Week 4- Brain and Behaviour Flashcards
What methods are used to examine the structure of the brain?
- Performing dissections of deceased people (invasive)
- Brain imagine (passive)
Outline electoencephalogram (EEG) including strengths and limitations
- Test that detects electrical activity in the brain, using small metal discs (electrodes) attached to the scalp. Activity shows up as wavy lines on an EEG recording. Detect electrical activity in brain
- Limitations:
- Poor spatial resolution (does not receive entire picture from across the brain, has access limit)
- Post synaptic potentials generated in superficial layers of cortex dendrites have far less contribution to EEG signals
- Strengths:
- Good temporal resolution (time resolution of a millisecond)
- Measures brain activity directly
Outline functional magnetic resonance imaging (fMRI) including strengths and limitations
- Detects changes within the blood flow
- Relies on fact that cerebral blood and neural activation are linked. Non invasive
- Strengths:
- Good spatial accuracy (reliability, robustness and ability to reproduce are increased)
- Limitations:
- Temporal responsive blood supply is poor relative to electrical signals
- Expensive (limits accessibility)
- Claustrophobic (limited ecological validity)
Outline magnetoencephalography (MEG) including strengths and limitations
- Functional neuroimaging technique
- Maps brain activity by recording magnetic fields produced by electric currents occurring naturally in the brain
- Uses sensitive magnetometers. Used primarily as measurement of time courses
- Strengths:
- can resolve events within 10 milliseconds or faster
- accurately pinpoints sources of primary auditory, somatic sensory and motor areas
- can create functional maps out of human cortex during complex tasks
Outline positron emission tomography (PET)
- Functional imaging technique using radioactive substances (radiotracers) to help visualise and measure changes in metabolic processes and other physiological activities
- Used heavily in imaging of tumours and clinical diagnosis of different brain diseases (e.g. dementia)
Outline lesions as a research method
- Observe people with conditions which have caused lesions (e.g. MS)
- Cannot cause lesions for study purposes
Outline deep brain stimulation as a research method
- Aim is to stimulate areas of the brain with electrodes
- Neurosurgical procedure involving placement of brain pacemaker, which sends electrical impulses through electrodes to targets in brain nuclei to treat movement disorders e.g. Parkinson’s and OCD
- DBS changes brain activity in a controlled manner
Outline single cell recordings as a research method
- Used to observe changes in voltage or current in a neuron
- Usually used on animals
- Microelectrode inserted into skull into a neuron in the area of the brain of interest
Outline electrocorticography (ECoG) as a research method
- Electrophysiological monitoring
- Uses electrodes placed directly on the exposed surface of the brain to record electrical activity from the cerebral cortex
- Looks like a circuitboard
Summarise the structure and function of the central nervous system
- Consists of brain and spinal cord
- The spinal cord relays information from the brain to neurons in the peripheral nervous system
- Can provide rapid responses to stimuli through the spinal reflex
Outline how the structures of the central nervous system are protected
- The brain, a part of the CNS, is protected by the skull
- The spinal cord is surrounded by bones called your vertebrae, or backbone
- Between these bones is a type of multilayered tissue, called meninges, which further protect your spinal cord
- Inside the channel formed by the meninges is the cerebral spinal fluid
- Cerebral spinal fluid is in the brain as well as the vertebrae, and the fact that the brain floats in this liquid prevents excessive injuries from brain trauma
Define ventricles and outline those involved in the CNS
- Ventricles are a communicating network of cavities filled with cerebral spinal fluid
- Two lateral ventricles, third ventricle, cerebral aqueduct, fourth ventricle
- Opens out to subarachnoid space, between the skull and the brain
- Cerebral fluid can circulate freely and protect from head injury (with skull)
List and define parts of the hindbrain
- Medulla oblongata- regulates physiological functions
- Pons- contains fibres connecting medulla and cerebellum with upper brain
- Cerebellum- “little brain”. Located at the back of the brain
- Reticular formation- neuron network from hindbrain to midbrain
Describe the role of the medulla oblongata
Regulates:
* Breathing
* Heartbeat and respiration
* Blood flow, muscle tone and reflexes
Describe the role of the pons
Regulates:
* Respiration
* Sleeping, including waking and dreaming
Describe the role of the cerebellum
Regulates:
* Fine muscle movement, coordination of smooth muscle
Assists with:
* Balance
* Learning, particularly low level relationships between sensory info and motor outputs
Describe the role of the reticular formation
- Assists in maintaining consciousness
- Regulates arousal
- Modulates activity
- Involved in integrating info from different pathways e.g. sound and visual input
- Contributes to blocking out info that happens when we fall asleep
List the parts of the midbrain
- Tectum
- Tegmentum
Describe the role of the tectum
- Processes visual (via superior colliculus) and auditory (via inferior colliculus) info
- Allows us to orient surroundings with eyes and body movements
Describe the role of the tegmentum
- Involved in movement and arousal
- Plays a role in learning, to produce behaviours, which minimise unpleasant and maximise pleasant consequences
- Implicated in the role of fear and reward behaviours
Outline the role of the forebrain and list the structures
- Forebrain is involved in complex sensory, emotional, cognitive and behavioural processing
- Hypothalamus
- Thalamus
Outline the roles of the hypothalamus and thalamus
- Hypothalamus:
- Eating
- Sleeping
- Sexual activity
- Emotions
- Detects changes in glucose levels, triggering hunger sensations
- Thalamus:
- Processing and transferring info
Outline the structures and functions of the sub-cortical structures (within cerebrum)
- Basal Ganglia
- Movement control
- ‘Automatic responses’
- Limbic System
- Pleasure and fear
Outline the structures and functions of the limbic system (forebrain)
- Septal area
- Pleasure
- Pain relief
- Emotionally significant learning
- Amygdala
- Learning and memory of emotional events
- Recognition of fear
- Hippocampus
- Storage of new memories
Outline the three main functions of the cerebral cortex
- Sequencing voluntary movement e.g. playing music
- Allows us to make subtle discriminations from different perceptual information
- Allows for symbolic thought to represent objects or concepts