Biopsychology | The Brain's Structure & Functions PDF

The brain Parts of the Brain: Anatomy, Structure & Functions Structure of the brain Hindbrain Location Function Medulla Top of the spinal Controls Sensory nerves coming from the column life-susta...

The brain Parts of the Brain: Anatomy, Structure & Functions Structure of the brain Hindbrain Location Function Medulla Top of the spinal Controls Sensory nerves coming from the column life-sustaining left and right sides of the body functions cross over (information from the left (heartbeat, side of the body goes to the right breathing, side of the brain, vice versa) swallowing) Reticular Network of neurons Responsible Allows people to ignore constant, Formation running through the for attention, unchanging information (eg. white middle of the alertness, noise) and become alert to changes medulla and the arousal in information pons and slightly  beyond Pons Above the medulla Influences Relays messages from between the sleep, cerebellum and cortex (motor dreaming, nerves carry messages from the arousal brain to body) Cerebellum Base of the skull, Controls all Learned reflexes stored here to behind the pons involuntary, become more automatic rapid, fine motor movement (balance) + muscle coordination Forebrain - Limbic system, cortex, basal ganglia Cingulate cortex In the cortex, right Important role in emotional and cognitive above the corpus processing callosum in the frontal and parietal lobes Limbic system: involved in emotions, motivation, memory, learning Location Function Thalamus Center of the brain Relay station. Processes sensory information (hearing, sight, touch, taste) that passes through it (except smell) before sending it to the cortex Hypothalamus Below and in front of Controls hunger, thirst, sexual behaviour,  the thalamus; above the sleepwalking and waking, and emotions pituitary gland Also controls the pituitary gland Hippocampus Temporal lobe Responsible for the formation of long-term declarative memories Amygdala Near the hippocampus Involved in fear response and memory of fear so that people can respond to danger quickly Cortex: outermost part of the brain Divided into two cerebral hemispheres connected by the corpus callosum Cortical areas and Location Function lobes Occipital lobe Back and base of Processes visual information from the eyes each hemisphere in the primary visual cortex Visual cortex Occipital, temporal Identify and make sense of visual and parietal lobes information from the eyes Parietal lobes Top and back of the cortex Somatosensory At the front of the Processes Cells at the top of cortex parietal lobes on information from the the brain receive either side of the skin receptors for information from the brain touch, temperature bottom of the body and body position and vice versa Temporal lobe Just behind the temples Primary auditory In the temporal lobe Language understanding cortex  Auditory association Analyses data about sound, allowing us to area recognise pitch/ melody Frontal lobe Front of the brain Higher mental functions of the brain: planning, personality, memory storage, complex decision making, language Connected to the limbic system; helps in controlling emotions Motor cortex Frontal lobe Controls the movements of the body’s voluntary muscles Association areas of the cortex - Made up of neurons in the cortex devoted to making connections between sensory information coming into the brain and stored memories, images and knowledge Association area Location Function Broca’s area Left frontal lobe Associated with the production of speech, speaking smoothly and fluently Damage to Broca’s area: Broca’s aphasia - Words will be halting and pronounced incorrectly Wernicke’s area Left temporal lobe Involved in understanding/interpreting the meaning of words Damage to Wernicke’s area: Wernicke’s aphasia - Speech is fluent but nonsensical (wrong words used) Midbrain - sensory and motor functions Brain hemispheres Contralateral pathways  Right side of the brain controls left side of the body, and left side of the brain controls the right side of the body Corpus callosum: Connects the left and right hemispheres of the brain - Split-brain patients (in which the corpus callosum has been severed to treat epilepsy) Hemispheric laterisation - Depends on the task; tendency of each part of the brain to exert control over different functions - Left hemisphere specialises in tasks that involve sequence and analysis - Right hemisphere processes information in a broader sense (perception, visualisation, recognition of patterns etc.) Methods to study the brain Lesioning studies Brain stimulation - Study individuals with damage in - Send mild electrical currents through their brains the brain that causes neurons to - For animals, researchers may react as if they have received a deliberately damage specific areas message of the brain - Does not change the brain neurons Eg. 1. Deep brain stimulation (DBS) - invasive 2. Transcranial magnetic Stimulation (TMS) - non-invasive 3. Transcranial electrical current stimulation (tECS) - non-invasive Neuroimaging techniques Brain structure Brain function 1. Computed Tomography (CT) 1. Positron emission tomography Creates a digital structural image of the (PET) brain using a series of x-rays Measures brain activity/ function by seeing Relatively lower resolution, but can still aid which cells are using up the low-level in detecting larger brain tumours etc. radioactive glucose that is injected in the person’s brain 2. Magnetic Resonance Imaging (MRI) Uses brief but powerful pulses of magnetic 2. Electroencephalography (EEG) energy and radiofrequency energy to create Records electrical activity of cortical highly detailed pictures of structures of the neurons (neurons in the cortex) using brain electrodes placed on the scalp 3. Functional Magnetic Resonance 3. Magnetoencephalography (MEG) Imaging (fMRI) Detects small magnetic fields generated by Uses brief but powerful pulses of magnetic the electrical activity of neurons energy and radiofrequency energy to measure changes in blood oxygen levels in 4. Functional near-infrared the brain, creating a ‘movie’ of changes in spectroscopy (fNIRS) the activity of the brain Uses near-infrared light to measure changes in blood-oxygen levels in the brain, and hence brain activity Nervous system Neurons - Specialised cell that receives and sends message within the nervous system Dendrites Soma Axons Axon terminals Receives messages Contains the Carries messages to Communicate with from other cells nucleus + keeps the other cells. Ends of other cells cell alive and axons branches to functioning form axon terminals Neurotransmission - Sending of messages to other cells Axon terminals contain synaptic vesicles which contain neurotransmitters Axon potential travels down the axon of the presynaptic neuron to the synaptic vesicles Synaptic vesicles release their neurotransmitters into the synaptic gap Molecules float across the synapse and fit themselves into the receptor sites of the postsynaptic neuron ○ Receptor sites allow only particular molecules of a certain shape to fit into it To clear the synapse for the next stimulation, reuptake occurs Neurotransmitters end up back in the presynaptic neuron, the repackages into the synaptic vesicles Except ACh Neurotransmitters (found at the synapses) Excitatory Inhibitory Increases activity of postsynaptic neuron Decreases activity of postsynaptic neuron Drugs may be Antagonists Agonists Block (receptor sites) which blocks/reduces Mimic/enhance the effects of a a cell’s response to the action of other neurotransmitter on the receptor sites fo the chemicals, neurotransmitters next cell Increasing/decreasing activity of the cell Central nervous system - Made up of the brain and spinal cord Spinal cord - Long bundle of neurons connecting the brain and peripheral nervous system Spinal cord reflex Afferent (sensory) neurons Interneurons Efferent (motor) neurons Neurons that carry Neurons in the centre of the Neurons that carry information from the senses spinal cord that receives messages from the central to the central nervous information from the afferent nervous system to the body system neurons and sends commands to the muscles through the efferent neurons Eg. touching a flame An afferent neuron will send the pain message up to the spinal column, where it enters into the central area of the spinal cord. The interneuron in that central area will then receive the message and send out a response along an efferent neuron, causing your finger to pull back Changes to synaptic connections Neuroplasticity Neurogenesis Pruning The ability to constantly Formation of new neurons Process of trimming unused change both the structure (and hence synapses) brain connections, making and function of many cells in neurons available for future development the brain in response to trauma or experience As people learn new things, dendrites grow and/or strengthen and new synapses form in some areas of the brain Peripheral nervous system - Made up of all the nerves and neurons not contained in the brain and spinal cord - Allows the brain and spinal cord communicate with the sensory systems, enabling them to control the muscles and glands of the body (senses, voluntary muscles) Somatic nervous system Sensory pathway Motor pathway Nerves carry messages (containing afferent Nerves carry messages (containing efferent neurons) from the senses to the central neurons) from central nervous system to nervous system the voluntary muscles of the body Autonomic nervous system Sympathetic division Parasympathetic division ‘Fight-or-flight’ system. Gets the body ready ‘Rest-and-digest’ system. Returns the body to deal with stress (heart pumps faster, to normal functioning after a stressful pupils dilate etc.) situation ends, where the activity of the sympathetic division will be replaced by the activation of the parasympathetic division  Typically active; responsible for most day-to-day bodily functioning (eg. regular heartbeat, normal breathing) Endocrine system Endocrine glands secrete chemicals (hormones) directly into the bloodstream, carrying them to their target organs - Influences body functions, behaviours, emotions, and development Pituitary gland Master gland: controls/ influences all other endocrine glands Located just below the brain and is connected to the hypothalamus