Brain Region/structures

Question 1

List hindbrain structures

Answer 1

1. Medulla
2. Pons
3. Cerebellum

Question 2

What is the function of the Medulla?

Answer 2

The medulla is responsible for:
-involuntary mouth and throat movements involved in swallowing, coughing, and sneezing, and it
-regulates a number of functions that are essential for survival including respiration, heart rate, and blood pressure.

*Brain injury and certain diseases and drugs (especially opioids) can disrupt the functioning of the medulla and result in death.

Question 3

What is the function of the Pons?

Answer 3

The pons:
-connects the two halves of the cerebellum
-helps coordinate movements on the two sides of the body
-relays messages between the cerebellum and cerebral cortex
-plays a role in respiration and the regulation of deep sleep and rapid eye movement (REM) sleep.

Question 4

What is the function of the Cerebellum?

Answer 4

The cerebellum coordinates voluntary movements and is responsible for maintaining posture and balance. It is:
-important for processing and storing procedural memories (e.g., running, playing a musical instrument, driving a car) and other implicit memories (memories that operate on an unconscious, automatic level).
-involved in some non-motor cognitive functions including attention, linguistic processing, and visuospatial abilities.

*Damage can cause ataxia which is characterized by symptoms associated with alcohol intoxication and include a lack of muscle control, impaired balance and coordination, slurred speech, nystagmus (jerky eye movements), and blurred or double vision.

Question 5

List Midbrain structures

Answer 5

The midbrain connects the hindbrain to the forebrain and includes:

1. Reticular Formation
2. Substantia Nigra

Question 6

What is the function of the Reticular Formation?

Answer 6

The reticular formation consists of a network of neurons that extend from the medulla into the midbrain. It’s involved in a variety of functions including:
-regulation of muscle tone,
-coordination of eye movements, and
-control of pain.

It contains the reticular activating system (RAS) which is also known as the ascending reticular activating system (ARAS). The RAS mediates
-consciousness and arousal,
-controls the sleep/wake cycle, and
-alerts the cerebral cortex to incoming sensory signals.

*Lesions in the RAS can cause a comatose state, while direct electrical stimulation or stimulation by sensory input can awaken a sleeping person and cause an awake person to become more alert.

Question 7

What is the function of the Substantia Nigra?

Answer 7

The substantia nigra plays a role in:
-reward-seeking,
-drug addiction,
-motor control (through its connection to the basal ganglia).

*Degeneration of dopamine-producing cells in the substantia nigra is a cause of the slowed movement, tremors, rigidity, and other motor symptoms associated with Parkinson’s disease.

Question 8

What are the Subcortical Forebrain Structures?

Answer 8

1. Hypothalamus
2. Thalamus
3. Basal Ganglia
4. Amygdala
5. Hippocampus

Question 9

What is the function of the Hypothalamus?

Answer 9

The hypothalamus regulates the body’s homeotasis and other functions critical to survival through its influence on the autonomic nervous system and pituitary gland. Its functions include regulating:
-body temperature,
-blood pressure,
-heart and respiration rates,
-thirst and hunger,
-growth,
-sexual activity,
-reproduction, and
-the body’s response to stress.

The hypothalamus is also involved in several other functions:
-regulating emotions (confirmed by studies showing that electrical stimulation or damage to different areas of the hypothalamus can elicit aggressive behavior and rage or produce crying or laughter)
-memory (via mammillary bodies)
-regulating sleep-wake cycle and other circadian rhythms (via suprachiasmatic nucleus (SCN)

Question 10

What are the two ways the Hypothalamus influences the Pituitary glad?

Answer 10

1. It produces hormones that stimulate or inhibit the release of hormones produced by the anterior pituitary.
   -Example: the hypothalamus initiates the development of secondary sex characteristics and regulates the maturation and maintenance of the reproductive system by secreting gonadotropin-releasing hormone (GnRH) which, in turn, stimulates the anterior pituitary to secrete gonadotropins that regulate the functions of the testes and ovaries.
2. The hypothalamus produces hormones that it sends to the posterior pituitary, which stores and then secretes them into the bloodstream.
   -Example: Oxytocin is one of the hormones produced by the hypothalamus. It stimulates uterine contractions during childbirth and milk release (“let-down”) during breastfeeding and is also involved in social bonding, sexual arousal, and stress relief. For example, with regard to the latter, there is evidence that women often react to stress with an oxytocin-mediated tend-and-befriend response which involves engaging in behaviors that support the initiation and maintenance of social relationships (Taylor et al., 2000).

Question 11

Where are the Mamillary Bodies and Suprachiasmatic Nucleus located?

Answer 11

Hypothalamus

Question 12

What is the function of the Thalamus?

Answer 12

The thalamus is described as a “relay station” because it receives and then transmits sensory information to the cortex for all of the senses except smell. It also plays an important role in the coordination of:
-sensory and motor functioning,
-language and speech, and
-declarative memory.

Question 13

What are the causes and symptoms of Korsakoff syndrome?

Answer 13

With regard to memory, Korsakoff syndrome is caused by a thiamine deficiency that’s often the result of chronic alcoholism and that damages neurons in the thalamus and mammillary bodies.

Its primary symptoms are anterograde amnesia, retrograde amnesia, and confabulation, which involves filling memory gaps (especially gaps in episodic memory) with false information that the person seems to believe is true.

Question 14

What does the Basal Ganglia consist of?

Answer 14

The basal ganglia consist of:
-the caudate nucleus,
-putamen,
-nucleus accumbens,
-globus pallidus.

The caudate nucleus, putamen, and nucleus accumbens are collectively referred to as the striatum and receive input from the cerebral cortex, while the globus pallidus transmits information to the thalamus.

(Note that some authors include the nucleus accumbens as part of the basal ganglia, while others include it as part of the limbic system. A reason for this inconsistency is because the nucleus accumbens connects these two systems and coordinates their activities, and some investigators are most interested in its role in the basal ganglia while others are more interested in its role in the limbic system.)

Question 15

What is the function of the Basal Ganglia and it’s structures?

Answer 15

These structures are involved in:
-the initiation and control of voluntary movements
-procedural and habit learning
-cognitive functioning (e.g., attention and decision-making)
-emotions

Question 16

What has damage to the Basal Ganglia been linked to?

Answer 16

Basal ganglia damage has been linked to a number of conditions including:
-mood disorders
-schizophrenia
-ADHD
-OCD
-Tourette’s disorder
-Huntington’s disease
-Parkinson’s disease

Question 17

What does the limbic system consist of?

Answer 17

The limbic system consists of several structures that are involved in emotion. It includes:
1) the amygdala
2) cingulate cortex
3) hippocampus.

Question 18

What is the role of the amygdala?

Answer 18

The amygdala plays an important role in:
-the experience of emotions
-recognition of fear and other emotions in facial expressions
-acquisition of conditioned fear responses
-evaluation of the emotional significance of events
-attachment of emotions to memories.

*With regard to memory, the amygdala is involved in the formation of flashbulb memories, which are vivid and enduring memories for surprising and shocking events.

Question 19

PTSD is associated with abnormal functioning of which brain structures?

Answer 19

The research has also found that PTSD is associated with abnormal functioning of the amygdala and ventromedial prefrontal cortex (VPC):
-Hyperactivity in the amygdala plays a key role in producing the distressing memories and other symptoms of PTSD
-Hypoactivity of the VPC reduces its normal regulation of activity in the amygdala (Koenigs & Grafman, 2009; Koenigs et al., 2008).

Question 20

What is Kluver-Bucy syndrome?

Answer 20

Kluver and Bucy (1939) found that bilateral lesioning of the amygdala, hippocampus, and temporal lobes in rhesus monkeys produced a set of symptoms that is known as Kluver-Bucy syndrome. Symptoms include:
-hyperphagia
-hyperorality
-reduced fear
-hypersexuality
-visual agnosia (which is also known as psychic blindness).

These investigators noted that the hippocampus is part of the Papez circuit, which is responsible for emotions and consists of mammillary nuclei in the hypothalamus, the cingulate cortex, and several other structures, and they proposed that lesioning the hippocampus interrupted this circuit, which means it also interrupted the normal functioning of the other structures in this circuit.

Question 21

What is the structure and function of the Cingulate Cortex?

Answer 21

The cingulate cortex contains:
1) the cingulate gyrus
2) cingulate sulcus

It’s a part of the limbic system and plays a role in motivation, memory, and emotions, including emotional reactions to pain.

Question 22

What happens with damage to the Cingulate cortex?

Answer 22

People with damage to the cingulate cortex experience pain but are not emotionally distressed by it.

Abnormalities in the cingulate cortex (and several other areas of the brain including the prefrontal cortex, orbitofrontal cortex, hippocampus, amygdala, and thalamus) have also been linked to major depressive disorder and bipolar disorder (Rajkowska, 2006).

Question 23

Major depressive disorder and bipolar disorder are associated with abnormal functioning of which brain structures?

Answer 23

-cingulate cortex
-prefrontal cortex
-orbitofrontal cortex
-hippocampus
-amygdala
-thalamus

Question 24

What is the function of the hippocampus?

Answer 24

The hippocampus is involved more in memory and less in emotions than the other limbic system structures are.

It’s responsible for transferring declarative memories from short-term to long-term memory and plays an important role in spatial memory (memory for the spatial characteristics of the environment)

Question 25

What is the impact of damage to the hippocampus on memory?

Answer 25

The impact of damage to the hippocampus on memory is demonstrated by research linking the degeneration of cells in the hippocampus and entorhinal cortex (an area adjacent to the hippocampus) to the impairments in episodic memory and spatial navigation associated with Alzheimer’s disease.

In addition, research has found that acute or chronic increases in cortisol levels in the hippocampus as the result of stress or other condition (e.g., Cushing’s syndrome, administration of cortisone) impairs the retrieval of declarative memories (Wolf, 2010).

There’s also evidence that hippocampal abnormalities contribute to major depressive disorder, bipolar disorder, schizophrenia, and PTSD (Zorumski & Rubin, 2011).

Question 26

What is the relationship between PTSD and hippocampus size?

Answer 26

For people with PTSD, the studies have found that the more extreme the traumatic stress and the more severe the person’s symptoms, the more likely the person would have a smaller-than-normal hippocampus.

However, some studies suggest that exposure to traumatic stress causes a reduction in hippocampal volume, while others suggest that reduced hippocampal volume is a risk factor for developing PTSD after exposure to traumatic stress (e.g., Lindgren, Bergdahl, & Nyberg, 2016).

Question 27

What are the components of the Frontal Lobe?

Answer 27

1) Broca’s area - major language area and is located in the dominant (usually left) frontal lobe.

2) Prefrontal cortex - plays an important role in executive functions, which are also known as higher-order cognitive functions and include planning, decision-making, social judgment, and self-monitoring. It also contributes to working memory, prospective memory (memory for future events), and emotion regulation.

3) Supplementary motor cortex - involved in planning and coordinating self-initiated complex movements and is active not only when people actually perform movements but also when they imagine performing them and when watching another person perform them. The supplementary motor cortex, like the premotor cortex and primary motor cortex, is somatotopically organized, which means that each part of the body is controlled by a specific cortical area.

4) Premotor cortex - involved in planning and coordinating complex movements that are triggered by external (sensory) stimuli. Like the supplementary motor cortex, the premotor cortex is active not only when people perform movements but also when they imagine performing them or watch others perform them.

5) Primary motor cortex - In response to signals from the supplementary motor cortex and premotor cortex, the primary motor cortex executes movements by sending signals to the muscles.

Question 28

What is the impact of damage to Broca’s area?

Answer 28

Damage to Broca’s area produces Broca’s aphasia, which is also known as expressive aphasia and nonfluent aphasia. People with this disorder have slow, labored speech that consists primarily of nouns and verbs. They also exhibit impaired repetition and anomia (an inability to recall the names of familiar objects), but their comprehension of written and spoken language is relatively intact.

Question 29

What are the 3 functionally distinct regions of the prefrontal cortex (PFC) and the impact of damage to each?

Answer 29

1) Dorsolateral prefrontal cortex (DLPFC): is involved primarily with executive functions, and damage can cause concrete thinking, impaired judgment and insight, poor planning ability, deficits in working memory, perseverative responses, and disinterest and apathy.

2) Orbitofrontal cortex (OFC): plays a role in emotion regulation, response inhibition, and social behaviors. Damage to this area can cause poor impulse control, social inappropriateness (e.g., immature behavior, offensive jokes), lack of concern for others, aggressive and antisocial behaviors, distractibility, and affective lability.

3) Ventromedial prefrontal cortex (VMPFC): is involved in decision-making, social cognition, memory, and emotion regulation. Damage can produce impaired decision-making and moral judgment, lack of insight, deficits in social cognition (e.g., impaired emotion recognition, reduced empathy), confabulation, and blunted emotional responses.

Question 30

Describe brain lateralization and the dominant functions of each hemisphere

Answer 30

While the right and left hemispheres participate to some degree in many functions, each hemisphere is dominant for some functions. For example (for about 95% of right-handed people and 50 to 70% of left-handed people):

LEFT hemisphere functions; written and spoken language, logical and analytical thinking

RIGHT hemisphere functions; positive emotions, holistic thinking, intuition, understanding spatial relationships, creativity, and negative emotions.

*Note that the hemisphere that’s dominant for language (the left hemisphere for the majority of people) is referred to as the dominant hemisphere, while the other hemisphere is referred to as the nondominant hemisphere.

Question 31

How do the the left and right hemispheres of the brain differ with regard to their control of sensory and motor functions?

Answer 31

In addition to differences in dominance, the left and right hemispheres differ with regard to their control of sensory and motor functions: (for most functions)

The right hemisphere controls the left side of the body and the left hemisphere controls the right side of the body. (An exception is smell: Odors that enter the left nostril are transmitted directly to the left hemisphere, and vice versa.)