Exam 1 Flashcards
What factors shape our perception?
- Our genetic makeup
- The epigenetic environment in which we develop
- Our experiences
illusion
A mistake in perception that happens when the brain misinterprets a stimulus, causing us to perceive things in a way that is different from the actual stimulus. Our brain relies on our experience to make predictions, but sometimes gets it wrong. Differ from hallucinations, daydreams, etc. because it is based on an ACTUAL stimulus.
perception
The processing and interpretation of information acquired by sensory systems
sensory system (and basic parts)
Any body system that transduces energy from the environment into patterns of neural impulses. They all include an organ that collects energy from the environment, receptor cells that capture that energy and transduce it into neural signals, afferent nerves to transport the signal, and brain circuitry to process it.
transduction
To change from one energy form to another. In sensory systems, it’s a change from environmental stimulus energy (light, chemical odorants, sound waves, etc.) to neural impulses (chemical and electrical signals)
What are the main parts of the central nervous system?
Brain and spinal cord
nucleus (in terms of gross anatomical structure)
a spatially segregated group of neurons with related function, located within the central nervous system
ganglion
a spatially segregated group of neurons with related function, located in the peripheral nervous system
cranial nerves
nerves that emerge directly from the brain
spinal nerves
nerves that emerge from the spinal cord
sensory vs motor nerves
Sensory neurons carry signals from the outer parts of your body (periphery) into the central nervous system. Motor neurons (motoneurons) carry signals from the central nervous system to the outer parts (muscles, skin, glands) of your body.
glial cells
supporting cells that surround neurons
What are ions and their role in the nervous system?
Ions are charged chemical particles. They are important in creating membrane potentials, which serve as transmission of a signal along neurons.
What ions are found inside and outside neurons?
Na + outside the cell (rushes in during AP), K+ inside cell (rushes out during AP)
Describe the flow of ions and changes in electrical potential that occur during the action potential
First, voltage-gated sodium (Na+) channels open, allowing Na+ to rush from the extracellular space into the cell, causing the interior of the cell to become even less negative with respect to the outside. At some point, the membrane potential actually becomes positive instead of negative. When the membrane potential becomes positive enough, the voltage-gated Na+ channels are inactivated and Na+ no longer enters the cell. At this point, voltage-gated K+ channels open, K+ rushes out of the cell, and the membrane potential becomes negative again (repolarizes). The rapid efflux of K+ from the cell causes a slight undershoot (hyperpolarization).
action potential
A rapid reversal of membrane potential, needs enough energy to meet the threshold to start
EPSPs and IPSPs
Graded potentials caused by different amounts of NT influx.
Excitatory post-synaptic potential: a depolarization caused by excitatory neurotransmitters that makes an AP more likely
Inhibitory post-synaptic potential: a hyperpolarization caused by inhibitory neurotransmitters that makes an AP less likely
ligand-gated ion channels
Ion channels that open/close based on the binding of chemicals.
voltage-gated ion channels
Ion channels that open/close based on voltage of the membrane potential
absolute refractory period of a neuron
The period during which another action potential cannot be generated under any circumstances
relative refractory period of a neuron
The period during which extra depolarizing current (an extra large EPSP) is needed to generate an action potential.
neurotransmitters
Excitatory: Glutamate, acetylcholine
Inhibitory: GABA, glycine
depolarization
When the inside of a cell becomes more positive relative to the outside of a cell
hyperpolarization
When the inside of the cell re-polarizes and becomes negative relative to the outside again, it overshoots a little and becomes even more negative than it was originally, for a short time
spatial summation
Occurs when an individual neuron receives simultaneous inputs from multiple sources. The small EPSPs contributed by many different synaptic terminals add up to produce a single large EPSP that may be sufficiently large to reach threshold.
temporal summation
Occurs due to the fact that every postsynaptic potential has a finite time-course, usually lasting at least several milliseconds. This means that if a second input arrives before the EPSP or IPSP elicited by the previous one has finished, the two can add together
convergence in neural circuits
Output from many neurons onto one. Many different presynaptic neurons provide input to a single postsynaptic neuron. These inputs may be excitatory or inhibitory, and may be active at different times.
divergence in neural circuits
Output from one neuron onto many. Each postsynaptic neuron receives input from the same presynaptic neuron, but may react to it differently.
How is information about the environment represented by neurons?
In spatio-temporal patterns of neural activity involving electro-chemical signals
What kinds of changes can occur in the brain of an adult (for example, as a result of learning)?
Reinforcing or weakening synapses between certain neurons; dying neurons; forming new synapses
How is information about taste and smell represented in patterns of neural activity?
spatio-temporal patterns
Where are the first neurons in the olfactory system located?
The olfactory receptor cells, which are true neurons, are located in the olfactory epithelium
How does experience early in life influence brain development?
Can influence which genes are expressed, resulting in different amounts of receptors, etc. Injury can also influence development.
psychophysics
The systematic study of the relationship between the physical properties of a stimulus in the environment and the perception of that stimulus