Midterm 1 Flashcards
Brain Stimulation
- Studying epileptic behaviour
- Stimulating certain areas produces certain behaviours
- Right hem: deja vu, religion, short term mem., faces, line perception
- Left hem: accelerate or block speech
Double Dissociation
- Neuro imaging, case studies
- Neural substrates of brain functions
- right hem lesion impairs function x not y, left hem lesion impairs function y not x
Patients with brain lesions
PG - removal of section of left temporal lobe, intelligence (slightly) and verbal memory (sig) decrease.
SK - removal from right temporal lobe, nonverbal memory recall sig. decrease
Split brain & Comissustory patients
- Due to epileptic seizures, corpus. callosum is separated
- The Interpreter: shown 2 images, asked to select 3rd matching image, each hand chooses an images corresponding the hem that is viewing image
Split Face Test
- pictures of faces are split down the middle and recombined
- When asked which was the original, they would say right side (left hem)
The Watta Test (Sodium Amobarbital Injection)
anesthetize a hem.
-patients cannot speak, move the contralateral arm or see through contralateral eye
Specialization Theories
- Unique functions for each hem.
- Extreme: only one hem. facilitates a given process
- Modern: left hem = collection of focal points, right hem = functions diffusely
Interaction Theories
- Cooperation between hems.
- 1: 2 hems function simultaneously but work of different processing
- 2: hems have capacity to inhibit or suppress the other
- 3: preferentially receive or pay attention to info
What is lateralized?
We do not know, no simple or general answer
Handedness - Environmental
Utility - mothers hold infant with left hand (soothing, freeing other hand)
Reinforcement - children were forced to use right hand (has not increased left handedness)
Damage - genetic bias to right, stress in utero (twins), genetic anomalies
Handedness - Anatomical
Enhanced maturation - left hem has enhanced mat. and development
Nature - heart is on left side, left temporal lobe is larger
Left hem dominant for motor control
Handedness - Hormonal
Testosterone (can be inhibitory on development)
- Acts on left hem, leading to greater development of right hem (left hand)
Handedness - Genetic
Potential dominant gene
Tasks Favouring Women
- Math Calc
- Recall
- Displaced objects
- Precision, fine motor
- Matching
Tasks Favouring Men
- Math Reasoning
- Geometric form
- mental rotation
- target motor skills
- visualizing
Motor Skill Sex Differences
- Men better at target throwing - difference is apparent in 3 yr olds, & chimps
- women have finer motor skills, also appears in children
Spatial Analysis Sex Differences
- Men learn routes in fewer trials
- Women remember more landmarks
Mathematical Sex Differences
- Gap closes as people age (adolescents 4:1)
- Women who are good at math tend to be good at language, not men
Brain Structure Sex Differences
- Production of estrogen
- Prefrontal & Paralympic & parietal cortex (sig. bigger in women)
- Angular gyrus (high vol. of androgen receptors in men
- males have uniform grey matter, women have high and low concentrations
Occipital Lobe - V1 and V2
V1 is heterogeneous
- blobs: colour info
- interblobs: process form & motion perception
V2 is heterogeneous
- thin stripes: colour perception
- thick stripes: process form info
- pale stripes: motion perception
Pathways
Dorsal Stream: visual guidance of movement (parietal pathway)
Ventral Stream: object perception and motion perception
STS Stream: object perception & motion perception
Damage to Occipital Lobe
V1 & V2:
- separate colour, form & motion
- Info from blobs to V1 to V4 for color proc.
- Info from V1 to V5 for motion
- Damage to V1 - essentially blind
V3: form perception
V4: colour perception
V5: motion perception
Anterior Parietal Zone
-Somatosensory: processes somatic sensations & perceptions
Posterior Parietal Zone
-Integrate parietal and occipital functions to control movements (PE, PF, PG)
Polymotal
Cells are input from more than one area
PE
-Spatially guided movements: somatosensory cortex, connections & outputs to primary motor cortex
PF
-Complex guided movements: input from somatosensory cortex thru PE, receives input from motor, premotor and PG
PG
- Receives most complex connections from visual, skin, proprioception, vestibular, ocular
- Involved in spatially guided behaviour
Parietal Premotor
How pathways - involved in reaching & grabbing & vision
Parietal Prefrontal
Responsible for visuospatial functions when it comes to working memory
Parietal Medial Temporal
Flows to hippocampus & implicated in spatial nav.
PA, PB, PC, PD
-Static eye movements
Right Parietal Deficits
- Object recognition (top down view is unfamiliar)
- Drawing
Left Parietal Deficits
Gerstmann syndrome
Difficulties with writing, reading, and grammar
Apraxia
Dyscalculia
Decreased digit span in verbal working memory
Difficulty with left–right discrimination
Gerstmann syndrome
-Area PG
-Finger agnosia, left-right confusion, agraphia, acalculia
Acalculia -inability to perform mathematical operations
Ataxia
neurological condition - uncoordinated movements and balance
Apraxia
Loss of skilled movements, not weakness or inability
Ideomotor apraxia
inability to copy movements
Constructional Apraxia
spatial organization is disturbed
Somatosensory Threshold
- Subject is blindfolded, has to report whether they felt 1 or 2 touches
- Points are set 1 inch apart, distance is reduced until subject only detects 1 touch
Tactile Form Recognition
- Blindfolded & manipulates blocks of basic shapes to place in hole
- Shapes and board are removed, subject is asked to draw shapes
- Shape manipulation area PE & PF
- Drawing - area PG
Contralateral Neglect
- Draw a vertical line in middle of horizontal line, dividing in half
- Some lines are on left side, others right
- Subjects w/ contralateral neglect shift line to right side
Visual Perception
- Draw the remainder of incomplete pictures or faces or objects
- Sensitive to damage to right temporoparietal junction
Spatial Relations
- Pictures of hands, feet, ears, etc. presented in different orientations, subjects must identify them as left or right
- Verbal asks patients to touch right side w/ left hand
- Left parietal and frontal lobe damage
Language
- 4 shapes in 5 colours
- Sensorimotor tasks starts simple and becomes more complex
- Damage to PG in left hem
Kimura Box Test
Asks subjects to make a sequence of precise movements
Superior Temporal Sulcus
- Separates superior & middle temporal gyrus
- Auditory and visual input (some somatic)
- eye gaze, lip movement, expression
- biological motion
- spatial processing specialized to right side (left visual field)
Disorders of Visual Perception
Damage to right temporal lobe - can describe a visual scene accurately but fail to notice things that are out of place
- impaired at discriminating complex patterns
- Fail to understand social cues
Split Face Test
- A(original), B(composite of right, C (composite of left)
- When asked to choose the original, they will pick C (left side, right hem facial preference)
- You would choose B for your own picture (mirror view)
- Damage to right temporal - can’t decide
How are Music and Language Different
- Music is complex, (tones) relies on relationships between auditory elements
- Brain primed for music (melodies at 20 wks, vowels/consonants at 36)
- Formants, context, speed, frontal lobe processing
- Loudness, Timbre, Pitch, Timing
Aprosodia
Inability to differentiate pitch
Congenital Amusia
tone deaf, no improvements
Left Temporal Damage
- Verbal memory
- processing speech sounds
- difficulty with speed of language
Right Temporal Damage
- non-verbal memory
- processing music, melodies
- facial recognition & expression
- Discrimination of complex frequency patterns
- Recognition of music and sound localization
Somatosensory Symptoms of Parietal Lesions
Difficulty with somatosensory thresholds and deficits in stereognosis (tactile perception)
Afferent paresis - loss of kinesthetic feedback
Clumsy movements - loss of feedback for where they are in space and their movements
Astereognosis
Inability to recognize objects by touch
Simultaneous Extinction
Inability to detect a sensory event even when paired with another
Occurs with right hem. parietal damage
Lose sight in visual field
PE & PF
Numb Touch
tactile issues (PE, PF, Left hem) resulting in complete agnosia of right side
Somatosensory Agnosias
Anosognosia: unawareness of illness
Anosodiaphoria: indifference to illness
Autotopagnosia: inability to locate and name body parts
Asymbolia for pain: lack of typical avoidance reactions to pain
Finger Agnosia
Difficulty performing rhythmic functions
Posterior Parietal - Balint Syndrome
- Bilateral parietal lesions
- Oculomotor apraxia: only perceive things within gaze (paralysis of gaze)
- Simultagnosia: tension directed towards an object, miss other stimuli
- Optic ataxia: visually guided movements are impaired
Disorders of Parietal Spatial Cognition
-Posterior lesions to PG and polymodal cortex of superior temporal
Left-parietal-lobe damage may impair the formation of the mental image
Right-parietal-lobe damage may impair the manipulation of the image
Mental manipulation of objects
Disorders of temporal Auditory and Speech Perception
- Damage to primary auditory cortex impairs the ability to discriminate rapidly presented and complex patterns of stimuli
- Patients with temporal lobe damage have difficulty discriminating speech, reporting that people are talking too quickly
- Damage to Wernicke’s area produces aphasia
Disorders of Temporal Music Perception
- right temporal lobe are impaired discriminating between sounds of different pitch
- discriminating between rhythms is associated with damage to the right posterior superior temporal gyrus
- discriminating between musical pieces with different meters is associated with damage to the anterior temporal lobe
Disturbance of Input Selection
- Damage to the right temporal lobe results in bilateral deficits in attention shifting
- Damage to the left temporal lobe results in unilateral deficits in attention shifting
- Patients with temporal-lobe damage are impaired shifting attention from one stimulus to another
Impaired Organization and Categorization
- Damage to the left temporal lobe results in impairment in categorization
- Unable to place words into categories
- Unable to use name members of a category such as “animals” when asked
Disorders of Odor Perception and Memory
- Temporal-lobe seizures are often associated with olfactory auras
- Temporal-lobe epilepsy and surgical damage to the temporal lobe to prevent seizures result in impaired perception of odors and memory for odors
Inability to Use Contextual Information
Damage to the right temporal cortex impairs the ability of people to interpret information from context
Memory Impairment
- Removal of the medial temporal lobe, including the hippocampus and adjacent cortex, resulted in anterograde amnesia, or the inability to form new memories
- Damage to the inferotemporal cortex interferes with conscious recall of information, and greater damage is associated with greater impairment
- Damage to the left hemisphere results in impairments for verbal material
- Damage to the right hemisphere results in impairments for nonverbal material
Altered Affect and Personality
- Stimulation of medial temporal cortex produces feelings of fear
- Temporal-lobe epilepsy is associated with personality changes that emphasize trivia and details in daily life
- Personality changes occur after damage to either lobe but are more common after damage to the right hemisphere
- Bilateral damage to the amygdala results in increased sexual behaviours
