The Brain and Neuropsychology Flashcards
Describe the autonomic nervous system.
Homeostasis:
Maintains a balanced internal state (e.g. temperature at 37°C) by monitoring activity of the body organs.
An automatic system:
No conscious control because functions are vital to life, e.g. heartbeat.
Sympathetic nervous system:
Physiological arousal, triggered when stressed and leads to fight or flight response.
Parasympathetic nervous system:
Opposite to sympathetic.
Produces rest and digest response to return body to resting state.
Describe the fight or flight response.
Brain detects threat:
Hypothalamus identifies a threat (stressor).
Sympathetic division of the ANS triggered, fight or flight.
Release of adrenaline:
ANS changes from parasympathetic rest state to aroused sympathetic state.
Stress hormone adrenaline released into bloodstream.
Fight or flight response:
Immediate and automatic.
Physiological changes due to action of adrenaline, e.g. increased heart rate, decreased digestion.
Gets body ready to confront threat (fight) or energy to run (fight).
Once the threat has passed:
Parasympathetic division of ANS takes over, ‘rest and digest’.
Describe the James-Lange theory of emotion.
Physiological arousal first:
Hypothalamus arouses sympathetic division of ANS.
Adrenaline released leading to physiological arousal (fight or flight).
Emotion afterwards:
Brain interprets physiological activity.
Causes emotion, e.g. love, fear.
An example:
Meet bear in forest.
Sympathetic arousal: muscles tense, heart rate increases.
Interpret as fear.
No physical changes = no emotion:
Speaking in front of class, no increase in heart rate means you don’t experience any sense of fear.
Evaluate the James-Lange theory of emotion.
Emotions do come after arousal:
Emotional states come after physiological arousal in the case of phobias.
Challenged by Cannon-Bard theory: Some emotions (e.g. embarrassment) occur at same time as physiological arousal.
James-Lange theory may be too simple:
Challenged by two-factor theory, we need social cues to label emotion (Schachter and Singer).
Describe the structure and function of the brain.
Two hemispheres, four lobes:
Top layer of brain is the cerebral cortex, divided into four lobes.
Frontal lobe, contains motor area:
At front of brain.
Controls thinking planning and motor area controls movement.
Parietal lobe, contains somatosensory area:
Behind frontal lobe.
Somatosensory area is where sensations are processed.
Occipital lobe, contains visual area:
At back of brain.
Controls vision.
Temporal lobe, contains auditory/ language area:
Behind frontal lobe and below parietal lobe.
Auditory (sound) area, related to speech and learning.
Cerebellum:
Receives information from spinal cord and the brain.
Coordinates movement and balance; attention and language too.
Describe localisation and function in the brain.
Specific brain areas do particular jobs.
Motor area:
Damage to the left hemisphere affects the right side of the body, and vice versa.
Somatosensory area
Most sensitive body parts take up most ‘space’.
Damage means less ability to feel pain.
Visual area
Damage to left hemisphere affects right visual field of each eye, and vice versa.
Auditory area
Damage can lead to deafness.
Language area
Usually in left hemisphere only.
Broca’s area: damage leads to difficulty remembering and forming words.
Wernicke’s area: damage leads to difficulty understanding and producing meaningful speech.
Describe Penfield’s study of the interpretive cortex.
Aim
To investigate the function of the temporal lobe using the Montreal procedure.
Method
Operated on patients with severe epilepsy.
Could stimulate areas of the brain in a conscious patient who reported their experiences.
Results
Temporal lobe stimulation: experiences and feelings (hallucinations) associated with those experiences including déjà vu.
Conclusion
Area of brain called interpretive cortex stores the personal meaning of previous event.
Evaluate Penfield’s study of the interpretive cortex.
Precise method:
He could stimulate the exact same area of the brain and have verbal reports from awake patients.
Unusual sample:
All participants had severe epilepsy so their behaviour may not reflect people with ‘normal’ brains.
Mixed results in later research:
The interpretative cortex may not always respond as Penfield had concluded.
Describe neurone and electrical transmission.
Types of neuron:
Sensory: From PNS to CNS. Long dendrite, short axon.
Relay: Connect sensory to motor. Short dendrite, short axon.
Motor: From CNS to muscles/ glands. Short dendrite, long axon.
Structure of neurons:
Cell body: Nucleus containing DNA.
Axon: Carries signals, covered in myelin sheath which helps and protects.
Myelin sheath: Fatty covering of axon with gaps (nodes of Ranvier), insulation and speeds signal.
Terminal button: End of axon, part of synapse.
Electric transmission - how neurons fire:
Resting state: negative charge.
When firing, the charge inside the cell changes which creates an action potential.
Describe synapses and chemical transmission.
The synapse:
Where neurons communicate with each other: terminal button at presynaptic neuron + synaptic cleft + receptor sites on postsynaptic neuron.
Release of neurotransmitters:
Electrical signal causes vesicles (in presynaptic terminal button) to release neurotransmitter into synaptic cleft.
Reuptake of neurotransmitter:
Neurotransmitter in synaptic cleft attaches to postsynaptic receptor sites.
Chemical message turns into electrical impulse.
Remaining neurotransmitter reabsorbed.
Excitation and inhibition:
Excitatory neurotransmitter increases postsynaptic neuron’s charge, more likely to fire.
Inhibitory neurotransmitter increases negative charge, less likely to fire.
Summation:
More excitatory than inhibitory signals means that neuron fires, creating an electrical impulse.
Describe the scanning techniques.
CT scans:
Large doughnut-shaped scanner that rotates.
Takes lots of X-rays of brain which are combined to give a detailed picture.
PET scan:
Patient injected with radioactive glucose.
Brain activity shown on computer screen.
fMRI Scan:
Measures changes in blood oxygen levels.
Displayed as 3-D computer image.
Evaluate the scanning techniques.
CT scans:
Strength:
Quality is higher than traditional X-ray.
Weaknesses:
High levels of radiation and only produces still images.
PET scan:
Strengths:
Shows brain in action and localisation of function.
Weakness:
Expensive and may be unethical because of radiation.
fMRI Scan: Strengths: Superior as produces clear images without use of radiation. Weaknesses: Expensive and have to stay very still.
Describe Tulving’s ‘gold’ memory study.
Aim:
To investigate if episodic memories produce different blood flow patterns to semantic ones.
Method:
Six participants injected with radioactive gold.
Repeated measures used with four episodic and four semantic memory trials.
Monitored blood flow using PET scan.
Results:
Different blood flow in three out of six participants.
Semantic memories in posterior cortex, i.e. parietal and occipital lobes.
Episodic memories in anterior cortex, i.e. frontal and temporal lobes.
Conclusion:
Episodic and semantic memories localised.
Memory has a biological basis.
Evaluate Tulving’s ‘gold’ study.
Objective evidence:
Evidence from brain scans is difficult to fake, producing unbiased evidence.
Problems with the sample:
The six participants included Tulving, and conclusion based on just three of the participants.
Are there different types of memory?:
Episodic and semantic memories are hard to separate, which may explain inconclusive evidence.
