Biological Bases of Behaviour Flashcards
Alan Hodgkin and Andrew Huxley
- Studied axons by removing them from squid.
- Wanted to know: “What is the nature of a neural impulse?”, “What happens when a neuron is stimulated?”
Donald Hebb
- Focused on how neurons link together to form networks (cell assemblies) and that they could not influence behaviour alone. It was the assembly that was most important.
- Learning happens when neuron stimulation repeatedly creates a change in the synapse.
Candace Pert and Solomon Snyder
- Did studies relating to morphine and found out that it exerts it effects by binding to receptor sites in the brain.
- They learned that the brain has receptor sites for this drug since it has a morphine like substance that is produced: endorphins
Wilder Penfield
Gifted neurosurgeon who was able to study and map the functions of the brain by performing brain surgeries on patients who were conscious.
James Old and Peter Milner
Discovered that animals will search out and preform actions that would stimulate their brains. They inferred that the animals were experiencing pleasure when they did this.
Doreen Kimura
Believed cognitive differences in gender (such as males’ better spatial ability and females’ better verbal abilities) may be caused by sex hormones in early development
Charles Darwin
- Naturalist who first explained natural selection
- 4 insights:
1. organisms vary in endless ways
2. some characteristics are inheritable
3. organisms produce offspring at rates that the environment cannot support
4. when specific traits support an organisms survival or reproductive success, those who possess it tend to have more offspring, thus increasing its prevalence in the population over time
Roger Sperry and Michael Gazzaniga
- Studied split-brain patients
- Found that subjects could verbally identify a picture that was flashed in their right visual field (left hemisphere) but could not in their left visual field (right hemisphere)
- Supports theory that the left hemisphere is crucial in language and that the right hemisphere is better at visual-spatial tasks
Absolute Refractory Period
Period of time following an action potential in which another one cannot be performed
Action Potential
- Shift in an neuron’s charge that travels along an axon
- Occurs when channels in the cell membrane open, allowing positive sodium ions into the cell
- Different neurons carry action potential at different speeds
- ie. thicker axons carry them faster than thinner axons
Explain the role of sodium and potassium ions.
- Potassium ions are found in the cell and are negatively charged
- Sodium ions are outside the cell and are positively charged
- The act of sodium ions entering the neuron is what causes an action potential
Adaption
- Traits in a population occurring in order to solve a problem or adapt to their environment
- ie. growing more body hair in order to adapt to a change in climate
Adoption Studies
Studies done on adopted children to see correlations between traits in relation to their biological or adoptive relatives
Afferent Nerve Fibres
- Carry information INTO the central nervous system
- Activated by external stimuli
ie. cold air - Called sensory neurons in the peripheral nervous system
- “A” for “Aaah! It’s cold outside, gotta go inside!”
Efferent Nerve Fibres
- Carry information AWAY from the central nervous system
- Called motor neurons in the peripheral nervous system
- “E” for “Ef away from me, you overgrown maggot!”
All-or-None Law
- Action potential either happens or it doesn’t
- ie. action potential is like firing a gun, you cannot half-fire a gun
- Action potentials are always the same strength, they only vary in frequency
Antagonist
A chemical that blocks the effects of neurotransmitters
ie. blocking receptor sites
Agonist
A chemical that mimics the effect of neurotransmitters
Autonomic Nervous System
- Contains smooth muscles, glands, heart and blood vessels
- One of the subdivisions in the peripheral nervous system
- 2 branches:
1. Sympathetic Divison
2. Parasympathetic Divison - Controls actions like digestion, heart rate, perspiration etc.
Axon
- Long, trunk-like structure on a neuron
- Carries action potential to the synapse
- The thicker the axon, the faster the action potential travels
- On certain neurons, the axon is coated in a myelin sheath
Behavioural Genetics
Studies the influence genetics have on behaviour and characteristics
Brain Plasticity
- States that the brain is flexible in the sense that it can change structure and function over time
- Studies show that experiences can shape the brain
- ie. certain areas in the somatosensory cortex are enlarged when they receive repeated input from the left hand
- Damage to the brain can lead to neural reorganization
- ie. the occipital lobe in blind people is often recruited to assist with other sensory tasks to compensate for the loss of sight
- Adult brains can generate new neurons through neurogenesis, but the effects of this are currently limited
Central Nervous System
- Contains brain and spinal cord
- Sends signals to the peripheral nervous system
- Protected by meninges and encased in cerebrospinal fluid, which is also found inside ventricles
Ventricle
Cavities in the brain filled with cerebrospinal fluid
Cerebellum
- Literally “little brain”
- Found inside the hindbrain
- Involved in movement and balance
- Damage impacts motor skills
- May be involved in attention, visual perception and planning
Cerebral Cortex
Outer layer of the cerebrum
Cerebrum
- Largest portion of the brain
- 2 hemispheres, separated by the corpus callosum
- 4 lobes
1. occipital lobe
2. parietal lobe
3. temporal lobe
4. frontal lobe
Cerebral Hemispheres
- Left and right sides of the brain that are specialized in completely different tasks
- ie. Left hemisphere controls the right side of the body and is better at language
- ie. Right hemisphere controls the left side of the body and it better at visual-spatial tasks
Cerebrospinal Fluid (CFS)
- Encases the brain and spinal fluid
- Provides protection and nourishment
Chromosomes
- Strands of DNA
- Each cell has 46 hormones, except sex cells which have 23
Corpus Callosum
- Long bundle of nerve fibres that connects the two cerebral hemispheres
- Promotes communication between both hemispheres
Critical Period
Limited time period when it is optimal for certain skills to emerge because of the heightened sensitivity to certain experiences
Dendrites
Long, branch-like fibers on a neuron that almost but don’t quite touch other neurons
Dominant Gene
The gene that is expressed when two traits in a gene pair are different
Recessive Genes
The gene that is hidden when two traits in a gene pair are different
Electrical Stimulation of the Brain
- Sends a weak electric current into different parts of the brain to stimulate them
- Advances understanding in brain-behaviour relationships
Electroecencephalograph (EEG)
- Device that records electrical activity in the brain
- Uses electrodes placed on the scalp to monitor activity
- Can be used to see brain patterns that occur when subjects experience different things or perform tasks
Endocrine System
- Contains glands that secrete hormones into the bloodstream
- Controlled by hypothalamus