Biological

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Five Main Perspectives

  • Describe Behaviour
  • Study the evolution of human behaviour
  • Observe the development of behaviour and its biological characteristics across the lifespan
  • Study the biological mechanisms of behaviour
  • Study the applications of biological psychology
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Approaches

  • Physiological psychology - direct manipulation of the brain
  • Psychopharmacology - effect of drugs
  • Neuropsychology - effects of brain damage
  • Psychophysiology - study of physiological activity
  • Comparative psychology - animals
  • Behavioural endocrinology - hormones
  • Behavioural genetics - influence of genes
  • Evolutionary psychology - influence of evolution on brain and behaviour
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The Nervous System

  • Divided into the Central Nervous System and Peripheral Nervous System
  • CNS is the brain and spinal cord
  • PNS is the nerves and sensory organs
  • Somatic Nervous System is the external environment, controlling movement and gathering info from sensory detectors
  • Autonomic Nervous System is the internal environment, regulating digestion, respiration, circulation, excretion and secretion of sex hormones.
  • Both use afferent (sensory information towards CNS) and Efferent nerves (motor information away from CNS to organs)
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Activating the Nervous System

  • Sympathetic Nervous System - activated by conditions that promote arousal eg. increase heart rate, energy expenditure
  • Parasympathetic Nervous System - activated by conditions of recovery eg. decrease heart rate, promote energy conservation
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Spinal Cord

  • Spinal cord relays info between the body and the brain
  • Includes sensory neurons carrying information from receptors in the skin, joints, muscles and viscera
  • Also includes motor neurons which carry information from the brain to nearby muscles and glands
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Navigating the Brain

  • Anterior and Posterior
  • Dorsal and Ventral
  • The Sagittal plane divides the brain left from right
  • Surrounded by meninges - Membranous layers
  • Cerebrospinal fluid - cushions the brain and spinal cord
  • Surface of brain is covered by cerebral cortex - grey matter (neuronal cell bodies) and white matter (myelinated axons) beneath it
  • Cerebral cortex is bumpy with bulges (gyri) separated by large grooves (sulci and fissures), increasing surface area
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Hemispheres of the Brain

  • Two cerebral hemispheres are connected via the Corpus Callosum
  • Two hemispheres provide contralateral control
  • Left controls right, vice versa
  • Lateralisation of function
  • In the womb, the neural tube forms 3 swellings - the forebrain, midbrain and hindbrain
  • These develop into 5 major divisions: Telencephalon and Diencephalon (Forebrain), Mesencephalon (Midbrain), Metencephalon and Myelencephalon (Hindbrain)
  • Telencephalon forms left and right cerebral hemispheres
  • Hindbrain forms the brain stem
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Hindbrain

  • Most ancient part of the brain - controls basic bodily functions such as sleep, heart rate, respiration and muscular co-ordination
  • Myelencephalon - Includes Medulla (Breathing, heart rate, reflexes)
  • Metencephalon - Includes Cerebellum responsible for movement and learning
  • Includes pons involved in sleep, arousal and movement
  • Spinal cord - Transmits info between brain and body
  • Brain stem
  • Medulla - regulates vital functions like breathing, circulation
  • Pons - sleep and arousal
  • Cerebellum - fine muscle movement and balance
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Midbrain

  • Tectum - Relays visual and auditory info from eyes (superior colliculus) and ears (inferior colliculus) 
  • Tegmentum - includes reticular formation which governs consciousness and arousal, sleep and motor control
  • Reticular formation - fibers that carry stimulation related to sleep and arousal through brain stem
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Forebrain

  • Most evolutionary recent part - diencephalon and telencephalon
  • Diencephalon includes thalamus - acts as relay station for sensory info transmitted to the cerebral cortex
  • Includes hypothalamus - sensor involved in hunger, thirst, temperature regulation and reproductive behaviour
  • Telencephalon - limbic system, involved in emotion- consists of Amygdala - fear and anger, and Hippocampus - memory
  • Pituitary gland - Master gland, regulates other endocrine glands
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Organisation of Cerebral Cortex

  • Primary areas (auditory, visual, motor, somatosensory) - Recieve sensory input from the body
  • Association areas (thinking) - what happens in between sensation and action, perceiving, learning, remembering, planning and acting - around 75% of human cerebral cortex
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Occipital Lobe

  • Visual processing (primary visual cortex)
  • Visual field is mapped onto the surface of the primary visual cortex
  • Damage will cause cortical blindness
  • Visual association cortex 
  • Lesions to association cortex result in difficulties such as recognising objects (visual agnosia)
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Temporal Lobe

  • Processes auditory info via the primary auditory cortex and association cortex
  • Damage to PAC results in hearing loss
  • Damage to LAC affects ability to understand and produce speech
  • Damage to RAC affects ability to recognise non-speech sounds and locate sounds in the environment
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Parietal Lobe

  • Perception of the body (somatosensation) 
  • Consists primarily of primary somatosensory and association cortices
  • AC is associated with spatial perception
  • Right parietal is associated with keeping track of the space around us - damage can lead to impaired map reading
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Frontal Lobe

  • Movement and higher cognitive functions
  • Primary motor cortex concerns the control of voluntary bodily movements
  • Damage can lead to paralysis
  • Prefrontal cortex - complex intellectual functioning - planning, higher thought functions
  • Damage can lead to difficulty generating solutions, changing strategies, planning
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Studying the Brain

  • Phrenology - infer character, personality and criminality from 'feeling the bumps on the head'
  • Non invasive - link changes in brain anatomy or function to observable changes in behaviour
  • Invasive - Activate areas of the brain and assess behaviour changes
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Neuroimaging Techniques

  • Allows us to visualise the brain to explore anatomy and function
  • Anatomy
  • CT
  • MRI
  • Function
  • PET
  • fMRI
  • EEG
  • TMS
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Anatomy: CT

  • Computerised Tomography
  • Computerised Axial Tomography (3D)
  • tomos = cut
  • x-ray moves around the head in a circular arc and creates a slice
  • Multiple slices can combine to produce a CAT
  • Common technique, poor spatial resolution
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Anatomy: MRI

  • Magnetic Resonance Imaging
  • High frequency alternating magnetic field to produce high resolution images
  • MRI can detect tumours, tissue degeneration, blood clots, vascular leaks (stroke) and major fibre bundles (Corpus callosum)
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Function: PET

  • Positron Emission Tomography
  • Changes in cerebral blood flow correlate with brain activity
  • Uses a radioactive tracer, taken up by active areas and emits positrons
  • Abnormalities in activity may be suggestive of tumours, lesions
  • Technically invasive
  • Poor temporal resolution
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Function: MRI

  • Functional Magnetic Resonance Imaging
  • Development of MRI based on changes in blood oxygen levels, indicate cortical activity
  • Active areas use more oxygen
  • Oxygenated blood has magnetic properties which can be detected by the scanner (BOLD)
  • fMRI is non-invasive, fast and has good spatial resolution
  • Can produce 3D images with structural and functional info
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Function: EEG

  • Electroencephalography
  • Measure gross electrical activity of the brain
  • Mesures electrochemical signalling between neurons, recorded via electrodes
  • EEG is less specific than fMRI
  • Often used to explore processes like sleep
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Function: TMS

  • Transcranial Magnetic Stimulation
  • Powerful magnet inhibits or increases brain activity
  • Allows researcher to directly manipulate activity and observe consequences
  • Can be a treatment for depression (George et al. 2013)
  • Targeting the limbic system and/or prefrontal cortex
  • Proposed for those who do not respond to antidepressants
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