Exam 1 Flashcards
Why doesn’t complete destruction of the geniculostriate pathway in humans leave the person completely blind?
There is another optic pathway, the Tectopulvinar pathway.
antagonists
decrease neurotransmission effectiveness
V2 (thin, thick, pale strips)
- Thin: color
- Thick: form
- Pale: motion
N’C
F’ick
PaM
Name & describe 3 types agnosia
Agnosia: inability to combine individual visual impressions into complete patterns
- Visual form: inability to recognize line drawings of objects
- Prosopagnosia: facial-recognition deficit
-
Object agnosia:
- Apperceptive: Failure in object recognition but basic visual functions (acuity, color, motion) preserved
-
Associative: Inability to recognize an object despite its apparent perception
- can copy a drawing accurately but can’t ID it
- Results from lesions higher in the processing hierarchy, such as the anterior temporal lobe
blobs
color perception
Agonist
drugs that increase effectiveness of neurotransmissions
area postrema
medullary structure in the brain that controls vomiting
Astereognosis
Astereognosis (or tactile agnosia if only one hand is affected) is the inability to identify an object by active touch of the hands without other sensory input, such as visual or sensory information.
Draw and briefly describe Von Economo’s cytoarchitectonic regions of the parietal lobes and their associated functions.
- PE: Somatosensory
- PF: receives heavy input from the primary somatosensory cortex (through PE) and a small visual input through area PG.
- PG: “parieto-temporo-occipital crossroads;” controls spatially guided behavior with respect to visual and tactile information.
Apraxia
inability to perform particular purposive actions, as a result of brain damage.
simultanagnosia
inability to perceive the visual field as a whole
Simultaneous Extinction
- Somatoperceptual disorder in which two stimuli would be reported if applied singly, but only one would be reported if both were applied together
- Associated with damage to areas of PE and PF
Describe the structural and functional differences between the ventral, dorsal, and STS visual streams. Draw the streams.
- Ventral: includes inferior temporal pathway and STS pathway, concerned w/ object perception (including color & faces) and perceiving certain types of movements
- Dorsal (parietal pathway): participates in the visual guidance of movement
- Superior temporal sulcus: multimodal
oculomotor apraxia
difficulty in fixating the eyes
optic ataxia
inability to move the hand to a specific object by using vision
How would you describe the functions of the left and right posterior zones of the parietal lobe in humans? Give an example from everyday life.
- Integrate info from vision w/ somatosensory info for movement & spatial function
- mental imagery; Esp. object rotation & navigation through space
- Damage to R parietal lobe:
- contralateral neglect:
- cause difficulty in making things (constructional apraxia),
- denial of deficits (anosognosia),
- and drawing ability.
- contralateral neglect:
- Patients w/posterior parietal damage:
- L-R Confusion & cannot do mental rotations
Anosognosia
Unawareness of denial of illness
Name the cranial nerves and draw a “face” picture of them that helps describe their function
- Olfactory: Smell
- Optic: Visual fields and ability to see
- Oculomotor: Eye movements; eyelid opening
- Trochlear: Eye movements
- Trigeminal: Facial sensation
- Abducens: Eye movements
- Facial: Eyelid closing; facial expression; taste sensation
- Auditory/vestibular: Hearing; sense of balance
- Glossopharyngeal: Taste sensation; swallowing
- Vagus: Swallowing; taste sensation
- Accessory: Control of neck and shoulder muscles
- Hypoglossal: Tongue movement
https://blog.cognifit.com/12-pairs-of-cranial-nerves/
Interblobs
- form and motion perception
nocioception
- Perception of pain, temperature, and itch.
- anterior spinothalamic tract
Hapsis
- Perceptual ability to discriminate objects on the basis of touch
- posterior spinothalamic tract
Proprioception
- Perception of the position and movement of the body, limbs, and head
- Anterior Spinothalamic Tract
What is a homunculus and how is the 2 point test relevant to the homunculus
- Homunculus: “Little Human”
- Represents relative sensitivity of body parts, so sizes are disproportionate
- Larger area = higher sensitivity
- The ability to recognize the presence of two pencil points close together, a measure called two-point sensitivity, is highest on the parts of the body having the most touch receptors.
Differentiate the role of premotor, primary, and prefrontal cortex in motor movement
- Posterior Cortex: Specifies movement goals and sends information to the prefrontal cortex
- Prefrontal Cortex: Generates plans for movement
- Premotor Cortex: Movement sequences
- Primary Motor Cortex: Executes movements
The first stage in recovery from contralateral neglect is termed ______.
a. extinction
b. reintegration
c. morphosynthesis
d. allesthesia
Allesthesia: person’s beginning to respond to stimuli on the neglected side as if the stimuli were on the unlesioned side.
The person responds and orients to visual, tactile, or auditory stimuli on the left side of the body as if they were on the right.
Your patient has had a stroke involving the left parietal cortex, particularly anterior areas 1, 2, 3a and adjacent cortex (parts of 43 and 5). What is your expectation regarding possible cognitive defects and how would you test for this?
- Areas 3, 2, 1 (postcentral gyrus): Impairment in all somatic sensations in contralateral side of body.
- Area 43: Gustatory
- 5: Contralateral astereognosis and sensory neglect (damage in nondominant hemisphere).
Describe the feedback circuit that allows the cerebellum to correct movements.
Intention, Action, Feedback: By comparing the message for the intended movement with the movement that was actually performed, the cerebellum sends an error message to the cortex to improve the accuracy of a subsequent movement.
Explain how activation of the GABA receptor can cause sedation. Why is it dangerous to mix benzodiazepines and barbiturates?
Limits the excitability of neuronal activity in all areas of the brain, resulting in sedation.
Both drugs work to suppress the CNS in different ways. When taken together, they may suppress them enough to stop breathing, blood flow…
What is the functional significance of brain regions that lack a blood-brain barrier? Give an example.
area postrema of the lower brainstem allows toxic substances in the blood to trigger a vomiting response.
pineal gland: open to the hormones that modulate the day–night cycles this gland controls.
- What is meant by the term blindsight?
- What brain systems are impacted?
- Give an example from one or more of the case studies given.
- blindsight aka agnosopsia:
- blindness due to damage to the primary visual cortex but the actual visual system (the eyes) are undamaged; person can sometimes respond to visual stimuli that they can ‘see’ with their eyes but their primary visual cortex cannot translate to the brain (i.e., perceived location without being able to perceive content)
- V1 (maybe V2)
- D.K.s right calcarine fissure was removed to surgically excise an angioma; was then able to “perceive” stimuli and could discriminate a 10degree difference in orientation
What are the seven major events in synaptic transmission?
- Neurotransmitter synthesis can take place in the cell, axon, or terminal
- Stored in storage granules or in vesicles until it is
- Released from the terminals presynaptic membrane to
- Act on a receptor embedded in postsynaptic membrane. Excess neurotransmitter in the synapse is either
- Deactivated or
- Taken back into presynaptic terminal (reuptake) for reuse.
- The synapse also has a mechanism for degrading excess neurotransmitter and removing unneeded-by-products.
Identify, in correct order, the major connections of the geniculostriate system from eye to cortex.
- Geniculostriate Pathway
- Optic nerves leave the eye and cross at the optic chiasm
- The right half of each eye’s visual field is transmitted to the left hemisphere; the left half of each eye’s visual field is transmitted to the right hemisphere
See: http://pip.ucalgary.ca/psyc-369/mod2-the-visual-system/unit2.3-visual-pathways/Geniculostriate.html
- What is a scotoma?
- What do such phenomena tell us about the organization of the visual system?
- Small blind spots in visual field; lesion on occipital lobe
- Our brains fill in missing bits of information?
How would damage to the dorsal portion of my right occipital lobe impact my visual field?
Briefly list the main functional role of each of the following: V1, V2, V3, V4, V5 (a sentence or two for each area is sufficient, if it is the right sentence or two).
- V1: (striate cortex) is the first processing level in the hierarchy, receiving the largest input from the lateral geniculate nucleus of the thalamus and projecting to all other occipital regions
- V2: second processing level, also projects to all other occipital regions
- V3: (aka MT; middle temporal) concerns dynamic form—the shape of objects in motion.
-
V4 damage: loss of color cognition (only see shades of gray)
- Cannot see, imagine, or recall color
- V5 damage: erases the ability to perceive objects in motion; can only see objects at rest
Compare the behavioral capacities of high and low decerebrate animals.
-
High:
- Moves toward auditory and visual stimuli but shows no evidence of vision (can see but can’t process)
- Can effectively perform:
- voluntary movements
- automatic movements
- Low: Difficulty maintaining consciousness, inactive if left alone, can’t regulate temperature, sensory stimulation elicits movement and typical affective behavior
Calcarine Sulcus
- Contains much of primary visual cortex (V1)
- Separates upper and lower visual fields
The visual system consists of many subsystems. For each subsystem listed on the left, choose the most appropriate alternative.
Visual cortex
A) orientation of head
B) voluntary eye movements
C) pupil size
D) pattern perception
Frontal eye fields
A) orientation of head
B) voluntary eye movements
C) pupil size
D) pattern perception
Superior colliculus
A) orientation of head
B) voluntary eye movements
C) pupil size
D) pattern perception
The visual system consists of many subsystems. For each subsystem listed on the left, choose the most appropriate alternative.
Visual cortex
A) orientation of head
B) voluntary eye movements
C) pupil size
D) pattern perception
Frontal eye fields
A) orientation of head
B) voluntary eye movements
C) pupil size
D) pattern perception
Superior colliculus
A) orientation of head
B) voluntary eye movements
C) pupil size
D) pattern perception
4 diagnostic features of Lewy Body Dementia
- Parkinsonian Symptoms
- Visual Hallucinations (“halLEWYcinations”)
- Cognitive Decline
- Waxing/Waning Symptoms
wPVC
Motor system: What is it?
usually reserved for those parts of the nervous system, charted in Figure 9.1B.
- Basal ganglia (force)
- Motor cortex (commands)
- Cerebellum (accuracy
- Brainstem and spinal cords (movements)
- Motor neurons
Draw a graph showing the relationship between wanting and liking over time?
Wanting = craving for drug
Liking = pleasure produced by taking the drug
How is the dopamine system differentiated from the endogenous opioid system?
- Dopamine system: associated w/ the incentive, preparatory aspect of reward (experienced as thrill, urgency, or craving; i.e., wanting)
- Opioid system: associated w/ more hedonic aspects of reward (feelings of enjoyment following drug use; i.e., liking)
Fruits or Faces: Explain.
Draw the Visual Processing Hierarchy
How/ what?
Grasping
dorsal / ventral
-
Dorsal Stream
- Visual guidance of movements for grasping
-
Ventral Stream
-
IT Inferior Temporal Cortex
- Object Perception
-
IT Inferior Temporal Cortex
-
STS Superior Temporal Sulcus
- Visuospatial functions
Left hemi, angular gyrus (Brodmann area 39) damage. What results?
Gerstmann Syndrome
- Finger agnosia of fingers on either hand
- Right-Left Confusion
- Agraphia (inability to write)
- Acalculia: (inability to do simple math problems)
- Disturbed language function
- Results from a left parietal lobe lesion (roughly the angular gyrus [PG]).
—–
- Damage to right intraparietal sulcus and the right angular gyrus results in Contralateral neglect.
