1
Q
How does your brain accomplish multitasking?
A
It is split into distinct regions specialized for specific tasks and abilities
2
Q
largest part of brain
A
cerebrum
3
Q
what are the parts of the cerebrum
A
two large seperate hemishperes (left side and right side)
4
Q
corpus callosum
A
the hemispheres are connected by a bundle of nerve fibres that carry information from one side of your brain to the other. Largest of these bundles forms a bridge between the cerebral hemispheres and is called the courpos callosum
5
Q
cerebral cortex
A
surface of the cerebrum. a deeply folded layer of nerve tissue. Deep folds increase the area of the cerebral cortex which creates space for more neruons, and therefore increases the brain’s processing power
6
Q
what do neuroscientists use to identify regions of each hemisphere as separate lobes?
A
they use the deepest divisions of the cerebrum
7
Q
Frontal lobes
A
front of the brain, immediately above the eyes. Parts of these lobes coordinate voluntary movements, speech, memory and emotion, higher cognitive skills (planning and problem-solving) and many aspects of personality.
8
Q
parietal lobes
A
located at top of brain, immediately behind the frontal lobes.
- integrate sensory signals from the skin
- process taste
- process some types of visual info
9
Q
occipital lobes
A
process visual information
- are responsible for recognizing colours, shapes and integrating them not complex visual understanding.
10
Q
temporal lobes
A
lie on the sides of the brain, at and below the levels of the eyes
- carry out some visual processing
- interpret auditory information
11
Q
hippocampus
A
- curved structures lying beneath the cerebral cortex
- region of the temporal lobes that encodes new memories
12
Q
amygdala
A
another deep structure within each temporal lobe
- integrates memory and emotion
13
Q
limbic system
A
- includes the hippocampus and amygdala
- a group of structures deep within the brain that help regulate our emotion and motivation
14
Q
other parts of the limbic system
A
- (aside from the hippocampus and amygdala),
- thalamus
- hypothalamus
- pituitary gland
15
Q
thalamus
A
- integrates sensory information and relays it to other parts of the brain
16
Q
hypothalamus
A
sends hormonal signals to the rest of the body through the pituitary gland
17
Q
forebrain
A
made up of limbic system structures discussed earlier, and the cerebral cortex
18
Q
midbrain
A
- beneath the thalamus
- includes distinct groups of neurons that coordinate eye-movements (blinking, focusing)
- trigger reflexes to sounds (startled jump)
- other regions will inhibit unwanted body movements
- coordinate sensory input and motor output to manage the fine motor control that enables you to perform intricate actions (writing, playing instrument)
19
Q
basal ganglia
A
- formed from some midbrain regions and parts of the forebrain
- helps regulate complex body movements
20
Q
hindbrain
A
- role in glucose regulation, and sleep and includes several regions that help control movement
21
Q
cerebellum
A
- underneath occipital lobe at very back of brain
- second largest part of brain in volume
- has over half of the brain’s neruons
- is deeply folded (like the cerebrum)
- also divided into 2 hemishpehers
- vareity of functions- corrdinates voluntary movement, helps brain learn new motor skills, roles in spatial and temporal (time) perception
- patient with damaged cereellum- maybe is unable to accurately touch finger to nose
22
Q
pons
A
infleunces breathing and posture
- below cerebellum
23
Q
medulla
A
- another part of the hindbrain
- carries nerve pathways connecting brain to the spinal cord
- has neural networks that help basic functions (swallowing, heart rate, breathing)
24
Q
brain stem
A
-medullla, pons, midbrain
25
nerve tracts
nerve fibres of region-spanning neurons form distinct bundles.
26
major nerve tracks
corpus callosum, smaller anterior commissure (taransmits signals between left and right temporal lobes)
27
neural netowork
a group of nerve tracks connecting a series of regions in the brain
-route signals through the brain along linear pathway, analyze and organize diff types of info within fractions of a second
28
what happens in the brain when watching a movie
- turns many moving shaped into recognizable characters and scenery
- photoreceptor signal s reach the optic nerve then travel through the optic tract, to the thalamus where neurons respond to the shape, colour, or movement of objects on the screen
- then, they pass these to the primary visual cortex in the occipital lobe
- in pvc, they detect edges of objects within the field of vision
- integrate the signals from each eye to create a three-dimensional rep
- image is further refined as signals are sent to parallel processing streams
- one stream: neurons in temporal lobe recognize and identify objects
- another stream- neurons in the parietal lobe detect the spatial location of these objects
29
photoreceptors
cells in the retina trigger electrical singals in response to specific wavelengths of light
-signals reach the optic nerve
30
thalamocortical loop
- two way circuit that connects the thalamus with parts of the cortex and back
- an example is the visual cortex that also sends signals back to the thalamus to become integrated with other sensory info
31
EEG
- electroencephalograph
- AS neuronal signals loop through the thalamus and cortex, they produce rhythmic electrical patterns, detectable with an EEG
- -- THESE SIGNALS ARE CALLED BRAIN WAVES
32
how many types of brain waves
- there are four disticnt types
| - each of them are recognized by their characteristic shapes on an EEG display/printout.
33
awake brain waves
- awake brain typically produces alpha and beta waves
34
alpha waves
- originate mainly in the pareital lobe and occiptal lobe
- occurs when brain is relaxed, eyes are closed
- characterized by frequencies between 8 and 13 Hertz
35
beta waves
- somewhat faster
- frequencies from 14 to 30Hertx
- produced from frontal and parietal regions of brainwhen it processes sensory input or concentrates on a task
- alpha and beta are when u r awake
36
theta waves and delta waves
typical of sleep
37
theta waves
are slower than alpha waves, ragnging from 4 to 7 Hzz
38
delta waves
- occur during deep sleep
-s;pw frequencies less than 3.5 Hz
(is this because there is less sensory input coming fro, the cortex?
39
alpha and delta waves
- typically of higher amplititude (stringer) than beta or theta
- when measured with electrictrodes on your scalp, these signals are in the microvolt range:
40
spinal tracts
- there are many distinct neural networks in the brain and spinal cord
- spinal tracts are chains of neurons that pass signals through the brainstem and the spinal cord
- these signals travel upward from sensroy receptors in the skin and muscles to the thalamus and parts of the cortex that interpret touch and pressure
- these signals move downwards from brain regions that induce movement, passing through the medulla nd spinal cord before projecting to the body's muscles
41
other neural netowrks...
provide feedback that helps integrate snseory and motor signals.
ex. basal ganglia
42
basal ganglia and feedback loop
part of a feedback loop that takes info from the cortical areas that elicit movement and produce signals that feed back to the core to excite or inhibit specific movements.
43
loops that connect the brainstem and the cerebellum
- infleunce the timing and strength of motor signals
- some of these loops incorporate tracts from the cerbral cortex that enable environemtnal and emotional context to influence your body's movement
44
netowrks that loop the hippocampus into sensory corte pathways
- help your brain analyze whether environmental signals are familiar or are part of a new situation.
45
netowrks that link the hippocampus to the thalmus and hypothalamus
- allow your memory to infleunce conscious behaviour as well as unconscious physiological responses.
46
reflex loops
- are circuits that elecit action well before thoughts
- actions are controlled locally by info going in and out of the spinal cord or subcortical regions of the brain, and never reach the cortex.
47
neural circuits
interconnected neurons that turn entering signals into output patterns that can be sent to other parts of the brain.
- the cerebral cortex is packed with these circuits
48
what happens to signals arrive at the brain
they engage local neural circuits
49
how are neruons in the nerual circuits of the cerbreal cortex organized?
-interconnected neurons that turn entering signals into output patterns that can be sent to other parts of the brain.
50
how are the nerual circuits organized
- The neurons in a column form a single chain, and signals that enter the circuit travel down that chain from one neuron to the next
- Circuits are arranged in columns, as each neuron forms connections with cells in the layers above and below.
51
what happens as signals that enter the circuit travel down that chain from one neuron to the next
-each time a signal is fed forward, it is transformed in some way
-outputs are built that encode complex info
_allows you to recognize people and plan where to catch a ball
52
how many neurons in the brain are exitatroy
- ,ajority (80 %) are excitatory
53
what is the most commony tupe of excitatory neuirons in the cerebral cortex
- the pyramidial cell
54
multi-branched axons
- send signals to multiple destinations
55
excitatory neurons
- neruons that pass signals forward through a circuit and eventually send outputs to other parts of the brain
56
inhibitory neruons
- typically local and often loop their responses back to earlier segments of a circiut
- interplay between these signals = important in learning, tuning and smoothing signals sent to other parts of brain and body
57
seizure disorders (like epilepsy)
- casued by imbalannce in the activity of excitatory and inhibitory neurons
58
feed forward inhibitory circuit
- inhibitory interneuyrons connect neighbouring neural circuits in such a way that excitatory signals in one column simultaneously send inhibitory signals to adhavent cuolumns--- reduces activity
59
feedback inhibition
- neurons send signals to their downstream excitatory neighbours and to internuerons that reach back and inhibit preceding layers of the same circuit
- ---- maybe does this mean that it kind of ends that whole circuit? Like everything is inhibited, the ones after and before?
- both exs, neurons inside interconnected circuits send feedback signals to one another
60
functional unit of neural circuits and networks
neuron
- transmit electrical signals to other nerve cels, muscles, glands
- all have a cell body, dendrites, axon
61
cell body
- aka soma
- contains neuron's nucleas and most of its cytoplasm
- molecular machinery for building and transporting proteins crictial to the cell's function.
-
62
dendrites
- branched projections that extend from the cell body and collect incoming signals from other neurons.
- neruon's electrical signals travel down its axon before ending by branching into axon terminals
63
axon terminals
- signal is passed across a synapse to other cells
| - axons can be as long as a fraction of cm, or more than meter.
64
glia
- support cells
| - ratio of glia to neuron varies considerably from region to region in the brain
65
four main types of glial cells in central nervous system
- astrocutes, m,icroglia, ependymal cells, oligodendrocytes
66
astrocytes
- form a netowrk inside the brain taht regulates ion concentrations around neruons, provides them with nutrients and helps regulate the fomrtion of new connections between neurons
67
microglia
- main immune cells of brain
- function as phagocytes
- help protect the brain from infections and cellular damage
- regulate the formation of new neuronal connections
68
ependymal cells
- make cerebrospinal fluid that cushions the brain inside the skull
69
oligodendrocytes
- improve neuron function by wrapping axons in a fatty sheath called myelin
70
ions
-electrically charged atoms that can only cross a neuron's cell membrane through ion channels
71
ion channels
- tunnel-lile proteins act like gates, allow some ions in and keeping others out
72
what happens when ions enter or leave the cell
voltage difference across membrane is changed
| -
73
what happens when there is a voltage change
- infleunces the neuron's likelihood of generating an electrical signal
- occurs when an action potential arrives at the axon terminal
- calcium ions flow into the cell
74
what happens when the calcium ions enter the cell
- they bind to package of neurotransmitter molecules called synaptic vesicles
75
synaptic vesicles
- they fuse with the cell membrane at the axon terminal and empty their contents into the synaptic cleft
- pieces of axon terminal membrane cycle back into the soma as new vesicles that are refilled with neurotransmitter molecules
76
substances that act as neurotransmitters
amino acids, fases, small organic chemicals and short peptides.
77
neurons can synthesize (in the axon terminal)...
small non-peptides (dopamine, acetylcholine) inside exon terminal
78
what cannot be synthesized in the axon terminal
- peptide based neurotransmitters
- axon terminals do not have the molecular machinery to build proteins
- they are therefore built in the ribosome rich space of the cell body
79
dendrites and neurotransmitter receptors
- they have a high concentration of them
| - different molecules act as neurotransmitters and each fits into specific receptors
80
ionotropic recceptors
- a neurotransmitter binds directly to part of an ion channel
- the normally closed ion channel's tunnel is widened as the receptor protein changes its shape when attached to the neurotransmitter
81
astrocytes
- mop up any excess neurotransmitters at the synapse so that receptors are not continuously activated.
82
metabotropic receptors
- receptor and ion channel are different proteins
- they are located at a distance from one another
- linked by a cascade of biochemical steps that are triggered when a neurotransmitter binds to the receptor
- less rapid response and activates a series of events in the postsynaptic vell
- some ion channel at a distance away or the activation of other intracellular molecules might occur
- through the activation of g proteins are able to affect other channels
83
what happens to the ion channels once the neurotransmitter detaches
- the ioin channels return to their resting state
| - the ion channels stop altering the change across their membrane
84
what happens to the neurotransmitters that detach from the membrane
- they are either broken down ir reabsorbed by the axon terminal in a process called reuptake
85
excitatory neurons make what type of neurotransmitter
- they ,ake make neurotransmitters taht open ion channels that depolarize the dendrite's membrane
86
inhibotry neurons make waht type of neuro transmitter
- they make ones that hyperpo;arize the neuron
87
most common excitatory neurotransmitter
glutatmate
88
most common inhibitory neurotransmitter
gamma-aminobutyric acid (GABA)
89
glutamate
- an amino acid used as a neurotransmitter by approx half the exctitaory synapses in the brain
- binds to several types of receptors
(most important are the AMPA and NMDA receptors.
90
AMPA receptors
- when activated, their action is fast and brief
| -
91
NMDA receptors
- are activated more slowly, especially in response to waves of multiple action potentials
- interactions betweenthese two are important for learning and memory
92
GABA
- most important inhibitory neurotransmitter
| - binds to both ionotropic and metabotropic
93
ionotropic GABA
-ion channels that let negatively charged chloride ions enter the cell
94
Metabotropic GABA
- open ion channels that realase potassium ions
| -
95
both Metabotropic and Ionotropic GABA
- ion movement pushes membrane potential downward and inhibits neurons from firing,
96
Molecules that change the way a neuron will function
hormones. prostaglandins
97
hormones
- send the brain specific cues about the condition and activity of distant tissues in the body
- includes neuromudulators such as
- endocannabinoids (cannabis-like chemicals that seem to suppress neurotransmitter release)
98
prostaglandins
-small lipids that change the brain's response (increasing pain sensitivity) to pain and inflammation
99
Individual neurons have receptros for different subsets of hormones and neuromodulators. These molecules are signals that trigger series of chemical reactions inside the cell. what is this process?
- one of the molecules binds to its specific receptors
- if receptors is on surface of the cel.l, the bound molecule changes the receptor's shape acrioss the cell membrane and starts chain of intracellular reactions
- this signal transduction pathway modifies neuronal function by shifting the cell's ion balance or by changing the activity of specific enzymes.
100
where else can a receptor be
- the receptor migth be a protein inside the neuorn's soma
- this occurs if a molecule can diffuse through the cell membrane (like with steroid hormones such as estradiol or cortisol)
- hormone binds to its receptors, the complex transforms into a transcription factor that is capable of entering the cell nucleus, binding to specific genes and changing htier activity.
101
true or false: all cells in body, including neurons, contain the same DNA housing the same gneese
true
- the differences that are present within these neurons are because of differences in which genes direct cellular activities (gene expression)
- although they may have the same genes, each cell builds proteins from a slightly different subset of genes in its genetic code
- neuruons express some genes and not others
- the mechanisms that cause this depend on chemical changes to chromatin
102
genes that a cell is using...
must be accessbile
| -associated with open, unfolded chromatin
103
unexpressed genes
- typically in tightly packed regions
- chemical changes that tighten or spread out chormatin complexes can shut down or activate the genes on that segment of DNA
- these reversible changes give neurons flexibility to alter fenes they express in response to hormonal cues and environmental changes.
104
genes and alleles
- genes specify trait, allele specifies the form the gene takes
- alleles are gene variants
- reflect differences in the nucleotide sequences that make up a gene
