Chapter 3 - Biological Psychology Flashcards
How many nerve cells in the brain?
~100 billion
Define: dendrites
-Extensions that receive information from neighbouring neurons
What are spines on dendrites for?
Result of lack of spines?
- Increase surface area
- Down syndrome
Define: Soma
- Cell body
- Integrates information from dendrites then passes it along axon
Define: Axon
- Think “axe”; a thing that goes away from the body!
- Long extension leading away from soma
- Covered with myelin sheath
Define: Axon Hillock
- Think “hill”; the culmination of something
- Last site on soma where synaptic inputs are summed before going down axon
Define: Myelin sheath
- Fatty glial cells that insulates axons
- Improves speed and strength of signals
Define: Axon terminal (or terminal button)
- Knob at the end of the axon
- Transmits signals to dendrites, cell bodes, muscles
Define: Synapse
- Entire junction where axon terminal communicates with receiving neuron across synaptic cleft
- 100 trillion of them
Define: Synaptic cleft
-Actual space between neurons (axon and receptor site)
Define: Synaptic vesicles
- Spherical sacs containing neurotransmitters
- small NTs made onsite; lg. NTs made in soma
Define: Glial cells
- Support cells
- promote healing, clearing debris
Which disease is caused by demyelination?
Multiple sclerosis
Two kinds of myelinating glial cells?
- Schwann cells (PNS) [Think Schwinn tires psi)
- Oligodendrocytes (CNS) [Think oligarchy=Central]
Define: Blood Brain Barrier
- Glial cells (astrocytes) wrapped around brain blood vessels and capillaries
- Don’t let through large or water soluble molecules
What are neurons responding to, by generating electrical activity?
Neurotransmitters
Define: Resting potential
- When no NTs are acting on neuron but ready to fire
- polarized, selectively permeable membrane
- negative 60mV charge on inside of neuron
- +and- particles flowing back and forth membrane
Define: Threshold
- Stimulation from sensory receptor or another neuron causes a change in membrane permeability, and degree of polarity
- When electrical charge gets high enough compared to outside (~55mV)
- Causes action potential
Which kind of ions are inside and outside neuron in resting potential?
Outside: Na+ [Think “on” or outside the cell]
Inside: K+ and negative protein
Define: Action potential
-Electrical impulse that travels down axon and triggers release of NTs
Three rules to action potentials
- TAA [Think “ta-ta, buh-bye, no stopping me now”]
1. Threshold
2. All-or-none phenomenon
3. Absolute refractory
Regarding threshold, intensity of stimulation within a single neuron is communicated by…
the RATE of firing.
Regarding threshold, intensity in the nervous system overall is communicated by…
the RATE of firing and NUMBER of neurons firing.
Define and explain what it does: Absolute refractory
- Tim;e when another action potential is impossible
- Limits firing rate
- AP propagates only in one direction
Give 6 steps of action potential.
- Threshold of excitation; Na+ begins to enters cell; voltage spikes
- K+ begins to leave cell
- Na+ channels become refractory; no more Na+ enters cell.
- K+ continues to leave cell; voltage drops to resting level.
- K+ channels close; Na+ channels reset
- Voltage is below resting from extra K+; K+ diffuses away; voltage rises slightly to resting potential
Define: Nodes of Ranvier
- Gaps in myelination on axon where ion flow occurs to regenerate and speed up signal.
- “Saltatory conduction” [Think “sauter” or jumping]
Define: Presynaptic and postsynaptic neurons
- Presynaptic is sending neuron
- Postsynaptic is receiving neuron
3 steps of Neurotransmission
- Release NT
- Binding of NT
- Stopping NT activity
Factors determining excitatory or inhibitory action of NT depends on…
where and how much is released
Roles of 4 NTs
Dopamine: motor function and reward (too much=schizophrenia; too little=parkinsons)
Serotonin: mood and temperature regulation; aggression; sleep cycles
Acetylcholine: Muscle contraction (PNS); Cortical arousal (CNS)
Norepinephrine: Brain arousal; mood, hunger, sleep
3 ways NTs are inactivated
- 90% by re-uptake into presynaptic neuron
- Enzymes (MonoamineoxidASE; acetylcholinestrASE)
- Drift away
Division of nervous system
CNS>Brain (forebrain, brainstem)/Spinal cord
PNS>Autonomic (sympathetic, parasympathetic)/Somatic
Define: forebrain/cerebrum
- Several structures involved in sensory-info processing, memory, learning, emotion
- Includes cerebral cortex
- Includes corpus callosum
Define: corpus callosum
-Thick band of connecting and communicating fibres, connecting R and L hemisphere
Name the four lobes of the cortex
Lobes:
- Frontal
- Parietal
- Temporal
- Occipital
General functions of the frontal lobe
- Executive functioning
- Complex thoughts and process
- Motor function
- Language
- Memory
Frontal lobe parts and what they do
-Pre-frontal cortex: thinking, planning, language
(PF cortex includes Broca’s area on left side; important for language;damage causes brocas aphasia or speechlessness)
-Motor cortex in the back half (movement)
Parietal lobe (generally)
- Involved in coordinating sensory information
- Perception of space, and numbers
Injuries to parietal lobe
- Left: Acalculia (difficulty with numbers and math)
- Right: Contralateral neglect (ignore opposite side of body)
What seperates frontal and parietal lobe?
Central sulcus
Temporal lobe (generally)
- Hearing and language comprehension
- Storing memories of our past
Primary auditory cortex
-Detection of discrete qualities of sound like pitch, volume
Auditory association cortex
-Processing and analyzing sounds
Wernicke’s area damage
-Difficulty understanding speech
What separates temporal lobe from rest of cortex?
-Sylvian fissure (lateral fissure, lateral sulcus)
Occipital lobe (generally)
-Associated with vision
Define: Primary visual cortex
-receives nerve impulses from visual thalamus
Define: Visual association cortex
-Analyzes visual date to form images
Occipital lobe injury
- Blindness
- Hallucinations
Basal ganglia (generally)
- Involved in voluntary controlled movement
- Initiation of movement by reward anticipation
Basal ganglia injury
-Parkinson’s disease
Brainstem. What and where is it?
- Primitive part of brain
- Between spinal cord and cerebral cortex
- Contains mid brain and hind brain (medulla, pons, cerebellum)
What are the parts of the brain stem?
-Midbrain and hindbrain (medulla, pons, cerebellum)
Define: Midbrain
- Part of brainstem between forebrain and hindbrain
- Help mediate sensory and movement information; reflexes triggered by sound
What is the Reticular Activating system?
- Key role in arousal
- Increases signal to noise ratio to cortex
- Associated with ADHD
Which part of brain might ADHD be related to and why?
- RAS (reticular activating system)
- Along with prefrontal cortex
Loss of neurons in midbrain are related to:
Schizophrenia and Parkinson’s
3 parts of the hindbrain
- Medulla
- Pons
- Cerebellum (Alcohol acts on it)
Define: Medulla
- Heart shaped [think “medal”]
- Automatic control centre: breathing, heartbeat, swallowing, vomiting
- Alcohol acts on it (can cause death)
Define: Pons
- [Think “bridge”]
- Connects cerebellum to cortex
- Involved with dreaming and body movement
Define: cerebellum
- “Little brain”
- Balance and coordination
- Alcohol acts on it
Cerebral ventricles
- Encapsulate brain and spinal cord in CFS
- 4 of them
- Protect from injury
- buoyancy
- Provides nutrients
- Eliminates waste
Spinal cord
- sensory nerves travel up and down
- Spinal reflexes (don’t require brain to respond)
Two parts of the Peripheral Nervous System
- Somatic
- Autonomic
Define: Somatic nervous system
- Carries messages from CNS to control and coordinate voluntary movement
- Stimulates muscle contraction with specialized cells
- Sensory nerves in muscles (toward CNS)
- Motor nerves (away from CNS)
Two parts of the Autonomic Nervous System and what they do
- Sympathetic [think “has sypathy, so reacts”]: Fight or flight, HR, breathing, sweating, pupils dilating.
- Parasympathetic: during rest and digestion
Define: Limbic System
- Emotional centre of brain
- Also memory, motivation, smell
Hypothalamus
- Master regulator of temperature, hunger, thirst, etc
- Controls Pituitary gland (master gland)
- Controls Oxytocin: love hormone, milk, trust, dilate cervix
- Controls Vasoppressin: regulates water retention by kidneys
Amygdala
- [Think “almond” cyanide=fear]
- Fear/fear conditioning
- Damage: inability to recognize fearful expressions
Hippocampus
- [Think “hungry hippos” gathering memories in space]
- Memory formation, especially spacial
- Contributes to fear conditioning (with Amyg. and PFC)
Thalamus
- [Think “salle” or relay room”]
- Relays sensory information to cerebral cortex
Phrenology
- Bumps on head associated with psych. traits
- Falsified
What did case studies of brain damage do for brain mapping?
-Allowed us to study brain functioning by following lesions
Electroencephalograph (EEG)
- Recording electrical activity at surface of brain
- High temporal resolution
- Low spatial resolution
Computed Tomography (CT)
- Structural
- Multiple xrays to make 3D images
- Cheaper
- Good for bony structures
Magnetic Resonance Imaging (MRI)
- Structural
- applied magnetic fields release energy from hydrogen atoms, which is measured
- Better for soft tissue
- No rad
Positron Emission Tomography (PET)
- Functional
- Inject radioactive glucose water
- Measure uptake in tissues
Functional MRI (fMRI) and Blood Oxygenation Level Dependent (BOLD)
- Functional
- Magnetic fields based on changes in oxygenated blodd flow
- Low res, shows changes over time
Define: Contralaterality
-Left side controls right side and vice versa
Define: Cerebral dominance
- One side is superior for certain basic funtions
- Handedness
Define: Hemispheric asymmetry or Lateralization
- Some support for specialization of some functions on one hemisphere or another
- No support for left/right brained people
Left Hemisphere specialization:
Language
Math
Logic
Coordinate complex movements
Right Hemisphere specialization
Visual/auditory patterns
Spatial orientation
Artistic/musical
Recognize emotions
Define: Plasticity
Ability to change in response to environmental stimulation
Sensitive period
-Easier to acquire certain skills but not impossible outside this period
Critical period
-Necessary period to acquire given skill
5 types of brain plasticity
- Neurogenesis (new cells)
- Migration (guided by glial cells)
- Synaptogenesis (+dendritic branching)
- Myelination
- Pruning (inadequate linked to infantile autism)
Brain volume growth and cortical convolutions happen:
prenatally
myelination of brain happens…
postnatally
