The dorsal pathway which is the "where" pathway does what? (occipitoparietal)
It deals with transformations from moment to moment information about the location of objects.
Used for analyzing the spatial configuration between different objects.
The ventral pathway which is the "what" pathway does what? (occipitotemporal)
It supports visual perceptual representation of objects. Allows us to identify objects and attach meaning and to accumulate knowledge about the world.
Bilateral Lesions to the temporal Lobe in monkeys caused what type of difficulty?
Bilateral Lesions to the parietal Lobe in monkeys caused what type of difficulty?
Lesion to the temporal lobe: difficulty discriminating between shapes
Lesion to the parietal lobe: difficulty discriminating where an object is in relation to another.
The "what" pathway receives what type of input?
It receives bilateral input.
Would lesions to the right striate cortex and Left Inferior Temporal Cortex cause a problem in the what pathways communication?
No, because they are still able to communicate bilaterally through the corpus callosum.
What would happen if the corpus callosum were severed in the what pathway?
Object Discrimination would then be impaired.
The "where" pathway primarily receives what type of input?
It receives unilateral input.
unilateral Lesion to the right striate cortex and left parietal cortex would cause what kind of impairment in the where pathway?
There would be a severe deficit in object location.
The where pathway is primarily intrahemispheric.
What would happen when the corpus callosum was severed in relation to the where pathway?
There would be a small impairment in object location.
What type of neurons are good for the "where" pathway?
What are the Parietal Neurons?
These neurons have a large receptive field
60% of these neurons have receptive fields outside of the fovea.
They have a non-selective response to small and large stimuli
Are ideally suited to detecting stimulus presence.
What type of neurons are good for the "what" pathway?
What are Temporal Neurons?
They have a large receptive field
Receptive field always includes the fovea
Most objects are sensitive to objects in the left or right visual field.
Responds to complex objects, rather than lines or spots.
Ideally suited to detecting object identity.
What is it called when you have an impaired object recognition in the prescence of preserved perception?
Lesions frequently fall along what pathway, that may extend into the parietal lobe?
The Ventral Pathway
In visual agnosia, what type of lesions tend to cause impairment?
When object recognition is intact, but visual information cannot be used to guide actions is what?
In optic Ataxia what type of lesions are associated with it?
Parietal Cortex lesions
In patient D.F. what kind of damage did she have?
She suffered from bilateral ventral stream damage.
What type of impairments did D.F. suffer from?
Object recognition; perception in object dimension and orientation.
What was patient D.F able to perform?
calibration of grasping movements
What is object Recognition supported primarily by?
When the same object is recognized as such regardless of changes in viewpoint, lighting, and occlusion is what?
What are two computational hurdles in object recognition?
Must be general enough to support object constancy
It must be specific enough to discriminate different exemplars from the same category.
When your perception depends on matching a visually represented object with a representation of that object stored in memory is called what?
View-Dependent Reference Frame
What is one disadvantage of the View-Dependent Frame?
Every object must have multiple representations in memory from different vantage points.
When your perception depends on certain object properties that are largely invariant across different views is called what?
View-Invariant Reference Frame
What would happen when a repeated object was presented from a different view in View-dependent and View-Invariant?
View-Invariant: New View=Repeated: Same View
View-Dependent: New View=New object
What is a gnostic unit ?
It is a type of neuron that can recognize a complex object.
A single gnostic unit (cell that preferentially responds to a known stimulus) recognizes grandma is known was what?
Grandmother Cell Hypothesis
What are some problems with the grandmother cell hypothesis
What if the cell that represents grandma dies
how do we perceive novel objects that don't have a gnostic cell
how would the cell that represents grandma adapt to her appearance changes.
When recognition is attributed to the collective activation of several cells that represent complex features is known as what?
Ensemble coding hypothesis
What is impaired visual object recognition?
What are two subtypes of Visual Agnosia?
When one experiences problems in failing to identify an object and to derive a coherent visual percept, they are suffering from what?
When someone not only has the inability to identify and object, but also fails to gain access to the meaning from a well derived percept they are suffering from what?
When performance is slightly impaired on tests that require fine discrimination of basic shapes and has problems when features must be inferred from different views or shadows, they might be suffering from?
when someone is unable to recognize or name a photo, picture or a drawing but has the ability to copy the image they might be suffering from what?
Which hemisphere has trouble with unusual views?
Which hemisphere has trouble with linking semantic information to visual output?
Semantic information depends on which hemisphere while perceptual information depends on which hemisphere?
Semantic: Left Hemisphere Perceptual: Right Hemisphere
When someone has difficulty integrating parts of an object into a coherent whole. The recognition depends on identification of a few salient features of an object. This is known as what?
When someone has the inability to recognize faces.
What are two distinct regions in the brain that are activated by the face?
Superior Temporal Sulcus
The Fusiform Gyrus also plays an important role in recognizing faces especially in the right hemisphere. What has this area become to be called today?
FFA- Fusiform Face Area
Parkinsons Disease results from cell death in what area of the brain?
Substantia Nigra which is part of the basal ganglia
Where do alpha motor neurons originate, exit and terminate?
Originate: Spinal Cord Exit: Ventral Root Terminate: In the muscle Fiber
What briefly happens in a Alpha motor neuron action potential?
Alpha Motor neurons activate acetycholine muscle contraction Effector-part of the body that moves
Excitatory signals are related to what type of muscle activation?
Inhibitory signals are related to what type of muscle activation?
Excitatory: Agonist Inhibitory: Antagonist
What are two prominent subcortical structures that play a role in motor control?
Cerebellum and the Basal Ganglia
What is this structure? Input: Somatosensory, Vestibular, Visual, Auditory, Association areas of the cortex
Output: Deep Cerebellar Nuclei to Extrapyrimidal Tract to Motor Cortex ia Thalamus.
What is this structure? Input: Caudate, Putamen, Straitum
Output: Globus Pallidus to motor/ frontal cortex via thalamus
How are motor representations somatotopically organized?
In Primary and Secondary Processing regions
Components of the motor system are hierarchically organized: what is the highest to the lowest.
Premotor: Cerebellum and the Basal Ganglia
Secondary Motor Cortices
Primary Motor Cortex
This area ensures that the selected motor plans are executed efficiently...what is it?
Premotor: Cerebellum and the basal ganglia
This is the goals of an action of the motor plan...what is it?
Secondary Motor Cortices
This is the muscle and direction based signals?
Primary Motor Cortex
This is the point of connection between the muscles and the brain and it mediates simple reflexive movements?
In Taub and Berman Study what were their findings in regard to monkeys and sesnory loss
They are not essential for movement, but animals prefer to use a limb with intact sensory signals.
In Sherringtons experiment what was his findings when severing the spinal cord?
That dogs were still able to walk and run.
Single neurons do not code exact directions of movement; movement direction is coded by what?
A population of neurons.
What is a cells preferred movement direction called?
What is the firing rate of a cell called?
Movement direction can be coded by the summed activity of how many motor neurons (population vector)?
Multiple neurons each contributing to their own vote.
What can population vectors be used as?
To predict Movement
what is Loss of voluntary movements on the contralateral side of the body, particularly in the distal effectors called?
True or False.... In hemiplagia reflexes are initially absent but can return in a couple of weeks and may become exaggerated?
This impairment is often due to a secondary hemmorrage of the middle cerebral artery.
Damage to the motor cortex can cause what type of impairment?
Where do Motor Cortex corticospinal fibers originate?
Primary Motor Cortex
Cells in the primary motor cortex code for what?
for direction of movement and muscular events.
Where does information from other cortical and subcortical processes converge at what level.
Primary Motor Cortex, which influences movement
What does the Internally guided motor control all have?
receives projections from the PFC and Basal Ganglia-Both have strong connectivity to limbic regions.
What does the Externally guided motor control consume?
Premotor cortex receives projections from parietal cortex and cerebellum- both are linked to motor control and to representation of multiple sensory channels.
In this motor control the movements are guided by visual, somatosensory, or auditory feedback.
Extrenally guided motor control
During Supplementary Motor Area activity, how are the actions guided?
They are internally disproportionate guided movements.
During Premotor cortex movement activity how are the actions guided?
They are active during externally disproportionate guided movements.
New Learning is associated with an increase of blood flow in what areas of the brain?
Lateral Premotor and prefrontal areas
Previously learned sequences were correlated with an increase of blood flow in what areas?
Supplementary Motor Area and the hippocampus
What syndrome can come from supplementary motor cortex damage?
Alien Hand Syndrome
This syndrome reflects a dominance of externally guided lateral premotor pathways. The sight of an object withing reaching distance evokes a motor plat to grasp the object.?
Alien Hand Syndrome
This is internally-guided or well-learned motor plans?
Supplementary Motor Area
This is externally guided or novel motor plans?
At what level is movement executed at?
What are the three divisions of the cerebellum?
What is the most primitive part of the cerebellum that appears first in fish?
What is the input and output in the Vestibulocerebellum?
Input: Primary Vestibular Afferents Output: Vestibular Nuclei in Brainstem
This area of the cerebellum is associated with coordinated head and eye-movements and in postural adjustments and balance.
Damage to the Vestibularcerebellum results in what?
Problems in eye movement
General Loss of Balance
This is the onlly cerebellar region that receives somatosensory input from the spinal cord?
What is the input and the output for the spinocerebellum?
Input: Vestibular and Somatosensory
Output: Fastigial Nuclei
This part of the cerebellum is involved in Coordination of Axial Musculature and Movements of Face, Mouth, Neck.
Damage to the interposed nuclei in the spinocerebellum is related to what impairment?
This is a impairment causing reduced muscle tone.
Two impairments caused from damage to the interposed nuclei in thge spinocerebellum?
This is rapidly initiated movements of a limb overshoot the target.
This is the select the appropriate action and initiate it normally, but ultimately the movement is clumsy, irregular and irratic
Part of the cerebellum that is Phylogenetically most recent; part of a high-level Cerebellar Contributions to Motor Function feedback loop that regulates cortical motor programs
What is the input and the output of the neocerebellum?
Input: Cerebral Cortex Output: Dentate nucleus to motor, premotor, and prefrontal cortex.
This contributes to smooth execution of voluntary movements and to motor timing.
Damage to the neocerebellum may result in what kind of impairment?
Decomposition of movement
damage to this part of the cerebellum disrupts the timing of movement components, which then appear to take place sequentially rather than smoothly
motor acts typically involve a sequence of well-coordinated, overlapping movements is known as what?
decomposition of movement
These type of neurons fire at 100ms prior to neurons in M1 or the interposed nucleus (which are more concerned with movement execution).
Cerebellum does not contribute directly to movement of effectors Provides cues about timing needed for effectors to successfully execute an action is known as what?
Motor Timing Hypothesis
Lesion to this area in the motor timing hypothesis abolishes the retention of a previously acquired conditioned response.
Deep Cerebellar nuclei
Lesion to this are in the motor timing hypothesis results in impaired timing of the previously acquired conditioned response.
cerebellum generates predictions of expected sensory experience (walking down steps and expect another stair when there isn?t one)
This is called what?
Basal Ganglia input is where?
Sensory, motor, and association cortices to striatum
Basal Ganglias output is where?
Globus Pallidus, thalamus or the substantia nigra, superior colliculus.
what are the two pathways of the basal ganglia?
Direct pathway and the indirect pathway
This pathway has direct inhibitory projections from the striatum to the GPi and SNr.
This pathway Striatum inhibits the external segment of the Globus Pallidus GPe inhibition results in decreased inhibition of the Subthalamic nucleus (i.e. release from inhibition) Excitatory signals from the STN to the output structures are increased
This exerts opposite affects on the direct and indirect pathways. Here the common neurotransmitter is Dopamine.
Substantia Nigra Compacta
What affect does dopamine have on the direct and indirect pathway.\\?
Direct Pathway: Excitatory effect Indirect: Inhibitory effect
In huntingtons disease, what pathway is affected?
The indirect pathway.
What are the cognitive impairments of huntingtons disease?
impaired memory, motor skill learning, and problem solving.
Hemiballismus is cause by what type of lesions? and what is the result?
Subthalamic nucleus lesions
Result: Violent, uncontrollable movements
what is the cause of Parkinsons Diseas?
Idipathic: no one knows
what is absence or reduction in voluntary movement, especially for initiation of new or different movements?
what is slowing of movement; once initiated movement may progress normally, but at a slower pace
What is the main effect of Parkinson's disease on the Basal Ganglis
it attacks the substantia Nigra which is the main production site for dopamine.
What are 3 treatments for parkinsons disease?
Deep Brain Stimulation
In this type of treatment it Successfully treats negative symptoms, but may result in severe and debilitating hyperkinesia with extended use
In this treatment Small lesions are made to the Globus Pallidus, which is hyperactive in the absence of inhibitory striatal effects Difficult to identify the appropriate location for a lesion; associated with significant risk
This treatment is a Surgical implantation of an electrode usually to the STN bilaterally; stimulation reduces thalamic inhibition
Coordination problems that cannot be linked to a deficit in controlling the muscles themselves (not hemiplegia) is called what?
What are the two types of Apraxia?
patients seem to have a relatively intact representation of the action, but fail to execute it, is called what?
knowledge about the intent of an action is disrupted
Apraxia is generally associated with which hemisphere region and is mostly observed with what cortex damage.
Left Hemisphere and the Parietal Cortex.
Sensory memory is divided into two types, what are they?
Iconic and Echoic
Iconic memory is used for what?
Echoic memory is used for what?
Sensory input from the environment must pass through 3 stages to be stored for a long time what are they?
Words at the beginning of the list benefit from more rehearsal and are transferred to LTM. This is known as what?
Words at the end of the list can be ?read-off? from STM. This is known as what?
What are the three stages that learning and memory can be divided into?
This is associated with retention over seconds to minutes...this is what?>
This is measured in days or years, an event from childhood or even last week is known as what?
How many items a person can hold in memory over a short period of time is known as what?
Immediate recall of a sequence of letters or words is grossly impaired when the words sound similar is known as what?
Phonological Similarity Effect
This represents a limited capacity store for retaining information over the short term and for performing mental operations on the contents of this store.
This is knowledge to which we have conscious access , including personal and world knowledge.
This is knowledge to which we have no conscious access, such as motor and cognitive skills.
What are the two subdivisions in which declarative memory can be broken down into?
Semantic and Episodic
What is episodic and semantic memory?
Semantic: World Knowledge Episodic: The recall of events in our lives
what are two main subdivisions of non declarative memory?
Procedural Memory and Perceptual Representation System.
This type of non-declarative memory involves learning of a variety of motor skills and cognitive skills.
This type of non-declarative memory involves the priming or the structure and the form of objects and words by prior experience.
Perceptual Representation System
Damage to the medial Temporal Lobe can lead to....(Amnesia).
Following damage to the midline diencephalon....(Amnesia)..
What structure is critical for representing spatial relationships among objects in the environment?
The loss of the ability to form new memories is known as what?
Have access to the samantic and episodic.
This is the loss of memories for events that happened in the past.
MTL Structures are critically involved in what?
Declarative memory depends critically on the structures in the...?
Medial Temproal Lobe
Non-Declarative Memory does not depend on MTL structures...T or F?
The acquisition of an ability MEMORY that extends to new items in a task is called what?
Benefit that Accrues from MEMORY Processing a Particular Stimulus in the Context of Some Task is called what?
The hippocampus is always necessary for forming and retaining what kind of memories?
In these specialized brain regions which ones are associated with what type of emotion? amygdala orbitofrontal cortex anterior unsula