Week 6 Flashcards
(64 cards)
1
Q
What does Rostral (anterior) mean?
A
‘toward the beak’
2
Q
What does Caudal (posterior) mean?
A
‘toward the tail’
3
Q
What does Dorsal (superior) mean?
A
‘toward the back’
4
Q
What does Ventral (inferior) mean?
A
‘toward the belly’
5
Q
What does Lateral mean?
A
towards the side
6
Q
What does Medial mean?
A
toward the midline
7
Q
What is the Corpus Callosum?
A
Consists of large bundle of axons that connect two hemispheres
8
Q
What does Homotopic mean?
A
Homotopic connects complementary region of other hemisphere
9
Q
What does Heterotopic mean?
A
Heterotopic communicates to a different brain regions
10
Q
What does the Ipsilateral mean?
A
Ipsilateral is communication on the the same side
11
Q
What is Callostomy
A
Callosotomy - procedure to cut the corpus collosum to stop severe epileptic seizures
- Prevents communication between hemispheres
12
Q
What is Telecephalon?
A
- Telencephalon is a subdivision of the forebrain & consists of the limbic system, Basal Ganglia and Cerebral Cortex
13
Q
What is the cerebral cortex?
A
- Cerebral cortex (the outer gray matter of the brain) - largest structure of human brain
- Divided into two cerebral hemispheres
14
Q
Difference between the inner white matter and outer gray matter of the cerebral cortex
A
- Inner “white matter” is pale because it has a
high proportion of axon fibres covered in fatty
myelin layer. - Outer “grey matter” where the neurons
synapse and connect together
15
Q
What is the function of the basal ganglia?
A
- the nuclei of the basal ganglia (including caudate nucleus & Putamen) are responsible for
controlling involuntary movement, particular aspects that are highly automatised or involuntary
(such as walking). - The basal ganglia are dysfunctional in patients with Parkinson’s disease which leads to
weakness, tremors, limb rigidity, poor balance and difficulty initiating movements
16
Q
What is the Limbic system?
A
1937 James Papez first proposed an emotion circuit in the brain
- The “limbic system” includes the hypothalamus, thalamus, cingulate gyrus,
fornix, hippocampus, amygdala & orbitofrontal cortex and some nuclei of the basal ganglia and was previously thought to be the emotion circuit.
17
Q
What does the limbic system consist of?
A
- The “limbic system” includes the hypothalamus, thalamus, cingulate gyrus,
fornix, hippocampus, amygdala & orbitofrontal cortex and some nuclei of the basal ganglia
18
Q
Differences between Amygdala and Hippocampus
A
While the amygdala plays a crucial role in emotion, it is now known the
hippocampus & parts of surrounding cortex are involved in learning & memory.
19
Q
What does the Diencephalon consist of?
A
Thalamus and hypothalamus
20
Q
What does the thalamus do?
A
Major relay station for sensory inputs to cerebral cortex
- Divided into several nuclei
21
Q
What does the hypothalamus do?
A
- Controls autonomic nervous system and endocrine (hormone) system
- Regulates survival behaviours (fighting, feeding, fleeing,
mating)
22
Q
What is another word for the midbrain?
A
mesencephalon
23
Q
Where is the midbrain located?
A
The midbrain (and hindbrain) are
located within the brainstem.
- The midbrain (or mesencephalon)
is at topmost region of brainstem and sits directly above the
hindbrain.
24
Q
What is the function of the midbrain?
A
- It connects the pons and
cerebellum with the forebrain. - plays an important role in motor movement particularly movement
of the eye, and in auditory and visual processing.
25
What is the Hindbrain also known for?
Metencephalon
26
What does the hindbrain involve?
Includes the cerebellum and the pons
27
What is the Cerebellum?
Located in the hindbrain, the cerebellum (‘little
brain’) receives information from visual, auditory, somatosensory
& vestibular (balance) systems helps coordination of movement.
Damage to the cerebellum causes problems with walking and leads to jerky, poorly coordinated movements and problems maintaining balance.
28
What are the pons?
The pons lies on the ventral surface
of the brainstem. It contains several
nuclei important in regulating sleep and arousal; it also relays information from the cerebral cortex to the
cerebellum.
29
What is the myelencephalon also known as?
the Medulla oblongata (or
Medulla)
30
What is the Medulla oblongata/myelencephalon?
The myelencephalon is more commonly
called the Medulla oblongata (or
Medulla) and links the hindbrain to the
spinal cord and contains neurons
important for autonomic functions like
respiration and hear rate.
31
The brain itself is divided into division (Forebrain,
Midbrain & Hindbrain).
True or False?
True
32
What is the primary visual cortex?
- Occupies medial and lateral parts of the occipital cortex/lobe at the
back/posterior of the brain.
- Receives sensory information from
retina.
33
How are we able to visually perceive through the primary visual cortex?
The left and right visual field are each projected to the contralateral hemisphere.
- Light stimulus from the
external environment from
both visual fields stimulate
the corresponding area of the retina within each eye.
34
What is the structure of the primary visual cortex?
- Different regions of the retina are represented by different areas within the primary visual cortex.
- areas further out in peripheral vision are processed by areas of
the visual cortex that extend into the calcarine fissure
35
Hubel and Wiesel won the Nobel prize in 1981 for this work. What was it?
Within the primary visual
cortex neurons show
“orientation selectivity”
36
What is the parietal lobe/ cortex?
Involved in attention and spatial awareness.
- sits on the dorsal surface of the cortex and is referred to as part of the dorsal stream and the “where” pathway – named
for its role in spatial localisation
37
What is the temporal lobe/ cortex?
Important in auditory processing.
- Also involved in more complex visual processing (faces & complex object recognition).
- sits on the ventral surface of the cortex and is part of the ventral stream and the “what” pathway – named for its role in complex object recognition.
38
What is the primary auditory cortex?
Occupies superior part of the temporal cortex, as well as a patch of cortex that is buried within the Sylvian fissure.
It receives auditory sensory information
from the cochlea (part of the inner ear concerned with hearing).
39
What is a tonotopic map?
Sounds of different
frequencies (e.g., low
versus high tones) are
represented by
different areas within
the primary auditory
cortex, forming a
tonotopic map.
40
What is the primary somatosensory cortex?
Located immediately posterior to the central sulcus (large grove between the frontal & parietal lobe)
- Receives sensory information from the skin (temperature, touch & pain).
- Different regions of skin surface represented by different areas along the strip of cortex, forming a somatotopic map (face & hands overrepresented).
41
What is the primary motor cortex?
Located on the precentral gyrus immediately anterior to central sulcus.
- Different parts of primary motor cortex
send signals that control different groups of voluntary muscles (e.g.,
hands, feet, lips).
- Like the primary sensory cortices, the primary motor cortex controls muscles
on the opposite (contralateral) side of
the body
42
what is the front lobe involved in?
“higher order” functions of the frontal lobes
- Voluntary, controlled behaviour
- Impulse control & emotional regulation
- Abstract reasoning & planning
- Social cognition
- Language
43
How is the frontal cortex different between humans and animals?
- relatively larger than non primates
- a higher level of connectivity with rest of the brain (compared to other apes)
44
What happened to Phineas Gage?
Phineas Gage – Classic case of altered “executive
functioning” with frontal lobe damage
- railway foreman in Cavendish, Virginia
accident involving ‘tamping iron’ (1848)
- survived profound damage to frontal lobe
behavioural changes (‘no longer Gage’ )
- personality changed profoundly
- angry, impatient, obstinate, capricious
- unable to plan for the future.
- not employable in old job, (only held jobs where he
did not make decisions)
45
What is an action potential?
When a neuron fires it is called an action potential and is caused by
changes in flow of charged molecules (ions) across the neuron’s cell
membrane.
The term “action potential” refers to the rapid change in the membrane potential of the neuron caused by this movement of ions.
46
What is the process of an action potential?
1. At rest the membrane potential of the
neuron is polarised at -70mV.
2. As positive (Na+) ions flow into cell the membrane potential depolarises,
(membrane potential moves from - 70mV closer to 0 mV). If membrane
potential reaches -50 mV an action potential will be triggered
3. After the action potential is finished there is a refractory period where the membrane
potential is hyperpolarised meaning that it is even further from the threshold of activation and the neuron will be less likely to trigger another action potential until
the membrane potential has returned to the resting potential of -70mV
47
What is the rate law of action potentials?
- The neuron firing is “all or none” so frequency of firing determines the
strength of the neural signal.
- Strong stimulus > leads to faster threshold for activation > more frequent
action potentials
48
What are Neurotransmitters?
Neurotransmitters are chemicals that are synthesised within the
brain/neurons and are often called “chemical messengers”.
- The action potential stops at the end of an axon so the presynaptic neuron can only influence the post-synaptic neuron through the release of
neurotransmitters across the synapse.
49
What is the process of neurotransmission?
1. An action potential in the pre-synaptic cell triggers synaptic
vesicles to move toward the cell membrane
2. This is followed by a fusion of the two membranes
3. Neurotransmitter molecules are then released
4. Neurotransmitter then flows into the synaptic cleft where it is
available to bind to receptors on the post-synaptic membrane.
50
What is neurotransmitter release?
When synaptic vesicle merges with the presynaptic membrane the contents are released into the synaptic cleft.
- Sometimes referred to as “kiss & run”
51
What is Neurotransmitter Reuptake?
The synapse has the capacity to
recycle and reuse neurotransmitter
molecules after they have been released.
- This is a process of reabsorption into
the synapse termed endocytosis
52
What is Neural excitation (ESPS)
Excitatory postsynaptic
potentials (EPSPs)
depolarise the
postsynaptic cell
membrane
53
EPSPs decrease the
likelihood that an action
potential will be triggered in the postsynaptic neuron
True or False?
False
EPSPs increase the
likelihood that an action
potential will be triggered in the postsynaptic neuron
54
What is the primary excitatory neurotransmitter?
Glutamate is the primary
excitatory neurotransmitter
55
What is neural inhibition (IPSP)
Inhibitory postsynaptic
potentials (IPSPs)
hyperpolarise the
postsynaptic cell membrane
56
IPSPs decrease the
likelihood that an action
potential will be triggered
True or False?
IPSPs decrease the
likelihood that an action
potential will be triggeredTrue
57
What is the main inhibitory neurotransmitter?
Gamma aminobutyric acid
(GABA) is the primary
inhibitory neurotransmitter
58
What is neural integration?
The combined effect of
EPSPs and IPSPs is called
neural integration
59
What is the process of neural integration?
Remember each neuron receives input from many other neurons.
- At any time, a single neuron can simultaneously receive excitatory and
inhibitory inputs impacting the flow of ions into the neuron.
- The neuron will only fire if the sum of the excitatory inputs is sufficiently
greater than the inhibitory inputs to cause the membrane potential to
pass the threshold of activation.
- Because each neuron integrates the signals from the incoming
neurons in this way, the combined effect of EPSPs & IPSPs is called
neural integration
60
What are some examples of neuromodulators?
Dopamine, Noradrenaline, Histamine, Serotonin
61
What is the process of neurotransmitters at receptors
Neurotransmitters don’t typically
enter the post-synaptic neuron
directly.
- To cause an effect on the postsynaptic neuron, the chemical message must be “received” by attaching to the binding site of a receptor sensitive to that
neurotransmitter.
- Opening an ion channel is one example of the effect caused by neurotransmitter binding to the
receptor
62
What are the features of neural receptors?
Receptors are very selective (lock and Key).
- Each receptor can generally only be activated by one neurotransmitter (or a drug that is designed to mimic that
neurotransmitter).
- Each receptor also have a very specific function/action.
- When a neurotransmitter binds to the receptor this will trigger the same event every time
63
What are features of drugs on neurotransmitters?
- Drugs act by “mimicking” natural neurotransmitters or neuromodulators.
- Can act as AGONISTS activating the receptor like the natural compound.
- Or can act as an ANTAGONIST blocking the receptor and preventing the natural compound from activating it.
- Drugs can impact every stage of neurotransmitter function
from synthesis to release to receptor binding
64
What is the influence of Neural signalling on behaviour
- Drugs impact psychological processes
ONLY because they mimic/trigger the
same biological responses triggered by
naturally occurring substances
(neurotransmitters, neuromodulators,
hormones etc)
- Psychological events directly impact the
biological processes (observing a traumatic accident, remembering a
poem at school etc) requires neurons to
fire and chemical messages to be sent
across neurons
