PSY502 Brain Mind and Behavior - Lectures
Lecture 1:
Pain vs Nociception
(related but not the same
thing!!)
https://nba.uth.tmc.edu/
neuroscience/s2/chapter06.html
Nociception is the capacity to
detect and respond to noxious
stimuli. Noxious stimuli are
stimuli that elicit tissue damage
and activate nociceptors. The
detection of a harmful stimulus
that signals current or
impending tissue damage.
Nociceptors are special nerve
cell endings that initiate the
sensation of pain all around our body. Nociceptors are sensory receptors that detect signals from
damaged tissue or the threat of damage and indirectly also respond to chemicals released from
the damaged tissue. Nociceptors are free (bare) nerve endings found in the skin muscle, joints,
bone and viscera.
https://www.verywellhealth.com/what-are-
nociceptors-2564616
Pain is an unpleasant sensory and emotional experience
associated with actual or potential tissue damage, or
described in terms of such damage. Pain is not an emotion,
but painful sensations can undoubtedly elicit emotions. Pain
is always subjective, there is no objective measure in pain. It
is always unpleasant and therefore also an emotional
experience. Pain signals you, in no uncertain terms, to break
contact with a potentially damaging agent and to begin
restoring the injured part. Activity induced in the nociceptor
and nociceptive pathways by a noxious stimulus is not pain,
which is always a psychological state, that is nociception.
Pain receptors in human beings are located in the skin, in sheath tissue surrounding muscles, in
internal organs, and in the membranes around bone. These receptors in animals are called
nociceptors (noxious meaning harmful or destructive) rather than pain receptors, because
neuroscientists cannot, with certainty, establish that what an animal feel is pain, whereas in
humans they are called pain receptors as we can report pain reliably to a certain level. Pain
receptors and nociceptors react mainly to physical stimuli that in essence irritate them into
activity.
:) 1 (:
,The spinal cord dorsal horn contains the first relay for
afferent inputs from the skin, muscles, and viscera of
the body. The superficial dorsal horn contains at least
some neurons that maintain the selectivity for
modalities encoded by the primary afferent endings.
These include a number of different modalities
including innocuous warming, innocuous cooling,
noxious mechanical, noxious thermal, noxious
chemical, prurigenic (itch producing), metabolic (non-
noxious signals from actively contracting muscles),
and innocuous mechanical stimuli of various forms as
well as other inputs from autonomic sensory neurons.
In the majority of neurons in the dorsal horn, various
combinations of these inputs are integrated to allow
detection of features (such as edges, speed of
movement, location on the skin, noxious hot objects,
etc.). Such integration allows for useful motor outputs
to be generated to compensate for the inputs
received, e.g., moving a limb away from a hot object,
scratching a biting insect, or wiping away an insect
crawling on the skin. Many neurons in the dorsal horn
also transmit selective afferent inputs, or integrated inputs to other regions of the central nervous
system, including other parts of the spinal cord, the medulla, midbrain, and thalamus as well as
the hypothalamus. Thus, the dorsal horn serves as the first integration and relay center for
nociceptive as well as a variety of non-nociceptive inputs. Dorsal horn neurons are modulated by
inputs from higher brain centers. Inputs from other centers can greatly modify the amplitude of
signals relayed from primary afferent neurons. Dorsal horn neurons are quite heterogeneous with
respect to the types of inputs that they encode,
and with respect to their intrinsic membrane
properties. In at least some cases, it appears that
the intrinsic membrane properties are associated
with the types of inputs they receive, and these
intrinsic properties may allow the neurons to
better integrate certain types of inputs.
Our pain matrix contains brain structures (parts
of brainstem, hypothalamus, thalamus,
amygdala, and areas of the cerebral cortex) that
process and regulate pain information; it is
capable of creating pain perception in the
absence of nociceptive information; can generate
a top-down response that regulates ascending
pain signals - may suppress (antinociception) or
amplify (pronociption signals).
:) 2 (:
,Individual differences
- Why do different people respond differently to the same pain stimulus?
- Why do the same people respond differently to the same pain stimulus at different times?
Between-individual differences: internal factors:
- Sex (small difference but reliable): there are sex differences in pain perception. Tends to depend
on stimulus type.
- Cultural affiliation: ethnicity in no longer considered a relevant factor in pain. Culture is. People
learn (through social acquisition) ways of dealing with and expressing pain appropriate to their
own culture.
- Personality characteristics (such as neuroticism, ex/introversion, self-efficacy, locus of control)
Internal factors interact with situational factors:
Benefits of incapacity:
- Alleviation of obligations
- Alleviation of responsibilities
- Sympathy and support
- Physical assistance
- Possible financial gain
Costs of incapacity:
- Removal of obligations
- Removal of responsibilities
- Loss of personal control
- Loss of autonomy
- Possible financial loss
Within-individual variation: external factors:
- Situational factors
- Automatic evaluation: pre-attentive processing of salient features in the environment. This is
universal, unconditional and non-volitional as people evaluate the valence of most, if not all
environmental information. It is also fast, classification occurs within 250ms. And affects
directly motivational state and subsequent behavioural tendency.
Conclusions
Pain is a psychological state (IASP)
Many factors influence the ultimate experience and report
Internal factors (such as sex, personality characteristics (particularly LOC and Self-efficacy) or fear
and anxiety).
External factors (such as affective-motivational state (eg automatic evaluation), or cognitive-
evaluation (eg possible (perceived) costs/benefits)).
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:) 3 (:
,Lecture 2:
Biological aspects of cognitive psychology
The nervous system: The human nervous system consists of the brain and spinal cord (central
nervous system) and all the neural tracts that run from the spinal chord out to muscles, organs,
glands, and other tissues (peripheral nervous system). The CNS includes all the parts of the
nervous system that lie within the bones of the skull and spine. The PNS can be divided into the
somatic nervous system, which consists of the nerves that carry information from the skin,
muscles, bones and joints to the spinal cord and reverse. The autonomic nervous system (ANS),
which are nerve structures that are largely responsible for regulating the body’s internal
environment: the heart, lungs, blood vessels, and other internal organs. Finally, the diffuse enteric
nervous system are the nerves that control the digestive tract.
Major anatomical divisions and subdivisions of the brain:
Forebrain
Telencephalon
Cerebral hemispheres
Amygdala
Hippocampus
Basal ganglia
Septum
Diencephalon
Thalamus
Hypothalamus
Midbrain Brainstem
Hindbrain
Medulla
Cerebellum
Pons
The forebrain
The forebrain structures, the telencephalon and the diencephalon, are generally credited with
performance of the highest intellectual functions: thinking, planning and problem solving.
The telencephalon: When you first look at the brain, the most prominent structures are the two
large, paired, left and right hemispheres of the cerebral cortex, the brain’s outermost layer. The
cortex of each hemisphere is subdivided into four sections, or lobes, by deep groves that are
called sulci. The occipital lobe is responsible for vision; the temporal lobe for hearing and, in
humans, speech as well as some memory and emotional functions; the parietal lobe for sensory
responses; and the frontal lobe for motor control and coordination of the functions of the other
cortical areas (executive functions, such as planning for tomorrow and next year). Under the
cortex lie the smaller regions of the telencephalon: the amygdala, the hippocampus, the basal
ganglia, and the septum. These function together to help regulate emotion, memory, and certain
aspects of movement. Together they are sometimes called the limbic system. The divide between
the motor cortex and the sensory cortex, the central sulcus, marks the boundary between the
frontal and parietal lobes.
:) 4 (:
, The diencephalon: The subdivisions of the diencephalon are the thalamus and hypothalamus.
Both of these structures, contain well-defined areas, fields, and nuclei. In the thalamus, these
locations serve as relay stations for almost all the information coming into and out of the
forebrain. In the hypothalamus are the relay stations for the internal regulatory systems,
monitoring information from the autonomic nervous system and commanding the body through
those nerves and the hormones of the pituitary.
The midbrain
It is the smallest of the major brain divisions and has the most difficult boundaries to recognise
when examining the brain. It is situated between the pons and the diencephalon. On its upper
surface are two pairs of small hills (colliculi), collections of cells that relay specific sensory
information from sense organs to the brain. The two closest to the pons - the inferior colliculi -
relay auditory information; and the two closest to the thalamus - the superior colliculi - relay
visual information.
The Hindbrain
The major parts of the hindbrain are the pons, the medulla oblongata and the cerebellum. The
structures within the pons, medulla and cerebellum generally interact with telencephalon
structures by relays through the midbrain and the diencephalon, with some exceptions. The fields
and nuclei of the pons and medulla, which control respiration and heart rhythms, are critical to
survival. The cerebellum stores the basic repertoire of learned motor responses. The hindbrain,
midbrain, and diencephalon together are also called the brainstem. This stem contains almost all
of the connections between the cerebral cortex and the spinal cord.
Some functional brain systems:
Sensory
Receptors in skin, muscle
Relay nuclei in spinal cord, thalamus
Cortical areas
Motor
Muscle and spinal motor neurons
Cerebellum, basal ganglis
Motor cortex, thalamus, and cortex
Internal regulatory (reproduction, appetite, salt and water balance)
Hypothalamic nuclei and pituitary
Behavioural state (Sleeping, walking, attention)
Medulla, pons, midbrain, and cortex
Neurons:
The billions of neutrons in the human nervous system work by receiving messages from and
sending messages to other nerve cells. Sending cells and receiving cells are linked to each other
in pathways called circuits. In this neuroscience sense, a circuit is composed of connected
:) 5 (:
