CNS and Nueroscience Techniques

Question 1

Cerebral cortex

Answer 1

The outermost layer of the brain
Contains many higher order abilities that are thought to be uniquely human u closing complex thinking and language learning

Question 2

Sub cortical structure

Answer 2

Below the cortex and are involved with motivation and emotion “primitive” processes needed across all species

Question 3

Size vs intelligence of the brain

Answer 3

Humans have physically bigger brain than animals like mice, cats and dogs but physically smaller brain than elephants and dolphins meaning intelligence does not equate to brain size

Question 4

Encephalisation Quotient (EQ)

Answer 4

Calculated by taking the log of a species avg brain mass and dividing it by the log of the species average body mass giving us a species brain size relative to body mass making a more accurate way to compare brain sizes across species

Animals more incapable of greater intelligence tend to have a higher EQ. Mammals being the highest.

However chihuahuas technically have a higher EQ than humans so this technique is not flawless

Question 5

Brain damage

Answer 5

Phineas gage 1847 iron rod through his skull damaging the orbital frontal cortex faced behaviour and personality changes going from diligent sociable and dependable to rude impatient and disorganised

Changes in psychological, cognitive or behaviour following a brain injury can help us understand the functionings of certain regions of the brain

Question 6

Psychosurgery

Answer 6

Surgeries conducted on animals where removal of brain tissues (ablation) or inserting electrodes into areas of the brain to examine how it disrupts behaviour often using animals similar to humans cats, rodents, primates.

Question 7

Hemispherectomy

Answer 7

When an entire hemisphere of the brain is removed due to it being the cause of seizures

Question 8

Deep brain stimulation (DBS)

Answer 8

Electrodes are inserted into the brain so specific regions of the brain can be electrically stimulated for therapeutic benefits. Used to treat MDD and motor tremor associated with Parkinson’s

Question 9

Neuroimaging

Answer 9

Attempt to measure neural activity through invasive and noninvasive measures. The three most commonly used are Electroebcephalography (EEG) functional magnetic resonance imagery (fMRI) and positron emission tomography (PET)

Question 10

EEG

Answer 10

Non invasive uses recording electrodes placed at various location in the scalp to record electrical activity can show the differences in the level of activity occurring in different brain regions very accurate in recording when something occurs in the brain but has poor location clarity (spatial resolution)

Question 11

MRI

Answer 11

Uses powerful magnetic fields to detect and measure different types of tissue in the brain and body using a static magnetic field and uses pulses to measure how hydrogen atoms respond to the field. Can be set up to measure white matter (nerve bundles), grey matter (neural bodies), cerebrospinal fluid and the skull. Offering high spatial resolution

Functional MRI measures neural activity indirectly by measuring oxygenated blood vs deoxygenated blood. The assumption is more oxygenated blood means more neural activity imprecise at measuring when a change occurs as blood flow isn’t instantaneous.

Question 12

PET

Answer 12

Uses radioactive chemicals injected intravenously. The radioactive materials (radio tracers) bind to different molecules in the brain (glucose or water). It shows how brain processes unfold over time it has good spatial resolution and poor temporal resolution.

Question 13

TMS

Answer 13

A non invasive brain stimulation that uses electromagnetic fields to induce electrical current within the brain. Can be used for cortical mapping, where certain brain regions are stimulated that represent different body parts and see how the body reacts to the stimulation. TMS can be administered to a part of the brain that involves cognitive ability to temporarily turn in it off the brain region.

Question 14

DBS

Answer 14

An invasive form of brain stimulation and used to treat Parkinson’s disease MDD and OCD. Requires brain surgery to insert the electrodes

Question 15

Hind Brain

Answer 15

Sits at the base of the skull comprised of several regions including the medulla oblongata, the pons, the reticular formation and the cerebellum

Medulla oblonganta:
At the top of the spine is considered an extension of the spinal cord important for cardiovascular control (heart and breathing rate) and life critical reflexes (vomiting, coughing, sneezing) has several motor and sensory pathways with the face, mouth, neck and shoulders.

The pons:
Sitting on top of the medulla oblongata contains several pathways that send information fron the face, eyes and ears to the brain. Is the location where neurons from one side of the brain crossover and connect with the opposite (contra lateral) side of the body. Also involved in regulating sleep especially REM

The reticular Formation
Found deep within the medulla and pons. Regulated attention, arousal, wakefulness and sleep. Damages to this area leads to comas contains the ascending pathway sends information from lower sections of the nervous system (from your body) to high cortical regions of the brain to be further processed and understood.

The cerebellum
A large structure that has many deep folds works unconsciously to coordinate aspects of motor control including balance, gait and posture helps smooth out motor movements

Question 16

Mid brain

Answer 16

Sits just on top of the hind brain. Comprised of several structure including the superior colliculus, inferior colliculus, tectum, tegmentum, substantia Nigra. The mid brain is important for keeping us alive and generally work unconsciously without our input it out conscious ability to control not associated with higher order abilities such as language, emotion or cognition.

Superior colliculus:
Involved in aspects of Vision and eye movements

Inferior colliculus
Which is involved in aspects of hearing

Substantia nigra:
Involved with things including movement, reward and motor control

Question 17

Forebrain

Answer 17

Located around and above the midbrain and is thought to be the location of many of our unique human functions. Including five prominent structure including the thalamus, the hypothalamus, the basal ganglia, the hippocampus and the amygdala

Question 18

Forebrain

Answer 18

Located around and above the midbrain and is thought to be the location of many of our unique human functions. Including five prominent structure including the thalamus, the hypothalamus, the basal ganglia, the hippocampus and the amygdala

Question 19

Thalamus

Answer 19

Found in the centre of the brain can be used as a reference point to navigate around the brain. Comprised of two structures one in the left and one in the right hemisphere. Acts as a relay station that sends sensory information on to the primary vortices for further processing. Sense of smell info does not enter the brain through the thalamus instead gets sent straight to the cerebral cortex

Certain regions within the thalamus connect with other brain areas. Taste us gathered from our tongue and is sent to the thalamus and then onto the gustatory cortex. Visual information from our eyes is sent to the lateral geniculate nucleus then to the primary visual cortex for visual processing. Sound information from our ears is sent to the medial geniculate nucleus then onto the auditory cortex for further processing. Touch information are sent from sensory neurons to the Thailand and then to the primary somatosensory cortex in the patrtial lives

Other functions of the thalamus involve spatial learning and non spatial memory

Question 20

Hypothalamus

Answer 20

Located below the thalamus involved with important motivational approach and avoidance behaviours. Specifically associated with the 4 F’s : fighting, fleeing, feeding and fornicating

Shown through Anand and Brobeck (1951) where researched examined the effects of lesioning specific regions within the hypothalamus in eating behaviours in rats. damaging the ventromedial hypothalamus resulted in increased eating and leading to obesity. Damaging the lateral hypothalamus resulted in decreased eating which led to starvation and death. Other studies in aggression in cats and rats showed electrical stimulation of certain parts of the hypothalamus can result in defensive behaviours in animals

Question 21

Basal Ganglia

Answer 21

Involved in several aspects of movement, emotional regulation and cognition. Comprising of several components including globus pallidus, caudate nucleus, putamen, the subthalamic nucleus and substantia nigra. Found deep within the Brain just beside the thalamus extending into the lower hindbrain region. Involved with the initiation of planned and coordinated movements (playing and instrument). Also involved in the intimation of spontaneous movement, damage to the basal ganglia have been implicated in movement disorder such as Parkinson’s.

Another function of the basal ganglia or more specifically nucleus accumbens are involved in reward seeking. Reward refers to any behaviour the organism finds pleasurable. Olds and Milner 1954 study showed the role of nucleus accumbens in reward by surgically implanting electrodes into the septum in a group of rats. When stimulating the region rats acted as if they had experienced something pleasurable. When allowing the rats to self stimulate its results in rates of 2000 times per hour the septum was later discovered to be connected to the nucleus accumbens

Question 22

Hippocampus

Answer 22

A subcritical region crucial to our memory. We have two hippocampi one in each hemisphere and they are located to the side of the thalamus and basal ganglia. Important role in encoding new memories and consolidating short term memory into long term memory

You also need ur hippocampus for spatial learning and memory. Whenever u need to generate a map in ur mind to go to a location you have been too before ur hippocampus becomes active

Study of HM who had his hippocampus removed as it was believed to be the cause of his seizures suffered anterograde amnesia meaning all of his existing memories remained in tact but he could not form any new long term memories HM could still learn certain physical or motor behaviours such as drawing the outline of a star using a reflection in a mirror increasingly well over time

Question 23

Hippocampus

Answer 23

A subcritical region crucial to our memory. We have two hippocampi one in each hemisphere and they are located to the side of the thalamus and basal ganglia. Important role in encoding new memories and consolidating short term memory into long term memory

You also need ur hippocampus for spatial learning and memory. Whenever u need to generate a map in ur mind to go to a location you have been too before ur hippocampus becomes active

Study of HM who had his hippocampus removed as it was believed to be the cause of his seizures suffered anterograde amnesia meaning all of his existing memories remained in tact but he could not form any new long term memories HM could still learn certain physical or motor behaviours such as drawing the outline of a star using a reflection in a mirror increasingly well over time

Question 24

Amygdala

Answer 24

Small almond shaped structure located near the rear end of the hippocampus similar to the hippocampus there is two amygdala in each hemisphere. Traditionally associated with fear and aggression responses in organisms.

SM a patient who had very localised damage to both of her amygdala due to a rare congenital disease that soared other regions of her brain. The patient was exposed to fear inducing situations like snakes and spiders and even though it was stated how much she disliked snakes and spiders she exhibited no fear or reservations about handling live snakes. Similarly in a haunted house she experienced no fear.

There is increasing evidence to show the amygdala are involved in a wider range of processes for example as a relevance detector. The amygdala may be a system which is constantly scanning for information which may or may not be relevant. fMRI studies show that it involved in processing negative and positive emotions, processing social information and supporting memory and learning

Question 25

Cerebral cortex

Answer 25

The outer most layer of the brain about 2 centimetre thick. One theory is that the folded shape increases the available surface area of the brain. The bulgy parts of the cortex are call the gyri sbd the valleys are called thr sulci the very deep valleys are referred to as fissures

Question 26

Corpus Callosum

Answer 26

The two hemispheres are connected by a bridge of neural tissues known as the corpus callosum allowing the hemispheres to share information.

This can be severed through split brain surgery often used as a treatment for epilepsy in cases where seizures begin in one hemisphere and migrate to the other resulting in grand mal seizure affecting both sides of the body. Splitting the corpus callosum can isolate the seizures to one side. Patients with a split brain display unusual behaviours in a simple naming task a patient with split brain is flashed an object to the left hemisphere they can band the object bc the left hemisphere contains our language centre if the image is flashed to the right hemisphere people report seeing nothing. However if u ask the patient to pick up the object they can correctly pick it up with their left hand despite reporting seeing nothing

Question 27

Lobes of the cerebral cortex

Answer 27

The outer layer of the cerebral cortex can be divided into four lobes: the frontal lobe, the parietal lobe, the temporal lobe and the occipital lobe. The loves are named after four large bones that make up the skull and sit above the corresponding brain region

Question 28

Lobes of the cerebral cortex

Answer 28

The outer layer of the cerebral cortex can be divided into four lobes: the frontal lobe, the parietal lobe, the temporal lobe and the occipital lobe. The loves are named after four large bones that make up the skull and sit above the corresponding brain region

Question 29

Frontal lobes

Answer 29

Located towards the front of the head before the midline. Comprised of several regions which are involved with self initiated voluntary movement, aspects of personality, working memory and reward and punishment

Primary cortex:
Involved with initiator of voluntary movement. Strip of brain that runs from the top of ur skull down to ur ears. The top regions control your feet, legs, groin and torso. The lower parts control you hands, arms, face and tongue. Bigger regions are devoted to movement of hands and face due to humans being capable of significantly more fine motor movements using our hands and face than with our legs and torso are.

Dorslateral prefrontal cortex
Found at the midpoint of the frontal lobes before the motor cortex. Involved in a collection of cognitive processes we call our executive functions including problem solving, holding items in working memory, engaging in deep thought, maintaining goals or rules when performing tasks, manipulating I formation for problem solving but also future planning and inhibition.

Broca’s area
Involved in language processing specifically influences our ability to produce speech. Tan one of Pierre Brocas patients lost his ability to speak at age 30 and experience deteriorating health over the next decade. Tan was able to follow instructions and command and could communicate by gesturing his speech was limited to a single word tan hence the nickname. An autopsy showed widespread atrophy if the brain but in particular the region now called Broca’s area.

Parietal lobes
Located just behind the frontal lobes involved with processing sensory information and helps us with spatial navigation and awareness

Primary somatosensory cortex
Located next to the primary cortex processes sensory information relation to feelings of touch. Similar to the motor cortex the legs, torso and feet are represented higher with hands, face and neck areas being further down. Or field and Boldrey 1937 found that sensations in tongue and mouth were much further down the sematosensory strip sensations in hands were about half way down the same region and sensations of legs and trunk were represented at the top of the brain. Their research resulted in the sensory homunculus image. The somantosensory and motor cortex line up functions allowing for quick bbbbcommunication.

The parietal love is involved with ensuring that we update our position in space allowing us to interact with object in our environment be it avoiding walls etc. the somantosensory cortex helps with spatial navigation because we need to br able to perceive in order to effectively move our body.

Occipital lobes
Found near the base of the spine above the hindbrain. House the regions involved with visual processing. Cortical blindness where a patient will be unable to see with extensive damage to the visual areas and an absence of alpha wave or visually evoked potentjals in the Brain. This lack of sight is not bc of damage to the eyes. Achromatopsia (colour blindness) and akinetopsia (difficulties perceiving movement) are also due to damage to the occipital lobes

Temporal lobes
Located below the frontal lobes before the occipital cortex associated with several important functions including auditory processing, object recognition and facial perception and memory processing.

Question 30

Fusiform face area FFA

Answer 30

Right temporal lobe contains a region that appears to specialise in recognition of human faces. We associate this as damage to the right temporal lobe can result in prosopagnosia where patients lose the ability to recognise previously familiar faces.

Question 31

Fusiform face area FFA

Answer 31

Right temporal lobe contains a region that appears to specialise in recognition of human faces. We associate this as damage to the right temporal lobe can result in prosopagnosia where patients lose the ability to recognise previously familiar faces.

Question 32

Wernicke’s Area

Answer 32

A region of the temporal love involved with language processing influencing our ability to comprehend speech. Named after Carl wernicke the first to describe a particular language disorder where patients retained the ability to produce fluent speech however their language comprehension was extremely poor. Now called fluent aphasia patients can produce fluent speech but often is nonsensical or not meaningful and conveys little substantive meaning they also struggle comprehending language in written and verbal form showing extreme difficulty articulating a response to answer a question

Question 33

Limitations of neurobiological approaches

Answer 33

First issues is the danger of conflating description with explanation so far we can describe different functions that appear to be associated with given regions if the brain we have not been able to explain how this works.

The second issue is the danger that the current approach may be a modern expression of phrenology which was a pseudoscience in the 1800-1900s based on the idea that specific lumps or structure on a persons head indicated aspects of personality this was later to be shown as highly innaccurate. Due to our current neuroimaging only being able to show brain regions being active and not at all exposing how or why we are still very limited on our knowledge

Finally no brain region acts in isolation all regions are heavily connected