Cerebral cortex

Gray matter

Cell bodies & dendrites on the outer surface

White matter

Myelinated axons extending inward

Longitudinal fissure

A deep groove that Separates the two hemispheres

Lateral (sylvian ) fissure

Deep groove separating the fronted & parietal lobes from the temporal lobe

Parieto-occipital sulcus

Groove separates the parietal & occipital lobes on the medial surface of the brain

Cingulate sulcus

Two bundles of axons

Neurons in each hemisphere communicate with the corresponding part of the other hemisphere through

Corpus Callosum & Anterior commissure

2 bundles of axons that connects the 2 hemispheres of the cerebral cortex & allow for communication

Laminae

6 distinct layers of cell bodies parallel to the surface of the cortex varying in prominence along areas

Columns

Organized cells (group of neurons with similar properties) of the cortex perpendicular to the laminae

Four lobes

Occipital, parietal, temporal, & frontal

Occipital lobe

Main target for visual information located at the posterior end of the cortex

Primary visual cortex / striate cortex

The posterior pole of the occipital lobe because its striped appearance in cross section

Cortical blindness

In related part of the visual field caused by damage in the striate cortex

Parietal lobe

Lies between the occipital lobe & the central sulcus, monitors info about eye, head & body positions and passes it on to brain areas that control movement

Central sulcus

A deep groove in the surface of the cortex

Post central gyrus

Area just posterior to the central sulcus that receives sensations from touch receptors, muscle-stretch receptors & joint receptors

Post central gyrus includes

4 bands of cells parallel to the central sulcus separate areas along each band receive simultaneous info from different parts of the body

2 bands receive

Mostly light-touch info, one receives deep-pressure info & one receives a combo of both

Temporal lobe

Lateral portion of each hemisphere near the temples is the primary cortical target for auditory info

Temporal lobe contributes

To complex aspects of vision, including perception of movement & recognition of faces & other objects , emotional & motivational behaviors

Left temporal lobe

Essential for speech & frequent auditory hallucinations are related to thinner auditory cortex in

Klüver-bucy syndrome

Temporal lobe damage leading to inappropriate sexual behaviours, overeating & excessive lip-smacking or other mouth movements

Hemispheric connections

Corpus callous & anterior commissure connect the right & left hemisphere to produce coordinated thoughts, speech & actions

Temporoparietal junction

Area where the parietal lobe & the temporal lobe meet near the occipital lobe conveniently located to receive input from vision, hearing & body senses, serves attention, body awareness & social cognition functions

Damage to temporaparietal junction

Especially in the right hemisphere, impairs the ability to imagine how something would appear from someone else's perspective

Frontal lobe

Containing the primary motor cortex & the prefrontal cortex extends from the central sulcus to the anterior limit of the brain

Frontal lobe involved

With judgement, attention and planning

Precentral gyrus ( primary motor cortex)

Specialized for the control of fine movements, each area along that gyrus controls one part of the body mostly on the contralateral side

Prefrontal cortex

Most anterior portion of the frontal lobe

Primary auditory cortex

Included in the temporal lobe of the cerebral cortex

Primary somatosensory cortex ( body senses & position)

Included in the parietal lobe of the cerebral cortex I postcentral gyrus

Primary visual cortex

Includes the occipital lobe of the cerebral cortex

Primary motor cortex

Included in the frontal lobe of the cerebral cortex, precentral gyrus

Default network

Areas in the prefrontal cortex & the temporaparietal junction that dominate activity when daydreaming & when brain replays recent experiences, important process for storing memories

Prefrontal lobotomy

Surgery consisted of damaging the prefrontal cortex or cutting its connections to the rest of the cortex

Prefrontal cortex function of 3 major regions

Posterior portion is associated with movement, middle zone associated with cognitive control, emotional reactions & certain aspects of memory, anterior zone is important for decision making, evaluating which of several courses of action is likely to achieve the best outcome

Damage to middle zone

People can form memories but not apply them to new situations

People with prefrontal cortical damage

Make decisions that seem impulsive because they have difficulty weighing all the likely pros & cons

Prefrontal cortex regions

Posterior, middle & anterior portion

Posterior portion

Control of movement

Middle portion

Working memory, cognitive control & emotion

Anterior portion

Compares various types of information for making a decision

Human Connectome project

An effort to map all the long-distance connections, analogous to the way the human genome project mapped all the genes on the chromosomes

Binding problem (large-scale integration problem)

Question of how various brain areas compline activity to produce a perception of a single object

Binding requires

Identifying the location of an object and perceiving all aspects of a stimulus as being simultaneous, when the sight & sound appear to come from the same location at the same time, we bind them as a single experience

Anterior prefrontal cortex

Specialized for choosing the action with the best probable outcome