 We will explore motor control in more detail in lecture 5 Primary motor cortexMotor output to skeletal musclesSupplementary motor cortexMotor planningBasal GangliaMotor patternsCerebellumMotor coordinationWe will explore motor control in more detail in lecture 5
12 The story of Phineas Gage PS1003: Introduction to Biological Psychology1 : Brain structure and functionThe story of Phineas GageGage was a young railway construction supervisor in VermontHe was well liked, reliable, energetic and good at his jobIn September 1848, while preparing a powder charge for blasting a rock, he tamped a steel rod into charge-filled hole, without putting in wadding.The charge exploded and blew the rod out of the hole straight at GageIt entered his head through his left cheek, destroyed his eye, traversed the frontal part of the brain, and left the top of the skull at the other side.After the accident he became extravagant anti-social, foulmouthed, bad mannered and a liar: he could no longer hold a job or plan his future. He died in 1861, thirteen years after the a ccident, penniless and epileptic: no autopsy was performed on his brain.Tamping Iron dimensions : 1 meter in length, 2.5 cm diameterwith 2.5 cm of diameter and more than one meter of lenght against his skull, at a high speedGage lost consciousness immediately and started to have convulsions.
13 Cortical areas controlling language We will explore language in more detail in lecture 6Arcuate fasciculusPrimarymotor cortexWernike’s areaBroca’s areaPrimary auditory cortexPrimary visual cortex
14 Summary of cortical function Frontal lobePlanningThinkingMotor planningMotor outputParietal lobeSpatial processingSpatial orientationSomatosensoryfunctionOccipital lobeVisionVisual processingTemporal lobeHearingSmellMemoryFeelings
15 Inter hemispheric communication the corpus callosum Corpus callosum : a large bundle of fibres connecting the left and right corticesLeftRightEyeVisual CortexLanguage CortexMotor CortexSPEECHLeft handCrossoveroutsidebrainBRAINInformation Transfer in aNormal Person"Split Brain" PatientC U T
16 Studies on ‘split brain’ patients Based on early work by Roger Sperry, for which he received a Nobel Prize in 1981The word “ball” is presented in the left visual field onlyThe subject is asked to say what it is …..….. and to select it from the objects behind the screenUnable to say what the object isbecause of the organisation of the visual pathway, only the right visual cortex receives information from the left visual fieldWe will explore laterality in more detail in lecture 7Can pick out the ball with his left hand, but not his rightright somatosensory cortex (left hand) ‘knows what it is looking for’, but the left (right hand) does not
17 The cranial nerves12 pairs of nerves on the base of the brain, which pass through holes in the skull (cranium): analogous to spinal nerves leaving the spinal cordI - OlfactoryII - OpticIII - OcculomotorIV - TrochlearV - TrigeminalVI - AbducensVII - FacialVIII - VestibulocochlearIX - GlossopharangealX - VagusXI - Spinal accessoryXII - Hypoglossal
18 Functions of the cranial nerves PS1003: Introduction to Biological Psychology1 : Brain structure and functionFunctions of the cranial nervesI Olfactory : SmellII Optic : VisionIII Occulomotor : Eye movement; Pupil dilationIV Trochlear :Eye movementV Trigeminal : SS information from the face and head; chewing muscles.VI Abducens : Eye MovementVII Facial :Taste (anterior 2/3 of tongue); SS from ear;muscles for facial expression.VIII Vestibulocochlear : Hearing; BalanceIX Glossopharangeal : Taste (posterior 1/3 of tongue); SS from tongue,tonsil, pharynx; muscles for swallowing.X Vagus : Sensory, motor and autonomic functions of viscera(glands, digestion, heart rate)XI Spinal accessory : Controls muscles used in head movement.XII Hypoglossal : Controls muscles of tongueSS = somatosensoryThe cranial nerves are composed of twelve pairs of nerves that emanate from the nervous tissue of the brain. In order reach their targets they must ultimately exit/enter the cranium through openings in the skull. Hence, their name is derived from their association with the cranium. The function of the cranial nerves is for the most part similar to the spinal nerves, the nerves that are associated with the spinal cord. The motor components of the cranial nerves are derived from cells that are located in the brain. These cells send their axons (bundles of axons outside the brain = a nerve) out of the cranium where they will ultimately control muscle (e.g., eye movements) , glandular tissue (e.g., salivary glands) or specialized muscle (e.g., heart or stomach). The sensory components of cranial nerves originate from collections of cells that are located outside the brain. These collections of nerve cells bodies are called sensory ganglia. They are essentially the same functionally and anatomically as the dorsal root ganglia which are associated with the spinal cord. In general, sensory ganglia of the cranial nerves send out a branch that divides into two branches: a branch that enters the brain and one that is connected to a sensory organ. Examples of sensory organs are pressure or pain sensors in the skin and more specialized ones such as taste receptors of the tongue. Electrical impulses are transmitted from the sensory organ through the ganglia and into the brain via the sensory branch that enter the brain. There are two exceptions to this rule that should be noted when the special senses of smell and vision are discussed. In summary, the motor components of cranial nerves transmit nerve impulses from the brain to target tissue outside of the brain. Sensory components transmit nerve impulses from sensory organs to the brain.