Download - OL and TL Presentation
-
7/30/2019 OL and TL Presentation
1/37
Temporal &Occipital Lobe
Dr Anjali Nagpal
-
7/30/2019 OL and TL Presentation
2/37
TEMPORAL LOBE
-
7/30/2019 OL and TL Presentation
3/37
Superior Temporal Gyrus Receives inputs from auditory,
visual and somatic regions as well as from Frontal, Parietal
and paralimbic cortex.
Middle Temporal Gyrus (Limbic Cortex) includes amygdala,uncus, hippocampus, subiculum, entorhinal& prirhinal
cortices and fusiform gyrus
Inferior Temporal Gyrus (Visual regions)Includes Fusiform
gyrus
Anatomy of Temporal Lobe
-
7/30/2019 OL and TL Presentation
4/37
Connections
Sensory pathwayVentral stream
From primary and secondary visualand auditory areas. For stimulus recognition
Dorsal auditorypathway
From auditory areas to PPC. For detectingspatial localization of auditory inputs
Polymodal Pathway Parallel projections from the visual andauditory association areas into the STS. Forstimulus categorization
Medial Temporalprojection
The visual and auditory associationareas into the medial temporal or limbic.Called: perforant pathway.For long term
memory.
Frontal lobe projection The visual and auditory association areasinto the FL. For movement control and shortterm memory
-
7/30/2019 OL and TL Presentation
5/37
Major Temporal Lobe Dysfunctions
Impaired auditory sensation Impaired visual and auditoryperception Disordered perception of music Impaired language comprehension
Impaired selection of visual and auditory input Impaired ability to organize and categorizeinformation
Poor use of contextual information Impairment in long-term memory Changes in personality and affect
-
7/30/2019 OL and TL Presentation
6/37
Anatomy of language areas
The primary brain areas concerned with language are
Arrayed along and near the sylvian fissure (lateral cerebral
sulcus) of the categorical hemisphere.
A region at the posterior end of the superior temporal gyrus
called Wernickes area is concerned with comprehension ofauditory and visual information.
It projects via the arcuate fasciculus to Brocas area (area 44)
in the frontal lobe.
-
7/30/2019 OL and TL Presentation
7/37
-
7/30/2019 OL and TL Presentation
8/37
The probable
sequence
of eventswhen a
subject
names
a visualobject
)
-
7/30/2019 OL and TL Presentation
9/37
ANOMIC
NON FLUENT
GLOBAL
APHASIA
FLUENT
BROCA'S AREA
WERNICKES AREACONDUCTION APHASIA
ANGULAR GYRUS
WIDESPREAD DAMAGE
TO SPEECH AREAS
EXPRESSIVE RECEPTIVE
-
7/30/2019 OL and TL Presentation
10/37
AREA LESION FAETURES
auditory associationareas
word deafness
visual associationareas
word blindness
Wernicke's Aphasia
Global Aphasia
unable to interpret the thought
Sensory Aphasia
Broca's Area Causes Motor Aphasia
Speech Disorder
-
7/30/2019 OL and TL Presentation
11/37
Lesion in the wernickes area
Speech itself is normal and sometimes the patients talk excessively.
However, what they say is full of jargon and neologisms that make little sense.
The patient also fails to comprehend the meaning of spoken or written words.
Fluent Aphasia - RECEPTIVE APHASIA,
POSTERIOR APHASIA
Conduction aphasia
Lesion in the auditory cortex (areas 40, 41 &42)
Patients can speak relatively well and have good auditory comprehensionbut cannot put parts of words together or conjure up words.
This is called conduction aphasia because it was thought to be due to
lesions of the arcuate fasciculus connecting Wernickes and Brocas areas.
-
7/30/2019 OL and TL Presentation
12/37
GLOBAL APHASIA (CENTRAL APHASIA)
This means the combination of the expressive problems of Broca's
aphasia and the loss of comprehension of Wernicke's.
The patient can neither speak nor understand language.
It is due to widespread damage to speech areas and is the
commonest aphasia after a severe left hemisphere infarct.
Writing and reading are also affected.
-
7/30/2019 OL and TL Presentation
13/37
Selection of Visual and Auditory Input
Not a conscious process
Selectivity in auditory perception- eg., attending to two different conversations or different
elements of a musical piece
Selectivity in visual perception- eg., watching a football game: where is the attention - the
quarterback or the runners?
Temporal lobe damage impairs selection- Dichotic listening task
Two words simultaneously presented in each ear- Normal result: Right ear words are recalled more (left temporal
lobe selectivity)- Patient: drop in correct recall of words, due to loss of selectivity(brain tries to simultaneously process information delivered toboth ears)
- Visual tasks involve simultaneous flashing of stimuli that are notcorrectly recalled
-
7/30/2019 OL and TL Presentation
14/37
Schizophrenia
Auditory hallucinations
- Perception of sound that is not externally present
- Patient hears fully formed verbal passages
Statements typically hostile and accusatory; feelings
engendered are of extreme paranoia
Spontaneous neural activity in the auditory cortex gives rise to
such hallucinations, interacting with the languageareas of thetemporal lobe
-
7/30/2019 OL and TL Presentation
15/37
Dierks et al (1999)
Conducted fMRI on schizophrenic patients duringauditory hallucinations
Compared results to neural activity in response toacoustic stimuli
Results: activation seen in Brocas area, primary auditory
cortex, and speech zone in posterior temporal cortex- Additional limbic areas also recruited (amygdala andhippocampus)- This probably was due to the engagement of memoryas well as emotional responses to hallucinatorycontent
-
7/30/2019 OL and TL Presentation
16/37
Temporal lobe epilepsy
Kluver-Bucy syndrome
Imposter syndrome / Capgras
syndrome
The Temporal Lobes Disorders
-
7/30/2019 OL and TL Presentation
17/37
Sensory/Thought: Emotional: Physical
dj vu or
Jamais vuFear/Panic Dizziness
Lightheadedness
Racing thoughts Pleasant feeling Headache
Smell
Sound
Taste
Stomach feelings
Nausea
Numbness
Visual loss or blurring
Strange feelings
Tingling feeling
Auras
Ph i l S t
-
7/30/2019 OL and TL Presentation
18/37
Seizure symptoms
Sensory/Thought Emotional
Black outConfusion
Deafness/Sounds
Fear/Panic
Electric Shock FeelingLoss of consciousnessSmellSpacing out
Out of bodyexperienceVisual loss or blurring
Physical Symptoms
Chewing movements
Convulsion
Difficulty talking
DroolingEyelid fluttering
Eyes rolling up
Falling down
Foot stomping
Hand waving
Inability to move
IncontinenceLip smacking
Making sounds
Shaking
Staring
Stiffening
Swallowing
Sweating
Teeth clenching/grinding
Tongue biting
Tremors
Twitching movements
Breathing difficulty
Heart racing
-
7/30/2019 OL and TL Presentation
19/37
After-seizure symptoms (post-ictal)
Thought EmotionalMemory loss Confusion
Writing difficulty Depression and sadness
Fear
FrustrationShame/Embarrassment
-
7/30/2019 OL and TL Presentation
20/37
2424
(time between seizures)
A distinct syndrome of inter-ictal behaviorchanges occurs in many patients withtemporal lobe epilepsy.
The Waxman and Geschwind Syndrome
Intrt-ictal Changes
Hyperemotionalism
hyperreligiosity
Hypersexuality
Viscosity
Aggression
Hypergraphia
Symptoms Waxman and Geschwind Syndrome
TLE inter-ictal changes-The Waxman-Geshwind syndrome
-
7/30/2019 OL and TL Presentation
21/37
HYPEREMOTIONALISM
Depression
Mania
liable to obsessions and fixed idea
HYPERSEXUALITY or HYPOSEXUALITY.
-
7/30/2019 OL and TL Presentation
22/37
VISCOSITY
Increased verbalization
Circumstantiality
Difficulty shifting topics in conversation.
Clingy Behavior
Restricted range of topics
-
7/30/2019 OL and TL Presentation
23/37
TLE and Aggression
Recurrent episodes with interictal affective
aggression area rare but well-recognized
problem in patients with temporallobe
epilepsy. They are referred to as episodicdyscontrol or,more precisely, as
intermittent explosive disorder (IED)
(Strauss, 1989).
-
7/30/2019 OL and TL Presentation
24/37
-
7/30/2019 OL and TL Presentation
25/37
The Capgras Syndrome
(named for Jean Marie Joseph Capgras).
Delusion is that people have been replaced by an impostor, an
exact double. Key figure -Spouse
May see himself as his own double.
The person is conscious of the abnormality of these perceptions.There is no hallucination.
Capgras Syndrome :(a.k.aDelusional misidentification, illusion of doubles,misidentification syndrome, nonrecognition syndrome, phantom double
syndrome)
-
7/30/2019 OL and TL Presentation
26/37
Causes of Capgras Syndrome?
Conscious ability to recognize faces is intact but damage tothe system that produces the automatic emotional arousal tofamiliar faces.
Damage of the nerve pathways between the vision areas ofthe temporal lobe and emotional processing associated withthe amygdala, thus, patient sees his mother but feels noemotional familiarity and thinks she is an impostor
-
7/30/2019 OL and TL Presentation
27/37
Recognition of Faces has been associated with the FusiformGyrus of the Temporal lobes. Visual Info is relayed from thetemporal lobes to the Amygdala as well as other brain regions
-
7/30/2019 OL and TL Presentation
28/37
Kluver- Bucy SyndromeAssociated with damage to both of the anterior temporal lobes of
the brain
Hypersexuality (like TLE)
Hyperorality
Aggressive Behaviors ( like IED in TLE)
Loss of normal fear and anger responses (Psychic blindness aninability to recognize "the emotional importance of events
Other symptoms may include visual agnosia (inability to visuallyrecognize objects)
The temporal lobes project to the Amygdala
Temporal Lobe damage may also involve underlying neural tissue -specifically the Amygdala
-
7/30/2019 OL and TL Presentation
29/37
The anterior pole of the temporal lobe is adjacent to theunderlying amygdala
-
7/30/2019 OL and TL Presentation
30/37
OCCIPITAL LOBE
-
7/30/2019 OL and TL Presentation
31/37
Three Short Sulci- Lateral and transverse occipital sulciand lunate sulcus
1. Lateral Occipital Sulcus- Divides the lobe intosuperior and inferior gyri
2. Lunate Sulcus It is the C shaped sulcus withforward convexity in front of occipital lobe
3. Transverse Occipital Sulcus Runs downwards intothe uppermost part of OL from the superomedialborder of hemisphere, a little behind theparietooccipital sulcus
Occipital Lobe Anatomy
-
7/30/2019 OL and TL Presentation
32/37
Object Agnosias Apperceptive
Associative
Other Visual Alexia
Visual-spatial agnosia
Agnosias
Other Symptoms of OL Damage1. Monocular Blindness
2. Bitemporal Blindness
3. Nasal Hemianopia
4. Homonymous Hemianopia
5. Quadrantanopia
6. Scotoma
Symptoms of OL Damage
-
7/30/2019 OL and TL Presentation
33/37
Cortical Pathways for Visual Perception
Output from occipital lobe follows two major fiber tracts
Superior longitudinal fasciculus to parietal lobe
Inferior longitudinal fasciculus to temporal lobe
Two distinct processing systems
Dorsal (occipito-parietal) is the where system specialized forspatial analysis
Ventral (occipito-temporal) is the
what
system specialized forobject perception and recognition
-
7/30/2019 OL and TL Presentation
34/37
Pohl experiments reveal double dissociation
Landmark task: monkeys with bilateral parietal lesion havedeficit, but monkeys with bilateral temporal lesion can learntask
Object discrimination task: monkeys with bilateral temporallesion have deficit learning task, but monkeys with bilateralparietal lesion do not
Other bilateral lesion experiments show dissociation withintemporal lobe
Anterior temporal lesions disrupt visual memory posterior temporal lesions disrupt visual discrimination
OL
-
7/30/2019 OL and TL Presentation
35/37
OBJECT AGNOSIA
a) Apperceptive agnosia: Cant recognize an object although basicvisual functions (color, motion etc.) are preserved. Cant copy or
match simple objects. Can see one thing at a time:Simultagnosia.Diffuse bilateral lesion in the ventral stream in OL.
Agnosias2. Monocular Blindness3. Bitemporal Blindness
b) Associative agnosia: Cant recognize objects in spite of beingto perceive them. Subjects can describe the object, know what itis for, copy it, but cant identify it. Lesion in ventral stream in TL.
Symptoms of OL Damage
OL
-
7/30/2019 OL and TL Presentation
36/37
Function of OL is vision, perception of form movement and color.
Three major routes: ventrally into the temporal lobe, dorsally into
parietal lobe, and a middle route going to the STS.Ventral stream for stimulus recognition, dorsal stream for guidance
of movements in space.
Some occipital regions are functionally asymmetrical: word
recognition on left and facial recognition and mental rotation on
the right.
Summary:
-
7/30/2019 OL and TL Presentation
37/37
THANK YOU