Chapter 6: perception

Question 1

Rods

Answer 1

Rods: work very well in a lot of light and are important for color perception.

Question 2

Cones

Answer 2

Work very well in the dark and are sensitive to light.

Question 3

Vertral pathway

Answer 3

The signal transfers from the primary visual cortex (V1) to the secondary areas V2 and V3, to V4 and then to the inferotemporal cortex. Important for the ‘what’.

Question 4

Dorsal pathday

Answer 4

The signal transfers form V1 to V2 and V3, to V5 (motion perception area) and then to the parietal cortex. Important for the ‘where’ and ‘how’.

Question 5

Gestalt principles

Answer 5

1. Proximity
2. Similarity
3. Common motion
4. Good continuation
5. Closure

Question 6

Visual field deficits

Answer 6

Results from damage between the retina and V1, which can cause a loss of part of the visual field. Brain damage in the left hemisphere leads to loss of vision in the right visual field and damage in the right hemisphere leads to loss of vision in the left visual field.

Question 7

Homonymous hemianopia

Answer 7

When visual field loss occurs in the same visual field in both eyes.

Question 8

Quadrantanopia

Answer 8

Blindness for a specific quadrant of the visual field.

Question 9

Blindsight (due to cortical blindness)

Answer 9

Damage that completely destroyed the V1 and resulted in blindness for the full visual field. Someone with cortical blindness can experience blindsight: someone does perceive what is there but is nog conscious about this. The patients show eye movement to a stimulus and perform above chance level on discrimination tasks, but to them they are just guessing.

Question 10

Visual anosognosia

Answer 10

People are cortically blind but not aware of their conditions, they are fully convinced that they can see.

Question 11

Cerebral achromatopsia

Answer 11

Loss of color vision due to damage in the V4 in the ventral pathway. People percieve the world in shades of gray.

Question 12

Cerebral dyschromatopsia

Answer 12

Damage to the V4 that leads to a limited ability to distinguish between colors.

Question 13

Akinetopsia

Answer 13

Inability to perceive motion. Caused by damage to the V5.

Question 14

Visual agnosia

Answer 14

Inability to recognise objects based on visual perception. These patients do have an intact visual field, but the information is not sufficiently integrated.

Question 15

Optic ataxi

Answer 15

Difficulty with reaching to and grasping of objects despite intact basis visual functions and object recognition. It’s caused by damage to the inferior parietal lobe and superior occipital cortex.

Question 16

Balint’s syndrome

Answer 16

A combination of optic ataxia, ocular apraxia and simultanagnosia. Ocular apraxia is the loss of control over intentional eye movement. Caused by bilateral lesions in the posterior parietal lobe.

Question 17

Visual neglect

Answer 17

Caused by a lesion in the parietal lobe that leads to a deficit in attention to half of the visual field. They can see, but don’t consciously perceive the information.

Question 18

Auditory perception

Answer 18

Results form the translation of vibrations into electrical signals. These vibrations move the eardrum back and forth, which is amplified in the middle ear, which sets fluids in motion behind the oval window. By moving the hair cells inside the cochlea, the vibrations are converted into electrical signals. The hair cells at the beginning of the cochlea respond to high requencies and the hair cells at the end respond to low frequencies. This electrical signal is sent to the brainstem, after which it is processed in the midbrain and the auditory cortex.

Question 19

Cortical deafness

Answer 19

Being unable to percieve sound even though there is no damage to the cochlea or middle ear that can explain this.

Question 20

Auditory agnosia

Answer 20

Impairments in receiving / recognizing auditory information. This can be for various types of auditory information of specifically for verbal information, environemental sounds or music.

Question 21

Amorphagnosia

Answer 21

A deficit in object discrimitation through tactile perception that effects the perception of macrogeometrical features, like shapes and sizes.

Question 22

Tactile agnosia

Answer 22

Patients can recognize an boject only with the ipsilateral hand. This is not a disorder in sensory perception, but a disconnection in areas for tactile perception and multimodel integration / semantic memory.

Question 23

Tactile apraxia

Answer 23

A disorder in the execution of different exploratory movements of the contralateral hand. This means for example feeling in your bag and making the movements with you finger to determine your are holding the keys.

Question 24

Ahylognosia

Answer 24

A deficit in object discrimination through tactile perception that affect the perception of microgeometrical features, like texture, material, hardness, weight and temperature.

Question 25

The gustarory system

Answer 25

Consists of tastebuds that transmit electrical signals to the cranial nerve, which projects to the solitary nucleus in the medulla and from there, via the pons and thalamus, to the insula.

Question 26

Olfactory receptors

Answer 26

Are embedded in the olfatory epithelium and send signals via the olfactory nerve to the olfactory bulb and then to the primary olfactory cortex. This is connected to the thalamus, hippocampus and other limbic areas so that the smell can be associated with emotions and memories.

Question 27

Ageusia

Answer 27

Loss of taste

Question 28

Hypogeusia

Answer 28

Reduced taste

Question 29

Dysgeusia

Answer 29

Change of taste

Question 30

Gustatory agnosia

Answer 30

Inability to recognize or idefntify taste

Question 31

Anosmia

Answer 31

Loss of smell

Question 32

Hyposmia

Answer 32

Reduced smell

Question 33

Phantosmia

Answer 33

Aolfactory hallucinations (smell)

Question 34

Olfactory agnosia

Answer 34

Inability to recognize or identify smell

Question 35

Spatial allignment

Answer 35

When 2 things originate from the same spatial location.

Question 36

Temporal allignment

Answer 36

When 2 things are percieved approximately at the same time.