Question

Situation #1

A neurosurgeon is about to perform brain surgery. The surgeon touches (stimulates with an electrode) a tiny portion of the patient’s brain, and the patient’s right finger moves. After noting the reaction, the surgeon stimulates a portion of the brain a short distance away and the patient’s right thumb moves.

Questions to Answer

1. What section of the brain has been stimulated? ____________ What lobe is this in? ______________
2. What hemisphere of the brain is being stimulated? ________________
3. During this stimulation, would the patient experience feelings of pain? Why or why not?

Situation #2

A woman has suffered some type of damage to the brain. She is being tested to see where the damage might be. She is first shown a picture of herself and she is unable to recognize this picture. When she is shown a picture of her family, she is unable to recognize family members. What part of the brain might be involved?

Situation #3

In the case of “The Lost Mariner”, Oliver Sacks writes about a 49 year-old man who suffered an accident at the age of 19. His scores on intelligence tests are unchanged over time, however, he has trouble learning new information. What would your diagnosis be? What part of the brain do you think is affected?

Situation #4

Jim falls frequently and shows poor balance and an unusual gait. He shows jerky and uncoordinated movement. These difficulties may be related to what part of the brain?

Situation #5

A 55 year old woman has suffered a minor stroke. Her major difficulty is that she has no interest in eating or drinking. What area of the brain may have been affected?

Situation #6

After a car accident, a young woman reports that she seems to have a hole in her field of vision. She can’t see objects in a particular location. Her eyes seem to be fine. What might be the problem?

Situation #7

You are watching a suspenseful video late at night and you hear a sudden crash in another room. You leap out of your chair in fear, then realize that your dog kicked over his water bowl. Your fear/stress reaction involved activation of the ______________nervous system. Calming down involved activation of the ______________nervous system.

Situation #8

After an accident, patient T. has trouble planning and making decisions about how to go about performing his job. He also has trouble paying attention in meetings. Before the accident he was a highly reliable employee. After the accident, he adopted an attitude that it did not matter whether he completed assignments or was courteous to clients. What area of the brain may have been affected?

Situation #9

The setting: You are a famous neurosurgeon who specializes in brain damage involving the language system. In each of the following cases, make a diagnosis concerning where you believe brain damage has occurred.

Case 1: A 56-year-old female has suffered a recent stroke. She speaks in a curious manner resembling fluent English but the phrases make no sense. You also find that she comprehends your verbal or written instructions and can even write them down, but has difficulty repeating them.

Case2:  An intelligent businessman comes to you and explains rather agitatedly that he awakened yesterday morning to find, much to his dismay, that he could no longer read. Your tests determine the following: a) He is totally blind in the right visual field. b) He speaks fluently and comprehends speech. c) He can write with his right hand but cannot read what he has written. d) He can copy written words but only with his left hand. You turn to your puzzled assistant and remark that this is indeed a tough one, but you are willing to bet that you will find brain damage in at least two areas, which are ________________ and _______________.

Answer 1

Section 1
Primary motor cortex: (Brodmann area 4) is a brain region that in humans is located in the dorsal portion of the frontal lobe. It is the primary region of the motor system and works in association with other motor areas including premotor cortex, the supplementary motor area, posterior parietal cortex, and several subcortical brain regions, to plan and execute movements

Frontal lobe
Left hemisphere:right part of body controlled by left hemisphere

Touch, Thermoception, and Noiception
Yes it will be stimulated
A number of receptors are distributed throughout the skin to respond to various touch-related stimuli .. These receptors include Meissner’s corpuscles, Pacinian corpuscles, Merkel’s disks, and Ruffini corpuscles. Meissner’s corpuscles respond to pressure and lower frequency vibrations, and Pacinian corpuscles detect transient pressure and higher frequency vibrations. Merkel’s disks respond to light pressure, while Ruffini corpuscles detect stretch
The skin can convey many sensations, such as the biting cold of a wind, the comfortable pressure of a hand holding yours, or the irritating itch from a woolen scarf. The different types of information activate specific receptors that convert the stimulation of the skin to electrical nerve impulses, a process called transduction. There are three main groups of receptors in our skin: mechanoreceptors, responding to mechanical stimuli, such as stroking, stretching, or vibration of the skin; thermoreceptors, responding to cold or hot temperatures; and chemoreceptors, responding to certain types of chemicals either applied externally or released within the skin (such as histamine from an inflammation). . The experience of pain usually starts with activation of nociceptors—receptors that fire specifically to potentially tissue-damaging stimuli. Most of the nociceptors are subtypes of either chemoreceptors or mechanoreceptors. When tissue is damaged or inflamed, certain chemical substances are released from the cells, and these substances activate the chemosensitive nociceptors. Mechanoreceptive nociceptors have a high threshold for activation—they respond to mechanical stimulation that is so intense it might damage the tissue. Sensory information collected from the receptors and free nerve endings travels up the spinal cord and is transmitted to regions of the medulla, thalamus, and ultimately to somatosensory cortex, which is located in the postcentral gyrus of the parietal lobe.
Pain can also stopped by touch by gate theory
The gate control theory of pain asserts that non-painful input closes the nerve "gates" to painful input, which prevents pain sensation from traveling to the central nervous system.

gating mechanism exists within the dorsal horn of the spinal cord. Small nerve fibers (pain receptors) and large nerve fibers ("normal" receptors) synapse on projection cells (P), which go up the spinothalamic tract to the brain, and inhibitory interneurons (I) within the dorsal horn.

The interplay among these connections determines when painful stimuli go to the brain:
When no input comes in, the inhibitory neuron prevents the projection neuron from sending signals to the brain (gate is closed).
Normal somatosensory input happens when there is more large-fiber stimulation (or only large-fiber stimulation). Both the inhibitory neuron and the projection neuron are stimulated, but the inhibitory neuron prevents the projection neuron from sending signals to the brain (gate is closed).
Nociception (pain reception) happens when there is more small-fiber stimulation or only small-fiber stimulation. This inactivates the inhibitory neuron, and the projection neuron sends signals to the brain informing it of pain (gate is open).
Descending pathways from the brain close the gate by inhibiting the projector neurons and diminishing pain perception.
This theory doesn't tell us everything about pain perception, but it does explain some things. If you rub or shake your hand after you bang your finger, you stimulate normal somatosensory input to the projector neurons. This closes the gate and reduces the perception of pain.

Section 2
Memory is the faculty of the brain by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action
Memory is often understood as an informational processing system with explicit and implicit functioning that is made up of a sensory processor, short-term (or working) memory, and long-term memory. This can be related to the neuron. The sensory processor allows information from the outside world to be sensed in the form of chemical and physical stimuli and attended to various levels of focus and intent. Working memory serves as an encoding and retrieval processor. Information in the form of stimuli is encoded in accordance with explicit or implicit functions by the working memory processor. The working memory also retrieves information from previously stored material. Finally, the function of long-term memory is to store data through various categorical models or systems.

Declarative, or explicit, memory is the conscious storage and recollection of data. Under declarative memory resides semantic and episodic memory. Semantic memory refers to memory that is encoded with specific meaning,while episodic memory refers to information that is encoded along a spatial and temporal plane. Declarative memory is usually the primary process thought of when referencing memory.Non-declarative, or implicit, memory is the unconscious storage and recollection of information
Memories aren’t stored in just one part of the brain. Different types are stored across different, interconnected brain regions. For explicit memories – which are about events that happened to you (episodic), as well as general facts and information (semantic) – there are three important areas of the brain: the hippocampus, the neocortex and the amygdala. Implicit memories, such as motor memories, rely on the basal ganglia and cerebellum. Short-term working memory relies most heavily on the prefrontal cortex.
Explicit memory
There are three areas of the brain involved in explicit memory: the hippocampus, the neo-cortex and the amygdala.

Hippocampus
The hippocampus, located in the brain's temporal lobe, is where episodic memories are formed and indexed for later access. Episodic memories are autobiographical memories from specific events in our lives, like the coffee we had with a friend last week

Neocortex
The neocortex is the largest part of the cerebral cortex, the sheet of neural tissue that forms the outside surface of the brain, distinctive in higher mammals for its wrinkly appearance. In humans, the neocortex is involved in higher functions such as sensory perception, generation of motor commands, spatial reasoning and language. Over time, information from certain memories that are temporarily stored in the hippocampus can be transferred to the neocortex as general knowledge – things like knowing that coffee provides a pick-me-up. Researchers think this transfer from hippocampus to neocortex happens as we sleep

Amygdala
The amygdala, an almond-shaped structure in the brain’s temporal lobe, attaches emotional significance to memories. This is particularly important because strong emotional memories (e.g. those associated with shame, joy, love or grief) are difficult to forget. The permanence of these memories suggests that interactions between the amygdala, hippocampus and neocortex are crucial in determining the ‘stability’ of a memory – that is, how effectively it is retained over time.

There's an additional aspect to the amygdala’s involvement in memory. The amygdala doesn't just modify the strength and emotional content of memories; it also plays a key role in forming new memories specifically related to fear. Fearful memories are able to be formed after only a few repetitions. This makes ‘fear learning’ a popular way to investigate the mechanisms of memory formation, consolidation and recall.

Implicit memory
There are two areas of the brain involved in implicit memory: the basal ganglia and the cerebellum.

Basal ganglia
The basal ganglia are structures lying deep within the brain and are involved in a wide range of processes such as emotion, reward processing, habit formation, movement and learning. They are particularly involved in co-ordinating sequences of motor activity, as would be needed when playing a musical instrument, dancing or playing basketball. The basal ganglia are the regions most affected by Parkinson’s disease. This is evident in the impaired movements of Parkinson’s patients.

Cerebellum
The cerebellum, a separate structure located at the rear base of the brain, is most important in fine motor control, the type that allows us to use chopsticks or press that piano key a fraction more softly. A well-studied example of cerebellar motor learning is the vestibulo-ocular reflex, which lets us maintain our gaze on a location as we rotate our heads.

Working memory
Prefrontal cortex
The prefrontal cortex (PFC) is the part of the neocortex that sits at the very front of the brain. It is the most recent addition to the mammalian brain, and is involved in many complex cognitive functions. Human neuroimaging studies using magnetic resonance imaging (MRI) machines show that when people perform tasks requiring them to hold information in their short-term memory, such as the location of a flash of light, the PFC becomes active. There also seems to be a functional separation between left and right sides of the PFC: the left is more involved in verbal working memory while the right is more active in spatial working memory,

memory disorders, particularly amnesia. Loss of memory is known as amnesia. Amnesia can result from extensive damage to: (a) the regions of the medial temporal lobe, such as the hippocampus, dentate gyrus, subiculum, amygdala, the parahippocampal, entorhinal, and perirhinal corticesor the (b) midline diencephalic region, specifically the dorsomedial nucleus of the thalamus and the mammillary bodies of the hypothalamus
Other neurological disorders such as Alzheimer's disease and Parkinson's disease can also affect memory and cognition. Hyperthymesia, or hyperthymesic syndrome, is a disorder that affects an individual's autobiographical memory, essentially meaning that they cannot forget small details that otherwise would not be stored. Korsakoff's syndrome, also known as Korsakoff's psychosis, amnesic-confabulatory syndrome, is an organic brain disease that adversely affects memory by widespread loss or shrinkage of neurons within the prefrontal cortex.