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MIND FROM BRAIN
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“MIND” IS AN EMERGENT ABSTRACTION OF “SELF”
OUT OF CORTICAL NEURONAL CIRCUIT ACTIVITY
UTILIZING:
- Sensory Inputs, Memory Storage & Recall
- Thalamic Gating of inputs to- Cortical Regions:
for Sensory Memory,
for Emotion (Cingulate)
for Basal Ganglial-Motor Control
for Cognition (Prefrontal)
Open Copyright 2009 D.E. Hillman
MIND VS BRAIN
The Brain and Body stand as physical elements
forming operational components sustaining
vertebrate life. Sensory-motor reflexes together
with programmed movements, from basal
ganglia, represent the bulk of brain operational
control over body movement.
In mammals advanced development of the
cerebral cortex and thalamus has generated an
emergent property of the functional brain
“THE MIND”. The emanation of the MIND
from sensory inputs defines: SELF with
MEMORY and EMOTIONS, produces
COGNITION forming frameworks of
understanding and MAKES DECISONS for
initiating motor actions expressing behavior and
speech content.
MIND
Hill man
BRAIN
B
O
D
Y
MIND & BRAIN FUNCTIONS
Two principal roles of the Central Nervous System (CNS) are in: 1) operating
motor control systems and 2) generation of the MIND. Motor controls are: a) spinal
cord and brainstem reflex-control of voluntary muscles producing involuntary
reflexes. Reflexes are direct sensory inputs to the spinal cord and brainstem eliciting
motor responses in skeletal muscles), b) homeostatic motor control of involuntary
muscles and gland secretions via sympathetic and parasympathetic systems, and c)
programmed automatic motor control via the basal ganglia and cerebellum acting to
produce basic and conditioned motor control of behaviors and speech capability.
Besides the control of reflexes, the BRAIN produces an emergent energy state,
“THE MIND”, forming self-awareness and yields consciousness. The MIND
manages sensory inputs and memories and associates them with “event emotions”.
Using memories and emotions, the MIND forms frameworks of understanding
expressing the intellect in cognition. Using intellect, the MIND makes decisions for
initiating volitional behavior and speech content.
While patterned movements are programmed in the action generators, basal ganglia,
producing behaviors and speech capability, the MIND makes decisions for selecting
and initiating patterns of movement but has limited control over reflexes or the
actual movement patterns themselves. Nevertheless, the MIND trains programs,
consciously by trial and error testing in order to enhance automatic movement
patterns represented by our movement finesse and behavior expressions.
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COMPONENTS OF MIND
CONSCIOUSNESS
– Awareness of:
• Sensory input
• Motor responses
MEMORY
– Memory Storage
– Memory Recall
– Memory Association (Thought)
– Memory Retention and Forgetting
MIND & VALUES DEFINED IN EMOTION
– Survival: Nutrition, Procreation
– Self-Esteem - Recognition of Self as based on Pleasure/Displeasure Principles
– Reinforcement of values by Culture and “For the Greater Good” of the Species
INITIATION OF BEHAVIOR AND SPEECH
– Decision Making for initiating patterns of movement
– Decision-Making for speech content
COGNITION
– Structural/Functional Framework of Understanding
– Determining Consequence of Actions
– Perceived Spatial - Temporal Order of Events & Related Structure
PREDICTION (INTUITION)
– Imagination
– Vision
PERSONALITY and SPEECH (Mind Initiated (volitional) Motor Actions)
»
D E Hillman 5/1/ 2008
CNS COMPONENTS
The Central Nervous System (CNS)
consists of the spinal cord, brainstem,
cerebellum, basal ganglia, thalamus and
cerebral cortex. The cord and brainstem
represent sensory nerve input regions
except for olfaction. The cord and
brainstem operate reflexes of spinal and
cranial nerves. Basal ganglia (BG) are
origins of patterned movements that are
passed through the thalamus to the cerebral
cortex. The thalamus is a timing gate for
synchronizing sensory inputs, motor control
and cognition to the cerebral cortex. The
Cerebral Cortex is the primary source of
MIND generating consciousness.
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FLOW IN THE FUNCTIONAL MIND
The flow of function in the conscious
MIND is from sensory inputs or
memory storage to emotion centers.
Values are placed on incoming sensory
inputs and memories by MIND.
Emotions are associated with inputs and
stored memories and are held in the
cingulate gyrus for recall. MIND’s
major utilizations of memory is in
forming frameworks of understanding
(cognition) leading to intellect and in
making decisions for motor actions of
behaviors and speech content.
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THE BASES OF MIND
•
“MIND” has no comparable descriptive terms. The source of the conscious MIND is from
synchronous functioning cortical pyramidal cells integrating sensory input, emotion, motor
control and cognition from thalamic relay sources. The collective activity of pyramidal
circuits yields a “conscious abstraction of self-awareness and intellect” that is expressed to
the world through behaviors and speech. This synchrony is controlled by the thalamus
allowing the intelligent MIND to integrate signals between 5 functional domains: 1) inputs to
sensory cortices; 2) memory storage and recall; 3) emotion generation; 4) motor decisionmaking; and 5) cognition, forming a frame-work of understanding.
•
An understanding of the conscious MIND must include: 1) spinal cord and brainstem
sensory-motor reflex organization, 2) thalamic gating of cortical sensory & motor inputs
allowing sleep, 3) thalamic-cortical synchronization of sensory-motor data packets producing
the awake conscious MIND, 4), emotion generation by amygdala, hippocampus and limbic
cortical circuits, 5) basal ganglial patterned-reflexes that are initiated by intelligent decisionmaking of the conscious MIND and, 6) cognition, forming frameworks of understanding that
emerge from the frontal lobe.
•
UNDERSTANDING
THE
MIND
The MIND emerges from phased-simultaneity of pyramidal cell
inputs across four processing regions of the cerebral cortex that
receive inputs by gating of inputs to the thalamus. The linking of
temporal activity between the thalamus and cortex synchronizes
activity states of cortical neurons across four cortical regions (primary
sensory, emotion, cognition and motor) producing an energy state
emanating as the MIND. The result is consciousness with the ability
to reason and initiate willful behaviors and specify speech content.
The essence of the conscious MIND appears as a melding of sensory
inputs and memories into a temporal state with emotions and then
through recall directs their passage to cognition centers for
understanding and motor decision making.
• Two temporal indicators of the relationship linking the consciousMIND and the cognitive-MIND are found in brain-wave signals. The
first is the EEG signal that begins each cycle of the frequency from 1
to 40 Hz. The second signal is a longer signal that of high amplitude
that appears with a latency from 300 to 600 milliseconds. The latter
lasts for a second or more and appears to be the energy state of
cognition and decision-making.
MIND & MEMORY
• Only conscious and dreaming MINDs contribute to memory storage. The MIND is
responsible for assembling memories from: 1) inputs to visual, auditory, olfactory,
taste and body contact, 2) sensory responses and consequences arising from motor
behavior or speech, and 3) emotions associated with sensory and motor events.
Memories are distributed in modality cortices, hippocampus, medial temporal lobe,
and cingulate, frontal and parietal cortices.
• Sensory MEMORY is distributed, broadly, across regions of the cerebral cortex.
Sensory inputs to primary cortices are processed for similarities and differences.
Details are processed in associational sensory cortices that surround primary sensory
targets. Also primary and associational cortices provide parallel access to memory
stores for comparisons with sensory inputs and processing for emotion and
cognition.
• The MIND can not operate without a functional brain but the brain & body operate
without the MIND. As soon as cerebral cortical or thalamic function is lost, the
MIND looses consciousness. In addition, the MIND is separable from the BRAIN
by the fact that consciousness is turned off during anesthesia, a contusion to the head
or states of sleep, yet, the brain keeps on serving homeostatic body functions. Even
when MIND-initiating motor-actions are quiescent, testing shows that basic reflex
actions still remain. MIND without inputs from sensory systems or memory recall
has difficulty to sustain consciousness and lacks ability to make decisions. Memory
is the grist for planning and imagination by the MIND.
FORMATION OF MEMORY
• MEMORY has two states: the first is unconsolidated memory and the second is
consolidated into circuitry. The first state is short term held by the physiological
property called LTP (long term potentiation). This short term memory is neuron
functional state that activates signaling genes, e.g. c-fos. These early genes trigger
phenotypic genes related to protein production during the second state.
• The second state occurs during sleep as the memory-consolidating phase that
produces long-term memory. New proteins forming synapses are produced and
inserted into synapses. These changes incorporate new sensory information or
modifications to motor actions into the circuit. This upgrading of synaptic sites can
only occur if LTP modifications are turned-off by sleep. Thalamic relay nuclei cease
to activate pyramidal cells due to the slowing of the EEG to 0.5 to 4 Hz during
sleep. This blocks all sensory inputs, memories and motor instructions by activity in
reticular thalamic nuclei and inhibition of pyramidal cell somata preventing
intracortical responses.
MIND & EMOTION
EMOTIONS are associated with specific visual images, (faces and
locations), sounds and sensory-motor inputs by comparison with
hippocampal templates for each sensory modality. The primary visual
cortex has a major subcortical projection via the lingula to the
parahippocampal gyrus and into the hippocampal perforant path.
Images from the visual cortex are processed in the hippocampus for
familiarity (friend or foe) and are then directed to the amygdala for
determining fright or flightthrough autonomic expressions of eithere
the sympathetic or parasympathetic systems.
Conscious emotions are determined in the hippocampus and these
project via the fornix to the hypothalamic mammary bodies. From
here emotions are relayed via the anterior group nuclei of the thalamus
to emotion storage in the cingulate cortex. The conscious MIND
associates incoming sensory memories and motor events as
comparisons to previous emotional responses of stored memories.
Memories associated with high-emotion are most lasting and are
easiest to recall.
MIND AND COGNITION
COGNITION is the ability of the MIND to formulate “frameworks of
understanding” from multiple sensory modalities, memory stores and integrative
sensory centers like Wernicke’s areas. The MIND recalls memories of past
experiences according to their emotions, related values, consequences of actions
and passes them through the medial dorsal nucleus of thalamus to the pre-frontal
cortex. Here, COGNITION assembles temporal and spatial order, and establishes
meaning of yet, unrealized sensory inputs, memories, motor actions and their
consequence into frameworks of understanding. The pyramidal circuitry of the
frontal lobe generates COGNITION as a MIND state of understanding that
represents the INTELLECT.
Perceptions that are generated by COGNITION give the MIND the ability to
extend understanding into PREDICTION. Fundamental to the cognitive process is
the ability to IMAGINE that leads to development of VISION. The COGNITIVE
capability of imagination and vision represent the creative breadth of the
individuals INTELLECT.
• The vast potential of Mind's ability to “imagine” meets limitations of the brain’s
ability to control body actions beyond muscles, glands and hormones. Through
creativity and ingenuity, the intellectual MIND engineers mechanical, chemical,
electronic and nuclear devices that aid and by-pass “BRAIN-BODY” limitations.
This ingenuity allows our limited motor capacity to capture and control vast
energy sources to meet Mind's goals of far reaching imagination.
MIND AND BEHAVIOR
The MIND’S power to reason, formulate cognition, and make
decisions initiating motor actions are the bases of expressing
behaviors and speech. However, much of behavior occurs from
involuntary reflexes, conditioned reflexes and predefined patterned
movements. Virtually, all behaviors are either hard-wired in reflex
circuits or are programmed in basal ganglia during development. For
the most part, the conscious MIND is the decision-maker for initiation
of movement for willful simple motions or selection of patternedmotor responses from a repertoire of expressions defining behavior.
The MIND uses consequence and pleasure principles to determine
behavior selections. Once these reflexes are initiated, the behaviors
play-out according to the program, so much so, they can be difficult to
interrupt. Examples are laughing, crying, patterns of movement and
emotional expression. The MIND can modulate the extent of some
reflexes but not entirely prevent them.
Behavior continued
Homeostatic reflexes control much of our basic survival
behaviors that include respiratory, cardiac, GI and urinary
function as well as fight or flight actions. The amygdala and
hypothalamus, being the centers of reflexive control of
emotions, are the primary areas of reflex based motivations.
The hypothalamus distributes involuntary actions through the
two opposed autonomic systems, sympathetic and
parasympathetic. Willful behaviors are based on the need to
fulfill food, sexual and self esteem desires. Motivations,
generated by the conscious MIND arise from the limbic
system while emotion related involuntary behaviors are
expressed through basal ganglia and motor cortices. Willful
motivations generated from the MIND originate from the
emotion-cortex, the cingulate gyrus. These arrive from the
hypothalamic mammillary bodies as projections to anterior
group thalamic nuclei and then to the cingulate gyri.
MIND & MOTIVATION
• Willful behaviors are based on the need to fulfill food, sexual and self
esteem desires. Motivations, generated by the conscious MIND arise
from the limbic pleasure centers while emotion related voluntary
behaviors are expressed through basal ganglia and motor cortices. The
hypothalamic mammillary bodies send projections to anterior group
nuclei and then to the cingulate gyri. Willful motivations of the MIND
come from emotions associated with action memories stored in the
cingulate gyrus. Self-esteem reinforcement is the principle motivating
factor for humanoids and is driven by a pleasure obtained intrinsic to
the MIND. The MIND obtains this pleasure basically from itself
through its own satisfactory decisions for actions. Yet the bulk of the
reinforcement for motivation is received from others as
acknowledgement, some being approval others disapproval.
Fundamentally, the MIND is looking to the mother and peers for a
recognition of their own existence. These sources expand rapidly at
young ages so that careful balances must be considered for amount
and kind. Teaching the individual to give proper recognition to others
and develop healthy exchanges is the fundamental base for
motovating positive behaviors.
BRAIN - BODY - MIND
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MIND & DECISION-MAKING
• The central role of MIND is intelligent decision-making for initiating actions
carried out by patterned movements for behaviors including the generation of speech
content. (Sensory driven reflexes have only limited control by the MIND). The
willful intent of MIND initiates self-serving motor control for survival and
reproduction. MIND initiated voluntary actions operate through programmed basal
ganglial control in passage through the ventral lateral (VL) and ventral anterior (VA)
thalamic nuclear relay gate to reach pre-motor and motor related cortices.
• When the MIND is not operating such as during sleep or unconsciousness, all
voluntary muscle controlled reflexes are quiescent. Nevertheless, homeostatic
reflexes (involuntary) operate without the MIND. When cortical neurons become
synchronously active, sensory awareness returns and the MIND initiates
programmed complex sensory-motor reflexes. Most basic are eye movements and
antigravity expression. Virtually, every action generated by basal ganglia (except
ballistic) is due to circuits wired for modulation in real-time by incoming sensory
signals to the cerebellum. Patterned movements form a repertoire of behaviors that
must be selected, initiated or stopped by MIND decisions. Conditioning of the
programmed behavior can modify MIND initiated voluntary actions that are
programmed in basal ganglia.
MIND vs REFLEXES and PROGRAMMED BEHAVIORS
•
The nervous system operates in three fundamental domains: 1)
reflex control organ, 2) control of programmed patterned movement
and 3) generation of the conscious self, “The MIND”. The caudal
part of the nervous system is, principally, sensory-motor
organization that we commonly revere as reflexes. The peripheral
nervous system, (spinal and cranial nerves) together with the spinal
cord and brainstem consists of hardwired circuits driving motor
operations that are activated by sensory inputs. Reflexes control
movements, involuntarily, through voluntary controllable muscles
(musculoskeletal system).
•
The rostral brain including the thalamus, basal ganglia and cortices
contain centers for programmed motor control of patterned
movements that are stored in basal ganglia. Many of these
movement patterns are hardwired before birth and others are
conditioned by experience. The cerebellum lies over the brainstem
and receives sensory cranial and spinal nerve inputs as well as
inputs from all cerebral cortices through the pons within the
brainstem.
The cerebellum provides detailed fineness for
programmed movements using sensory inputs and cortical control.
•
The neocortex, together with the thalamus is the source of the
MIND. Sensory inputs to cortices bring the MIND to consciousness
and forms memories. The active MIND selects programmed
movements and initiates: objective movements, behaviors and
speech content. The MIND also incorporates emotion into
memories as well as formulates frameworks of understanding that
represent the intellect. The MIND has limited capacity to control
programmed movement because of complexity. The MIND selects
and initiates movements.
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MIND & MOTOR CONTROL
• The brain operates motor control, reflexively, through spinal nerves of
the spinal cord and cranial nerves of the brainstem and as movement
patterns that are programmed in basal ganglia. The MIND's major
role is to make conscious decisions for initiating behavior, speechcontent and specific movements. In addition, the MIND can
consciously modulate or subdue some reflex activity but can not
totally stop reflexes.
• Furthermore, the MIND is involved in training basal ganglial
patterned-movements by conscious trials and observing their
consequence. We observe and instruct our voluntary movement
initiation across single joints or group actions in a conscious manner.
This method is used to improve precision or increase speed and
effectiveness. There are two types of MIND-initiated patternedmovements: One is modifiable patterned movement and the other
is ballistic movements; both are programmed in the basal ganglia.
PROGRAMMED MOVEMENT
• Modifiable patterned movements from basal ganglia are slower than
ballistic movements and allow updating of sensory status to the
cerebellar cortex and to the basal ganglial pattern generator during
movement. These patterned movements are from a repertoire that can
be initiated and stopped by the MIND or changes being made by
MIND-decision during their execution. These patterns play-out from
basal ganglia and are being optimized, continually, for
agonist/antagonist muscle tone by the cerebellum in order to enhance
fine control of movements.
• In normal behaviors, the MIND does not control detail of movement
but only the selection and the initiation of movement patterns. These
behaviors are programmed using pre-wired reflexes, conditioned
reflexes but can be modified by learning during development and
young adults and are not changed much after adulthood is reached.
Basal Ganglia Patterned Movement
& Cerebellar Control (Indirect pathway)
external
S. Nigra
Compacta
Internal
Lat. Corticospinal Tr.
Matrix
Enkephalin
Sup. Cerebellar Peduncle
Cerebral Peduncles
ASSOCIATION CORTEX
Cortical inputs to the indirect pathway
Frontal, Parietal, Temporal, Occipital & Limbic Premotor - Sensori-Motor Cortex
come from the premotor cortex. These
excitatory afferents synapse on inhibitory
Striatum
striatal neurons of the matrix containing
enkephalin modulatory receptors. The
VA
Globus Pallidus
matrix neurons project inhibition on
VL
neurons of the external segment of globus
Thalamus
pallidus which has it’s main output to the
subthalamic nucleus and is also inhibitory.
Subthalamic Nucleus
PONS
The excitatory response of the subthalamic
N. is excitatory onto the internal segment
Cerebellar
Granule cell
to PCs
of GP. The internal segment of GP is
INDIRECT BASAL GANGLIAL PATHWAY =
inhibitory to the motor thalamus (VA &
The cerebellar cortex with pontine inputs from
VL). These inhibitory inputs to VA & VL cerebral cortex and from sensory inputs to the
(relay nuclei) are modulated by cerebellar cerebellar granule cell system provide ongoing
nuclear excitatory outputs and the
agonist/antagonist tone control through projections of
integrated responses are temporally
inhibitory PC’s to cerebellar nuclei producing
released to the premotor cortex by thalamic excitatory inputs to VA & VL relay nuclear cells to
gating.
balance globus pallidus inhibition of the indirect
pathway. The effect is B.G. generated patternedmovement with cerebellar control.
Cbl Nuc
MOSSY FIBERS
MODIFYABLE PAT T ERNED MOVEMENTS
Sp. Cord
Middle Cerebellar Peduncle
BALLISTIC MOVEMENTS
Ballistic movements are programmed in the basal ganglia to provide
high speed and up to maximal strength. Ballistic movements are
mostly selected for execution by the MIND.
These movements can not be modified by the pattern generator or
cerebellar control after initiation by the MIND (e.g. golf swing).
Also, ballistic movements have associated non-ballistic movements
that form a skeletal platform adjusting for the ballistic outcome.
Examples are batting a baseball from a high speed pitch. The swing
is ballistic but the knees raise or lower to adjust the height of the
swing-platform in order to meet the ball. Programming is done by
trial and error using sensory feedback, consequence of action and
suggestions from extrinsic observers(coach) to encourage changes in
specific types of actions. Cerebellar control during ballism is limited
but must participate in releasing tone of antagonistic muscles that are
actively tonic at the beginning the movement. This important function
is described in the relationship between basal ganglial and cerebellar
control.
Ballistic Movement Generation (
Direct pathway).
Cortical inputs to basal ganglia come from the premotor cortex. These afferents synapse on
inhibitory striatal neurons in substance “P” patches of the striatum. Dopamine of substantia nigra
compacta upregulates these inhibitory neurons increasing striatal inhibitory output to the internal
segment of the globus pallidus (GPi) & substantia nigra reticulata ( SNr). The output is inhibition
to the motor thalamus (VA & VL) and excitation of these neurons by cerebellar nuclei. The
integrative result is ballistic motor output to agonist muscles through premotor & motor cortices.
DIRECT BASAL GANGLIAL PATHWAY BALLISTIC PATTERNED MOVEMENT
Internal
Reticulata
Sp. Cord
Cbl Nuc
Lat. Corticospinal Tr.
Patches
Subt "P"
Sup. Cerebellar Peduncle
Cerebral Peduncles
FOR AGONIST MUSCLES
FOR ANTAGONISTIC MUSCLES
The effect is that dys-inhibition of GPi by
Premotor - Sensori-Motor Cortex
striatal output results in patterned
movements without control from sensory
Striatum
input modulation or from the cerebellar
cortex. Thus, ballistic movement patterns
are unchecked by the subthalamus (See
Globus Pallidus
VA
indirect pathway). The movement pattern is
Substantia Nigra
VL
preset for ballistic movements by motor
Subs Nigra Compacta
Thalamus
cortex driving agonist motor neurons of the
INFERIOR
cord or brainstem and antagonist muscle
OLIVE
relaxation from cerebellar tone production
CLIMBING FIBERS
Cerebellar
that is controlled by cerebellar nuclear
Purkinje Cells
outflow. The inhibitory output of the globus
pallidus meets cerebellar nuclear excitation The cerebellar granule cell activation of PC’s is too
slow for ballistic movement so that these actions are
in VA & VL and these are gated to the
premotor and motor cortex. The cerebellar interceded by antagonist related high speed climbing
nuclei for antagonist tone are controlled by fiber input that activates PCs to inhibit cerebellar
climbing fiber activation of Purkinje cells. nuclei that release antagonist muscle tone.
SOURCE OF THE MIND
The emergence of the conscious MIND out-of functional circuitry is
based on input gating to four neocortical regions from the
THALAMUS. Pyramidal cells and cortical circuitry are synchronouslyphased across regions of the neocortex by four inter-linked thalamicrelay timing gates. EEGs are remote-recorded potentials from the
cranial-surface showing a spindle marker potential appearing every
second to 26- 28 milliseconds (at 40 Hz). The marker signals partition
EEGs that are followed by high frequency signals (see Gerber et al.
2008). During cognition, the rate is 40 Hz while during sleep, the
reticular thalamic nuclei slow thalamic outputs to 0.5-4 Hz. MEG’s
indicate that the 40 Hz signal is also present during sleep (Llinas &
Ribary 1993) and suggest that eye movements are being replayed for
visual memory consolidation during REM sleep. EEG’s, MEG’s ERP’s
and local depth electrodes reveal a second larger amplitude signal,
“event-related-potentials”. These extend across the neocortex and
reoccur after stimuli at latencies of 300-600 milliseconds. These
appear to be the true signals of cognition and decision-making.
The thalamus acts as the gate-keeper of outputs
from thalamic relay nuclei to respective cortical
regions. Sensory inputs from spinal and cranial
nerves project to sensory thalamic relay nuclei
(VP) and are gated by laterally placed reticular
thalamic nuclei (RN). The RN act as the
clocking timer for all cerebral inputs.
Motor actions are initiated by MIND decision
from pre-motor cortex onto the basal ganglia
(BG) and cerebellum and then to the VA-VL of
thalamus for interpolation with cerebellar
control. Motor gating by synchronization of the
VA-VL connections to motor cortices signal
spinal and cranial motor neurons.
The anterior group (AG) incorporates emotion
into memories while the medial dorsal (MD)
thalamus carries sensory attention, memories,
emotion and motor responses into frontal and
parietal lobes for formulation of understanding
by the COGNITIVE MIND.
INPUTS FORMING MIND
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THALAMUS: GATEWAY TO
CORTEX
The THALAMUS has four distinct relay
functional regions that project to respective
cerebral cortical regions. The caudal thalamus
projects sensory inputs, arising from various
types of receptors, i.e. vision, audition, touch,
pain etc.. The motor thalami (ventral lateral
and anterior lateral nuclei) are relay gatingnuclei for signaling motor behaviors and
speech that are generated from basal ganglia
and the cerebellum. Sensory inputs pass from
primary sensory cortices through the
hippocampus determining “friend or foe” and
applies “fight or flight” reflexes through the
hypothalamus. Also, the hippocampus
projects signals to the anterior-group relay
nuclei incorporating and storing emotionlinked memories in emotion-cortex. A fourth
thalamic nuclear region is the medial thalamus
that carries inputs for cognition. This relay
nucleus projects to prefrontal cortex
producing frameworks of understanding that
give rise to intellect. The MIND emanates as
consciousness and intellect arising from
phased-synchronous activity across the four
target regions of the neocortex.
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THALAMIC-GATING
The thalamus temporally blocks relay nuclei passage of sensory, motor,
emotion and cognitive signals to the cerebral cortex during sleep (EEG
frequencies below 5 Hz). Blocking of cortical inputs during sleep
stops sensory and motor activity in order to prevent interruption of
memory updating. In addition, extensor motor expression (standing) is
blocked to prevent walking and injury during sleep.
On awakening, the reticular thalamic nuclei increase the gating rate
from 5-13 Hz. The thalamic relay nuclei of input gates “spike-train
snippets”, briefly to respective cortices within each EEG cycle. At 40
Hz (cognitive), “event related potentials” (ERP’s, Miller et.al 2008 &
MEG’s, Llinas & Ribary 1993) show a phased-synchrony of EEG’s
and MEG’s over the cranium. This phasing appears to be due to the
cascade of heirarchy from sensory input, emotion, cognition to motor
decision making for selection and initiation of movement.
SOURCE OF GATING
The reticular thalamic nucleus cups the lateral surface of the thalamus and sends
projections, radially, into each of the thalamic relay nuclei. The close association and
coupling of the reticular neurons are ideally positioned for synchronized release of relay
nuclei firing to the cortex. Functional activity of reticular neurons synchronize the
inhibitory gate on relay neurons slowing bursts to as little as one per second during
sleep but to 15 to 40 Hz in the awake to cognitive individual. An other group of
neurons, intralaminar thalamic nuclei, are distributed along the rostral-caudal
circumference of the thalamus that is marked by an internal medullary lamina.
Different laminar groups appear to projection to specific regions of the cerebral cortex.
These afferents target the most distal, dendritic terminals of pyramidal cell dendrites in
layer I. We propose that this intralaminar input is excitatory to pyramidal cells resulting
in total depolarization of the the entire dendritic arbor by activating voltage sensitive
calcium channels. The result is a short barrage of dendritic spikes (similar to climbing
fiber-Purkinje cell responses) and that these correspond to spindles of the EEG and
marks the beginning of the relay input. Following the total dendritic depolarization
there is a coordinated re-polarization of pyramidal cells creating synchrony of equal
resting potential levels throughout specific cortical region. Thus, all of the pyramidal
cells begin to receive the relay barrage at the same time and thus produce a meaningful
activity status in pyramidal cells to maximize the fidelity of pyramidal cell reception
during subsequent thalamic relay inputs for 20 msec or so duration.
GATING BY THALAMIC RELAY NUCLEI
DEH
Dorsal View
All cortical inputs to the neocortex are
gated within the temporal frame that
AFFERENT CORTICAL GATING BY THALAMUS
Coronal View
represents cortical input passage
CEREBRAL CORTEX
through thalamic relay nuclei. The gate
AG
is controlled by the reticular thalamic
RT
nucleus (RT) as interval blocking and
MD
release of outputs of the relay nuclei RETICULAR
to
Anterior group
CM
Emotion
AG
the neocortex. Intralaminar nuclei THALAMIC
NUCLEUS
VPM
(VA)
RT
VPL
(black-blue) target pyramidal cells, we
Ventral
Anterior
believe, sync these cortical neurons for
Motor
receiving relay input. Relay nuclei for
MEDIAL
(VL)
DORSAL
RT
vision and audition are in the geniculate LGB
Ventral
(MD)
Lateral
MEDIAL
Cognition
bodies while environmental and self
INTRALAMINAR
Motor
THALAMUS
NUCLEi
sensations are relayed through the
MGB
RETICULAR
ventral posterior thalamus (VPL for
(VPL)
CM
THALAMIC
RT
SENSORY
Ventral
NUCLEUS
body and VPM for head). Programmed
Posterior Lateral (VPM)
THALAMUS LATERAL
Ventral
GENICULATE
Sensory Posterior
LGB
motor control of basal ganglia are
Medial
BODY
RT
relayed by the ventral lateral (VL) and
PULVINAR
/`
anterior (VA) nuclei. Emotions are
relayed through the anterior group of
nuclei while cognition is passed through
the medial dorsal thalamic nuclei.
THALAMIC GATE & MIND
The conscious MIND is an emergent state from operational cortical
circuitry representing four major components.
MIND
AWARENESS
MOTOR DECISIONS
PRIMARY
SENSORY
MOTOR
ASSOCIATION
SENSORY
MOTOR
CORTICES
Pyramidal
Cells
SENSORY RELAY
THALAMUS
MOTOR
THALAMUS
COGNITION
FRONTAL
WORKING
MEMORY
CORTICES
MEDIAL DORSAL
THALAMIC NUC
EMOTION
LIMBIC
HIPPOCAMPAL
MEMORY
Pyramidal
Cells
ANTERIOR GROUP
THALAMIC NUC
INTRALAMINAR THALAMIC NUCLEI-- PYRAMIDAL CELL SYNCHRONIZATIONS
RETICULAR THALAMIC NUCLEAR GATE
SENSORY
INPUTS
BASAL GANG
CERBELLUM
INTEGRATED
UNDERSTANDING
HIPPOCAMPUS
HYPOTHALAMUS
The four types of inputs at
the bottom enter the relay
thalamic nuclei, but are
held by the reticular gate.
The the pyramidal cells of
the four cortical regions are
receive inputs to the entire
dendritic tree, In addition
the most apical dendrites in
layer one receive
intralaminar inputs the
temporal relation of the
cascade in circuit
processing gives rise to the
MIND informational state.
This summary shows,
diagrammatically, how the
characteristic components of MIND
relate to functional expressions of
motor actions. Consciousness of
sensory inputs are processed into
memory. Memories are associated
with emotions that give values. A
major role of the MIND is to make
decisions of basal ganglial patterned
movements that determine willful
movements, behaviors and speech.
PERSONALITY and INTELLECT
emanate as products of MIND that
reveal the individuality of SELF and
cognitive capacity.
ROLES OF
MIND
QuickTime™ and a
decompressor
are needed to see this picture.
OVERVIEW
MIND & SOUL
BRAIN & BODY
The brain controls the
SOUL
body, unconsciously,
through homeostatic
VALUES
reflexes. Voluntary
consciousness
movements for
REASON
MIND MEMORIES
survival and
DECISIONS
reproduction are
initiated by decision of
BRAIN
the MIND.
Hill man
These decisions are for
programmed behaviors
determining actions
and personality.
B
O
D
Y
The MIND is emergent from
neuronal activity of the
cerebral cortex signaling
sensory awareness,
consciousness and the power
to reason. MIND’s
experiences establish
VALUES that become the
basis of our personality,
dictate our actions, and
define the spirit of self. This
SPIRIT transcends the active
brain in the SOUL that is
held in the MINDS of others
& in antiquities.
SIGNIFICANT REFERENCES
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Basilis Zikopoulos1 and Helen Barbas Prefrontal Projections to the Thalamic Reticular Nucleus form
a Unique Circuit for Attentional Mechanisms. The Journal of Neuroscience, 26(28):7348 –7361 2006
Brian T. Miller⁎, Leon Y. Deouell, Cathrine Dam, Robert T. Knight, Mark D'Esposito Spatiotemporal dynamics of neural mechanisms underlying component operations in working memory
Brain Research 1206: 61- 75 2008
Gerber, P et. al., Interobserver agreement in interpretation of EEG patterns . . . . J. Clin NeuroPhys
25: 241-249 2008.
http://en.wikibooks.org/wiki/Consciousness_studies
Long, M.A. et al. Small clusters of electrically coupled neurons generate synchronous rhythms in the
thalamic reticular nucleus. J. Neurosci. 24, 341–349 (2004)
Migno, E Why We Sleep: The Temporal Organization of Recovery. PLoS Biology 6:0661-669
(2008) www.plosbiology.org
Pablo Fuentealba, Igor Timofeev, and Mircea Steriade Prolonged hyperpolarizing potentials precede
spindle oscillations in the thalamic reticular nucleus PNAS 101 9816-9821 2004
Pablo Fuentealba, Mircea Steriade The reticular nucleus revisited: Intrinsic and network properties
of a thalamic pacemaker. Progress in Neurobiology 75 (2005) 125–141
Llinas,R, , Ribary, U (1993) Coherent 40-Hz oscillations characterizes dream state in humans. Proc.
Natl. Acad. Sci. USA 90:2078-2081
Steriade, M. et al. The deafferented reticular thalamic nucleus generates spindle rhythmicity. J.
Neurophysiol. 57, 260–27 (1987)
Zhang, L and Jones, EG. Corticothalamic inhibition in the thalamic reticular nucleus. J Neurophysiol
91: 759–766, 2004.