Parts of the Forebrain Flashcards

1
Q

What regions make up the Forebrain?

A

The Forebrain contains regions derived from the Diencephalon and Telencephalon as follows:

Diencephalon derivatives: Thalamus, Hypothalamus, Posterior Pituitary Gland, Pineal Gland

Telencephalon derivatives: Cerebral Cortex, Basal Ganglia, Limbic System

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2
Q

Define/describe the function of the Thalamus:

A

The Thalamus is a portion of the Forebrain that serves as a relay and sorting station for sensory information, and then transmits the information to the cerebral cortex.

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3
Q

Define/describe the function of the Hypothalamus:

A

The Hypothalamus is a portion of the Forebrain that controls homeostatic and endocrine functions by controlling the release of pituitary hormones.

The Hypothalamus is subdivided into the lateral hypothalamus, ventromedial hypothalamus and anterior hypothalamus.

The hypothalamus is also the primary regulator of the Autonomic Nervous System and is important in drive behaviors such as hunger, thirst & sexual drive.

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4
Q

Define/describe the function of the Lateral Hypothalamus (LH):

A

The Lateral Hypothalamus is referred to as the hunger center because it has special receptors thought to detect when the body needs more food or fluids.

In extirpation of lab rats, destruction of the LH would cause the lab rats to die from dehydration/starvation due to their refusal of eating/drinking and if not force-fed through tubes.

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5
Q

Define/describe the function of the Ventromedial Hypothalamus (VMH):

A

The Ventromedial Hypothalamus is identified as the ‘satiety center’ and provides signals to stop eating.

Studies have shown that brain lesions in this region usually led to obesity.

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6
Q

Define/describe the function of the Anterior Hypothalamus:

A

The Anterior Hypothalamus is the structure that controls sexual behavior and regulates sleep & body temperature.

In extirpation of lab rats, stimulation of this region resulted in the lab rats mounting everything including inanimate objects.

In extirpation of lab rats, destruction of this region resulted in permanent inhibition of sexual activity.

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7
Q

Mnemonic:
What are the (Four) Functions of the Hypothalamus?

Hint: The Four F’s

A

The Four Fs:

  1. ) Feeding
  2. ) Fighting
  3. ) Flighting
  4. ) (Sexual) Functioning
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8
Q

Mnemonic:
What is the function of the Lateral Hypothalamus?

Hint: LH

A

When the Lateral Hypothalamus (LH) is destroyed, one Lacks Hunger.

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9
Q

Mnemonic:
What is the function of the Ventromedial Hypothalamus?

Hint: VMH

A

When the VentroMedial Hypothalamus (VMH) is destroyed, one is Very Much Hungry.

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10
Q

Mnemonic:
What is the function of the Anterior Hypothalamus?

Hint: AH

A

When the Anterior Hypothalamus is destroyed, one is Asexual Honestly.

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11
Q

Define/describe the function of the Posterior Pituitary Gland:

A

The Posterior Pituitary Gland is the “master gland” of the endocrine system comprised of axonal projections from the hypothalamus that triggers hormone release in other endocrine glands.

The PPG releases antidiuretic hormone (ADH aka vasopressin) and Oxytocin.

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12
Q

Define/describe the function of the Pineal Gland:

A

The Pineal Gland is a brain structure located near the thalamus that secretes melatonin.

Melatonin regulates circadian rhythms.

The Pineal Gland is a key player in several biological rhythms and receives direct signals from the retina for coordination with sunlight.

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13
Q

Define/describe the function of the Basal Ganglia:

A

The Basal Ganglia is a portion of the Forebrain that coordinates muscle movement and routes information (via the Extrapyramidal Motor System) from the cortex to the brain and spinal cord.

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14
Q

Define/describe the function of the Extrapyramidal System:

A

The Extrapyramidal Motor System is part of the basal ganglia that modulates motor activity.

It gathers information about body position and carries this information to the CNS, but does not function directly through motor neurons.

The Basal Ganglia help make our movements smooth and our posture steady.

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15
Q

How does Parkinson’s Disease affect the Basal Ganglia?

A

Parkinson’s Disease is one chronic illness associated with destruction of portions of the basal ganglia and is typically characterized by jerky movements and uncontrolled resting tremors.

The Basal Ganglia may also play a role in schizophrenia and OCD.

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16
Q

Define/describe the function of the Limbic System:

A

The Limbic System is a portion of the cerebrum that is comprised by a group of interconnected structures looping around the central portion of the brain and is primarily associated with emotion and memory.

The Limbic System’s primary components include the Septal Nuclei, Amygdala and Hippocampus.

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17
Q

Describe/define the function of the septal nuclei:

A

The Septal Nuclei is one of the primary pleasure centers in the brain.

Stimulation of the septal nuclei is reported to be intensely pleasurable and there is a suggestive association between these nuclei and addictive behavior.

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18
Q

Define/describe the function of the Amygdala:

A

The Amygdala is a structure that plays an important role in defensive and aggressive behaviors including fear & rage.

Damage of the Amygdala has shown markedly reduction in aggression and fear reactions. Additionally, lesions in the Amygdala resulted in docility and hypersexual states.

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19
Q

Define/describe the function of the Hippocampus:

A

The Hippocampus plays a vital role in learning and memory processes. The Hippocampus helps consolidate information to form long-term memories and can redistribute remote memories to the cerebral cortex.

The Hippocampus communicates with other portions of the Limbic System through the Fornix.

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20
Q

Define/describe the function of the Fornix:

A

The Fornix is a long connection from the Hippocampus that connects to other nuclei in the Limbic System.

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21
Q

What is Anterograde Amnesia?

A

Anterograde Amnesia is a form of memory loss in which new long-term memories cannot be established.

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22
Q

What is Retrograde Amnesia?

A

Retrograde Amnesia is a form of memory loss which impacts long-term memories of events prior to the time of injury.

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23
Q

What is the Cerebral Cortex?

A

The Cerebral Cortex is the outermost layer of the cerebrum responsible for complex perceptual, behavioral & cognitive processes.

The Cerebral Cortex is sometimes referred to as the Neocortex due to it being the most recent brain region to evolve.

24
Q

What are gyri and sulci?

A

A Gyrus (or Gyri [plural]) is a ridge of the cerebral cortex.

A Sulcus (or Sulci [plural]) is a fold in the cerebral cortex.

Rather than having a smooth surface, the Neocortex have numerous bumps and folds (gyri & sulci) which provides increased surface area.

25
Q

How is the Cerebrum structurally divided?

A

The Cerebrum is divided into two halves called Cerebral Hemispheres.

26
Q

How is the surface of the Cerebral Cortex structurally divided?

A

The surface of the Cerebral Cortex is divided into four lobes:

  1. ) Frontal Lobe
  2. ) Parietal Lobe
  3. ) Occipital Lobe
  4. ) Temporal Lobe.
27
Q

Mnemonic:
What are the lobes of the Brain?

Hint: F-POT

A
  1. ) Frontal Lobe
  2. ) Parietal Lobe
  3. ) Occipital Lobe
  4. ) Temporal Lobe
28
Q

What is the function of the Frontal Lobe?

A

The Frontal Lobe is a portion of the cerebral cortex that controls motor processing, executive function and the integration of cognitive and behavioral processes.

29
Q

What two basic regions comprise the Frontal Lobe?

A
  1. ) The Prefrontal Cortex

2. ) The Primary Motor Cortex

30
Q

What is the function of the Prefrontal Cortex?

A

The Prefrontal Cortex is an association area that manages executive function by supervising and directing the operations of other brain regions. This region supervises processes associated with perception, memory, emotion, impulse control and long-term planning.

Additionally, the Prefrontal Cortex communicates with the reticular formation in the brainstem to regulate attention and alertness by telling an individual to wake up or relax depending on the situation.

31
Q

What is the Prefrontal Cortex’s role in memory?

A

In memory, the Prefrontal Cortex does not store any memory traces BUT rather reminds the individual that he or she has something to remember at all.

32
Q

What is an Association Area?

A

An Association Area is an area that integrates input from diverse brain regions.

i.e. Multiple inputs may be necessary to solve a complex puzzle

33
Q

What is a Projection Area?

A

A Projection Area is an area that performs more rudimentary or simple perceptual and motor tasks.

i.e. Visual cortex which receives visual input from the retina

34
Q

What does damage to the Prefrontal Cortex cause?

A

Damage to the Prefrontal Cortex impairs its overall supervisory functions.
An individual with a Prefrontal Cortex lesion may be more impulsive & generally less in control of their behavior, or depressed.

i.e. Someone being apathetic or making vulgar remarks

35
Q

What is the function of the Primary Motor Cortex?

A

The Primary Motor Cortex is a projection area that initiates voluntary motor movements by sending neural impulses down the spinal cord toward the muscles.

The Primary Motor Cortex is located on the Precentral Gyrus (just in front of the Central Sulcus that divides the Frontal & Parietal lobes).

36
Q

What sulcus divides the frontal and parietal lobes?

A

The Central Sulcus

37
Q

What is the Motor Homunculus?

A

An organizational pattern where the neurons in the Primary Motor Cortex are arranged systematically according to the parts of the body to which they are connected.

Due to certain sets of muscles require finer motor control than others, they take up additional space in the cortex relative to their size in the body.

38
Q

Define/describe the function of the Broca’s Area:

A

Broca’s Area is a brain region located in the inferior frontal gyrus of the Frontal Lobe which is largely responsible for the motor function of speech.

Broca’s Area is usually found in only one hemisphere, the so-called “dominant” hemisphere. For most people (both for right- and left- handed individuals), the Broca’a Area is located on the left hemisphere.

39
Q

What are the three important areas of the Frontal Lobe?

A
  1. ) The Prefrontal Cortex
  2. ) The Primary Motor Cortex
  3. ) Broca’s Area
40
Q

What hemisphere is Broca’s Area typically located?

A

Broca’s Area (for most individuals) is found in the Left Hemisphere aka the “dominant” hemisphere.

41
Q

What is the function of the Parietal Lobe?

A

Located to the rear of the Frontal Lobe, the Parietal Lobe is a portion of the cerebral cortex that controls somatosensory and spatial processing.

The central portion of the Parietal Lobe is associated with spatial processing and manipulation. This region makes it possible to orient oneself and other objects in three-dimensional space, to do spatial manipulation of objects and to apply spatial orientation skills such as those required for map-reading.

42
Q

Define/describe the function of the Somatosensory Cortex:

A

The Somatosensory Cortex is a projection area of the Parietal Lobe located on the Postcentral Gyrus (just behind the Central Sulcus) and is involved in somatosensory information processing.

The Somatosensory Cortex is a destination for all incoming sensory signals for touch, pressure, temperature and pain.

43
Q

What is the Postcentral Gyrus?

A

The Postcentral Gyrus is a prominent structure in the parietal lobe of the human brain and an important landmark that is the location of the primary somatosensory cortex, the main sensory receptive area for the sense of touch.

44
Q

Define/describe the function of the Occipital Lobe:

A

The Occipital Lobe is a portion of the cerebral cortex that controls visual processing.

Areas in the Occipital Lobe have also been implicated in learning and motor control.

45
Q

Define/describe the function of the Visual Cortex:

A

The Visual Cortex is the region of the Occipital Lobe devoted to processing visual information.

The Visual Cortex is sometimes referred to as the “Striate Cortex” due to its furrowed or striped appearance when observed under a microscope.

46
Q

Define/describe the function of the Temporal Lobe:

A

The Temporal Lobe is a portion of the cerebral cortex that controls auditory processing, memory processing and emotional control and language.

The Temporal Lobe also function in memory processing, emotion and language.

47
Q

Define/describe the function of the Auditory Cortex:

A

The Auditory Cortex is the primary site of most sound processing, including music, speech and other sound information.

48
Q

Define/describe the function of Wernicke’s Area:

A

Wernicke’s Area is a brain region located in the Superior Temporal Gyrus of the Temporal Lobe ( usually in the left hemisphere) and is largely responsible for language comprehension.

49
Q

Where is Wernicke’s Area located?

A

The Temporal Lobe

50
Q

What is the result of electrical stimulation of the Temporal Lobe?

A

Studies have shown that electrical stimulation of the Temporal Lobe can evoke memories for past events.

This data correlates in a way as the Hippocampus is located deep inside the Temporal Lobe.

51
Q

What types of communication do cerebral hemispheres partake in?

A
  1. ) Contralateral processing

2. ) Ipsilateral processing

52
Q

What is “Contralateral” processing?

A

Contralateral processing is the processing of information on the opposite side of the body (typically a side of the brain).

i.e. Motor neurons on the left side of the brain activate movements on the right side of the body.

53
Q

What is “Ipsilateral” processing?

A

Ipsilateral processing is the processing of information on the same side of the body (typically a side of the brain).

i.e. In hearing, the cerebral hemispheres communicate with the same side of the body.

54
Q

How can you distinguish between the Dominant and Non-dominant Hemispheres?

A

The dominant hemisphere is typically defined as the one that is more heavily stimulated during language reception and production.

Previously, it was assumed that Right-handed individuals had Left-dominant brains and Left-handed individuals had Right-dominant brains however, the data did not correlate with this assumption.

55
Q

Define what the Dominant Hemisphere is:

A

The Dominant Hemisphere is the side of the brain that provides analytic, language, logic and math skills. In most individuals, the Dominant Hemisphere is the Left hemisphere.

i.e. The Dominant Hemisphere screens incoming language to analyze its content, and the Non-Dominant Hemisphere interprets it according to its emotional tone.

56
Q

Define what the Non-Dominant Hemisphere is:

A

The Non-Dominant Hemisphere is the side of the brain associated with sensitivity to the emotional tone of language, intuition, creativity, music and spatial processing. In most individuals, the Non-Dominant Hemisphere is the Right hemisphere.

i.e. The Dominant Hemisphere screens incoming language to analyze its content, and the Non-Dominant Hemisphere interprets it according to its emotional tone.

57
Q

Compare the functions between the Dominant and Non-Dominant Hemispheres.

A
  1. ) Visual System:
    a. Dominant Hemisphere: Letters, Words
    b. Non-Dominant Hemisphere: Faces
  2. ) Auditory System:
    a. Dominant Hemisphere: Language-Related Sounds
    b. Non-Dominant Hemisphere: Music
  3. ) Language:
    a. Dominant Hemisphere: Speech, Writing, Reading, Arithmetic
    b. Non-Dominant Hemisphere: Emotions
  4. ) Movement:
    a. Dominant Hemisphere: Complex Voluntary Movement
    b. Non-Dominant Hemisphere: N/A
  5. ) Spatial Processess:
    a. Dominant Hemisphere: N/A
    b. Non-Dominant Hemisphere: Geometry, Sense of Direction