Biological
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- Created by: carolinemather
- Created on: 04-05-18 18:12
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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