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Discuss in one sentence:
1. African fish
2. Cerebellum
3. Telencephalon
1. African fish have the biggest brain to body ratio.

2. Half of the cells in our brains are located in the cerebellum.

3. Humans have a very noticable telencephalon.
What is The peripheral nervous system?
The peripheral nervous system:
All nervous elements that lie outside the central nervous system,
i.e. ganglia and peripheral nerves.
What are the 2 major divisions of the peripheral nervous system?
1) Somatic System
2) Autonomous System
Discuss the Somatic System?
The Somatic System consists of Sensory and motor nerves of the spinal and cranial nerves: sensory neurons of the dorsal root and cranial ganglia receive information from the periphery about somatosensory, proprioceptive, environmental, etc. information, and transmit it to the brain via the spinal cord and the brain stem
Discuss the Autonomous System ?
The autonomic division innervates the motor systems for the viscera, the smooth muscles of the body and the exocrine glands. the sympathetic system, the parasympathetic system, and the enteric nervous system.
The sympathetic system governs the body’s reaction to stress (“fight and flight reaction”). The parasympathetic system counteracts the effects of the sympathetic system by acting to conserve the body’s resources and to restore homeostasis. The enteric nervous system controls the smooth muscles of the gastro-intestinal tract.
What is unique about the somata of the somatic and cranial motorneurons ?
The somata of the somatic and cranial motorneurons are located inside the CNS but their axons travel into the periphery and can be considered part of the somatic division of the PNS.
What are the 6 divisions of the CNS?
1)the spinal cord
2) the medulla oblongata
3) the pons and the cerebellum (metencephalon)
4) the midbrain (mesencephalon)
5) the diencephalon (thalamus and hypothalamus)
6) the cerebral hemispheres (telencephalon)
What makes up the brainstem?
The medulla oblongata (2), the pons and cerebellum (3) and the midbrain (4) are collectively referred to as the brainstem.
Differentiate btw:
1. Organization of the spinal cord

2. Organization of the brainstem
1. The spinal cord is organized to control the extremities and the trunk of the body

2. The brain stem is organized to control the specialized structures of the head, such as the jaws, the tongue, the extraocular muscles, the eye lids and the vocal organs.
Where does the spinal cord sensory info and how does it get it?
The spinal cord gets sensory info from the skin, joints and muscles of the trunk, arms and legs through the dorsal root.
How does the spinal cord execute motor commands?
Motor commands to control the same muscles are transmitted to the periphery via motoneurons and the ventral roots. Ventral roots also have axons of preganglionic sympathetic and parasympathetic neurons.
How is the spinal cord and medulla oblongata related?
The spinal cord and the medulla oblongata share controlling the viscera and the internal organs, such as the heart, the gastro-intestinal system and the respiratory system.

Spinal cords are smaller in humans than in other animals.
How is sensory input and motor output transmitted in the peripheral nervous system?
The sensory input and motor output to the brainstem is transmitted by cranial nerves. Motor portions of the cranial nerves control the movement of the head and neck.

The cranial nerves are located in the brain stem.
What are the 12 cranial nerves and their actions?

See diagram
What controls the tensor tympani?
The trigeminal nerve controls the tensor tympani which is important for hearing so if we do not have this nerve, everything will sound loud or what is known as hyperacousis.
What is Nucleus ambigus?
Nucleus ambigus is the muscle for swallowing and vocalization.
What is the importance of Locus Coeruleus?
Locus Coeruleus is important for arousal, sleep and wakefulness. This is found in the reticular formation and the RF is found within the brainstem.
What are the 2 separations of the mesencephalon?
1. The dorsally located tectum (roof of the midbrain)

2. Subjacent tegmentum.
What are the 2 divisions of the tectum?
1. superior collicili
2. inferior colliculi.
What is the role of the superior colliculi?
The superior colliculus always receives visual information and is involved in saccadic eye movements or rapid eye movements. The superior colliculus is somewhat of an ancient structure.
What are 2 things located in the tegmentum?
The tegmentum contains:

1. part of the reticular formation

2. oculomotor (III) nuclei.
1. Describe the human eye in one sentence?

2. Describe the blind spot in one sentence?
1. Humans have an inverse eye which is an invagination of the diencephalon. Also, Because we came from the water, we can only see a certain degree of light.

2. The blind spot is where the optic nerve goes back into the brain.
Describe the crossing of:

1. Lateral geniculate
2. Optic nerve
3. Nasal fibers
1. Lateral geniculate ipsilaterally crosses the visual cortex. The lateral geniculate system is part of the thalamus.

2. The optic nerve partially crosses and partially stays ipsilaterally in the optic chiasma.

3. The nasal fibers cross over whereas the temporal fibers stay lateral.
How does the lateral geniculate relay info to the primary visual cortex?
It relays info via the optic radiation.
Describe the Law of Weber-Müller-Gudden?
It illustrates that the more frontal the eyes are, the more ipsilateral fibers there are. Lateral eyed animals have completely crossed optic nerves.
Compare the visual field for:

1. Frontal eyes

2. Lateral eyes
1. For frontal eyes, the visual field for the left eye is seen by the nasal retina of the left eye and the temporal retina of the right eye and the left field is still shown by the right side of the brain. Moreover, The optic nerves for frontal eyes were rewired instead of the whole brain being rewired.

2. For lateral eyes, the visual field for the left eye is seen by the left eye and is cetrally represented by the right CNS.
Why is it that some animals see better than mammals?
Animals that see better than mammals is due to the fact of cone diversity. Mammals hear the best and smell the best.
Which part of the brain has the most cells?
The cerebellum. Half of the cells in the brain are located in the cerebellum. The cerebellum have:
1. parallel fibers
2. purkinje cells
What are the roles of:

1. Climbing fibers?

2. Purkinje cells?
1. Climbing fibers are involved in input which make a lot of contacts.

2. Purkinje cells are the major output cells
What happens to the output from the cerebellum?
The output from the cerebellum goes to the striatum, cortical loop, pontine nuclei and to the motor thalamus. Stiatum is the basal ganglia. The motor thalamus, cortex, and striatum feeds back into the motor thalamus.
What is known as the horizontal module?
It is the zone where the cerebellum modulates eye movement.

Cerebellar input-output relations occur in modular form.
What are 3 role of the cerebellum?
1. Motor control
2. Motor learning
3. Cognitive function
How is the cerebellum involved in motor control?
The cerebellum plays a role in motor control by evaluating disparities between intention and action and by adjusting the operation of motor centers in the cortex and brain stem while a movement is in progress as well as during repetitions of the same movement.
What are the 2 input systems to the cerebellum?
1. Mossy fibers
2. Climbing fibers
What is the only output system of the cerebellum?
Purkinje cell axons

There are 40 times more input fibers than output fibers
Define hypotonia?
lack of muscle tone.
Ataxia is what?
lack of motor coordination: delay in initiating responses basically clumsiness
What is dysmetria?
Inability to control the range of movements
What is dysdiadochokinesia?
the inability to do fast coordinated movements
What is intention tremor?
A slow tremor of the extremeties that increases on attempted voluntary movement and is observed in certain diseases such as multiple sclerosis
What is postural disturbance?
have problems standing
What is scanning speech?
Scanning speech is when a patient will address one word at a time.
What is the diencephalon and what are its 3 main divisions?
The diencephalon is the region of the brain that is located below the telencephalon and above the mesencepahon. Its 3 main divisions are :

1. Epithalamus = most dorsal
2. Thalamus = ventral to epi
3. Hypothalamus = ventral to thalamus

It is located above the mesencephalon of the brain stem.

Sensory information is relayed between the brain stem and the rest of the brain regions.
Name 2 structures in the epithalamus?
1. Pineal gland
2. Habenula
What is the role of the thalamus?
It is mainly a filtering relay for sensory information before reaching the cortex.
What is the role of the motor thalamus and where is it located?
The so-called motor thalamus is involved in motor functions and embedded in the thalamo-cortical-cerebellar-basal ganglia circuits (e.g., the subthalamic nucleus).
What is the role of the hypothalamus?
It functions in many homeostatic behaviors, such as feeding, thermoregulation and reproduction), and controls hormone secretion via the posterior pituitary.
What is unique about the retina?
It is a part of diencephalon and it develops as a laterally directed evagination of the ventralmost hypothalamus.
The suprachiasmatic nucleus of the hypothalamus is involved in what?
It controls circadian rhythm.
What is the only sensory input to the cerebral cortex that the thalamus does not relay?
Why is the cortical surface important and what are its 2 divisions?
The cortical surface has a representation of the human body. Its 2 divisions are:

1. Precentral: has motor area and

2. Postcentral has somatosensory area.
Describe the role of cortico spinal tract neurons and where they originate from and where do they go?
The corticospinal tract originates in the giant pyramidal neurons (Betz cells) of the motor cortex (N1)and goes through the internal capsule. It is involved in fine motor control. This is what makes us humans. It conducts at 250m/s and it is highly myelinated
Damage to cortico-spinal tract neurons leads to what?
Hemipareisis which is caused by a stroke and this is what makes this tract very vulnerable. It goes all the way down to the ventral spinal horn. It crosses at the medulla oblongata spinal cord.


The corticospinal or pyramidal tract is a massive collection of axons that travel between the cerebral cortex of the brain and the spinal cord.

The corticospinal tract contains exclusively motor axons. About 85% of the axons cross over in the medulla oblongata (at a point known as the pyramidal decussation). This explains why movement of one side of the body is controlled by the opposite side of the brain.
Name 2 major Supra-spinal systems descending to the spinal cord and their components?
The descending spinal tracts are concerned with somatic and visceral motor activities and their 2 major divisions are:

1. Tractus cortico-spinalis (motoneurons)
2. Tractus rubro-spinalis

B. VENTRO-MEDIAL SYSTEM (axon collaterales):
1. Tractus vestibulo-spinalis
2. Tractus interstitio-spinalis comes from interstitial nucleus of cahall?
3. Tractus tecto-spinalis
4. Tractus reticulo-spinalis
How is the cerebellum related to:

1. cortico-cerebello-cortical fibers

2. interposito-rubral, fastigio-vestibular and fastigio-reticular fibers
1. Cerebellum provides important feed-back loop via cortico-cerebello-cortical fibers.

2. Cerebellum controls circuits via interposito-rubral, fastigio-vestibular and fastigio-reticular fibers
What is the basal ganglia and what are its 5 major components?
The basal ganglia are a group of nuclei in the brain associated with motor and learning functions. The five individual nuclei that make up the primate basal ganglia are:
1. Striatum,

2. External segment of the globus pallidus (GPe),

3. Internal segment of the globus pallidus (GPi),
4. Subthalamic nucleus (STN),
5. Substantia nigra.

Some of these nuclei may be further subdivided.
Whaw are the 3 divisions of striatum?
Striatum is separated into the
1. putamen,
2. caudate nucleus,
3. nucleus accumbens; the
Substantia nigra is generally divided into what 3 parts?
The substantia nigra is generally divided into
1. Pars compacta (SNc),
2. Pars reticulata (SNr),
3. Pars lateralis (SNl).
What makes up the Dorsal striatopalliadal complex?
1. Caudate nucleus
2. Putamen
What makes up the globus pallidus?

Basal ganglia, with the substantia nigra and the subthalamic nucleus
What makes up the Ventral striatopalliadal complex?

1. Nucl. accumbens
2. Tuberculum olfactorium, 3. Ventral pallidum
1. What makes up the Dorsal striatum?

2. What is the role of striatum?
Nucl. caudatus + Putamen (truly one nucleus divided by the internal capsule = fibers of the cortico-spinalal tract)
What do we notice from one group of vertebrates to the order regarding the basal ganglia?

We observe a quantitative change of the principal targets of the axons coming from the basal ganglia, e.g., connections towards the tectum in reptiles and birds are replaced by connections towards the cerebral cortex in mammals.
1. Where do the afferences from the striatum go to?

2. Where do the efferences of the basal ganglia go to?

1. The striatum goes into the motor thalamus.

2. Efferences go to the striatum.

None of this directly goes back to the motor nerve center. Only the cortex projects out but it modulates the output of the motor cortex.


Classically, these nuclei were considered to be connected as shown (left). The striatum is the primary (but not exclusive) input zone for other brain areas to connect to the basal ganglia. Via the striatum the basal ganglia receives input from the cortex, with a majority of projections from the motor and prefrontal cortices.

The circuitry of the basal ganglia is often divided into two major pathways, the direct pathway and the indirect pathway:

1. Direct pathway: striatum -→ GPi/SNr -→ thalamus +→ cortex

2. Indirect pathway: striatum -→ GPe -→ STN +→ GPi/SNr -→ thalamus +→ cortex
How does a population of neurons play a crucial role in disinhibiting other neurons?

Populations of neurons may play a crucial role in disinhibiting other neurons via:
- decreasing phasic discharges thereby gating or facilitating cortically initiatied movements.
-Other populations which show an increase of phasic discharge may have the opposite effect by suppressing antagonistic and competing movements.

Neuronal discharges may be preparatory or movement-related.


The circuitry of the basal ganglia is often divided into two major pathways, the direct pathway and the indirect pathway:

Direct pathway: striatum -→ GPi/SNr -→ thalamus +→ cortex
1. Indirect pathway: striatum -→ GPe -→ STN +→ GPi/SNr -→ thalamus +→ cortex

2. The direct pathway is thought to disinhibit the thalamus - cortical activity exciting areas of the striatum leads to inhibition of areas of the GPi and SNr, which in turn removes their tonic inhibition from the thalamus. This removal of inhibition via inhibition is called disinhibition. The indirect pathway, in contrast, is thought to have an inhibitory effect on the thalamus.
What are the 2 major classification of basal ganglia disorders?

These disorders maybe facilitating movement or supressing movements and the 2 are :

1. Hypokinetic: e.g., Parkinson’s (akinesia which is no movement; bradykinesia which is rapid movement)

2. Hyperkinetic:e.g., Huntington (dyskinesia, “ballism”; hypotonia)


The symptoms of Parkinson's disease result from the loss of dopamine-secreting (dopaminergic) cells and subsequent loss of melanin, secreted by the same cells, in the pars compacta region of the substantia nigra (literally "black substance"). These neurons project to the striatum and their loss leads to alterations in the activity of the neural circuits within the basal ganglia that regulate movement, in essence an inhibition of the direct pathway and excitation of the indirect pathway.

The direct pathway facilitates movement and the indirect pathway inhibits movement, thus the loss of these cells leads to a hypokinetic movement disorder. The lack of dopamine results in increased inhibition of the ventral lateral nucleus of the thalamus, which sends excitatory projections to the motor cortex, thus leading to hypokinesia.
Basal Ganglia disorders have what 3 characteristic types of motor disturbances?
1. Tremor and other involuntary movements

2. Changes in posture and muscles tone

3. Poverty and slowness of movement without paralysis
A disorder of the basal ganglia that results in diminished movement is?

Parkinson’s Disease: It is a degenerative disease and increase in the inhibition of the globus palladus onto the motor thalamus is a consequence of Parkinson’s disease. PD acts from the striatum to the globus palladus by a decrease of the dopamine in the substantia nigra. This in turn gives an inhibitory output to the cortex and decreases the output to the cortex. The subthalamic nucleus excites the globus pallatus which is an inhibitory output nucleus. Removing this controls inhibition and can bring the pathway back to normal function again suppressing the PD disorder.


The symptoms of Parkinson's disease result from the loss of dopamine-secreting (dopaminergic) cells and subsequent loss of melanin, secreted by the same cells, in the pars compacta region of the substantia nigra (literally "black substance"). These neurons project to the striatum and their loss leads to alterations in the activity of the neural circuits within the basal ganglia that regulate movement, in essence an inhibition of the direct pathway and excitation of the indirect pathway.

The direct pathway facilitates movement and the indirect pathway inhibits movement, thus the loss of these cells leads to a hypokinetic movement disorder. The lack of dopamine results in increased inhibition of the ventral lateral nucleus of the thalamus, which sends excitatory projections to the motor cortex, thus leading to hypokinesia.
A disorder of the basal ganglia that results in excessive movement is?

Hungtington Chorea, which can happen after a stroke or due to a gene that has been identified. Output from the motor thalamus to the cortex is increased in Huntington Chorea which is why people move a lot in this disorder.


Huntington's disease or Huntington's chorea (HD) is an inherited disorder characterized by abnormal body movements called chorea, and loss of memory.
Symptoms of the disorder include loss of cognitive ability (thinking, speaking), changes in personality, jerking movements of the face and body in general and unsteady walking. These symptoms develop into dementia and cognitive decline (not mental retardation which is an older term referring to the lack of development of mental ability rather than loss of it) and an advanced form of rapid jerking called chorea, the Greek word for dance. Degeneration of the caudate and the putamen (striatum) can be found
How does hearing get to the auditory cortex.
Hearing gets to the auditory cortex by the medial geniculate nucleus. Hearing is really developed in primates.

The medial geniculate nucleus is a nucleus of the thalamus that acts as a relay for auditory information. It receives its input from the inferior colliculus and sends information out to the auditory cortex.
What is the broca motor area?

The broca motor area is the place on the frontal cortex that deals with language. If there is a lesion on this area, then one is not able to speak. You are not able to move your tongue and your larynx anymore because of a lesion to the Broca area but you are able to understand speech.
What is the Wernicke area?

The border of the parietal-temporal cortex deals with sensory. Lesions here do not allow for comprehension causing sensory aphasia. This is called the Wernicke area. Damage to the right temporal of the Wernicke area disturbs the understanding of the emotional content of language. Incapability to use exact grammar: paragrammatism.

In the majority of the population, i.e., right-handed persons, these areas are found in the left hemisphere. A lesion of both areas results in a global aphasia.


Wernicke's area is a part of the human brain that forms part of the cortex, on the left posterior section of the superior temporal gyrus, posterior to the primary auditory cortex, on the temporo-parietal junction (part of the brain where the temporal lobe and parietal lobe meet).

Approximate location of Wernicke's area highlighted in gray and it can also be described as the posterior part of Brodmann area 22.

It is usually located in the left hemisphere, as the majority of people have brain areas specialized for language skills located on the left.
This area is also one of the affected in schizophrenia.

It is connected to Broca's area by a neural pathway called the arcuate fasciculus.
Discuss emotions and the brain?
A number of brain structures are involved in emotional responses, related in particular to pleasure, fear, anxiety, anger, etc. These feelings can be traces around vital functions such as food intake, sexual desire, competition, etc. A number of interconnected structures have been identified to be involved
What interconnected structures are involved with emotion?

1. The “inner” loop of the limbic system formed by:

a. hippocampus,
b. fornix
c. mammilary bodies,

2. The “outer” loop formed by :

a. cingulate gyrus
b. parahippocampal gyrus.

3. Interconnected are:
a. amygdala
b. hypothalamus
c. prefrontal cortex.

Besides involvement of some of these structures in spatial memory and acquisition of memory, lesions or stimulations leads to distinctive emotional behaviors and responses.

The fornix is a C-shaped bundle of fibres (axons) in the brain, and carries signals from the hippocampus to the mammillary bodies and septal nuclei.

The fibres begin in the hippocampus on each side of the brain; the separate left and right side are each called the crus of the fornix. The bundles of fibres come together in the midline of the brain, forming the body of the fornix. The inferior edge of the septum pellucidum (a membrane the separates the left and right ventricles) is attached to the upper face of the fornix body.
Lesion of the amygdala causes what?
Klüver-Bucy syndrome. Klüver-Bucy syndrome. Klüver-Bucy syndrome.
Where is the limbic system available and what is the limbic system?
Limbic systems are only available in primates and humans.

The limbic system is a group of brain structures that are involved in various emotions such as aggression, fear, pleasure and also in the formation of memory. The limbic system affects the endocrine system and the autonomic nervous system. It consists of several subcortical structures located around the thalamus:

hippocampus: involved in the formation of long-term memory
amygdala: involved in aggression and fear
cingulate gyrus (the circular shape of the cingulate gyrus resembles that of a belt, hence the name)
fornicate gyrus
hypothalamus: controls the autonomic nervous system and regulates blood pressure, heart rate, hunger, thirst, sexual arousal and the sleep/wake cycle. Connected to the pituitary gland and thus regulates the endocrine system. (Not all authors regard the hypothalamus as part of limbic system.) The limbic system is highly interconnected with the brain's so-called pleasure center, a structure known as the nucleus accumbens. The nucleus accumbens is involved in sexual arousal and in the "high" derived from certain recreational drugs. These responses are heavily modulated by dopaminergic projections from the limbic system.
What is the function of the lateral and prefontal cortex?
It is what makes us human. These are decision making areas so you can say that these deal with free will
What will happen if there is a lesion in the lateral and prefrontal cortex ?
. A lesion here will cause a loss of social coherence and people become anti-social and probably criminals.
Discuss brain size in terms of:

1. Its correlate
2. Size
3. Limits
1. Social intelligence is probably a fairly general correlate of relative brain size.

2. Brain size increases by increasing neuron number, not neuron size.

3. Limits on brain size: space constraint, energy consumption
Discuss brain complexity in terms of vertebrae evolution?
: brain complexity (increased and decreased several times during the time of vertebrate brain evolution). Important for mammalian neocortex (isocortex) development: lamination
Discuss the role of lamination in mammalian neocortex (isocortex) development?
Lamination means composed of or arranged in layers. This is important in mammalian neocortex (isocortex) development because it allowed efficient transmission of information within short distances, i.e., it saves space and energy; and it facilitated the development of maps, i.e., the representation of the outside world in different sensory modalities that are in register.
What are the 5 characteristics of multisensory integration?
1. Sensory systems are not perfect

2. Noise reduction

3. Animal economy

4. Disambiguisation of ambiguous or contradictory signals

5. Extrapolation of sub-optimal signals to obtain meaningful messages
Compare the somatosensory system of mammals to that of reptiles and birds and the main reason for this comparison?
The somatosensory system of mammals is extremely well developed in comparison to that of reptiles and birds. There are speculations that one of reason for such an excellent development is the evolution of hair.
How is hair related to the somatosensory system and the higher development of the system in mammals compared to reptiles and birds?
Due to the vast increase in number of hairs, a vast improvement of sensitivity to touch became possible. This improved sensitivity finally allowed fine motor control observed in the manual dexterity of primates. Manual dexterity developed in parallel with the evolution of the cortico-spinal tract. Manual precision, naturally, requires exact sensory feed-back.
Why is the human brain more complex and what is used as a mechanism to increase brain complexity?
Our brains are more complex because we have more sets of genes.

Induction of an ectopic brain region by fibroblast growth factor 8 (FGF8) is a mechanism to increase brain complexity
List 7 Landmarks in mammalian evolution, leading to human evolution?
1. Homeothermia
2. Hair
3. Laminated cortex (space
saving and rapid
communication between
4. “Re-invention” of color vision (tri-chromatic) in primates
5. Upright (bipedal) walking
6. Language
7. Development of lateral prefronal cortex (innovation, decision making, “free will”, etc)
State in 1 sentence:

1. What is unique about lobes in human brain?

2. location of language center in the brain

3. location of face recognition in the brain

4. location of spatial orientation

5. discu
1. humans have disproportionately larger parietal and frontal lobes, and striking brain ASYMMETRIES

2. The language centers are in left hemisphere

3. The face recognition center is in the left inferior temporal lobe

4. The spatial orientation center is in the right parietal/temporal lobe

5. There is reduced interhemispheric connectivity via the corpus callosum.

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