PSYCH 104 Midterm 2 (The brain) Flashcards
Depolarization
Depolarization: the reduction of a membranes resting potential so that it is less negative (closer to zero)
Action potential
Action potential: electrical impulse that travels down the axon triggering the release of neurotransmitters
Repolarization
Repolarization: Na+ channels close, K+ channels open
Hyperpolarization
Hyperpolarization: the overshoot of repolarization
Refractory period:
Refractory period: the time at which it takes repolarization and hyperpolarization to occur
Postsynaptic potential (PSP)
Postsynaptic potential (PSP)
A voltage change at a receptor site on a postsynaptic cell membrane
Excitatory PSP
Excitatory PSP
○ A positive voltage shift that increases the likelihood that the postsynaptic neuron will fire action potentials (because it gets closer to the -55mV threshold)
Inhibitory PSP
Inhibitory PSP
○ A negative voltage shift that decreases the likelihood that the postsynaptic neuron will fire action potentials (because it gets further from the -55mV threshold)
Reuptake
Reuptake
○ Reobsorbtion of the neurotransmitter from the synaptic cleft by the presynaptic membrane
Amino acids
- Amino acids
§ Glutamate, GABA
Monoamines
Monoamines
○ Catecholamines
§ Dopamine
§ Norepinepherine
○ Indolamines
§ Serotonin
Acetylcholine
- Acetylcholine
○ Released by motor neurons
○ Contributes to the regulation of attention, arousal and memory
○ Nicotine stimulates Ach receptors
○ Memory enhancers increase ach
○ Insecticides block the breakdown of Ach creating excess amounts
○ Botox causes paralysis by blocking Ach
○ Alzheimer’s disease is associated with low levels of Ach
(is a small molecule neurotransmitter)
Unconventional neurotransmitters
- Unconventional neurotransmitters
○ Soluble gases
○ Endocannabinoids
§ Anandamide
Large molecule neurotransmitters
(What are they?)
Large molecule neurotransmitters
- Pituitary peptides
- Hypothalamic peptides
- Brain-glut peptides
- Opioid peptides
- Miscellaneous peptides
- Endorphins
- Dopamine’s (DA)
- Dopamine’s (DA)
○ Contributes to control of voluntary movement
○ Cocaine and amphetamines elevate activity in DA synapses
○ Dopamine circuits in medial forebrain bundle characterized as “reward pathway”
○ Degeneration of DA neurons is believed to be responsible for symptoms of Parkinson’s disease
- Serotonin (5-HT)
- Serotonin (5-HT)
○ Involved in regulation of sleep and wakefulness eating and aggression
○ Prozac and similar antidepressant drugs affect serotonin circuits
- Norepinepherine (NE)
- Norepinepherine (NE)
○ Brain arousal and other functions like mood, hunger, sleep, and sexual behavior
○ Drugs such as amphetamines and methamphetamines increase NE levels ○ Also known as nonamphetamine
- GABA
- GABA (ONLY INHIBITORY)
○ Gabba-aminobutyric acid
○ The brain’s main inhibitory transmitter
○ Contributes to regulation of anxiety and sleep/arousal
○ Contributes to regulation of anxiety and sleep/arousal
○ Valium and similar antianxiety drugs work at GABA synapses
Glutamate
- Glutamate
○ Main excitatory neurotransmitter in the nervous system participates in relay of sensory information and learning - an amino acid
Anandamide
- Anandamide
○ Binds to the same receptors as THC, the active ingredient in cannabis leaves
○ Comes from the Sanskrit word Ananda which means joy
○ Occurs in both the central and peripheral nervous system
○ Likely plays a role in eating, memory, motivation and sleep
CIPA
(CIPA: the ability to not feel pain)
Endorphins
- Endorphins (they work as a morphine and neurotransmitter)
○ More of these means less pain
○ Opposite is true
○ A naturally occuring analgesic
○ Inhibit the communication of pain signals to the spinal cord
○ Exercise causes more of these to appear
Neural plasticity
Neural plasticity: the ability for neural tissue to change and adapt over time
Neuroplasticity (Job in early development)
Job in early development:
1. Growth of dendrites and axons
2. Synaptogenesis
○ Formation of new synapses
3. Pruning
○ The removal of extra synapses to increase the efficiency of a neural network
○ Occurs until age ten
○ About 70% of neurons die off
4. Myelination: the insulation of axons
Neuroplasticity (Job in learning)
Job in learning:
- Long term potentiation of synapses
○ A long lasting enhancement in signal transmission between two neurons that results from stimulating them synchronously
- Structural changes
○ Axonal growth
○ Dendritic branching / growth
Neuroplasticity (Jobs in injury)
Jobs in injury: (99% time damage is permanent)
- Brain regions can sometimes take over functions previously formed by others
- Researchers are searching for treatments to promote healing and prevent cell damage
○ Stem cell: a cell with the ability to specialize into any cell we need
- Neurogenesis: creation of new neurons
Meninges
Meninges
- Three protective membranes that cover the brain and spinal cord
○ Dura matter
§ Thickest
○ Arachnoid matter
○ Pia matter
Cerebral ventricles
Cerebral ventricles: pockets in the brain that contain cerebrospinal fluid (CSF), which provide the brain with nutrients and cushion against injury
- Note: CSF is also found in the subarachnoid space
Franz Joseph Gall
Franz Joseph Gall
- 1758 - 1828
- He stated that
○ All mental functions arise from the brain
○ Mind and body are not separate entities
○ Brain consists of functional regions
§ Also a proponent of phrenology unfortunately
HE WAS LATER PROVED TO BE WRONG IN THAT THE BRAIN HAS REGIONS
Cerebral cortex
Cerebral cortex: outermost part of the forebrain
- Responsible for
○ Analyzing sensory information processing and higher brain functions
Cerebral hemispheres
Cerebral hemispheres
- Two halves of the cerebral cortex
Corpus collosum:
Corpus collosum:
- Large band of fibers connecting the two cerebral hemispheres
The frontal lobe (purpose)
The frontal lobe: performs functions that coordinate other brain areas, motor planning, language, and memory.
The frontal lobe (Primary motor cortex)
- Primary motor cortex
○ Part of the frontal lobe responsible for bodily movement
The frontal lobe (Prefrontal cortex)
- Prefrontal cortex
○ Part of the frontal lobe responsible for thinking, planning and language
The frontal lobe (Broca’s area)
- Broca’s area
○ Language area in the prefrontal cortex that helps to control speech production and some aspects of speech comprehension
The parietal lobe (purpose)
The parietal lobe
- Processes touch information, integrates vision and touch
○ Primary somatic sensory cortex
§ Regions of the cerebral cortex that initially processes information from the senses
The temporal lobe (purpose)
The temporal lobe
- Processes auditory information, language, and autobiographical memory
○ Wernicke’s area
§ Part of the temporal lobe involved in understanding speech
The occipital lobe (purpose)
The occipital lobe
- Back part of the cerebral cortex
○ Specialized for vision
The basal ganglia (purpose)
The basal ganglia
- A group of nuclei (clusters of neurons) located beneath the cerebral cortex
○ Involved in goal directed motor control
○ Contains dopamine neurons and is closely associated with reward and motivation
The limbic system (purpose)
The limbic system
- A loosely connected network of structures located roughly along the border between the cereberal cortex and deeper subcortical areas
○ Plays a role in olfaction (smell), memory, motivation, and emotion
The thalamus (Purpose)
The thalamus (like a relay station)
- Gateway from the sense organs to the primary sensory cortex
○ All sensory information (except smell) is relayed through the thalamus
The hypothalamus (purpose)
The hypothalamus
- The part of the brain that regulates the pituitary gland and is responsible for maintaining a constant internal state
○ The four Fs (fleeing, fighting, fornification)
○ Body temp
○ Hunger and thirst
○ Sleep
○ Emotional behavior
The hippocampus (purpose)
The hippocampus:
- The part of the brain that plays a role in spatial memory and may be necessary for new memories
- We have one in our left and one in our right brain
Clive Wearing
He suffered from severe retrograde and anograde amnesia
- He lost the ability to memorize written things
Amygdala (purpose)
Amygdala:
- Plays a role in fear, excitement, and arousal
- We have one per hemisphere
The brain stem (purpose)
The brain stem
- Part of the brain between the spinal cord and cereberal cortex that contains the midbrain, pons, and medulla
○ Midbrain
§ Part of the brain stem that contributes to movement, tracking visual stimuli and reflexes triggered by sound
Cerebellum (Purpose)
Cerebellum (not actually a part of the brain stem - hindbrain)
- Hindbrain structure responsible for our sense of balance
- Likely plays a role in other areas
○ Executive function
○ Spatial abilities
○ Aspects of language
Reticular formation (Purpose)
Reticular formation
- A complex network of about 100 tiny nuclei that occupies the central core of the brain stem
○ Contains the reticular activating system
§ The hypothetical System of the reticular formation
§ Responsible for arousal and conciousness
Spinal cord (purpose)
Spinal cord:
- Thick bundle of nerves that conveys signals between the brain and the body
Interneurons (purpose)
Interneurons:
- Neuron that sends messages to other neurons nearby
Reflex (What is it?)
Reflex:
- An automatic motor response to sensory stimulus
Peripheral nervous system (Two main branches)
The peripheral nervous system
- Divided into two main functions
○ The somatic system
§ Controls voluntary movement
○ The autonomic nervous system
§ Automatic neural activity
□ Sympathetic
□ Parasympathetic
Phrenology (what is it?)
Phrenology:
- Not a widely accepted view
- Basically your brain can be divided into sections each responsible for their own psychological trait
- They could examine these by looking at bumps on the skull
- It was killed by the fact that when someone was injured things were not predictable by phrenology
When is brain surgery often done?
Brain surgery is almost always done with the individual awake and alert
Brain damage:
Brain damage:
- Localized brain functions can be assessed by examining brain damage and seeing what behavioral issues arise from it
○ Via post-mortem examination or stereotaxic lesions in lab animals
Electrocochleograph (EEG)
Electrocochleograph (EEG)
- Records the brains electrical activity at the surface of the skull
○ Pros
§ Used in human and non-human animals
§ Detects rapid changes in electrical activity
§ Non invasive
○ Cons
§ Shows only large aggregates of natural activity (has low spatial resolution)
Computed tomography (CT)
- Computed tomography (CT)
○ A scanning technique using multiple X-rays to construct three dimensional images
- Magnetic resonance imaging (MRI)
- Magnetic resonance imaging (MRI)
○ Technique that uses strong magnetic fields to indirectly visualize brain structures
§ Better suites than CT scans for visualizing soft tissues like brain tumors
- Positron emission tomography (PET)
Functional brain scans
- Positron emission tomography (PET)
○ An invasive imaging technique that measures consumption of glucose like molecules, yielding a picture of neural activity in different brain regions
○ You get a glucose injection beforehand and it measures the use of glucose
- Functional MRI (fMRI)
- Functional MRI (fMRI)
○ Technique that uses magnetic fields to visualize brain activity using the BOLD response
○ BOLD = Blood Oxygen Level Dependent
○ Highly sensitive to motion
○ Questions about data analysis
○ They work by collecting a baseline measure
§ They then take another measure when something is being done
§ The grey area is what saw no change in activity levels
§ A coloured area is when there’s a difference
- Transcranial magnetic stimulation (TMS)
Magnetic stimulation
- Transcranial magnetic stimulation (TMS)
○ A technique that applies strong and quickly changing magnetic fields to the surface of the skull that can either enhance or interrupt brain function
§ Non invasive
○ It can actually depolarize or hyperpolarize neurons
○ Allows us to manipulate brain areas
○ May be known as a treatment for depression someday
○ Very new technology
Neuroanatomical techniques
- Golgi stain
Neuroanatomical techniques
- Golgi stain
○ A neural stain that completely darkens a few of the neurons in each slice of tissue, thereby revealing their silhouettes
Was actually discovered by accident
Neuroanatomical techniques
- Nissl stain
- Nissl stain
A neural stain that has an affinity for structures in neuron cell bodies
Neuroanatomical techniques
- Electron microscopy
- Electron microscopy
○ A microscopy technique used to study the fine details of cellular structure
○ They coat the tissue with electrons and magnify them
