Brain and Behavior Flashcards
The 💡master control for the entire body and the 💡starting
point for virtually all behavior is probably one of the most complex and challenging topics for anyone to study.
Its myriad neurons dozens of chemical messengers and infinite interconnections provide the fascination that attracts neuroscientists to study it.
BRAIN
💡Front part of the brain; involved in 💡planning, 💡organizing, 💡problem solving, 💡selective attention, 💡personality and a variety of 💡”higher cognitive functions” including 💡behavior and emotions.
FRONTAL LOBE
It is called the 💡prefrontal cortex.
It is very important for the 💡higher cognitive functions and the 💡determination of the personality.
Anterior (Front) Portion
It consists of the 💡premotor and 💡motor areas.
Posterior (Back) Portion
Nerve cells that produce 💡movement are located in?
Motor areas
They serve to 💡modify movements
Premotor Areas
Parts of the Frontal Lobe
Precentral Gyrus Broca's Area Supplementary Motor Area Prefrontal area Paracentral Lobule
Precentral Gyrus Function:
Motor cortex; contralateral movement - face, arm, leg, trunk
Precentral Gyrus Impairment
Monoplegia or hemiplegia (depending on extent of damage)
Broca’s Area Function
Dominant hemisphere - expressive center for speech.
Broca’s Area Impairment
(Inferior part of dominant frontal lobe)
- Results in Broca’s dysphasia
Supplementary Motor Area Function
Contralateral head and eye turning
Supplementary Motor Area Impairment
Paralysis of head and eye movement to opposite side.
Head turns towards diseased hemisphere and eyes look in the same direction.
Prefrontal Area Function
Personality, initiative
Prefrontal Area Impairement
Damage is often bilateral , change in personality with antisocial behavior/ loss of inhibitions.
Paracentral Lobule Function
Cortical inhibition of bowel and bladder voiding
Paracentral Lobule Impairment
Damage to posterior part of the superior frontal gyrus results in incontinence of urine and feces
Loss of cortical inhibition
3 Prefrontal Syndromes are recognized:
Orbitofrontal Syndrome (DISINHIBITED)
Frontal Convexity Syndrome (Apathetic)
Medial Frontal Syndrome (AKINETIC)
Orbitofrontal Syndrome (DISINHIBITED)
Disinhibition, impulsive behavior Poor Judgement Emotional Lability Distractibility
Frontal Convexity Syndrome (Apathetic)
Apathy
Indifference
Poor abstract thought
Medial Frontal Syndrome (AKINETIC)
Akinetic
Incontinent
Sparse verbal output
One of the two parietal lobes of the brain located behind the frontal lobe at the top of the brain
PARIETAL LOBE
The non-dominant parietal lobe is important in the __ and the __.
Concept of body image
Awareness of the external environment
The ability to construct shapes, etc. results from such __.
Visual/proprioceptive skills
The dominant parietal lobe is implicate in the __.
Skills of handling numbers/calculation
It receives 💡afferent pathways for appreciation of 💡posture, 💡touch, and 💡passive movement.
Postcentral Gyrus (Granular Cortex)
It make up part of 💡Wernicke’s language area.
This is the 💡receptive area where 💡auditory and visual aspects of comprehension are integrated.
Supramarginal and Angular Gyri (dominant hemisphere)
-
Wernicke’s Area
The fibers of the 💡optic radiation (lower visual field) – pass deep through the parietal lobe.
The visual pathways
Disease of either dominant or non-dominant sensory
cortex (postcentral gyrus) will result in 💡contralateral
disturbance of cortical sensation:
Postural sensation disturbed
Sensation of passive movement disturbed
Discrimination between one and two points (normally 4mm on finger tips) is lost
Appreciation of size, shape, texture, and weight may be affected with difficulty in distinguishing coins placed in hand, etc. (astereognosis).
It is when 💡two stimuli, 💡one applied to each side (e.g.
light touch to the palm of the hand) simultaneously, the patient is 💡only aware of that one contralateral to the normal parietal lobe
As the 💡gap between application of stimuli is increased (approaching 2-4 seconds) the patient becomes aware of both
Perceptual rivalry (sensory inattention)
Damage to the optic radiation deep in the parietal lobe will produce a __.
Lower homonymous quadrantanopia
● It is important in the concept of 💡body image and the 💡awareness of the external environment.
● The ability to construct shapes etc. results from such visual/proprioceptive skills.
Non-dominant PARIETAL LOBE
Non-dominant PARIETAL LOBE Impairment
● No longer aware of opposite limbs- even when densely hemiparetic; denies weakness- 💡Anosognosia
● Difficulty in dressing, e.g. getting arms into pajamas- 💡Dressing Apraxia
● Disturbance of geographical memory- 💡Geographical Agnosia (e.g.
patient cannot find his bed in ward)
● Cannot copy geometrical pattern- 💡Constructional Apraxia.
● It is implicated in the skills of 💡handling numbers/ calculation.
Dominant PARIETAL LOBE
Dominant PARIETAL LOBE Impairment
● GERSTMANN’S SYNDROME
● Finger Agnosia
● Acalculia
● Agraphia
Confusion of 💡right and left limbs
GERSTMANN’S SYNDROME
Difficulty in distinguishing💡fingers on hand
Finger Agnosia
Disturbance of 💡calculation
Acalculia
Disturbance of 💡writing
Agraphia
Help in sorting new information and are believed to be responsible for 💡short-term memory
TEMPORAL LOBE
💡Verbal memory (i.e., memory for words and names)
Left TEMPORAL LOBE
💡Visual memory (i.e., memory for pictures and faces)
Right TEMPORAL LOBE
It lies on the 💡upper surface of the superior temporal gyrus, 💡buried in the lateral sulcus (Heschl’s gyrus)
Auditory Cortex
It is important in the 💡hearing of language
Auditory Cortex (dominant hemisphere)
It is important in the 💡hearing of sounds, rhythm, and music.
Auditory Cortex (non-dominant hemisphere)
Close to the auditory cortex labyrinthine function is represented
True
Auditory Cortex Impairment
Cortical Deafness
Auditory hallucinations
may occur in temporal lobe disease
Lesions which involve surrounding association
areas may result in 💡difficulty in hearing spoken words (dominant) or 💡difficulty in appreciating rhythm/music (nondominant)
AMUSIA
They are concerned with 💡learning and memory
Middle and Inferior Temporal Gyri
Middle and Inferior Temporal Gyri Impairment
Disturbance of memory/learning
Disordered memory may occur in complex partial seizures either after the
vent – postictal amnesia – or in the event – déjà vu, jamais vu
-
Déjà vu
-
Jamais vu
Limbic Lobe
The inferior and medial portions of the temporal lobe, including the hippocampus and parahippocampal gyrus
The 💡sensation of olfaction is mediated through this structure as well as 💡emotional / affective behavior
Limbic Lobe/ System
They pass 💡deep in the temporal lobe around the posterior horn of the lateral ventricle.
Visual Pathways
Visual Pathways Impairment
Homonymous quadrantanopia
Wernicke’s dysphasia.
Damage to the 💡optic radiation will produce an __.
Homonymous quadrantanopia
Dominant hemisphere lesions are associated with __
Wernicke’s dysphasia
The main function is, to 💡control the perception of vision.
OCCIPITAL LOBE
Mnemonics: occipital- ocular (Eye)
The visual cortex lies along the pathway of __ also called as __ due to highly striated appearance.
“Calcarine Sulcus”
“Striate cortex”
Partial loss of vision
Cortical blindness
2 types Cortical blindness:
Congenital
Acquired
It is due to 💡perinatal stoke in baby (usually during labor or a week after birth)
Congenital Cortical blindness
It is due to the 💡loss of blood supply to occipital lobe.
Acquired Cortical blindness
Migraine -> due to occipital lobe -> visual hallucinations
Migraine -> due to occipital lobe -> visual hallucinations
Also in Epilepsy when seizure source on occipital cortex.
Also in Epilepsy when seizure source on occipital cortex.
The objects seems 💡different from actually it is
Illusion
The 💡false perception of absent thing
Hallucination
The objects appear 💡smaller than they are.
Micropsia
The objects appear 💡larger than they are
Macropsia
💡Unable to recognize faces (even oneself), naming of objects, match colors.
Prosopagnosia
The lower extension of the brain where it 💡connects to the spinal cord.
It is the 💡pathway for all fiber tracts passing up and down from peripheral nerves and spinal cord to the highest parts of the brain.
BRAIN STEM
BRAIN STEM Function
For survival (breathing, digestion, heart rate, blood pressure)
For arousal (being awake and alert)
Most of the __ come from the brainstem.
Cranial nerves
It contains the 💡respiratory, 💡vasomotor and 💡cardiac centers, as well as many mechanisms for 💡controlling reflex activities such as 💡coughing, 💡gagging, 💡swallowing and 💡vomiting.
MEDULLA OBLONGATA
MEDULLA OBLONGATA Function:
Functions primarily as a relay station for the crossing of motor tracts between the spinal cord and the brain.
It is a 💡bridge-like structure which 💡links different parts of the brain and serves as a 💡relay station from the medulla to the higher cortical structures of the brain.
It contains the 💡respiratory center.
PONS
It serves as the 💡nerve pathway of the cerebral hemispheres and contains 💡auditory and 💡visual reflex centers.
MIDBRAIN
MIDBRAIN contains centers for:
Postural reflexes
Righting reflexes
It concerned with the 💡position of the head in relation to the trunk and with the 💡adjustments of the extremities and the eyes to the position of the head
Postural reflexes
It concerned with the 💡orientation of the head in space
Righting reflexes
MIDBRAIN
Two major ascending dopaminergic pathways:
Nigrostriatal Pathway
Mesolimbic Pathway
Fibers arising from the💡substantia nigra and
travelling to the 💡neostriatum (caudate nucleus and putamen)
Nigrostriatal Pathway
Positive Symptoms
Fibers that arise from the💡ventral tegmental area of
the midbrain and ascend to the frontal and 💡limbic regions of the forebrain
Mesolimbic Pathway
Negative Symptoms
Mesocortical Pathway
Prolactin function
Tubulo-infundibular Pathway
Eating disorder
Hypothalamic Pathway
The antipsychotic effects of neuroleptic agents are
mediated by __ in the mesolimbic pathways
Postsynaptic dopamine blockade
BRAIN STEM Parts:
MEDULLA OBLONGATA
PONS
MIDBRAIN
- A functional component of 💡reticular formation.
- It includes 💡centrally located areas of the brain stem from the caudal medulla to the diencephalons.
- It receives input from 💡all sensory pathways.
RETUCULAR ACTIVATING SYSTEM
Function of RETICULAR ACTIVATING SYSTEM
- Cortical arousal and reception of stimuli
o Arousal: establishment and maintenance of an awake state. - Important in sleep, attention, memory, and habituation (gradual adaptation to a stimulus)
Composed of both 💡cortical and 💡subcortical tissues
Closely associated with the temporal and frontal lobes
and the ANS
Shell shaped
LIMBIC SYSTEM
It is involved in the control of many 💡vegetative functions (e.g. regulation of body temperature, thirst, hunger)
Hypothalamus
LIMBIC SYSTEM FUNCTION:
Elaboration of impulses to and from higher cortical centers
Important role in mediating 💡emotions
DYSFUNCTIONS OF LIMBIC SYSTEM:
- Irritative lesions associated with psychomotor seizures
- Hippocampal lesions can result in memory deficits
- Dysrhythmia (seizure-like activity) in LS may be associated with episodic psychoses
LIMBIC SYSTEM PARTS:
Hippcampus Subiculum Fornix Hypothalamus Anterior nuclei of the thalamus Septum Amygdala Cingulate Gyrus
💡Learning and memory
Sends hippocampal input on to the cortex
Hippcampus Subiculum
Tract from hippocampus to the hypothalamus (some fibers tot the thalamus),. 💡tying cortical input to the autonomic and endocrine systems
Fornix
💡Receives input from tha hippocampus, amygdala, and brain stem. Projects reciprocally and also to the spinal cord and pituitary. Regulates the 💡physiologic correlates of emotion. It is also important for 💡water and 💡weight balance, 💡reproduction, and 💡growth
Hypothalamus
Receives input from the 💡mammillothalamic tract and 💡fornix and 💡projects to cingulate cortex, providing a 💡key connection between hypothalamus and cortex.
Anterior nuclei of the thalamus
💡Connects to hippocampus, amygdala and hypothalamus.
Septum
💡Recieves input from the hypothalamus, locus ceruleus, and substantia nigra and 💡projects to the cortex, striatum, and many limbic structures.
💡Modulates hypothalamic function and has a 💡role in the integration of emotional behavioral, and autonomic responses.
Amygdala
Projects to the hippocampus through the 💡entorhinal cortex, completing the circuit that starts at the hippocampus.
💡Helps regulate emotion and pain
Response to 💡unpleasant experiences.
💡Prediction or avoidance of negative consequences, an important feature of memory
Cingulate Gyrus
These are primarily used to include and exclude organic factors that could be contributing to psychiatric symptomatology.
Brain Imaging Studies
Brain Imaging Techniques
Computerized Tomography (CT) Magnetic Resonance Imaging (MRI)
Computerized Tomography (CT) key features:
Detection of intracranial mass lesions, intracranial calcification, skull fracture
Magnetic Resonance Imaging (MRI) key features:
Coronal, sagittal, transverse images for detection of subtle lesions including tumors, strokes and demyelinization…
Measures regional cerebral blood flow.
Assessment of stroke and in discriminating Alzheimer’s Disease from multi-infarct dementia
Single Photon Emission Computed Tomography
Measures localized metabolic activity by measuring regional glucose utilization.
Research tool with superior image resolution
Positron Emission Topography (PET)
Assess seizure activity measure of brain electrical activity
Electroencephalography (EEG)
