Neuroscience Flashcards
(24 cards)
Name 5 brain imaging techniques.
Magnetic resonance imaging (MRI)
Functional magnetic resonance imaging (fMRI)
Positron emission tomography (PET)
Computerised tomography (CT)
Electroencephalography (EEG)
How does an MRI scan work?
Uses a powerful magnetic field to cause protons from hydrogen atoms in water molecules to align. Radio waves then knock protons out of alignment. radio waves turned off. Protons realign and emit radiation to receivers. Signals used to produce a 3D cross-sectional image.
Describe an advantage of using an MRI scan.
High resolution distinguishes tissues and provides more detail than ultrasound or CT scans.
How does an fMRI scan work?
Uses radio waves and magnetic field to assess brain function through the visualisation of blood flow in brain capillaries.
Shows where most aerobic respiration occurs and changes in brain activity.
How does a PET scan work?
A radioactive isotope (e.g. carbon) with a short half-life is injected and used by the body to synthesise molecules. Isotope decays and emits gamma radiation to a detector. Active areas show higher radioactivity.
What is a CT scan?
A medical imaging technique that uses specialised X-ray equipment and computer software to create detailed images of internal organs.
How does an EEG scan work?
Electrodes attached to scalp detect electrical signals between nuerons.
Records changes in the electrical activity of different regions of the brain.
What is neuroplasticity?
The ability of the brain to form new connections and pathways in response to environmental changes, disease, or injury.
When does neuroplasticity occur?
Neuroplasticity takes place throughout an organism’s life.
What is developmental plasticity?
The formation of new connections and pathways in the brain during development as a result of environmental changes and sensory stimulation.
What stage of development is known as the critical period?
Early childhood.
Describe synaptic pruning.
The elimination of unused synapses in the brain during development.
When does mass ‘pruning back’ of synapses usually occur?
Adolescence
Describe the importance of the critical period, using language development as an example.
At around 7 months, the majority of babies produce speech-like sounds. Obvious deficits in early vocalisation of congenitally deaf infants. Evidence that children raised in completely language deprived environment never learn more than basic communication.
Define epigenetics.
The study of changes in gene expression that are not due to alterations in the nucleotide base sequence of DNA.
Describe the link between epigenetics and mental illness.
Altered gene expression in childhood (e.g due to abuse) may increase the risk of an individual developing a mental illness or addiction later in life.
What is cortisol?
A steroid hormone produced by the adrenal glands in response to stress.
Compare the average concentration of cortisol in adults who experienced traumatic childhoods and those who did not.
Adults who have experienced traumatic childhoods tend to have higher concentrations of cortisol.
Describe the link between cortisol concentration and mental illness.
Higher concentration of cortisol, higher background stress levels, greater vulnerability to mental stress.
What type of mechanism controls the production of cortisol?
Negative feedback mechanism.
Name the structure in the brain that controls the production of cortisol.
Hippocampus.
Describe the process by which cortisol is secreted.
Hippocampus sends impulses to hypothalamus in response to stress. Hypothalamus secretes corticotrophin-releasing hormone and arginine vasopressin. Hormones stimulate pituitary glands to secrete adrenocorticotrophin into the blood. Adrenal glands take up hormone and secrete cortisol.
Describe negative feedback mechanism by which overproduction of cortisol is inhibited.
Cortisol binds to glucocorticoid receptors on the hippocampus.
Hippocampus sends nerve impulses to the hypothalamus, inhibiting the secretion of corticotrophin-releasing hormone and arginine vasopressin. This prevents further release of cortisol.
Why is the negative feedback system by which cortisol is produced important?
It prevents chronic stress.
